This abnormality diagnosis system for diagnosing abnormalities in a plant is provided with: an abnormality diagnosis control unit which, with respect to an instrument parameter measured in a plant determined to have an indication of abnormality, predicts the development of the instrument parameter by extrapolation, and which generates an abnormality manifestation pattern that is a pattern of behavior of the instrument parameter after prediction; and a data storage unit which stores a plurality of abnormality model patterns PA, PB that are patterns of behavior of the instrument parameters corresponding to causes CA1, CA2, CB1, CB2 of plant abnormality. The abnormality diagnosis control unit makes a matching determination between the abnormality manifestation pattern that has been generated and the plurality of abnormality model patterns PA, PB stored in the data storage unit, and identifies, as the cause of the abnormality in the abnormality manifestation pattern.

A process signal control and monitoring system, includes: a signal processing device which is installed on an outside of a nuclear reactor containment vessel, an internal electrical power source, an analog-digital conversion part, an internal communication part which transmits the digital signal to the signal processing device, an internal repeater, and an external repeater which transmits the received signal to a communication satellite. When electric power supply from the signal processing device is disconnected, the internal electrical power source supplies electric power which is charged in the rechargeable battery, to the analog-digital conversion part and the internal communication part; and the internal communication part judges whether communication with the signal processing device is continued or disconnected; and when the communication is judged to be continued, the internal communication part continues transmitting the digital signal to the signal processing device.

The present invention provides a method for early warning of an abnormality sign of a device, which includes device importance and warning validity determination, and a system therefor. The method for early warning of the abnormality sign of the device comprises: a first step of determining by an early warning processing apparatus whether a device monitoring signal value exceeds a normal operation range by using a weight value on the basis of monitoring-parameter-specific importance data which has been previously analyzed by an operator; a second step of generating a warning by the early warning processing apparatus when the device monitoring signal value exceeds the normal operation range; and a third step of determining by a warning determination apparatus whether the generated warning is a valid warning, which is subject to a warning analysis and to be traced.

A method for calculating the uncertainty of a data-based model, includes: a memory data generation step (S10); a measurement data receiving step (S20); a Euclidean distance calculation step (S30); a kernel function calculation step (S40); a weighted area-specific effective number calculation step (S50) of calculating a weighted area-specific effective number (Nn); a weighted value setting step (S60) of setting a weighted area-specific weighted value (Wn); a total effective number calculation step (S70) of calculating a total effective number (Nt) according to a weighted value; a prediction data calculation step (S80) of calculating prediction data (Xq) about measurement data (Q); a weighted standard deviation calculation step (S90) of calculating a weighted standard deviation (Sw); and an uncertainty calculation step (S100) of calculating uncertainty (U) so as to determine the reliability of prediction data by means of the calculated uncertainty (U).

The invention relates to methods for protecting a nuclear reactor core, such as a boiling water reactor core, from fuel and cladding damage due to thermal hydraulic instability in extended operating power flow conditions and, in particular, when an extended power uprate is implemented. The methods employ existing licensed stability methodologies and incorporated minor changes, e.g., to the Average Power Range Monitor (APRM)-based trip system to preclude operation inside the stability vulnerable region of the power/flow map. The APRM-based trip system is modified to set down the APRM flow-biased scram line when core flow is less than a predetermined core flow to prevent the core from entering an unstable region of operation.

A plurality of signal anomalies are identified in a number of tubes in a steam generator. Since the geometry of the steam generator is known, the location of each signal anomaly along each tube is converted into a location within the interior of the steam generator. If a plurality of signal anomalies are at locations within the steam generator that are within a predetermined proximity of one another, such a spatial confluence of signal anomalies is determined to correspond with a loose part situated within the steam generator. Additional methodologies can be employed to confirm the existence of the loose part. Historic tube sheet transition signal data can be retrieved and subtracted from present signals in order to enable the system to ignore the relatively strong eddy current sensor signal of a tube sheet which would mask the relatively weak signal from a loose part at the tube sheet transition.

A nuclear reactor protection system includes a plurality of functionally independent modules, each of the modules configured to receive a plurality of inputs from a nuclear reactor safety system, and logically determine a safety action based at least in part on the plurality of inputs; and one or more nuclear reactor safety actuators communicably coupled to the plurality of functionally independent modules to receive the safety action determination based at least in part on the plurality of inputs.

In an encore nuclear instrumentation system which is equipped with a movable type neutron detector, an object of the invention is to control measurement errors due to the degradation of the system. The incore nuclear instrumentation system includes a neutron detector which is to be installed in a nuclear reactor stored in a containment vessel, and an instrumentation unit which has a current detector circuit and is to be installed on the outside of the containment vessel. An output signal of the neutron detector is inputted into the current detector circuit, and the instrumentation unit remembers a matrix which shows a relation among a reactor power of the nuclear reactor, a gain of the current detector circuit, and an output voltage Vn of the current detector circuit, and the calibration of the current detector circuit is performed with reference to the matrix.

A method of determining a core design parameter of a nuclear reactor, includes: calibrating an isolated voltage output from a NIS cabinet associated with the nuclear reactor using a calibrated signal source as an input to the NIS cabinet; recording values of the calibrated signal source used in the calibrating and corresponding values of the output voltage from the calibrating in an as-left cabinet calibration data table; using a computing device connected to the isolated voltage output from the NIS cabinet, converting the voltage output signal to a converted detector signal using at least some of the values in the as-left cabinet calibration data table in an improved signal conversion equation; and using the computing device, employing the converted detector signal to determine the core design parameter.

Methods and systems for in-vessel natural circulation alkali metal reactor systems, purification systems, and associated methods are disclosed. A nuclear reactor vessel system includes an inner vessel that defines an inner volume sized to at least partially enclose a reactor. The reactor includes a plurality of nuclear fuel elements at least partially enclosed within a cladding, the reactor being cooled by a liquid metal coolant in a primary coolant loop. A pool of immersing fluid occupies a volume inside the inner vessel. The reactor vessel system includes an outer vessel sized to wholly or substantially enclose the inner vessel. A nuclear reactor power system includes a reactor core including an active fuel region; and a rotatable drum including at least one of a neutron absorbing material, a neutron leakage enhancing material, or a neutron reflecting material, the rotatable drum positioned external to the active fuel region of the reactor core.