APPARATUS FOR THERMAL PERFORMANCE MONITORING AND SAFE OPERATION OF A NUCLEAR POWER PLANT
20250140428 ยท 2025-05-01
Inventors
Cpc classification
G21C7/32
PHYSICS
International classification
G21C7/32
PHYSICS
Abstract
This invention relates to the monitoring and diagnosing of the nuclear power plant for both its thermal performance and safety using the NCV Method. Its applicability comprises any nuclear reactor such as used for research producing a useful output. Its greatest applicability lies with conventional Pressurized Water Reactor and Boiling Water Reactor nuclear plants generating an electric power. Its teachings of treating fission as an inertial process, a phenomena which is self-contained following incident neutron capture, allows the determination of an absolute neutron flux. This process is best treated by Second Law principles producing a total fission exergy. This invention also applies to the design of fusion thermal systems regards the determination of its Second Law viability and absolute plasma flux.
Claims
1. A computing apparatus for improving system control and/or safety of a nuclear power plant, said plant comprising a Reactor Vessel (RV) containing a fissioning material and a Turbine Cycle (TC), the computing apparatus comprising: a data acquisition device which collects data associated with the nuclear power plant comprising Operating Parameters which include a set of Off-Line Operating Parameters and set of On-Line Operating Parameters, the data acquisition device producing a set of acquired system data; a computer with a means for processing instructions; a set of computer instructions which describe the NCV Method through which a complete thermodynamic understanding of the nuclear power plant is achieved, said understanding based on a plurality of First and Second Laws of thermodynamics which produce computational nexus between a set of neutronic and system thermodynamic parameters including a neutron flux dependent term, thermodynamic boundary conditions and system fluid mass flows; means for programming the computer with the set of instructions, resulting in a programmed computer; means for receiving as input to the programmed computer the set of acquired system data; execution of the programmed computer, based on the set of acquired system data producing the complete thermodynamic understanding of the nuclear power plant which includes a set of Thermal Performance Parameters; and actions instigated by the operator based on the complete thermodynamic understanding of the nuclear power plant and the set of Thermal Performance Parameters, resulting in improved system control and/or safety of the nuclear power plant.
2. The computing apparatus of claim 1 within the set of instructions step, includes a plurality of thermodynamic formulations which solve simultaneously for the set of neutronic and system thermodynamic parameters, the plurality of thermodynamic formulations comprising: a Second Law exergy analysis of the nuclear power plant, a First Law conservation of the nuclear power plant, a First Law conservation of the TC, and a fourth independent equation based on thermodynamic laws.
3. The computing apparatus of claim 1 within the set of instructions step, wherein the neutron flux dependent term is selected from the group consisting of: an average neutron flux [.sub.TH], a Temporal Fission Density [.sub.TH
4. The computing apparatus of claim 2 wherein the set of instructions step, and further wherein the the Second Law exergy analysis of the nuclear power plant includes, the Second Law exergy analysis of the nuclear power plant wherein the fissioning material is described as an inertial process comprising a total nuclear power term.
5. The computing apparatus of claim 2 wherein the set of instructions step, and further wherein the First Law conservation of the nuclear power plant includes, the First Law conservation of the nuclear power wherein description of the fissioning material requires conversion of the recoverable nuclear power to an energy flow based on an Inertial Conversion Factor.
6. The computing apparatus of claim 5 wherein the Inertial Conversion Factor is based on an explicit, non-iterative computation.
7. The computing apparatus of claim 5 wherein the Inertial Conversion Factor is based on a ratio of the fissioning material antineutrino and possible neutrino release (
8. A computing apparatus producing a Core Thermal Power associated with a nuclear power plant, said plant comprising a Reactor Vessel (RV) containing a fissioning material and a Turbine Cycle (TC), the computing apparatus comprising: a data acquisition device to collect data associated with the nuclear power plant comprising Operating Parameters which includes a set of Off-Line Operating Parameters, set of On-Line Operating Parameters and an applicable Regulatory Limit to Core Thermal Power, the data acquisition device producing a set of acquired system data; a computer with a means for processing instructions; a set of computer instructions which describe the NCV Method through which a complete thermodynamic understanding of the nuclear power plant is achieved, said understanding based on a plurality of First and Second Laws of thermodynamics which produce computational nexus between a set of neutronic and system thermodynamic parameters including a neutron flux dependent term, thermodynamic boundary conditions and system fluid mass flows; means for programming the computer with the set of instructions, resulting in a programmed computer; means for receiving as input to the programmed computer the set of acquired system data; execution of the programmed computer, based on the set of acquired system data producing the complete thermodynamic understanding of the nuclear power plant including a computed Core Thermal Power; and action instigated by the operator based on the understanding of the nuclear power plant such that the computed Core Thermal Power does not exceed the applicable Regulatory Limit.
9. The computing apparatus of claim 8 within the set of instructions step, includes a plurality of thermodynamic formulations which solve simultaneously for the set of neutronic and system thermodynamic parameters, the plurality of thermodynamic formulations comprising: a Second Law exergy analysis of the nuclear power plant, a First Law conservation of the nuclear power plant, a First Law conservation of the TC, and a fourth independent equation based on thermodynamic laws.
10. The computing apparatus of claim 8 within the set of instructions step, wherein the neutron flux dependent term is selected from the group consisting of: an average neutron flux [.sub.TH], a Temporal Fission Density [.sub.TH
11. The computing apparatus of claim 9 wherein the set of instructions step, and further wherein the the Second Law exergy analysis of the nuclear power plant includes, the Second Law exergy analysis of the nuclear power plant wherein the fissioning material is described as an inertial process comprising a total nuclear power term.
12. The computing apparatus of claim 9 wherein the set of instructions step, and further wherein the First Law conservation of the nuclear power plant includes, the First Law conservation of the nuclear power wherein description of the fissioning material requires conversion of the recoverable nuclear power to an energy flow based on an Inertial Conversion Factor.
13. The computing apparatus of claim 12 wherein the Inertial Conversion Factor is based on an explicit, non-iterative computation.
14. The computing apparatus of claim 12 wherein the Inertial Conversion Factor is based on a ratio of the fissioning material antineutrino and possible neutrino release (
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0051]
[0052]
[0053]
[0054]
[0055]
[0056]
DETAILED DESCRIPTION OF THE INVENTION
[0057] To assure an appropriate teaching, descriptions of the NCV Method and its apparatus are divided into the following sub-sections. The first two present Definitions of Terms and Typical Units of Measure, and the important Meaning of Terms. The remaining eight subsections, representing the bulk of the teachings, are divided into: Second Law Foundational Equation; First Law Equations; Second Law Pseudo Fuel Pin Model etc. This DETAILED DESCRIPTION section is then followed by the important INDUSTRIAL APPLICABILITY section.
Definitions of Terms and Typical Units of Measure
Nuclear Terms:
[0058] B.sub.P.sup.2=Nuclear pseudo-buckling used in the PFP Model; cm.sup.2. [0059] C.sub., C.sub.d& C.sub.FLX=>Defined constants associated with SEP & COP via Eqs.(5), (55) & (63); unitless. [0060] C.sub.MAX=Defined by TABLE 2 regarding conversion of .sub.MAX to an average .sub.TH; unitless. [0061] k.sub.EFF=Effective neutron multiplication coefficient; unitless. [0062] M.sub.FPin=Number of fuel pins heating the nuclear core's coolant; unitless. [0063] M.sub.TPin=Number of total fuel pin cells available for coolant flow within the nuclear core; unitless. [0064] M.sub.T.sup.2=Thermal neutron migration area (M.sub.T is the diffusion length plus Fermi Age); cm.sup.2. [0065] Q.sub.REC=Recoverable exergy flow from fissile materials; Btu/hr. [0066] Q.sub.TNU=Total antineutrino (and possibly neutrino) exergy flow from fission, same as Q.sub.NEU-Loss; Btu/hr. [0067] V.sub.Fuel=Volume of nuclear fuel consistent with the total macroscopic cross section; cm.sup.3. [0068]
System Terms:
[0078] C.sub.FWF & C.sub.RVF=>Defined constants associated with SEPs via Eqs.(66) & (67); unitless. [0079] C.sub.CDP-k3=Ratio of the k3.sup.th pump mass flow in the Condensate System to a reference m.sub.FW; mass ratio. [0080] C.sub.TUR-Aux=Ratio of the Auxiliary Turbine mass flow at throttle to a reference m.sub.FW; mass ratio. [0081] FCI.sub.Loss-k=FCI for the k.sup.th process descriptive of an irreversible loss; unitless. [0082] FCI.sub.Power=FCI for the NSSS's process of creating a useful power output; unitless. [0083] g(hh.sub.Ref)T.sub.Ref(ss.sub.Ref), fluid specific exergy (also termed available energy); Btu/lbm. [0084] G.sub.IN=Total exergy flow supplied to a thermal system (e.g., nuclear & shaft power inputs); Btu/hr. [0085] h.sub.Ref=Reference fluid specific enthalpy used for exergy's definition: (P.sub.Ref, x=0.0); Btu/lbm. [0086] I.sub.k=Irreversibility of the k.sup.th process; Btu/hr [0087] L.sub.Elect=Generator electrical losses, variable as (P.sub.GEN); KWe. [0088] L.sub.Mech=Generator mechanical losses, fixed as (P.sub.GEN); KWe. [0089] m or {dot over (m)}=Mass flow of fluid; lbm/hr. [0090] mg or {dot over (m)}g=Exergy flow, also termed available power; Btu/hr. [0091] mh or {dot over (m)}h=Energy flow, also termed thermal power; Btu/hr. [0092] MC.sub.nn=Dilution Factor for COP .sub.nn, used in Eq.(68); unitless. [0093] P.sub.FWP-Aux=Energy flow credit for a TC Auxiliary Turbine driving a FW pump, see Eq.(15); Btu/hr. [0094] P.sub.GEN-REF=Reference useful power output delivered to the turbine-generator, via Eq.(14A); Btu/hr. [0095] P.sub.GEN=Useful power output delivered to the turbine-generator, via Eq.(14B); Btu/hr. [0096] P.sub.X-ii=Motive power delivered to the ii.sup.th individual X subsystem pump; Btu/hr. [0097] P.sub.Ref=Reference pressure for exergy analysis: P.sub.Ref=(T.sub.Ref, x=0.0); psiA. [0098] P.sub.UT=Gross electric power output measured at the generator terminals; KWe. [0099] Q.sub.CTP=Core Thermal Power, an energy flow, defined herein; Btu/hr. [0100] Q.sub.Loss-RV=Vessel insulation losses from the RV, given T.sub.RVI is the vessel's shell temp.; Btu/hr. [0101] Q.sub.Loss-SG=Vessel insulation losses from the SG, given T.sub.FW is the vessel's shell temp.; Btu/hr. [0102] Q.sub.Loss-TC=Misc. TC equipment insulation losses (turbine casing, FW heaters, etc.); Btu/hr. [0103] Q.sub.REJ=Condenser heat rejection from the TC, an energy flow; Btu/hr. [0104] Q.sub.SG=Net energy flow delivered to PWR's SG from the RV or directly to the BWR's TC; Btu/hr. [0105] Q.sub.TCQ=Net energy flow delivered to the Turbine Cycle including pump power; Btu/hr. [0106] r=Core radius, fission chambers are assumed at the core's boundary, r.sub.FC=R; cm. [0107] r.sub.0=Outside radius of the fuel pellet, for the PFP Model; cm. [0108] s.sub.Ref=Reference fluid specific entropy used for exergy analysis: (P.sub.Ref, h.sub.Ref); Btu R.sup.1 lbm.sup.1. [0109] T.sub.Ref=Reference temperature for exergy analysis, defined by user, etc., or via Eq.(10); F. or R. [0110] T.sub.Sat=Saturation temperature associated with the shell-side of a heat exchanger; F. or R. [0111] u=Fluid specific internal energy; Btu/lbm. [0112] v=Fluid specific volume; ft.sup.3/lbm. [0113] x=Steam quality; mass fraction. [0114] y=Axial distance of active nuclear core from entrance, at temperature; cm. [0115] z=Axial distance of active nuclear core from centerline, at temperature; cm. [0116] Z=Half-height of the active nuclear core, at temperature; cm. [0117] =Second Law effectiveness (some text books use Second Law efficiency); unitless. [0118] =First Law efficiency; unitless. [0119] .sub.mm=Difference between the mm.sup.th SEP and its reference value; local units. [0120] .sub.nn=The nn.sup.th Choice Operating Parameter; local units.
