Abstract: 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, each of the functionally independent modules comprising a digital module or a combination digital and analog module, an analog module electrically coupled to one or more of the functionally independent modules, 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.

Abstract: A neutron detector is disclosed herein. The neutron detector can include a housing defining a cavity, wherein the housing is configured to permit an amount of neutrons emitted from a core of a nuclear reactor to enter the cavity. The neutron detector can also include an amount of a neutron sensitive material dispositioned within the cavity, wherein the neutron sensitive material is configured to generate and emit gamma rays upon interacting with the amount of neutrons. The neutron detector can further include an amount of electron emissive material configured to generate and emit a current of electrons upon interacting with the emitted gamma rays, wherein the current of electrons is indicative of the amount of neutrons emitted from the core of the nuclear reactor.

Abstract: An angle detecting apparatus is obtained. The angle detecting apparatus is capable of correcting an electrical angle frequency component of an angle signal contained angle signal. An angle detecting apparatus computes an angle signal of a rotary machine from a sine signal and a cosine signal obtained from the angle signal. Offset correction values for the sine signal and the cosine signal are computed from the angle signal. The computed offset correction value for the sine signal is added to the sine signal to correct the sine signal, and the computed offset correction value for the cosine signal is added to the cosine signal to correct the cosine signal.

Abstract: A transmitter device includes a neutron detector structured to detect neutron flux, a capacitor electrically connected in parallel with the neutron detector, a gas discharge tube having an input end and an output end, and an antenna electrically connected to the output end. The input end is electrically connected with the capacitor. The antenna is structured to emit a signal corresponding to the neutron flux.

Abstract: A detection apparatus includes a resonant electrical circuit supported within an interior of a nuclear fuel rod generates a response pulse in response to an excitation pulse and transmits the response pulse through a cladding of the fuel rod to another location within a reactor in which the fuel rod is housed and without any breach in the cladding. A characteristic of the response pulse is indicative of a condition of the fuel rod. The detection apparatus also includes a transmitter positioned outside the cladding, in the reactor, in the vicinity of the fuel rod and configured to generate the excitation pulse and transmit the excitation pulse through the cladding to the resonant electrical circuit. A receiver is supported within the reactor outside of the cladding and, in response to the response pulse, communicates a signal to an electronic processing apparatus outside of the reactor.

Abstract: A detection apparatus includes a resonant electrical circuit supported within an interior of a nuclear fuel rod generates a response pulse in response to an excitation pulse and transmits the response pulse through a cladding of the fuel rod to another location within a reactor in which the fuel rod is housed and without any breach in the cladding. A characteristic of the response pulse is indicative of a condition of the fuel rod. The detection apparatus also includes a transmitter positioned outside the cladding, in the reactor, in the vicinity of the fuel rod and configured to generate the excitation pulse and transmit the excitation pulse through the cladding to the resonant electrical circuit. A receiver is supported within the reactor outside of the cladding and, in response to the response pulse, communicates a signal to an electronic processing apparatus outside of the reactor.

Abstract: A sample holder for the measurement of nuclear heating in a nuclear reactor, comprises: a body configured to contain a heat-sensitive sample along a longitudinal axis; and means for removing heat from the body to the exterior of the sample holder, wherein the means for removing heat from the body to the exterior of the sample holder comprise: a peripheral structure located on the periphery of the body; and a central structure mechanically linking the body and the peripheral structure, the central linking structure being configured to transfer heat radially, i.e. perpendicularly to the longitudinal axis, between the body and the peripheral structure. A calorimeter cell for the measurement of nuclear heating in a nuclear reactor, comprises: at least one sample holder; a seal-tight casing in which the sample holder is placed; and temperature-measuring means.

Abstract: A nuclear instrumentation system includes a source range channel, an intermediate range channel, and a power range channel. Each channel includes one detector installed around the pressure vessel. The detectors of the power range channel and the intermediate range channel both include several fission chambers. The detectors of the intermediate range channel and power range channel share several fission chambers. Since some detectors employ fission chambers, the Gamma radiation resistance property, anti-noise property, and anti-electromagnetic interference property are improved. Sharing fission chambers reduces the number of detectors to be installed, thus relieving the installation workload and the positioning of a follow-up detector. Further, the system increases the number of some channels, which increases redundancy and improves system reliability.

