A method of dynamic control rod reactivity measurement for a reactor using a fission chamber as an out-of-reactor measuring instrument includes: maintaining the reactor in a critical state having a set output by inserting a reference control bank into a reactor core to a first depth; completely inserting the reference control bank into the reactor core from the first depth at a maximum allowable speed and immediately completely withdrawing the reference control bank from the reactor core at the maximum allowable speed, and measuring a first signal of the out-of-reactor measuring instrument from before the insertion of the reference control bank to after the withdrawal of the reference control bank; and determining static controllability of the reference control bank by adding residual controllability measurement value of the reactor to a first static reactivity of the reactor calculated using the first signal of the out-of-reactor measuring instrument.

Disclosed herein is a stellarator comprising two sets of coils, namely a set of encircling coils which encircle the plasma axis, and a set of shaping coils which do not encircle any other coil or the plasma. In some embodiments, the encircling coils include a structural element to maintain their shape under magnetic forces. In some embodiments, the shaping coils are mounted onto one or more structural elements which, together with the shaping coils, constitute a field shaping unit. Also disclosed is a controller which may modify the electrical current flowing in one or more subsets of the coils in order to achieve target plasma parameters. Also disclosed is a method of designing a set of shaping coils by discretizing a surface dipole or current potential distribution.

A method of removing floating foreign substances that may interfere with a normal operation of an electromechanical mechanism of a control rod drive mechanism and a device for executing the same are provided. The method of removing the foreign substances from the control rod drive mechanism comprising a driving shaft including a plurality of teeth and disposed in a vertical direction in the control rod drive mechanism, a first part configured to hold or release a lower end portion of the driving shaft depending on whether a stationary gripper coil is activated, a second part configured to hold or release an intermediate portion of the driving shaft depending on whether a movable gripper coil is activated, and a third part configured to move the second part in the vertical direction depending on whether a lift coil is activated may include: activating at least one of the stationary gripper coil, the movable gripper coil, and the lift coil to drive the first part, the second part, or the third part in a state in which the driving shaft is not able to move; and removing the foreign substances from the first part, the second part, or the third part.

An energy source using low-enriched nuclear fuel to produce heat contains a compact transportable pressure vessel containing a cylinder with the core with heating element formed by nuclear fuel and continually agitated by a directed flow of heat-exchange liquid, to which a second pressure vessel is connected with a closed water bath circuit and a heat exchanger for production of steam, while the compact transportable pressure vessel can be placed in a space selected from the group underground concrete space with stainless steel lining, sea-river vessel and container modification for road and/or railway transport.

A method for calculating a PCI margin associated with a loading pattern of a nuclear reactor including a core into which fuel assemblies are loaded according to the loading pattern is implemented by an electronic system. The fuel assemblies include fuel rods each including fuel pellets of nuclear fuel and a cladding surrounding the pellets. This method includes calculating (100) a reference principal PCI margin for a reference loading pattern of the fuel assemblies in the core; calculating (110) a reference secondary PCI margin for the reference pattern; calculating (120) a modified secondary PCI margin for a modified loading pattern of the fuel assemblies in the core, and calculating (130) a modified principal PCI margin for the modified pattern, depending on a comparison of the modified secondary PCI margin with the reference secondary PCI margin.

Control rod drives include all-digital monitoring, powering, and controlling systems for operating the drives. Each controlling system includes distinct microprocessor-driven channels that independently monitor and handle control rod drive position information reported from multiple position sensors per drive. Controlling systems function as rod control and information systems with top-level hardware interfaced with nuclear plant operators other plant systems. The top-level hardware can receive operator instructions and report control rod position, as well as report errors detected using redundant data from the multiple sensors. Positional data received from each drive is multiplexed across plural, redundant channels to allow verification of the system using independent position data as well as operation of the system should a single channel or detector fail. Control rod drives are capable of positioning and detecting position of control elements in fine increments, such as 3-millimeter increments, with plural position sensors that digitally report drive status and position.

A method of governing a pressurized water nuclear reactor can simultaneously consider and balance a large number of control goals. The method includes iteratively considering a large number of randomly varied possible trajectories (Ta) of actuating variables for controlling reactor core reactivity for a future time interval. Each trajectory (Ta) of actuating variables is assigned a figure of merit (Σ) on the basis of a Value Table which contains weighting or penalty values for a number of events or adverse reactor core states which are characterized by preset conditions or values of the actuating variables, the process variables and/or variables derived from them. The trajectory (Ta) of actuating variables is chosen such that the figure of merit (Σ) has a local extremum, and corresponding actuators are moved accordingly.

A method to determine a global core reactivity bias and the corresponding estimated critical conditions of a nuclear reactor core prior to achieving reactor criticality. The method first requires collection and evaluation of the inverse count rate ratio (ICRR) data; specifically, fitting measured ICRR vs. predicted ICRR data. The global core reactivity bias is then determined as the amount of uniform reactivity adjustment to the prediction that produces an ideal comparison between the measurement and the prediction.

A method of removing floating foreign substances that may interfere with a normal operation of an electromechanical mechanism of a control rod drive mechanism and a device for executing the same are provided. The method of removing the foreign substances from the control rod drive mechanism comprising a driving shaft including a plurality of teeth and disposed in a vertical direction in the control rod drive mechanism, a first part configured to hold or release a lower end portion of the driving shaft depending on whether a stationary gripper coil is activated, a second part configured to hold or release an intermediate portion of the driving shaft depending on whether a movable gripper coil is activated, and a third part configured to move the second part in the vertical direction depending on whether a lift coil is activated may include: activating at least one of the stationary gripper coil, the movable gripper coil, and the lift coil to drive the first part, the second part, or the third part in a state in which the driving shaft is not able to move; and removing the foreign substances from the first part, the second part, or the third part.

The present disclosure relates to an online monitoring method of a nuclear power plant system based on an isolation forest method and a sliding window method. An isolation forest method used in the present disclosure is an abnormal detection model based on the idea of binary tree division, and has no requirements on the dimension and linear characteristics of monitoring data. In view of the characteristics of strong nonlinearity and high dimension of operation data of the nuclear power plant system, in the process of state monitoring, system abnormalities can be detected more quickly and accurately. In the present disclosure, a sliding window method is used to improve an isolation forest model, so that the improved isolation forest model has the functions of model online updating and real-time state monitoring, and the usability of an isolation forest state monitoring method is enhanced.