Subscripts and Abbreviations:
[0121] b, hh, i, ii, iii, j, jj, jjj, k, kk, k1, k2, k3, k4, k5, k6, mm, m1, n, nn=>Denote indices: 1, 2, 3, . . . [0122] BOP=Balance-of-Plant refers to all equipment & subsystems outside the Secondary Containment. [0123] CDP-k3=The k3.sup.th pump found in the Turbine Cycle's Condensate System. [0124] CDS=Condenser's saturation temperature, a function of its shell's operating pressure. [0125] COP=Choice Operating Parameter. [0126] CTP=Core Thermal Power. [0127] FCI=Fission Consumption Index. [0128] FWP-k2=The k2.sup.th Feedwater pump found in the Turbine Cycle (i.e., non-Condensate pumps). [0129] FWH-k6=The k6.sup.th Feedwater heater. [0130] HP or LP=High or Low Pressure [0131] HWR=Heavy Water Reactor. [0132] LMFB=Liquid Metal Fast Breeder reactor. [0133] LWR=Light Water Reactor. [0134] MCRF=Mechanisms for Controlling the Rate of Fission. [0135] MSR=Moisture Separator Reheater. [0136] MWD/MTU=Megawatt-Days per Metric Tonne of Uranium metal. [0137] NFM=Nuclear Fuel Management. [0138] NRC=United States Nuclear Regulatory Commission. [0139] NSSS or NSS System=Nuclear Steam Supply System [comprising RV, SG (if used) and BOP]. [0140] PFP=Pseudo Fuel Pin Model. [0141] RV=Reactor Vessel. [0142] RVP-k1=The k1.sup.th Reactor Vessel pump. [0143] SEP=System Effect Parameter. [0144] SG=PWR Steam Generator. [0145] TC=Turbine Cycle. [0146] TUR=Main steam turbine [the k4.sup.th HP or k5.sup.th LP stage group], or the Auxiliary Turbine [Aux]. [0147] X=Indication of a NSSS pump [RVP, FWP or CDP], or a steam turbine [TUR]. [0148] XX=Indication of a fission release defined in TABLE 3 and discussion; [e.g., XX=REC].
Subscripts Referencing a Fluid's Intensive or Extensive Property [e.g., h.sub.RVI=RV Inlet Enthalpy]: [0149] FW=Final feedwater from the TC,
Subscripts Referencing Differences Between Quantities [e.g., h.sub.RVQ=h.sub.RVUh.sub.RVI]: [0160] RVQ[=]RVURVI [0161] RVX[=]RCURCI [0162] SGQ[=]SGISGU, for a PWR; or [=]THFW, for a BWR [0163] STQ[=]STUSTI, for a PWR; or [=]THFW, for a BWR [0164] STX[=]STUSCI, for a PWR; or [=]THFW, for a BWR [0165] TCQ[=]THFW
Meaning of Terms
[0166] The words Operating Parameters used within the general scope and spirit of the present invention, are broadly defined as common off- and on-line data obtained from a nuclear power plant as used by the NCV Method. Operating the NCV Method in real-time results in a complete thermodynamic understanding of the nuclear power plant. Operating Parameters comprise Off-Line Operating Parameters and On-Line Operating Parameters. Further, two subsets of Operating Parameters consist of System Effect Parameters (SEP .sub.mm) and Choice Operating Parameters (COP .sub.nn) which are exclusively used by the Verification Procedure. Although taught throughout this disclosure, formal definitions of the Neutronics Model, Calorimetrics Model and Verification Procedure are contained in Clarity of Terms, intended to be read in context after a thoroughly understanding the DETAILED DESCRIPTION (which also contains definition of terms). Note well, the NCV Method requires no special instrumentation to operate, routine power plant instrumentation found in a typical NSSS will afford NCV all required intensive properties.
[0167] Nuclear Fuel Management (NFM) is an important aspect of the NCV Method since its resultant data are considered a portion of either Off-Line or On-Line Operating Parameters. NEM is herein defined as meaning the nuclear fuel computations which describe burn-up behavior of the fissioning fuel. Such production comprises nuclear fuel isotope behavior as a function of initial enrichment, fissile loading, and irradiation time (i.e., so called burn-up data). Burn-up data routinely includes the following as a function of irradiation time: Megawatt-Days per Metric Tonne of Uranium metal (MWD/MTU); the rate of .sup.235U & .sup.238U depletion; the rate of .sup.239Pu & .sup.241Pu build-up; and the computation of typical neutronic parameters as a function of irradiation time (initial nuclear core material number densities and data leading to macroscopic cross sections); such data is further discussed in Neutronics Data. Static and preparatory NFM computations are considered a portion of Off-Line Operating Parameters and comprise: geometric buckling (B); thermal neutron migration area (M.sub.T.sup.2); equivalent data contained in TABLE 3 as appropriate; and like data. NFM on-line computations, or if predictive temporal trends are established by NSSS staff or by fuel vendors before NCV installation, are all considered a portion of On-Line Operating Parameters. NFM computer programs capable of on-line computations are termed fuel pin cell codes and available from Argonne National Lab's Code Center [refer to <www.ANL.gov/nse/software> for listings of programs dependent on the reactor's type (LWR, HWR, LMFB, etc.)].
[0168] A set of Off-Line Operating Parameters is herein defined as comprising: static NFM data; generic system design parameters; specific equipment design data (e.g., throttle valve design pressure drop, L.sub.Mech, L.sub.Elect, data from the turbine vendor's Turbine Kit, and similar data); the limitations imposed by Eqs.(5), (55), (63), (66), & (67) when using the Verification Procedure; data required for the fourth independent equation based on thermodynamic laws [e.g., for the PFP Model comprising axial neutron flux profile, NFM data; the DTL location and TABLES 1 & 2 data, or their equivalence]; regulatory limitations [e.g., found in the NRC's 10CFR50.36 Technical Specifications] including the applicable Regulatory Limit associated with a Core Thermal Power; acceptable Operating Tolerance Envelope; establishing highly accurate or highly reliable and consistent Reference SEPs, if used; the SEP Power Trip Limit, if used; and other common power plant data. The SEP Power Trip Limit is herein defined as a limiting value of either .sub.GEN or .sub.EQ82; given .sub.GEN or .sub.EQ82 exceed this Limit a TRIP must be instigated (invoking Safety Mechanisms). In addition, an important portion of Off-Line Operating Parameters is the identification of appropriate NSSS plant instrumentation which will lead to thermodynamic extensive properties required by the Calorimetrics Model. Said instrumentation includes intensive measurements of pressures (P) and temperatures (T), and/or measured or assumed fluid qualities (x). Examples of said identification comprise the following instrumentation: P & T for all described fluid pumps regarding their suctions & discharges; working fluid properties of turbine extractions, MSR and Feedwater heaters; SG data; PWR RV coolant inlet & outlet nozzle P & T; BWR RV coolant inlet P & T, and outlet P & x; etc.
[0169] A set of On-Line Operating Parameters is herein defined as data collected while operating on-line, said data comprising: dynamic NFM, thermodynamic fluid properties consistent with requirements of the Calorimetrics Model, and data required for the sets of selected .sub.mm and .sub.nn including required extensive properties. Thermodynamic fluid properties comprise extensive properties of the nuclear power plant fluids, comprising specific enthalpy, specific exergy and specific entropy of: the RV coolant, the SG fluids (if used) and the TC working fluid. The words working fluid is commonly meant that fluid which is used in a TC, thus responsible for producing the useful power output. Said extensive properties are based on intensive properties comprising measured pressure, measured temperatures and/or measured or assumed fluid qualities. Note that measuring fluid quality requires special instrumentation, or the vendor-designed quality is typically assumed, or quality may be an elected COP .sub.3. On-Line Operating Parameters also comprise: dynamic NFM data; measured pump motive powers (P.sub.RVP-k1, P.sub.FWP-k2 and P.sub.CDP-k3); acquiring the indicated fission chamber signal (.sub.FC, used for trending); acquiring indicated mass flows including M.sub.RV, m.sub.FW and those in the Condensate System (used for trending); acquiring drain flows from the MSR (used for trending); measured inlet pressure to the LP Turbine (used for performance monitoring); temperature profiles about TC Feedwater heaters; turbine extraction pressures; TC boundary states; and similar data. On-Line Operating Parameters further includes data which may be used to replace an unknown parameter with a declared known parameter. Said data comprises: a measured gross electric power leading to useful power output, a directly measured useful power output and/or an independently computed Neutronic Flux Term. For example, an independently computed Neutronic Flux Term, say [.sub.TH
[0170] Choice Operating Parameters (COP .sub.nn) are herein defined as any subset of the Operating Parameters (on- or off-line) which only indirectly impact the Calorimetrics Model. They are used exclusively by the Verification Procedure. It is assumed COPs have errors, although their absolute accuracies (at least superficially) are unknowable, their ranges are knowable. COPs are selected by the user of the NCV Method from an available set. .sub.nn values are varied such that .sub.mm.fwdarw.0.0.
[0171] System Effect Parameters (SEP) are herein defined as selected Operating Parameters (on- or off-line) which directly impact the Calorimetrics Model. They are used exclusively by the Verification Procedure in conjunction with their Reference SEP. Reference SEP are also Operating Parameters but knowable with high accuracy or are established by operational experience as being highly consistent and reliable. The difference between a SEP and its Reference SEP, is denoted as .sub.mm, defined as a SEP difference. For example, if the computed electric power is declared a SEP, its Reference SEP is the directly measured electric power (P.sub.UT) resulting in P.sub.GEN-REF. Computed power is thus verified, processed via a Verification Procedure given:
Second Law Foundational Equation
[0172] It is an important assumption that the fission phenomenon is an inertial process. Such a process is herein defined by the following: a) a process which is self-contained following incident fission neutron capture; b) its total MeV release, after deducting for incident neutron kinetic energy, is constant and independent of its environment; c) said total release is ideal and entirely available for power, that is a pure potential to produce power; and, d) processing of antineutrino & neutrino exergies thru a Carnot Engine has no meaning. Further, the release's recoverable portionan entropy increase at constant temperature, initiated spontaneouslyresults in an exergy dispersal (typically in the fluid, or melting UO.sub.2). However, in a generic sense, the total release from inertial fission is more correctly defined as a pure Free Exergy, G.sub.Pure. Such a Free Exergy is only proportional to Temporal Fission Density [.sub.TH
[0173] This invention teaches a foundational description of the entire NSSS based on destruction of a total exergy flow supplied (G.sub.IN). This includes thermodynamic processes within the Secondary Containment and the Balance-of-Plant (BOP). The Secondary Containment comprises the Reactor Vessel (RV) for a PWR & BWR, and a Steam Generator (SG) and pressurizer for a PWR; the BOP includes processes producing a useful power output and a Condenser heat rejection. For the typical PWR & BWR the BOP comprises a Turbine Cycle producing electric power. Computation of consistent irreversible losses (I.sub.k) is critical for the foundational equation and development of Fission Consumption Indices (FCI), described by Eq.(53) more fully discussed under the FCI section.