Abstract: A nuclear reactor system for generating electricity includes a nuclear reactor that uses water as a coolant and a moderator, and generates thermal energy through nuclear fission. The reactor includes a reactor vessel and a reactor core. The reactor core comprises a plurality of fuel assemblies and one or more core baffles. In an embodiment the reactor core is square-shaped with a hollow center portion, and is concentric with the reactor vessel. The reactor permits decay-heat removal from the fuel assemblies in the absence of the coolant. A power conversion system is arranged to indirectly receive thermal energy generated by the reactor core and to generate electricity. A refueling water storage tank is useable when the reactor core is refueled with nuclear fuel. A containment surrounds the reactor vessel and the refueling water storage tank.

Abstract: A neutron detector detects a neutron flux distribution of the inside of a reactor. The neutron detector includes a thimble guide tube that is inserted inside of the reactor, for inserting the neutron detector. A drive apparatus is connected to the thimble guide tube for inserting or extracting the neutron detector into or out of the thimble guide tube. A vacuum unit controls the vacuum state in the thimble guide tube. A supply unit supplies carbon dioxide gas. A gas purge unit is connected to the supply unit and conducts gas purge in the thimble guide tube. A gate valve is provided between the thimble guide tube and the drive apparatus, and performs an open/close operation. A control apparatus controls the gate valve, the drive apparatus, the vacuum unit, the supply unit, and the gas purge unit.

Abstract: A combined semiconductor controlled circuit (CSCC) includes a semiconductor controlled switch (SCS). The SCS includes anode, cathode, anode gate and cathode gate terminals connected to P1 anode, N2 cathode, N1 anode gate and P2 cathode gate layers. The SCS also includes P-N junctions between P1 anode and N1 anode gate layers, N1 anode gate and P2 cathode gate layers and P2 cathode gate and N2 cathode layers. The CSCC also includes a Zener diode having a current path flowing from the cathode terminal to the anode gate terminal, a feedback resistor connecting cathode and cathode gate terminals and a substrate. A solid-state spark chamber includes a CSCC, a DC bias voltage source and an RC load having a parallel-connected load resistor and capacitor. The solid-state spark chamber also includes a plurality of measurement terminals and a ground. A method of making a solid-state spark chamber includes connecting the above components.

Abstract: A method of removing the upper internals assembly from a nuclear reactor pressure vessel for refueling that simultaneously disconnects two or more of the in-core instrument thimble assemblies from the reactor vessel penetrations through which their signal cables extend. The signal cables are connected to the penetrations with an electrical connector that supports the two or more in-core instrumentation thimble assembly signal leads. Before the electrical connector is disconnected, water in the vessel is lowered below the connection so that the process is performed in a dry environment.

Abstract: A neutron monitoring system for a nuclear reactor can correct measured neutron flux by taking into consideration neutron moderation based on whether a neutron detector is fully immersed in coolant water or exposed above the water level. The neutron detector and a water detection sensor are mounted at the same height in the nuclear reactor. The water detection sensor includes a thermocouple and a heating element positioned to heat the thermocouple. A temperature measuring component is connected to the thermocouple. A water existence determining component can determine, based on temperature measured by the temperature measuring component, whether the water detection sensor (and thus the neutron detector) is underwater. A correction component can correct a neutron detection signal from the neutron detector in accordance with whether the neutron detector is below or above the water level.

Abstract: A system and method for measuring and monitoring axial flux to determine subcriticality in a spent fuel pool of a nuclear power plant. In certain embodiments of this invention, one or more neutron detectors are operable to generate signals resulting from neutron interactions in the spent fuel pool, a counting device counts the signals which are generated by the one or more neutron detectors, a connecting means electrically connects the one or more neutron detectors to the counting device, a signal analyzer is used to determine reactivity of the fuel assemblies in the spent fuel pool based on the counted signals, a power supply provides power for the neutron detectors, the counting device and the system analyzer, and a software code containing an axial flux curve index is used to correlate the counted signals to determine the subcriticality of the spent fuel pool.