[0184] Eq.(2ND), developed from Eq.(2), is NCV Method's foundational equation. The total exergy flow supplied by fission is presented on the left-hand side of Eq.(2), plus shaft power added to the system. Its right-side contains useful power output plus a set of system irreversible losses. Antineutrino (and possibly neutrino) losses are defined by Q.sub.LRV. Convection losses (Q.sub.Loss) from the RV, SG and TC to the environment are processed through Carnot Engines. Loss associated with a k1.sup.th RV pump is given by [P.sub.RVP-k1m.sub.RVP-k1g.sub.RVP-k1], assuming the aggregate of all RV pump flows is m.sub.RV. Exergy flows added by TC pumps is given as: [P.sub.FWP-k2m.sub.FW
[0185] In Eq.(2): .sub.j=1,4 indicates summation of temporal fissile isotopes (.sup.235U, .sup.238U, .sup.239Pu & .sup.241Pu); and .sub.F-j is the conventional macroscopic fission cross section consistent with the fuel's volume The term [.sub.j=1,4.sub.F-j(.sub.REC-j+.sub.TNU-j)] is replaced with resultant averaged values [
In Eq.(2ND) and elsewhere, the following definitions apply:
[0186] Traditional treatment would assume the unrecoverable term,
where: .sub.LRV(t)=.sub.TH
Verification means that a resolved .sub.LRV(t), either as COP .sub.6 or an assumed constant, produces a consistent
[0187] To illustrate the practicality of nexus between flux and RV coolant mass flow, consider the following example. Assume typical data associated with a 1270 MWe PWR, given a vendor-quoted flux of 1.010.sup.13 1n.sub.0 cm.sup.2 sec.sup.1 and a computed RV flow of 136.3712710.sup.6 lbm/hr. The vendor-quoted flux is assumed to be based on Neutron Transport Theory (an application of First Law continuity of the .sup.1n.sub.0 population). Compute the recoverable nuclear power using Eq.(3B2), and then compute the average neutron flux via Eq.(3B1) assuming a virgin core. Next, use Eq.(3D) to compute an accurate CTP; then (incorrectly) back-calculate a flux. If .sub.TH is computed based on CTP's {dot over (m)}h, one quickly sees a factor of two error. Although CTP has no prima facie dependence on .sub.TH, the NCV solution of .sub.TH and system thermodynamics is critical to CTP given its resolved and system verification of m.sub.RV. An accurate CTP is simply a by-product of NCV's solution nexus of neutron flux and P.sub.GEN, M.sub.RV & Q.sub.REJ.
TABLE-US-00001 P.sub.RCU = 2109.6000 psiA h.sub.RVU = h.sub.RCU = 657.16993 Btu/lbm g.sub.RCU = 229.17338 Btu/lbm s.sub.RCU = 0.8483145 Btu/lbm-R V.sub.Fuel = 8.8884385 10.sup.6 cm.sup.3 T.sub.Ref = 45.059109 F. (see below) h.sub.Ref = 13.100347 Btu/lbm s.sub.Ref = 0.0262969 Btu/lbm-R P.sub.RCI = 2158.000 psiA h.sub.RVI = h.sub.RCI = 566.05350 Btu/lbm g.sub.RCI = 181.64622 Btu/lbm s.sub.RCI = 0.761958 Btu/lbm-R .sub.TOT-35, .sub.REC-35, .sub.TNU-35 [=] Table 3 .sub.F-35 = 0.6564365 cm.sup.1 (at 4% .sup.235U) m.sub.RV = 136.37127 10.sup.6 lbm/hr [C.sub.EV.sub.Fuel .sub.F-35.sub.REC-35] = 6.4579552 10.sup.4 Q.sub.Loss-RV = (mh).sub.Misc = 0.0
Use Eq.(3B) to compute coolant's available power, then calculate correct & consistent .sub.TH:
Use Eq.(3D) to compute a correct CTP, then back-calculate an incorrect .sub.TH:
[0188] The practically and safety advantages of nexus between flux and coolant flowand nexus between neutronics and useful power output, etc.has eluded the industry. For example, given Enrico Fermi's background in both thermodynamics and nuclear engineering, it is remarkable that he did not translate his computed nuclear power, correctly described in '656, to a change in the coolant's potential ({dot over (m)}g). Indeed, Fermi's nuclear power was the recoverable exergy flow supplied to CP1 (its G.sub.IN less antineutrino losses). Fermi's CP1 design led directly to the large N Reactor. A recognition of nexus between a fission reactor's neutron flux and a viable coolant {dot over (m)}g, thus leading to an accurate Core Thermal Power ({dot over (m)}h) and a consistently computed .sub.TH, simply went missing.
[0189] The above is not academic, it is not abstract. When Eq.(2ND) is coupled with three additional equations, in the Preferred Embodiment, four unknowns are then solved simultaneously by matrix solution yielding a defined complete thermodynamic understanding of the nuclear power plant. This is broad; but understanding any thermal system means, fundamentally, to consistently determine boundary conditions and its principal coolant and working fluid mass flows. The above Second Law Foundational Equation teaches formulating a Second Law exergy analysis of the nuclear power plant.
First Law Equations
[0190] An important consideration for PWR analyses is a First Law conservation about the Steam Generator (SG). Note that h.sub.SGQ & Q.sub.Loss-SG are taken as positive energy flows out of the SG. For a BWR: h.sub.STX=h.sub.SGQ=h.sub.TCQ; Q.sub.Loss-SG=0.0; and m.sub.FW=m.sub.RV before bleed-off. Eq.(6B) is used throughout given m.sub.RV is a declared unknown (the reverse would apply if m.sub.FW were declared unknown).
[0191] If applied conventionally, application of the First Law of thermodynamics to any inertial nuclear process is wrong at the prima facie level; the concept of potentials is absent. However, consideration of routine Second Law irreversible losses versus First Law energy flow losses, suggests the opportunity of an additional and unique equation. A paradox exists: the entire inertial fission release is a pure exergy flow, G.sub.Pure, [.sub.TH
[0192] The Preferred Embodiment leads to a computed, non-iterative as follows. Based on the above assumptions, a pure exergy release means both its recoverable portion, heating a fluid, and its irreversible loss, must be treated ideally. Its irreversible release can only be described as [.sub.TH
where (t) is averaged across the nuclear core and becomes, given:
and where T.sub.Ref as used to define fluid exergy, a (g.sub.RCX), is then reduced from Eq.(9):
when used in the fourth independent equation when involving axial integration, e.g., Eq.(PFP):
[0193] Inclusion of antineutrino & neutrino production is critically important as their use in Eqs.(2ND) & (PFP), affecting .sub.TH, is consistent with correcting for a First Law recoverable release. Eq.(10) provides an explicit, non-iterative determination of the absolute reference temperature (T.sub.Ref). Although independent of .sub.TH, T.sub.Ref is temporally dependent on U depletion & Pu buildup via
[0194] Eq.(10A) predicts a maximum theoretical reference temperature (
[0195] First Law conservation of energy flows for a complete NSSS comprises the following, of course incorporating . m.sub.FW is replaced with m.sub.RV per Eq.(6B) for the Steam Generator.
[0196] First Law conservation of energy flows is also formed about an isolated Turbine Cycle, devoid of neutronics, forming a third equation. Other than the declared unknowns, P.sub.GEN, Q.sub.REJ & m.sub.RV, all quantities in Eq.(3RD) are known with high accuracy; they are based on direct measurements and/or based on common treatment of TC equipment. As examples, common treatment assumes the Q.sub.Loss-TC is principally composed of 0.2% loss from turbine casings; a 1% FW heater shell loss/heater; and that the driving temperature of vessel losses is the outer annulus or shell temperature.
when rearranging terms and substituting for m.sub.FW:
If the useful power output is shaft power delivered to a turbine-generator set, and P.sub.GEN is declared an unknown, and a Verification Procedure is invoked per Eq.(61) or (62); then its referenced SEP, P.sub.GEN-REF, is based on the directly measured generation (P.sub.UT) plus generator losses. P.sub.UT is always assumed to be measured with high accuracy at generator terminals (gross output in KWe). Generator losses, (P.sub.GEN) in KWe, are determined using established art.
However, if the useful power output (P.sub.GEN) is assumed to be a known quantity, thus a supplied input to Eqs.(2ND), (1ST) & (3RD), its value is then based on measured generation (PUT) plus generator losses:
[0197] In Eqs.(2ND), (1ST) & (3RD), the convective loss terms Q.sub.Loss-RV & Q.sub.Loss-SG are determined based on the thermal load of the air filtration & conditioning system of the Secondary Containment. The NSSS thermodynamic boundary is considered the confinement of the working fluid in the Condenser's shell, thus a Q.sub.REJ (at T.sub.CDS) is lost to the environment. T.sub.RVI & T.sub.FW are surface temperatures of the RV & SG (if used), consistent with total Secondary Containment losses and noting that the entering colder fluid is routed to the outer annulus of the RV & SG vessels. For the typical PWR and BWR a fission neutron is absorbed, on average, as a thermal neutron (0.025 eV). The thermal region of flux is typically considered from 0.010 to 100 eV. Throughout these teachings it is understood that integrations comprising flux, microscopic cross sections, etc. are functions of incremental exergy.
[0198] Evaluations of Q.sub.Loss-TC and pump energy terms requires a detailed knowledge of the Turbine Cycle as suggested in the following listing of terms; these quantities are considered summations and/or weighted averages of either environmental energy flows, or equivalent net shaft powers.
It is important that T.sub.TC of Eq.(2ND) in association with Q.sub.Loss-TC be evaluated consistently. The Preferred Embodiment is to mix the energy flows of Eq.(15) to thereby determine an equilibrium state and thus an average T.sub.TC consistent with Q.sub.Loss-TC. In addition to these losses, there are, of course, a number of minor energy flows associated with ancillary systems found in any power plant. For an NSSS such ancillary systems comprise: energy flows associated with Shim Control fluid injections; SG blow-down losses; control rod drive cooling; RV coolant pump miscellaneous seal flows; and the like. Given the definition of Core Thermal Power, correcting Eq.(3D)'s Q.sub.CTP for minor RV non-nuclear energy flows must be considered if substantially affecting h.sub.RVI (in general, such effects are a small, <110.sup.4 of CTP). The above First Law Equations teaches both formulating a First Law conservation of the nuclear power plant ending with Eq.(1ST), and teaches formulating a First Law conservation of the Turbine Cycle ending with Eq.(3RD), both supported by teachings throughout.
[0199] The cornerstone of the NCV Method is verification. Eqs.(2ND), (1ST) & (3RD) could well be solved for the unknowns .sub.TH, Q.sub.REJ & m.sub.RV. These equations with three unknowns, are presented as viable Alternative Embodiments. Consider however, that the nuclear power plant offers no parameter, with one exception, having a priori high reliability, high accuracy and is knowable at any time which may serve verification. Measured electrical power, P.sub.UT, is this parameter. If using Verification Eq.(61) or (62), P.sub.GEN-REF of Eq.(14A) follows directly from the measured P.sub.UT. However, if P.sub.GEN is declared an unknown in Eqs.(2ND), (1ST) & (3RD) a fourth independent equation based on thermodynamic laws is required. Once solved simultaneously, P.sub.GEN is then driven to P.sub.GEN-REF as provided via the Verification Procedures.
[0200] If the NSS System is producing electric power, then consistency between the computed useful power output, P.sub.GEN, and the directly measured generation, P.sub.UT, leading to P.sub.GEN-REF, has obvious import. If L.sub.Mech and L.sub.Elect are known with high accuracy, then P.sub.GEN-REF will well serve a Verification Procedure. However, questionable generator losses must be resolved such that a computed P.sub.GEN-REF via Eq.(14A), or P.sub.GEN via Eq.(14B), has high reliability and high accuracy. Mechanical losses, L.sub.Mech, are constant and well established in the industry. L.sub.Elect, although typically linear with a P.sub.GEN, can be suspect given questionable vendor records, generator upgrades, and the like. After an operating history is established, differences between a computed P.sub.GEN/3412.1416, versus a measured P.sub.UT, knowing L.sub.Mech, will allow computation of L.sub.Elect given its P.sub.GEN dependency.
[0201] Eqs.(2ND) & (1ST) have declared unknowns .sub.TH, P.sub.GEN, Q.sub.REJ and m.sub.RV; Eq.(3RD) with unknowns P.sub.GEN, Q.sub.REJ and m.sub.RV. Thus four unknowns given three equations. Thus a fourth independent equation based on thermodynamic laws is required. Said equation is herein defined as any derivative of the above First and/or Second Law formulations as descriptive of a nuclear power plant or its components, which does not compromise the solution's Rank (e.g., four equations with a Rank of 4, three equations with a Rank of three, etc.). For example, a fourth independent equation could be formed: from a Second Law exergy analysis of an isolated RV based on Eq.(2ND); from a First Law conservation of an isolated RV following Eq.(1ST); from a combination of Second and First Law formulations of the RV; from traditional heat transfer analyses; and others developed by the skilled provided the Rank is not compromised. The Preferred Embodiment's fourth independent equation is a Pseudo Fuel Pin (PFP), a PFP Model, based on Eq.(2ND), which employs an average fuel pin whose average axial neutron flux, TH, is the same flux satisfying Eqs.(2ND) & (1ST); however its axial profile is not symmetric (it is skewed). In solving simultaneously for these four unknowns, the governing equations must establish nexus between flux and system thermodynamics and upon resolution produce a set of Thermal Performance Parameters.
Second Law Pseudo Fuel Pin Model
[0202] As the fourth independent equation, the PFP Model describes an average fuel pin having the same fuel pellet radius (r.sub.0), clad OD, cell pitch, height of the core (2Z), enrichment and burn-up, as the core's average. Although the PFP Model is theoretical, its computed average neutron flux, .sub.TH, is the real, actual flux satisfying Eqs.(2ND) & (1ST). The pin's axial buckling is the core's theoretical, geometric buckling at criticality. The PFP Model assumes: [0203] the PFP is positioned within the core such that (r)/r=0.0; [0204] the pin's radial flux profile is constant, (r)/r=0.0; [0205] the PFP's axial flux profile assumed is the skewed Clausen Function of Order Two, Cl.sub.2(); [0206] the average convection loss from RV to the NSSS boundary per fuel pin, is given as: [0207] (1.0T.sub.Ref/T.sub.RVI) Q.sub.Loss-RV/M.sub.FPin, assuming a (h.sub.RVIh.sub.RCI) loss before core entrance; and [0208] the average flux .sub.TH satisfying Eqs.(2ND) & (1ST), defines PFP's average flux.
It is obvious that enhanced sophistication could be applied to any of these assumptions. However, such enhanced sophistication cannot affect the base concept: employing a skewed flux profile with partial axial solution of the exergy rise, thus adding a unique fourth equation. This is clearly preferred over using traditional heat transfer analysis (a First Law method) involving fuel radiation and fluid convection & conduction correlations. Such correlations are: empirical fits of static experimental data; based on temperature profiles; and are de-coupled from neutronics and Second Law analyses.
[0209] Neutron diffusion theory traditionally assumes a cosine flux profile for its axial solution. For the PFP Model, Eq.(21) assumes a pseudo geometric buckling, B.sub.P.sup.2.
When Eq.(21) is classically solved for a finite cylinder, a [.sub.MAX-COJ.sub.0(2.4048r/R)cos(z/2Z)] relationship results. The Bessel J.sub.0 function (or the modified I.sub.0 for the solid PFP) is unity given above assumptions. Theoretical axial boundary at Z is taken as the location for assumed axial zero flux. Refer to
[0210] The hydraulic annulus surrounding the PFP is the reactor's total area less fuel pin, control rods and structural areas, divided by the number of pin cells available for coolant flow, M.sub.TPin. The number of pins producing nuclear power is M.sub.FPin. A given an axial z (or y) slice, the pin's coolant will see an exergy increase proportional to the local Temporal Fission Density times
Q.sub.RVX represents the totals of Eq.(24) where g.sub.RCI is taken at the nuclear core's entrance after vessel loss. Applying the PFP Model means integration of Eq.(24) from the nuclear core's entrance, not to its outlet (RCU) but to some distance less, measured from its entrance (at Z or y.sub.1).
[0211] Since solution to Eq.(21) describes the shape of the flux, independent of power, for all symmetric trigonometry functions the .sub.MAX-CO value will always be found at the centerline, at z=0.0 or y=Z. For non-boiling reactors, any symmetric trigonometry function will always produce an essentially symmetric axial exergy gain. Thus an Eq.(2ND)-like formulation is simply repeated; changes in specific volume, viscosity, fluid velocity, etc. are simply not sufficient to effect significant asymmetry. In developing the PFP Model, although the partial integration of a symmetric Eq.(26) is useful for parametric studies, to maximize computational independence integration of an asymmetric function is the Preferred Embodiment. Such a function, (), should satisfy: a) ()=0.0 at =b, b=0,1,2, . . . ; b) integrates to unity from zero to ; c) is periodic and odd over any 2b; d) () is skewed; and e) ideally, has a non-unity peak. This is the Clausen Function of Order Two, Cl.sub.2().
[0212] Cl.sub.2() is defined by a Fourier series, reduced using a sixth-order polynomial fit with coefficients E.sub.m1, where is a function of both axial position (shifted by M.sub.T) and B.sub.P.
Thomas Clausen developed his function in 1832; it is well known to mathematicians. There are a number of schemes for computing Cl.sub.2(); e.g., using Chebyshev coefficients and others. Its direct integration is apparently elusive, however, a polynomial, normalized to exactly unity area, satisfies all functionalities. For use with the NCV Method, (y) is off-set accounting for the buckling phenomenon assuming zero flux at the profile's boundaries: (y.sub.0=M.sub.T)=0.0, and at: (y.sub.3=2Z+M.sub.T)=2(Z+M.sub.T)B.sub.P=. Refer to
[0213] The Clausen when applied to the PFP results in the following, as based on Eq.(26).
[0214] The peak flux, .sub.MAX-CO or .sub.MAX-CL, as with any such function must be substituted for the average flux .sub.TH, determined by average integration over the entire active length of the PFP. In Eq.(30A), the (2/B.sub.P) factor reflects the integration of a sin[(y)]d function, and the unique method of evaluating (y) that is, when employing B.sub.P of Eq.(22).
[0215] When converting the cosine axial peak .sub.MAX-CO to the average, the literature repetitiously assumes: .sub.MAX-CO=(/2).sub.TH. This is not correct. As taught here, one must evaluate the average flux associated only with the active core; i.e., its production of nuclear power. Thus, .sub.TH must be evaluated as the average of the integration about the z-axis given the chopped cosine from Z to +Z(not Z). For the common PWR, Eq.(29) becomes significant. Given a 12 foot active core with M.sub.T taken as 6.6 cm, Eq.(29) yields C.sub.MAX-CO1.518 (vs. the traditional /2); see TABLE 1. Thus if ignoring Eq.(29), the computed flux would be high by 3.5%. Such an error would catastrophically bias computed electrical power, reactor coolant flow, etc. Clausen's C.sub.MAX-CL, is computed in the same manner. Results of the average integration, Eq.(30), were taken from y.sub.1=0.0 to y.sub.2=2Z. Note that Eqs.(29) & (30B) produce a PFP Kernel herein defined as: [(2/)(1.0+M.sub.T/Z)]. This term appears in all trigonometrically-based profiles applicable for any .sub.MAX to .sub.TH translation, and reflects a correct integration.
[0216] In summary the method exampled by Eqs.(29) & (30B) applies to any system employing a neutron or plasma flux, given leakage at boundaries, and derived from an integratable function. TABLE 1 presents relationships between .sub.MAX and .sub.TH; per PFP Kernel where M.sub.T=6.6 cm, and 2Z=144 in.
TABLE-US-00002 TABLE 1 Summary of C.sub.MAX Flux Profile C.sub.MAX = .sub.MAX/.sub.TH Cosine, no leakage (M.sub.T = 0.0) /2 = 1.57079633 Cosine with leakage Eq. (29) => 1.51835422 Clausen, no leakage (M.sub.T = 0.0) Eq. (30B) => 1.76589749 Clausen with leakage Eq. (30B) => 1.70603654
[0217] As applied to the NCV Method, PFP integration of Eq.(28) is made from the nuclear core's entrance to the point that asymmetry is most pronounced, designated as y=
[0218] After matrix resolution, the resolved .sub.TH and m.sub.RV may then be used in conventional analytics for separate study. In separate study, post-matrix, the DTL may be changed. Thus the PFP Model allows determination of the axial position where: h(y)h.sub.f, i.e., liquid saturation is being approached, thus an approach to DNB for the BWR.
[0219] For the BWR, it has been found that a Clausen Function if taken in mirror image matches the average BWR flux profile remarkably well given changes in void fraction in the upper half of the nuclear core. The mirror image is achieved through a -Shifted Clausen, meaning both its profile and integrations are shifted left by [2(Z+M.sub.T)] as follows:
TABLE-US-00003 TABLE 2 Clausen Boundaries for Core Integrations to the DTL Standard -Shifted (y.sub.1 = 0) = (y.sub.1 + M.sub.T)B.sub.P (y.sub.1 = 0) = | (y.sub.1 2Z M.sub.T) | B.sub.P (y =
[0220] The above Second Law Pseudo Fuel Pin Model teaches formulating a fourth independent equation based on thermodynamic laws. Once the above First Law conservation of energy flows and Second Law exergy analyses are solved, the following set of First Law thermal efficiencies may then be determined; a portion of Thermal Performance Parameters. As discussed, a First Law efficiency of an inertial process has no meaning; the nuclear core's efficiency is assigned unity. However, RV pump & installation losses, pipe installation and P affects between the SG and RV are assigned to .sub.RV. PWR Steam Generator efficiency includes pipe installation and P affects between the TC and SG. For the BWR: h.sub.SGQ=h.sub.TCQ. The product of these efficiencies produces NSSS efficiency, .sub.SYS. Efficiencies may be converted to the commonly used heat rate term (Btu/kw-hr) via the ratio [3412.1416/Efficiency].
[0221] Although the above discussion presents classic efficiencies, the Calorimetrics Model affords a more direct determination of .sub.TC based on the computed Q.sub.REJ and measured P.sub.UT. Thermal efficiency is fundamentally useful power output divided by energy flow supplied to the system. Q.sub.TCQ of Eq.(13) is principally useful power output plus heat rejectionwhich, indeed, is energy flow supplied to the system. Thus to increase .sub.TC accuracy by eliminating the influence of uncertain Condenser energy flows (i.e., LP turbine exhaust extensive properties and its mass flow, Feedwater heater drain and turbine seal energy flows, etc.), Eqs.(13) & (14B) are combined, given a resolved m.sub.FW, results in Eq.(36). Eq.(36) considerably improves accuracy of .sub.TC given it is essentially independent of Condenser {dot over (m)}h (minor pump terms aside), but dependent principally on the system computed Q.sub.REJ and measured P.sub.UT.
Neutronics Data
[0222] As will be seen, resolved calorimetrics, leading to the computed irreversibilities and FCI.sub.Loss-k, are dependent on base neutronics and Nuclear Fuel Management (NFM) computations forming the static portion of the Neutronics Model. If NFM computations are placed on-line, their importance becomes obvious within the NCV Method, as it would provide temporal neutronics data.
[0223] The most consistent recoverable exergy per fission values available are presented in TABLE 3. Decay quantities are time dependent; listed in TABLE 3B are infinite irradiation times. It is important to recognize the details of assuming an inertial process. This said, the true inertial recoverable exergy is: F1+F3+F4+F9+F10+F11. These individual exergies are solely associated with the fission phenomenon following fission neutron capture. For the purposes of Eq.(2ND) and its derivatives, the actual recoverable exergy flow is driven by F13, the summation including F2 & F6. Thus recoverable exergy of the system is enhanced by the incident neutron's kinetic energy, .sub.INC-j, and non-fission capture, .sub.NFC-j. In summary, Column F5 is: F1+F2+F3+F4. Column F7 is F5+F6. Column F12 is the total delayed recoverable: F9+F10+F11. Column F15 is the total release, F13 plus the prompt neutrino F8 and delay antineutrino F14. Note that the literature employs the word energy as in energy per fission, total energy release, etc. In the context of this disclosure, energy invokes First Law quantities which have no meaning per se for nuclear fission, the term exergy is correct; i.e., exergy per fission, total exergy release, and like terms. However, the word energy is applicable for conversion of insulation losses; e.g., Q.sub.Loss-RV processed via a Carnot Engine. References, listed in order of importance, include: R. Sher, Fission-Energy Release for 16 Fissioning Nuclides, NP-1771 Research Project 1074-1, Stanford University, prepared for Electric Power Research Institute, Palo Alto, CA, March 1991; M. F. James, Energy Released in Fission, Journal of Nuclear Energy, vol. 23, pp. 517-36, 1969; R. C. Ball, et al., Prompt Neutrino Results from Fermi Lab, American Institute of Physics Conference Proceedings 98, 262 (1983), placed on the internet at/doi.org/10.1063/1.2947548; S. Li, Beta Decay Heat Following .sup.235U, .sup.238U and .sup.239Pu Neutron Fission, PhD Dissertation, U. of Massachusetts, 1997; and T. K. Lane, Delayed Fission Gamma Characteristics of .sup.235U, .sup.238U and .sup.239Pu, Applied Nuclear Technologies, Sandia National Lab.