Abstract: A TIP monitoring control equipment has: a process computer, a TIP control panel, and data transmitting unit. The process computer includes a operation input unit, a TIP scanning unit, a first TIP level data transmitting and receiving unit, and a TIP level data storage unit. To a first TIP level data transmitting and receiving unit, an LPRM level signal, an APRM level signal and TIP level data accumulated in the TIP control panel are input in synchronization with a TIP position signal. The TIP control panel includes a TIP driving control unit, a TIP level processing unit, a TIP position processing unit, a TIP level data accumulation unit and a second TIP level data transmitting and receiving unit. The second TIP level data transmitting and receiving unit transmits TIP level data accumulated in the TIP level data accumulation unit to the process computer via the data transmission unit.

Abstract: A method of non-destructive inspection of a subject body including an element is comprised of irradiating the subject body with a neutron ray through a first measurement point and a second measurement point; measuring an elapsed time after a first time point when a resonant neutron specific to the element passes through the first measurement point and before a second time point when a prompt gamma ray made emitted by the resonant neutron from the subject body is detected at the second measurement point; and determining a location of the element in the subject body by the first measurement point, the second measurement point, a relative position toward a surface of the subject body, and the elapsed time.

Abstract: The present invention relates to a method for detecting the drop of a cluster in a pressurized-water nuclear reactor, comprising the steps of: detecting a negative time derivative of the neutron flux, and comparing the absolute value of said time derivative to a first threshold value (S1); triggering a time delay (?T) if said absolute value is greater than said threshold value (S1); detecting a positive time derivative of said neutron flux, and comparing the absolute value of said time-derivative to a second threshold value (S2); and triggering the emergency shutdown of the reactor if the absolute value of said positive time derivative of said flux becomes greater than said second threshold value (S2) during said time delay (?T).

Abstract: A telescoping guide for extraction and reinsertion support handling of in-core instrument thimble assemblies in the area above the upper support plate in the upper internals of a pressurized water reactor. The telescoping guides extend between the upper ends of the upper internals support columns and an axially movable instrumentation grid assembly which is operable to simultaneously raise the telescoping guides and extract the in-core instrument thimble assemblies from the reactor fuel assemblies.

Abstract: According to an embodiment, an oscillation power range monitor system has a plural of OPRM units. Each of the OPRM units has: the receiving cell-output set signals and averaging the cell-output set signals; a time average calculating unit calculating a time average cell value; a normalized cell value calculating unit calculating a normalized cell value; a trip determining unit outputting a reactor trip signal if amplitude or growth rate of oscillation or period of oscillation of the normalized cell value has exceeded a prescribed condition; a signal and prescribed value adjusting unit adjusting the relation between the normalized cell value and the specific value, thereby compensating for the deterioration in the neutron flux sensitivity of any LPRM detector in order to keep outputting the reactor trip signal.

Abstract: A method for monitoring changes in the boron concentration in the coolant of a reactor during a nuclear plant outage that applies temperature compensation to the source range detector output. The method then monitors the compensated output signal to identify changes in the detector count rate above a preselected value.

Abstract: An in-core nuclear detector for detecting the neutron population surrounding the detector. The detector is an ion chamber having a cylindrical outer electrode that is insulated from a central electrode and capped to contain an Argon gas. An electron radiator that produces prompt neutron capture gamma radiation that is substantially, directly proportional to the local neutron population is disposed between the outer tubular electrode and the central electrode.