[0224] The temporal sum of recoverable exergies, .sub.REC-j(t) within Eq.(44), is a function of .sup.235U depletion, .sup.238U capture or fast fission, and Pu buildup. The sum
///
///
///
///
///
TABLE-US-00004 TABLE 3A MeV/Fission, Prompt (0 < t < 1 sec) Product Incident Prompt Prompt Non-Fiss. Prompt Prompt Kinetic Neutron Fission Gamma Prompt Capture Recoverable Neutrino Energy .sub.INC-j Neutron .sub.PGM-j Total .sub.NFC-j .sub.PRC-j .sub.PNU-j Isotope F1 F2 F3 F4 F5 F6 F7 F8 .sup.235U 169.12 0.03 4.79 6.88 180.82 8.80 189.62 0.68 .sup.238U 169.57 3.10 5.51 6.26 184.44 11.10 195.54 0.86 .sup.239Pu 175.78 0.03 5.90 7.87 189.58 11.50 201.08 0.56 .sup.241Pu 175.36 0.03 5.99 7.83 189.21 12.10 201.31 0.69
TABLE-US-00005 TABLE 3B MeV/Fission, Delayed (1 sec < t < 10.sup.8 sec) & Totals Total Total Delayed Delayed Delayed Delayed Recov. Antineutrino Exergy Neutron Gamma Beta Total .sub.REC-j(t) .sub.DNU-j(t) .sub.TOT-j(t) Isotope F9 F10 F11 F12 F13 F14 F15 .sup.235U 0.01 6.33 6.50 12.84 202.46 8.07 211.21 .sup.238U 0.02 8.02 8.25 16.29 211.83 10.22 222.91 .sup.239Pu 0.00 5.17 5.31 10.48 211.56 6.58 218.70 .sup.241Pu 0.01 6.40 6.58 12.99 214.30 8.16 223.15
[0225] TABLE 3 suggests both neutrino and antineutrino exergies are produced from the fission event, columns F8 & F14. The startup of a virgin core with a well insulated Reactor Vessel (say equivalent to 0.00 MeV/Fission)thus with no delayed antineutrino production, and without shaft input, has no identifiable irreversible lossand violates the Second Law. If prompt
[0226] However, given the traditional literature is based on mass defects, supporting Column F15 less .sub.INC-j & .sub.NFC-j, the totals of TABLE 3 are conserved. For the Preferred Embodiment, prompt neutrinos are assumed to be 7.8% of the traditional antineutrino exergy after infinite irradiation, as [.sub.DNU-j()], thus maintaining traditional totals. It could be argued that the traditional totals are in error, that prompt neutrino exergy is in proportion to observed prompt gamma radiation. Resolution requires applying this disclosure over a number of operational years, noting .sub.LRV & .sub.LRV are COP .sub.4 & .sub.6.
As a practical matter, the NCV Method is principally concerned with monitoring a system at steady state. Typical data averaging is based on 15 minute running averages. However, given extension of the PFP Model, and Alternative Embodiments, antineutrino & neutrino considerations become important; seconds become important. Delay times associated with TABLE 3B quantities are typically less than 2 minutes (the half-life of the first of six energy groups of the important delayed neutrons is 55 seconds, the second at 22 seconds, the third, etc. <6 seconds). Expansion of such time dependencies is well known art and amenable for NCV dynamic modeling. References include: Ball, cited above; and M. Fallot, Getting to the Bottom of an Antineutrino Anomaly, Physics, 10, 66, Jun. 19, 2017, American Physical Society.
Fission Consumption Indices
[0227] This invention teaches, after solving consistent calorimetrics for the NSSS, to then perform analyses for locating a set of thermal degradations within the NSSS. Locating the set of thermal degradations means providing information to the operator as to where in the system such degradations occur. Of course, this means the system must be truly understood . . . the vehicle for this lies with resolution of .sub.TH, P.sub.GEN, Q.sub.REJ and m.sub.RV, a system solution leading directly to GIN of Eq.(3A). G.sub.IN is the total exergy flow supplied to the system, including recoverable and unrecoverable exergies, and shaft power additions; this is Fermi's theoretically potential, a potential totally available to produce power. GIN is destroyed by the system, resulting in only actual useful power output (P.sub.GEN) and thermodynamic irreversibilities, I.sub.k. I.sub.k herein defined as a set of system irreversible losses, given a specific NSSS.
where: G.sub.IN and I.sub.k are then used to define nuclear power plant Fission Consumption Indices (FCIs) by dividing Eq.(51B) through by G.sub.IN, and multiplying by 1000 for numerical convenience:
Flowing from G.sub.IN, FCIs are fundamentally a unitless measure of the Temporal Fission Density, assigned thermodynamically to those individual components or processes responsible for the destruction of fissile material. FCIs quantify the exergy and power consumption of all components and processes relative to G.sub.IN; by far its predominate term is the fission's recoverable exergy. Given such resolution, it becomes obvious that locating a set of equipment thermal degradations in the nuclear power plant by observing increased FCI.sub.Loss-k values, herein defines a set of identified degraded FCI.sub.Loss-k.
[0228] For the typical NSSS, three to four dozen FCIs are commonly employed: FCI.sub.Power, FCI.sub.TNU, FCI.sub.Cond, FCI.sub.LOSS-RV, FCI.sub.Loss-SG, FCI.sub.Misc-TC, FCI.sub.RVP-k1, FCI.sub.FWP-k2, FCI.sub.CDP-k3, FCI.sub.TUR-k4 (HP turbine), FCI.sub.TUR-k5 (LP turbine), FCI.sub.TUR-Aux, FCI.sub.MSR, FCI.sub.FWH-k6, etc. as required by the operator. Such a set is defined as a set of system FCI.sub.Loss-k which are, of course, unique to any given NSSS; they sum to Eq.(52)'s FCI.sub.Loss-k. For example, if the Turbine Cycle's FCI.sub.Cond increases from 200 to 210 (i.e., higher irreversible losses) which is just offset by a decrease of 10 points in FCI.sub.Power, with no other changes, the operator has absolute assurance that a 5% higher portion of the Temporal Fission Density is being consumed to overcome higher Condenser losses, at the expense of useful power output . . . thus recent changes to the Condenser have had an adverse effect on the system. Thus, FCI.sub.Cond is the set of identified degraded FCI.sub.Loss-k. Such examples are endless given design nuances and operational philosophies. In the most general case, the nuclear power plant operator by monitoring trends in FCIs, will instigate changes such that the FCI.sub.Power is maximized and the set of identified degraded FCI.sub.Loss-k are to be minimized, thereby improving the nuclear power plant's system effectiveness, .sub.SYS of Eq.(57). Specifically, the NSSS operatorfor the first timehas a nexus between neutronics, component losses and electrical generation . . . provided G.sub.IN and I.sub.k are consistently defined.
[0229] For the nuclear fission or fusion system, FCI.sub.Loss-k losses are based on irreversibilities computed via Eq.(53), details afforded via Eq.(1). The Second Law demands, for all non-power components within a non-passive system, that: I.sub.k>0.0. However, for any given component it is possible that I.sub.k<0.0. For example, the Condenser whose sink temperature is <T.sub.Ref, will produce a negative I.sub.Cond. This is equivalent to exergy analysis of a refrigeration system in which the lowest sink temperature could be well below T.sub.Ref, producing I.sub.k<0.0 for its chiller component. Engineering judgement of components must apply.
[0230] The first right-hand term of Eq.(53) describes the Carnot Engine loss. The second term are pump losses, reducing to [m.sub.X-iiT.sub.Refs.sub.X-ii]. Q.sub.NEU-Loss is the sum of ideal nuclear losses originating from the inertial process, principally antineutrino & neutrino productions. The last term d(mg).sub.jj traditionally represents any non-passive process having exergy exchange. For example, viable feedwater heaters in a TC, must produce a negative exergy flow. A negative d(mg), produces an increase in irreversibility; e.g., viable heat transfer from shell to tube for a FW heater. As herein defined, this term includes both the traditional definition (typically describing heat exchangers), and also any non-shaft addition of an exergy equivalence to the inertial process. For an isolated fission RV, d(mg)=0.0, irreversibilities then reduce to Eq.(54). The upper limit of Eq.(55) is reasonably defined by the user consistent with the inertial process; a best mode practice suggests C.sub.d=2.0 given quantum parity.
where: if
[0231] However, in support of the nuclear importance and teachings of Eq.(53), consider d(mg).sub.jj and Q.sub.NEU-Loss in combination as applied to an inertial fusion process employing magnetic confinement of its plasma, as used in the popular Tokamak design. If using magnetic confinement, description of the fusion process must include its exergy equivalence as a d(mg).sub.MC term. The value of magnetic confinement in terms of an equivalent exergy flow is taken as the difference in the actual, real power delivered to the confinement, less the ideal power associated with zero inductive reactance. Said equivalent exergy flow is always positive, thus reducing I.sub.k. This may well violate the Second Law and thus the viability of a given fusion design. For example, the exergy yield from a D-T reaction is 17.6 MeV/Fusion, its neutrino exergy is approximately 5 MeV/Fusion. A proportionally large Q.sub.NEU-Loss implies a large influence on a computed plasma flux; however, an even larger influence may stem from a positive d(mg).sub.MC term and thus will oppose viability. Such a fusion scenario reduces Eq.(53) to:
[0232] Eq.(56) states that for fusion viability, that is conserving the Second Law, exergy flow supplied from magnetic confinement must be less than the sum of the Carnot Engine conversion and neutrino loss. This principle applies to any inertial process, fission or fusion. Eq.(56) may be achieved by increasing Q.sub.Loss-hh, but at the obvious expense of system viability. A goal of d(mg).sub.MC<Q.sub.NEU-Loss would appear both desirable and practicable for the design of fusion systems if producing a useful output greater than burning paperwork. If this is not achieved through use of low magnetic power, using superconductors, or star-like compression, then the fusion system will not function given a computed system I.sub.k<0.0. In support of Eq.(53) & (56), note that: a sun's fusion process is only viable in the presence of cold gravity; a fusion bomb is initiated via extreme pressure (not temperature per se); and the collision of two suns could well result in extinction of their fusion fires (a form of adding an exergy equivalence to each star from its colliding star's outer mantel and convective zones). Recently it has been reported that, under certain circumstances, two colliding stars result in nothing . . . one, bigger, brighter star is not formed. From Prof. A. Sills, When Stars Collide, Astronomy Magazine, May 2020, pp. 68: [0233] In star clusters, the stars are moving relatively slowly, and so [this results] in the two stars merging into one new, more massive star that we call a blue straggler. . . . [However, in] the center of the galaxy [involving higher closing speeds a] collision there is much more destructive, and often the aftermath is just star bits (that is, mostly hydrogen gas) spread out all over interstellar space.
[0234] The common term of merit for any system exergy analysis is its effectiveness. .sub.RV, .sub.SG and .sub.TC are effectivenesses for the RV, SG & TC following Eq.(35); their product produces the NSS System effectiveness, .sub.sys. These are a portion of Thermal Performance Parameters.
Embodiments and Resolution of Unknowns
[0235] The Preferred Embodiment's Calorimetrics Model invokes four governing equations, solved simultaneously, for the unknowns: .sub.TH, P.sub.GEN, Q.sub.REJ and m.sub.RV. The governing equations are herein defined as comprising: a Second Law exergy analysis of the nuclear power plant, a First Law conservation of the nuclear power plant, a First Law conservation of the TC and a fourth independent equation based on thermodynamic laws. These equations resolve four unknowns by routine 44 matrix solution; routine, given these equations have a computed Rank of 4. In summary, resolution of these unknowns means using the Calorimetrics Model to solve simultaneously: the average neutron flux (.sub.TH), the useful power output (P.sub.GEN), the Turbine Cycle heat rejection (Q.sub.REJ) and the Reactor Vessel coolant mass flow (m.sub.RV) thus yielding a complete thermodynamic understanding of the nuclear power plant. The Preferred Embodiment includes verifying results using a Verification Procedure, thereby improving nuclear safety and assuring that the applicable Regulatory Limit is ever exceeded.
[0236] Further, given teachings leading to the Preferred Embodiment, one skilled will observe that if useful power output (P.sub.GEN) is input as a known constant, then one equation is eliminated. Thus three embedded unknowns .sub.TH, Q.sub.REJ & m.sub.RV are solved simultaneously using routine 33 matrix solution; these establish Alternative Embodiments A through E. Although the skilled will observe additional Alternative Embodiments, useful ones are listed below. Note that attributes of Alternative Embodiments A through E comprise: a) all equation sets are solved for the three embedded unknowns; b) all equation sets assume P.sub.GEN is a known input based on Eq.(14B); c) all equation sets, individually, yield a computed Rank of 3; d) all are amiable to Verification Procedure; and e) may be processed assuming either steady state or transient conditions. All are further detailed in INDUSTRIAL APPLICABILITY. [0237] Alternative Embodiment A: consisting of Eqs.(2ND), (1ST) & (PFP); [0238] Alternative Embodiment B: consisting of Eqs.(2ND), (3RD) & (PFP); [0239] Alternative Embodiment C: consisting of Eqs.(1ST), (3RD) & (PFP); [0240] Alternative Embodiment D: consisting of Eqs.(2ND), (1ST) & (3RD); [0241] Alternative Embodiment E: is an iterative computation of two equation sets, resolving ; [0242] Alternative Embodiment F: .sub.TH is replaced with a related Neutronic Flux Term; [0243] Alternative Embodiment G: is a grouping of two equations used for transient monitoring; and [0244] Alternative Embodiment H: forms single equation used for transient & safety monitoring.
[0245] Alternative Embodiment E independently solves for the Inertial Conversion Factor using two sets of equations. The B set of Eqs.(2ND), (3RD) & (PFP)none dependent on and solved with either set A, set C or set D. These two sets are then solved in an iterative manner converging on an independently computed used in Eq.(1ST). This accomplishes: a) confirmation of an estimated or computed Inertial Conversion Factor; b) confirms, given years of operational experience, the elusive antineutrino and neutrino productions; and c) greatly adds to system-wide verification given should vary uniformly given Pu buildup (i.e., yielding d
[0246] Alternative Embodiment F involves replacing .sub.TH with the Temporal Fission Density [.sub.TH
[0247] Alternative Embodiments G and H teach the use of governing equations but assuming flux and useful power output are known constants, thus reduced to two or one equation. These allow for simple functionalities, normalized to steady state solutions, useful for monitoring cycles, processed every second.
[0248] Any of these Alternative Embodiments, individually, present the bases for either steady state or transient thermodynamic analysis. P.sub.GEN, if based on an essentially instantaneously measured P.sub.UT, provides a transient nexus between .sub.TH (or a Neutronic Flux Term; e.g., [.sub.TH
Verification Procedure
[0249] Equations sets associated with the Preferred and Alternative Embodiments may be embedded with Choice Operating Parameters (COP .sub.nn). COP are: constrained by recognized limits; and, generically, act as a vehicle for fine-tuning the NCV Method. Examples of imposed limitations on COPs and SEPs include: C.sub.d & C.sub. when .sub.4, .sub.5 & .sub.6 are assigned; and C.sub.FLX, C.sub.FWF & C.sub.RVF when .sub.FLX, .sub.FWF & .sub.RVE are assigned (all defined in Definitions of Terms and Typical Units of Measure). Selection of COPs is chosen by the user comprise:
TABLE-US-00006 .sub.1 = B.sub.P Square root of the pseudo buckling used in Eq. (PFP); cm.sup.1. .sub.2 = x.sub.RVU Steam quality leaving the RV, used for initial benchmarking; mass fraction. .sub.3 = x.sub.TH Steam quality entering the TC's throttle valve; mass fraction. .sub.4 =
The above list defines a unique group of COPs consisting of .sub.1 through .sub.14, wherein said group any one or more .sub.nn may be selected for use in the Verification Procedure. Obviously any .sub.nn will affect its specific equation. However, all declared unknowns will also be affected by any .sub.nn, as dutifully apportioned given matrix solution. By design, all equations employ only loss terms and system constants in the augmented matrix. Selecting a set of COPs must depend on common knowledge of a specific nuclear power plant and associated relationships between neutronics, physical equipment and instrumentation viability.
[0250] In general a Verification Procedure corrects SEP differences (.sub.mm) by varying assigned COPs. Adjustments are made using one of two methods: a) apply judgement based on a nuclear engineer's experience with a particular signal (e.g., plot signals vs. time, compare multiple signal readings, talk to plant operators, etc.) and then change the COP manually; or b) use the Preferred Embodiment which exercises multidimensional minimization analysis based on Simulated Annealing resulting in computed correction factors applied to individual COPs.
[0251] COP correction factors are determined through successive Calculational Iterations comprising multidimensional minimization and matrix analyses. Multidimensional minimization analysis minimizes an Objective Function in which a set of SEP differences are minimized by varying a set of COPs. An SEP difference is defined by .sub.mm. In the Preferred Enablement only .sub.GEN should be used until the system is well understood. P.sub.GEN is employed in Eqs.(2ND), (1ST) and (3RD); P.sub.GEN-REF is defined by Eq.(14A). The set of .sub.mm follows. Use of .sub.FWF and/or .sub.RVF comes with caution; their reference signals must have an established consistency over the load range of interest, but is rarely achieved.
The above list defines a unique group of SEP differences consisting of: .sub.GEN, .sub.EQ82, .sub.FLX, .sub.RVU, .sub.FCS, .sub.FWF, .sub.RVF and .sub.MISC; wherein said group any one or more .sub.mm may be selected for use in a Verification Procedure. Reference SEP signals must have unquestioned consistency and reliability.
[0252] The NCV Method uses multidimensional minimization analysis which drives an Objective Function, F({right arrow over (x)}), to a minimum value by driving chosen .sub.mm.fwdarw.0.0. Although COP values (.sub.nn) do not appear in the Objective Functionby designthey directly impact SEPs by exercising the Calorimetrics Model. After iterations between the matrix solution and minimization analysis, the preferred SEP of useful power output, leaning to electrical generation, is driven towards its Reference SEP and thus the computed parameters, or combinations, of .sub.TH, Q.sub.REJ, m.sub.RV and P.sub.GEN are: a) internally consistent, b) form nexus between neutronics and calorimetrics, and c) results are verifiable given .sub.mm0.0.
[0253] The preferred multidimensional minimization analysis is based on the Simulated Annealing method by Goffe, et al. Goffe's Simulated Annealing is a global optimization method, driven by Monte Carlo trials, as it distinguishes between different local optima. Starting from an initial point, the algorithm takes a step and the Objective Function is evaluated, including matrix solution of the chosen equation set. When minimizing the Objective Function, any downhill step is accepted and the process repeats from this new point. An uphill step may be accepted. Thus, optimization can escape from local optima. This uphill decision is made by the Metropolis criteria. As the optimization process proceeds, the length of the steps decline and the algorithm closes in on a global optimum. Since the algorithm makes very few assumptions regarding the Objective Function, it is quite robust with respect to possible non-linearity behavior of COP interactions. The reference is: W. L. Goffe, G. D. Ferrier and J. Rogers, Global Optimization of Statistical Functions with Simulated Annealing, Journal of Econometrics, Vol. 60, Issue 1-2, pp. 65-100, January/February 1994.
[0254] The following is the Objective Function found to work best with Simulated Annealing:
As used in Eq.(68), the Bessel Function of the First Kind, Order Zero (J.sub.0) has shown to have intrinsic advantage for rapid convergence in conjunction with the Annealing's global optimum procedures. Also, MC.sub.nn is termed a Dilution Factor, here assigned individually by COPs resulting in greater, or less, sensitivity. Dilution Factors are established during pre-commissioning of the NCV Method, being adjusted from unity. In Eq.(68) the symbol .sub.kkK indicates a summation on the index kk, where kk variables are contained in the set K defined as the elements of. For example, assume the user has chosen the following for a PWR: [0255] .sub.2 is to be optimized to minimize the error in .sub.GEN & .sub.FLX, K.sub.1=2; [0256] .sub.4 is to be optimized to minimize the error in .sub.GEN, K.sub.2=1; [0257] .sub.11 is to be optimized to minimize the error in .sub.EQ82, K.sub.3=1; and [0258] .sub.14 is user defined as SG blow-down mass flow, to minimize the error in .sub.GEN, K.sub.4=1.
Therefore: {right arrow over ()}=(.sub.2, .sub.4, .sub.14, .sub.11), K={.sub.2, .sub.4, .sub.14, .sub.1}; {right arrow over (x)}=(x.sub.1, x.sub.2, x.sub.3, x.sub.4); x.sub.1=.sub.2; x.sub.2=.sub.4; x.sub.3=.sub.14; x.sub.4=.sub.11; and as found from pre-commissioning: MC.sub.2=MC.sub.4=1.20 & MC.sub.14=MC.sub.11=0.90. Thus:
Upon optimization, correction factors, C.sub.nn, are determined as: C.sub.nn=.sub.nn-kk/.sub.nn-0, for the kk.sup.th iteration. The only output from the Verification Procedure are these corrections factors applied to the initial .sub.nn-0. However, given verification where .sub.mm0.0, the entire solution becomes verified. Thus, after use of the Verification Procedure, parameters are then verified parameters; for example: verified RV coolant mass flow; verified Core Thermal Power; verified Thermal Performance Parameters including verified G.sub.IN, P.sub.GEN, I.sub.k, FCI.sub.Power, FCI.sub.Loss-k, etc.; and the like.
INDUSTRIAL APPLICABILITY
[0259] The above DETAILED DESCRIPTION describes how one skilled can embody its teachings when creating a viable NCV Method application. This section describes its industrial applicability. That is, how to physically enable the NCV Method at a nuclear power plant: how to configure its computer (the Calculational Engine); how to process plant data; how to configure its equations for pre-commissioning and, separately, for routine operations; and, most importantly, presents specific recommendations as to what the plant operator needs to monitor (i.e., to absorb NCV output information and to act upon that information). Such enablement is presented in four sections: Calculational Engine and Its Data Processing, Clarity of Terms, a summary Final Embodiments and Enablements, and Detailed Description of the Drawings all teaching a typical NCV installation.
Calculational Engine and its Data Processing
[0260] To correctly enable this invention the user must be mindful of three important aspects of NSSS on-line monitoring: a) how data is collected; b) how it is presented for analyses, that is reducing and averaging techniques employed; and c) the nature of the monitoring computer. All power plants process instrumentation signals using a variety of signal reduction devices; i.e.,
[0261] The second problem is how the set of synchronized data is reduced and averaged before it is presented for various analyses. Data reduction comprises units conversion, gauge pressure and head corrections, temperature conversions, and the like. The NCV Method, through its NUKE-EFF program provides options of using running averages of data over 5, 15, 20, 25 and 30 minutes. The data acquisition process, using the set of synchronized data, forms 1 minute averages of each data point, relying on, say, 1 signal input each 10 seconds (or faster for certain RV data), averaging this data over a minute, and then forming a running average (over, say, 15 minutes). The choice of running averages is left to the plant engineer knowing the fluid transport times through his/her NSSS. Typically a unit of fluid passes from the TC's throttle valve to its final feedwater connection in 10 to 20 minutes (the longest transport times are encountered in the Condenser hot well and other fluid storage vessels). From the final feedwater connection through the RV, and then back to the throttle valve requires 4 to 8 seconds. If the operator chooses a shorter time for averaging than the fluid transport time, he/she risks aliasing data when assuming steady state.
[0262] A PFP Model option, if run, processes reactor transient computations in parallel with routine monitoring. This is done through Alternative Embodiments, when used, involving no data averaging (or running averages over just seconds); thus a monitoring cycle every 1 to 3 seconds. The third aspect of power plant on-line monitoring is the nature and function of the computer (
Clarity of Terms
[0263] To summarize, the NCV Method comprises three parts: a Neutronics Model [N]; a Calorimetrics Model [C] and a Verification Procedure [V]. The Neutronics Model is herein defined as comprising a set of Off-Line Operating Parameters including static NFM data, equipment design data and the applicable Regulatory Limit. Meaning of Terms formally defines Off-Line Operating Parameters, and NFM static and dynamic details.
[0264] The expression Calorimetrics Model is herein defined as meaning the teachings and support analytics used to develop a plurality of First Law conservation of energy flows and Second Law exergy analyses. The NCV Method's Preferred Embodiment consists of two First Law conservations and two Second Law exergy analyses, as taught through development of governing Eqs.(2ND), (1ST), (3RD) & (PFP). These same equations lead to Alternative Embodiments A through H, applicable for either steady state or transient analyses.