Abstract: A nuclear reactor comprises a pressure vessel, a nuclear reactor core comprising fissile material disposed in the pressure vessel, and a core basket disposed in the pressure vessel and containing the nuclear reactor core. An incore instrument is disposed in a guide tube of the nuclear reactor core. The incore instrument has a cable extending out of the bottom of the nuclear reactor core and making a 180° turn. A bottom support element is attached to the bottom of the core basket and defines or includes a routing tube that routes the cable of the incore instrument through the 180° turn. In some embodiments, the pressure vessel includes upper and lower vessel portions, the nuclear reactor core and core basket are disposed in the lower vessel portion, and the vessel penetration is through the lower vessel portion or through a mid-flange connecting the upper and lower vessel portions.

Abstract: A neutron monitoring system for monitoring a state of a fuel used in a nuclear power plant includes the following: neutron detector; a structural material to which the neutron detector is mounted; a water detection sensor mounted at a position corresponding to the same height as is the neutron detector, the water detection sensor including a thermocouple and a heating element; an amplification circuit configured to amplify a neutron monitoring signal sent from the neutron detector; a temperature measuring circuit connected to a thermocouple of the water detection sensor via strands; a heater power supply connected to a heating element of the water detection sensor via heater lead wires; a water existence determining control section configured to determine whether the water detection sensor is underwater; and a correction circuit configured to correct an output signal value of the amplification circuit in accordance with a determination signal from the water existence determining control section.

Abstract: Embodiments are directed to comparison-based methods of conditionally assessing the excess in correlation of an unknown neutron count measurement compared to the correlation present in a data defined as background, and to providing a technical definition of excess correlation intended to properly handle the measured excess correlation. The degree of correlation between an unknown source and background can be used to prevent masking of neutron count data for the source by background radiation.

Abstract: An improved support apparatus is structured to support a dosimetry system within an interior region of a containment apparatus. The dosimetry system is supported in a region between an interior surface of the containment apparatus and an exterior surface of a reactor apparatus that is disposed within the interior of the containment apparatus. The support apparatus includes a retention apparatus having a plurality of brace elements that each have a receptacle formed therein. The receptacles are aligned with one another when installed within the interior of the containment apparatus. The support apparatus further includes a tube apparatus that includes a plurality of tube segments that are connectable together. The dosimetry system is situated within an elongated cavity formed in the tube apparatus. The tube apparatus is situated in the receptacles and thereby supports the dosimetry system on the containment apparatus.

Abstract: According to an embodiment, a radioactivity evaluation method has: a first input step; a selection step in which the calculating section selects a representative neutron energy spectrum and a representative neutron fluence rate; a second input step; an radioactivity calculating step in which the calculating section calculates quantities of the radioactivity that correspond to the representative neutron energy spectra and the representative neutron fluence rates; a data storing step; a nuclide-by-nuclide radioactivation reaction rate calculating step in which the calculating section calculates a radioactivation reaction rate of each nuclide based on the neutron energy spectra at the position of each of the object sections; an object-by-object adding-up step; a nuclide determining step; and an object position determining step.

Abstract: A system and method for measuring and monitoring axial flux to determine subcriticality in a spent fuel pool of a nuclear power plant. In certain embodiments of this invention, one or more neutron detectors are operable to generate signals resulting from neutron interactions in the spent fuel pool, a counting device counts the signals which are generated by the one or more neutron detectors, a connecting means electrically connects the one or more neutron detectors to the counting device, a signal analyzer is used to determine reactivity of the fuel assemblies in the spent fuel pool based on the counted signals, a power supply provides power for the neutron detectors, the counting device and the system analyzer, and a software code containing an axial flux curve index is used to correlate the counted signals to determine the subcriticality of the spent fuel pool.

Abstract: The present invention relates to devices and methods for measuring neutron fluence at a pre-selected location which is positioned in a nuclear power plant. The devices and methods include passing neutrons through a fiber optic cable. The fiber optic cable has disposed therein a neutron sensitive material which is capable of absorbing the neutrons to produce a gas. The gas results in a build-up of pressure in the fiber optic cable which causes a change in the optical stress birefringence pattern. This change is measured and used to determine the amount of gas in the fiber optic cable, the number of neutrons absorbed by the neutron sensitive material and subsequently, the neutron fluence at the pre-selected location. In particular, the devices and methods of the invention are effective without the need to employ a radioactive material.