[0265] The expression Verification Procedure is herein defined as generically meaning that results from a thermal system's analytical description, satisfy First Law conservation of energy flows and/or Second Law exergy analysis. The Verification Procedure's Preferred Embodiment requires a set of plant SEPs with a set of corresponding Reference SEPs, resulting in a set of paired SEPs (.sub.mm); and a method of minimizing the .sub.mm set. Said minimization is achieved by varying a set of COPs (.sub.nn) such that .sub.mm.fwdarw.0.0. The set of .sub.mm parameters consists of Eqs.(61) through (67) and .sub.MISC. The Preferred Embodiment of such minimization employs multidimensional minimization analysis based on Simulated Annealing, summarized via Eq.(68), its Objective Function, and associated discussion.
[0266] The expressions Nuclear Steam Supply System (NSSS) and nuclear power plant mean the same and are herein defined as a thermal system comprising a Reactor Vessel and a Turbine Cycle. Generically, Reactor Vessel is herein defined as containing a fissioning material (e.g., .sup.235U) and, given the inherent presence of an average neutron flux, producing a nuclear power. This power is transferred to a Turbine Cycle via a Reactor Vessel coolant mass flow. Generically, Turbine Cycle is herein defined as using nuclear power to produce a useful power output (e.g., the TC's electrical generation), commensurate with a Condenser heat rejection.
[0267] In detail, the expression Turbine Cycle (TC) is herein defined as both the physical and thermodynamic boundary of a Regenerative Rankine Cycle. A typical Turbine Cycle comprises all equipment bearing working fluid including, typically, a turbine-generator set producing electric power, a Condenser, pumps, MSR and Feedwater heaters. The Condensate System is herein defined as the low pressure portion of the TC containing all equipment and subsystems downstream from the Condenser outlet to the Deaerator bearing condensed working fluid; this, typically, before drains and miscellaneous flows are added to achieve a final Feedwater flow. Further details are provided in
[0268] The word instigating is herein defined as: to cause a deliberate action to occur, said action implemented using voice commands, a physical movement (e.g., turning a valve, pressing a control actuator), written instructions to subordinates and/or using a computer system.
[0269] The set of Thermal Performance Parameters (i.e., actionable indicators) is herein defined as comprising: First Law efficiencies, Eqs.(35) & (36); Second Law effectivenesses, Eq.(57); Core Thermal Power, defined via Eq.(3D); the total exergy flow supplied to the nuclear power plant (G.sub.IN), used throughout, defined via Eq.(51A); the useful power output (P.sub.GEN) used throughout, a declared unknown; the set of system irreversible losses, I.sub.k, Eqs.(53) detailed via Eq.(1), and as used in Eqs.(2ND) & (PFP); Fission Consumption Indices, see its section, defined in Eqs.(51A) thru (56); any combination of resolved unknowns (.sub.TH, P.sub.GEN, Q.sub.REJ and m.sub.RV); individual First & Second Law loss terms computed for Eqs.(2ND), (1ST), (3RD) & (PFP), for example Q.sub.Loss-SG, Q.sub.Loss-TC in Eq.(1ST); the converged SEPs .sub.mm (especially .sub.GEN & .sub.EQ82) and resultant COPs .sub.nn; and, a set of temporal trends of these Thermal Performance Parameters as monitored by the operator.
[0270] Within the expression a Calorimetrics Model of the nuclear power plant based only on a plurality of thermodynamic formulations the words based only on a plurality of thermodynamic formulations is defined herein as meaning the reasonable number of thermodynamic formulations, taken from the governing equations, which are required to solve for the number of declared (specified) unknown parameters (e.g., one of common skill would use four governing equations to solve for four specified unknowns; three governing equations for three unknowns, and two governing equations for two unknowns). Further, said set of equations associated with a given Embodiment are mathematically independent (their Rank being 4, 3 or 2). However said words are also meant to restrict the use of any non-thermodynamic application (e.g, statistic and/or scholastic technique) which would replace a governing equation. Statistic and/or scholastic techniques could well add to a set of governing equations, but not replace. Further, these words also imply that the number of thermodynamic formulations employed is governed by the number of unknowns within the set of declared unknowns. In this context, plurality does not infer the number of unknowns to be solved, but rather taken from the group comprising the four governing equations. For example, if solving simultaneously for declared unknown parameters consisting of three, the solution matrix would process any three of the governing equations (each chosen set having a Rank of three); said resulting solution could be augmented by statistic and/or scholastic techniques.
[0271] Throughout this disclosure, the expressions First Law, First Law conservation and like expressions mean the same; that is, an application of First Law of thermodynamic principles descriptive of the conservation of energy flows within a thermal system. An example of First Law is Eq.(11) in which the left-hand side presents energy flows added to the system; the right, a statement of their conservation (i.e., producing a useful power output and energy flow losses to the environment). Note that Neutron Transport Theory basically is conserving a neutron population (its total mass), and not energy flows per se, and thus has no applicability other than computing an independent .sub.TH (or related Alternative Embodiment F terms), which may then be used as a known input to all equations herein. Throughout this disclosure, the expressions Second Law, Second Law exergy analysis and like expressions mean the same; that is, an application of Second Law of thermodynamic principles descriptive of an exergy analysis. Exergy analysis describes the destruction of a total exergy flow supplied to a thermal system (G.sub.IN), and its concomitant creation of useful power output (P.sub.GEN) and the set of system irreversible losses (I.sub.k). An example of Second Law is Eq.(2) in which the left-hand side presents the total exergy flow supplied to a nuclear system (a function of Temporal Fission Density) and shaft power supplied; the right, a statement of useful power output P.sub.GEN and the set of system irreversible losses, I.sub.k, computed based on Eqs.(1) & (53). The words thermodynamic laws is herein defined as meaning the First Law and/or the Second Law.
[0272] In the context of describing this invention, the words acquiring and using mean the same. The word acquiring is sometimes used for readability. They both mean: to take, hold, deploy or install as a means of accomplishing something, achieving something, or acquiring the benefit from something; in this context, the something is the NCV Method or its equivalence. Also, these words do not imply ownership of anything, or to any degree, concerning the NCV Method.
[0273] As used herein, the root words obtain, determine and establish, and their related derivatives (e.g., obtaining, determining and establishing) are all defined as taking a certain action. The certain action encompasses: to directly measure, to calculate by hand, to calculate using a programmed computer, to authorize calculations using a programmed computer at a facility controlled by the authorizer, to make an assumption, to make an estimate, and/or to gather a database.
[0274] As used herein, the words monitoring or monitored are meant to encompass both on-line monitoring (i.e., processing system data in essentially real time) and off-line monitoring (i.e., computations involving static data). A Calculational Iteration or monitoring cycle is meant to be one execution of the processes described in
[0275] As used herein, the words Secondary Containment refer to a vessel used to reduce radiation release to the environment. Inside a PWR's Secondary Containment comprises the Reactor Vessel (RV), the Steam Generator(s) (SG), coolant pump(s), the pressurizer and miscellaneous safety equipment. Inside a BWR's Secondary Containment comprises the RV, coolant pump(s), and miscellaneous safety equipment. The Secondary Containment defines the physical boundary for all major nuclear equipment placed inside. Equipment outside the Secondary Containment, including Turbine Cycle equipment is considered Balance-of-Plant (BOP) equipment. Within the RV its equipment comprises the nuclear core (or core), control rods and supporting structures and reactor safety systems. The typical nuclear core comprises hundreds of fuel assemblies. Each fuel assembly comprises: fuel pins positioned axially by a number of grid spacers; flow nozzles are positioned at the top and bottom, the bottom supporting fuel pin's weight; hollow tubes and/or spaces designed for control rod insertion; and axial structures which mechanically connect the flow nozzles. PWR & BWR typical fuel pins comprise enriched uranium, as UO.sub.2, placed in a metal tube (termed a fuel pin's clad), see
[0276] As used herein, the word indicated when used in the context of data originating from the thermal system, is herein defined as the system's actual and uncorrected signals from a physical process (e.g., pressure, temperature or quality, mass flow, volumetric flow, density, and the like) whose accuracy or inaccuracy is not assumed. As examples, a system's indicated Reactor Vessel coolant mass flow, or its indicated Turbine Cycle feedwater mass flow denotes system measurements, the accuracy of which is unknown (they are as-is, with no judgement applied). Such indicated measurements are said to be either correctable or not. It may be that the corresponding computed value tracks the indicated value over time. For example, for the case of an indicated RV coolant mass flow, when used as a SEP, it may be shown that the NCV computed mass flow tracks the indicated flow.
[0277] As used herein, the words programmed computer or operating the programmed computer or using a computer are defined as an action encompassing either to directly operate a programmed computer, to cause the operation of a programmed computer, or to authorize the operation of a programmed computer at a facility controlled by the authorizer.
[0278] The meaning quantifying in the context of quantifying the operation of a nuclear power plant is herein defined in the usual dictionary sense, meaning to determine or express the quantity of . . . ; for example, at a minimum, what is being quantified is a complete thermodynamic understanding of the nuclear power plant and/or improving operations of the nuclear power plant and/or the ability to understand the nuclear power plant with improved confidence given use of verified results. The word understanding, in context of the NCV Method, is herein defined as having gained sufficient comprehension of a nuclear power plant that instigated actions taken by the operator result in improved system control and/or improved safety. The word temporal means having time dependency.
[0279] Teachings leading to Eqs.(26) & (28), and then Eq.(PFP), present a new and unique thermodynamic description combining neutronic and coolant exergy flows and, given partial axial integration necessitated to achieve asymmetry, lead to an additional equation allowing useful power output (P.sub.GEN) to be solved. Eqs.(9B) & (1ST) demonstrate how First Law conservation and Second Law exergy analyses can be coupled without compromising the computation of an absolute flux.
[0280] A common practice with reactor design is to separate gamma & beta heating of the reactor coolant from exergy liberated within the fuel pin (principally, exergy associated with dispersion of fission product kinetic energy within the fuel). The fraction of such heating relative to TABLE 3, column F13, is typically taken as 2.6%. One reason for such separation is to compute the fuel pin's centerline temperature with additional accuracy (producing a lower temperature). This is not correct. Centerline temperature should be computed based on Eq.(26) or (28). When evaluating losses it is important to understand that kinetic energies of fission fragments travel only 6 to 10 microns in UO.sub.2 fuel. Beta & gamma radiation rarely escape coolant channels, thus losses from the RV annulus are due principally from inadequate vessel insulation. Given the objectives of the NCV Method, internal pin temperatures are not an immediate objective. However, if gamma & beta heating affects the RV outer annulus, this is completely accounted for via: [g.sub.RCU(T.sub.Ref)g.sub.RCI(T.sub.Ref)]. The PFP Model is ideal for fuel pin studies, after system solution, given the average neutron flux (thus the Temporal Fission Density) and coolant flow would have been resolved and fully verified.
[0281] Although the present invention has been described in considerable detail with regard to certain Preferred Embodiments thereof, other embodiments within the scope and spirit of the present invention are possible without departing from the general industrial applicability of the invention. For example, general description of this invention assume that a nuclear reactor's coolant is light water; however, procedures of this invention may be applied to any type of coolant. Examples of other fluids are: molten chloride, molten salt, organic fluids, liquid metals, gas, etc. The descriptions of this invention assume that the nuclear fuel is enriched uranium, formed as UO.sub.2; however, the general procedures of this invention apply to any fissioning material encapsulated in any configuration.
Final Embodiments and Enablements
[0282] Enablement of this invention is accomplished through a) implementation of the Calculational Engine and data processing, described above; b) manipulation of its four governing equations solving for a set declared unknowns; and c) verification of the system solution. These four equations are the Preferred Embodiment. The fundamentals of these equations, based solely on thermodynamic laws, is well taught. However, it becomes obvious that Alternative Embodiments, flowing directly from the Preferred, with no changes in fundamentals, offer viable steady state and transient tools for improved NSSS safety. Alternative Embodiments do not limit the invention. Indeed, all described Embodiments establish guideposts, structures, for one skilled in the art to install, to implement, to manipulate this invention and to use this invention in every way and to every extent possible. The following paragraphs present: Preferred and Alternative Embodiment's best mode practices; pre- and post-commissioning techniques; a set of Thermal Performance Parameters; and finally a general discussion of the NCV Method.
[0283] Preferred Embodiment equations are summarized below, but stylized for readability as Eqs.(XXX). The constants A.sub.iii, B.sub.iii, etc. represent coefficients to the declared four unknowns. Nomenclature is referenced to Eq.(2ND), whose coefficients are designated A.sub.iii; Eq.(1ST) as B.sub.iii; Eq.(3RD) as C.sub.iii; and Eq.(PEP) as D.sub.iii. The augmented matrix comprises loss terms, the constants L.sub.jjj; noting L.sub.D=0.0. For example: A.sub.1=C.sub.EV.sub.Fuel
[0284] Alternative Embodiments A through E are stylized equations Eqs.(XXX), following Eqs.(XXX). In these Embodiments, P.sub.GEN is supplied as a known constant based on Eq.(14B). Thus any three of the four Eq.(XXX) are solved for three unknowns .sub.TH, Q.sub.REJ and m.sub.RV, at the expense of .sub.GEN.
[0285] Alternative F teaches to replace .sub.TH with a Neutronic Flux Term which typically becomes the declared unknown. This type of substitution is applicable for all Preferred and Alternative Embodiments; no change in their solution methodologies is required. For example, if .sub.TH is replaced by [.sub.TH
[0286] Alternative Embodiments G and H are based on stylized equations Eqs.(XXX), following Eqs.(XXX). These Embodiments assume that both neutron flux (.sub.TH), or its substitution as a Neutronic Flux Term, and useful power output (P.sub.GEN) are supplied as known constants. .sub.TH being determined by: a) user estimate based on experience or fission chamber .sub.FC; b) relying on vendor data; and/or c) using a computed value, for example by engaging Neutron Transport Theory. P.sub.GEN is based on Eq.(14B). Alternative Embodiment G reduces appropriate combinations of the four Eqs.(XXX) to two viable equations with two unknowns Q.sub.REJ and m.sub.RV. Examples include: Eqs.(2ND) and (PFP); or Eq.(2ND) less Eq.(1ST) and Eq.(3RD). Alternative Embodiment H reduces appropriate combinations of the four Eqs.(XXX) to a single equation and unknown, having single variate or bivariate functionality. As examples: m.sub.RV may be trended with a single variate functionality [m.sub.RV=(.sub.TH)] as found in: Eq.(PFP); or Eq.(1ST) less Eq.(3RD). Bivariate functionality [m.sub.RV=(.sub.TH, P.sub.GEN)] as found in: Eqs.(2ND); or Eq.(1ST); or combinations. Note that Eq.(3RD), cannot be used as a stand-alone equation for any Embodiment: a) it is very old art; and b) is independent of the Second Law.
[0287] It is obvious that Alternative Embodiments G and H offer little for the complete thermodynamic understanding of the nuclear power plant. However, viability is afforded if a complete Preferred Embodiment produces a verified .sub.TH, optimizing on .sub.GEN, say, every 15 minutes. The verified .sub.TH and P.sub.GEN are then used to normalize real time fission chamber .sub.FC and P.sub.UT signals (producing .sub.TH & P.sub.GEN in real time); thus allowing Embodiments G and H to be computed every second.
[0288] The following is best mode practice for pre-commissioning, as with any large computer system, one is advised to step through the simplest of exercises, ending with the best mode after commissioning, unique to a specific NSSS. The following Steps are suggested for pre-commissioning: [0289] Ia) Using Alternative Embodiment B, Eqs.(2ND), (3RD) & (PFP): elect no active COPs setting all .sub.nn to constants; set minor losses to zero; and assume P.sub.GEN is a known input. Use NSSS design data for intensive properties and mass flows. Note that specific enthalpies, specific entropies and T.sub.Ref must be generated to produce specific exergies. Equipment vendors typically assume zero vessel losses; and errors in TC Thermal Kits are legendary. Neutronics data should represent a virgin core using unirradiated fissile material. With such data, set-up a spreadsheet program to demonstrate the simplest simulation. This will greatly ease preparation of TC irreversible losses. Process the computed Eq.(XXX) coefficients through an acquired 33 matrix solution. Compare the computed Q.sub.REJ and m.sub.RV to vendor data. Vendor methods used for their reported .sub.TH must always be questioned. [0290] Ib) After corrections, given Q.sub.REJ and m.sub.RV agreement with vendor data, transfer all inputs to the Calculational Engine's NCV software. Confirm the previous findings. This process forces the user to understand details of inputs, and to check the NCV software for programming errors. Throughout pre-commissioning, a simple method for debug is to temporally use COP .sub.9, .sub.10 and .sub.11 to optimize SEP .sub.EQ82 in order to discover which subsystem, RV, SG or TC, is the most sensitive for correcting. Basically one is replacing an unknown discrepancy with a theoretical subsystem loss. [0291] Ic) Next add P.sub.GEN as an unknown using the Preferred Embodiment's four equations Eq.(XXX) Once operational, begin to add losses to the system, noting that the sum of losses plus useful power output must equal G.sub.IN (the spreadsheet from Step Ia will assist). Also one must confirm that all intensive properties and related parameters (pressures, pressure heads, ambient pressure, temperatures and/or quality) are processed correctly by the Calculational Engine; including review of instrumentation tag-lists. [0292] II) Use the Step I results, but now employ the set of four Eq.(XXX) and the Verification Procedure by optimizing .sub.GEN and .sub.EQ82 using COP .sub.8 and others. The important SEP Power Trip Limit, applied individually to .sub.GEN and .sub.EQ82, must be established using sensitivity studies. Other COPs to be used for initial debug, especially if the turbines are aged, are .sub.12 and .sub.13 per Eq.(1E). Adjust the MC.sub.nn parameters to improve computer execution times. [0293] III) Use the equations from Step II, but freeze the selected .sub.nn to the values found; add COP .sub.6, again optimizing on SEP .sub.GEN and/or .sub.EQ82 for the purpose of adjusting MC.sub.6 to improve computer execution times. If .sub.REC is questioned, uncertainties likely are associated with Non-Fission Capture (TABLE 3, Col. F6). [0294] IV) Repeat the above process, proceeding with more complexity by adding thermal COPs to establish additional sensitivities and benchmarks. It is also important to add a mix of nuclear irreversible terms; e.g., using COP .sub.4 & .sub.5 versus constants. Optimizing on Operating Parameters other than P.sub.GEN must proceed with great caution, as taught. If the plant operator has established a long history of consistently monitoring feedwater flow over the load range, and it matches the computed (perhaps with a constant off-set) then consideration of using .sub.FWF can be made; this will speed convergence. NCV Method allows for corrections to the indicated TC and RV flows. [0295] V) An important final pre-commissioning step is to evaluate all system irreversible loss terms; i.e., conventional, radiation, pump and turbine, etc. In addition to these losses, a design review of all resolved COP .sub.nn parameters is required, especially the nuclear. Questions must arise as to the appropriateness of
[0296] The above Steps are designed for enablement before commissioning. To enable the NCV Method in achieving the best mode post-commissioning, computer installation, data management and pre-commissioning all have obvious import. The following Steps VI & VII, as routine practice, offer suggested practice for on-line application of the NCV Method. [0297] VI) Select Eqs.(2ND), (1ST), (3RD) & (PFP), adding the resolved appropriate COP .sub.nn values as constants. It is good practice to optimize COP .sub.11, and/or other loss terms by minimizing the errors in SEP .sub.GEN and .sub.EQ82, and then compare to changes in the Turbine Cycle's set of identified degraded FCI.sub.Loss-k terms (especially FCI.sub.Misc-TC). [0298] VII) At every monitoring cycle of the Calculational Engine, the NCV Method normally proceeds with its Verification Procedure; producing a set of verified Thermal Performance Parameters which must be examined for both absolute values and their trends over time. Through successful Verification Procedure computations, the NSSS operator will become satisfied that the system is well understood. Thus changes in the set of verified Thermal Performance Parameters will be credible. They simply allow the operator, for the first time, to make informed decisions, having an established record of verification (e.g., .sub.GEN.sub.EQ82 0.0 over time).
[0299] A set of Thermal Performance Parameters comprise the following list. Note that if a Verification Procedure is employed, both SEPs and their associated Reference SEPs are presented with suggested observations. The parameters described in Eqs.(35), (36) & (57) are a portion of the set of verified Thermal Performance Parameters. The user of the NCV Method is advised to plot all Thermal Performance Parameters over time, reviewing for temporal trends and operator instigated changes. Examples are obvious to any skilled NSSS operator; for example if FCI.sub.Power decreases, the operator will observe higher losses within the NSSS, located by reviewing changes in the set of identified degraded FCI.sub.Loss-k. For example, investigating a decrease in final Feedwater temperature would involve trending FCI.sub.Power and a set of identified degraded FCI.sub.Loss-k comprising: FCI.sub.FWH-k6, FCI.sub.Misc-TC and FCI.sub.Cond. FCI.sub.Power to be maximized, the set of identified degraded FCI.sub.Loss-k must be minimized. The following are important parameters for best mode monitoring, critically important parameters are marked with [0300] Combined SEP .sub.GEN and .sub.EQ82 which provides extreme sensitivity to upset conditions; [0301] FCI.sub.Power as a function of time; [0302] The set of identified degraded FCI.sub.Loss-k; [0303] FCI.sub.Loss-RV as a function of time; [0304] FCI.sub.Misc-TC as a function of time; [0305] a set of irreversible losses (FCI.sub.Loss-k) relevant to the perceived degradation; [0306] P.sub.GEN and P.sub.GEN-REF must match as a function of time; [0307] Core Thermal Power given it must always be less than the applicable Regulatory Limit; [0308] .sub.TC as a function of time; [0309] .sub.SYS as a function of time; [0310] .sub.TC as a function of time; [0311] .sub.TH and [C.sub.FLX .sub.FC] as a function of time, trending with constant slope over load changes; [0312] Temporal Fission Density [.sub.TH
The operator must be aware that the NCV Method produces consistent absolutes: an absolute flux and power generated will always be consistent with computed reactor coolant flow, the resultant feedwater flow, etc. Thus if computed power agrees with the measured power, and feedwater flow trends downward, then recent operational changes have improved effectiveness. Such examples are endless given a complex NSS System, the above parameters offer an initial outline.
[0317] The NCV Method results in adjusting operating parameters by the plant operator instigating certain actions, these actions comprise: MCRF which directly affect the system's ability to legally operate; corrective measures taken given identification of thermally degraded equipment and processes; and to TRIP the nuclear power plant based on early warnings of dangerous conditions. In particular, NCV, before on-line operation, establishes a Neutronics Model (comprising of Off-Line Operating Parameters which includes instrumentation lists), then formulates a Calorimetrics Model (the uses of its equations are described above) such that a set of declared unknown parameters can be solved, identifying MCRF unique to the plant, and, if optioned, formulating a Verification Procedure. Following this, while operating on-line, the NCV Method acquires On-line Operating Parameters comprising extensive properties necessary to execute the Calorimetric Model required by the set of declared unknown parameters. It then uses the Calorimetric Model to solve simultaneously for the set of declared unknown parameters, resulting in a set of Thermal Performance Parameters. These steps are further detailed in the descriptions of
Detailed Description of the Drawings
[0318] The descriptions and implied teachings presented in the following sections related to the appended drawings are considered examples of the principles of the invention and are not intended to limit the invention. Rather, said descriptions and implied teachings establish guideposts, a structure, for one skilled in the art to install, to implement, to manipulate, and to use the invention in every way and to every extent possible, limited only by the CLAIMS herein.
[0319]
[0320]
[0321]
[0322]
[0323]
[0324]
[0325]
[0326]
[0327]
[0328]
[0329]
[0330]
[0331]
When testing Eq.(81) in a Verification Procedure involving .sub.EQ82, the following definitions apply:
[0332] The right-hand terms composing Eq.(82) describe the same system: differences in terms composing P.sub.Avail, must be identical to differences in terms composing P.sub.Therm. Thus the complexity of computing Carnot Engine losses [requiring uncertain surface temperatures, e.g, Eq.(1) and the conglomerate of Eq.(15)], consideration of vague antineutrino losses, etc., becomes non-trivial versus common First Law energy flow losses. Thus, although balancing Eq.(81) does not afford direct verification of a measured generation P.sub.UT, it does afford, more importantly, verification of computed Second and First Law loss terms . . . critical in understanding a nuclear power plant. In summary, if exergy analyses and conservation of energy flows are supplied viable extensive properties and properly computedas found in Eqs.(2) & (11)-Eq.(81) will balance. Using SEP .sub.EQ82, defined as [|P.sub.AvailP.sub.Therm|/P.sub.GEN-REF] per Eq.(62), will produce ultimate verification of system losses. As observed through