Abstract: [Solving Means] A resonance calculation program is configured to calculate an effective cross section including Step S4 of setting a calculation point in the gray range in the resonance region; Step S5 of calculating a neutron flux set at the calculation point and corresponding to a macroscopic cross section based on Method of Characteristics; Step S6 of fitting a fitting equation to the calculated macroscopic cross section and the calculated neutron flux, and calculating first and second rational coefficients; Step S7 of calculating a background cross section based on the first rational coefficient; Step S8 of interpolating the effective cross section, with the background cross section used as an argument; Step S9 of calculating the neutron flux based on the background cross section; and Step S10 of calculating the effective cross section based on the effective cross section, the neutron flux, and the second rational coefficient obtained at the coefficient calculation step.

Abstract: The power monitoring system has: a local power range monitor (LPRM) unit that has a plurality of local power channels to obtain local neutron distribution in a nuclear reactor core; an averaged power range monitor (APRM) unit that receives power output signals from the LPRM unit and obtains average output power signal of the reactor core as a whole; and an oscillation power range monitor (OPRM) unit that receives the power output signals from the LPRM unit and monitors power oscillations of the reactor core. The output signals from the LPRM unit to the APRM unit and the output signals from the LPRM unit to the OPRM unit are independent.

Abstract: A reactor core coolant temperature measuring apparatus for measuring the temperature of the coolant flowing in the reactor core of a nuclear reactor comprises a ?-ray thermometer having a temperature measuring section arranged below the bottom of the reactor core and a ?-ray heat generation detecting section arranged between the bottom and the top of the reactor core, a cable for transmitting the signal output from the temperature measuring section and an output signal processing means for receiving the signal and computationally determining the local temperature of the coolant at the position of placement of the temperature measuring section.

Abstract: A method for measuring the neutron flux in the core of a nuclear reactor, the method including several steps recurrently performed at instants separated by a period, the method comprising at each given instant the following steps: acquiring a total signal by a cobalt neutron detector placed inside the core of the reactor; assessing a calibration factor representative of the delayed component of the total signal due to the presence of cobalt 60 in the neutron detector; assessing a corrected signal representative of the neutron flux at the detector from the total signal and from the calibration factor; assessing a slope representative of the time-dependent change of the calibration factor between the preceding instant and the given instant; the calibration factor at the given instant being assessed as a function of the calibration factor assessed at the preceding instant, of the slope, and of the time period separating the given instant from the preceding instant.

Abstract: Provided are a neutron detector for detecting a neutron flux distribution of the inside of a reactor, a drive cable connected to the neutron detector, a drive unit for driving the drive cable, a plurality of guide thimbles provided being inserted from the outside of the reactor into the reactor, for inserting the neutron detector, a storage tube for storing the neutron detector, a path transfer device connected to the drive unit, for selecting one of insertion of the neutron detector into each of the guide thimbles and insertion of the neutron detector into the storage tube, and an inspection guide tube connecting the drive unit and the storage tube. The drive unit has a switching unit for switching between the path transfer device side and the inspection guide tube side.

Abstract: An in-core neutron monitor that employs vacuum microelectronic devices to configure an in-core instrument thimble assembly that monitors and wirelessly transmits a number of reactor parameters directly from the core of a nuclear reactor without the use of external cabling. The in-core instrument thimble assembly is substantially wholly contained within an instrument guide tube within a nuclear fuel assembly.

Abstract: An object of the invention is to embody a small and inexpensive passage selector, which can be applied by commonly using an index device even if the number of detector passages is changed, and which is easy to make inspection and maintenance. The passage selector of a reactor in-core nuclear-measuring apparatus of the invention includes: a drive motor; an index device that is driven by the drive motor and that makes a rotary output of a predetermined index number; a central rotating shaft that is driven to rotate by the index device and that causes a passage selecting guide tube to be located in opposition to any detector passage; and a speed-increasing and decreasing device that is interposed between an output shaft of the index device and the central rotating shaft, and that adjusts the index number of the central rotating shaft.

Abstract: A method to perform signal validation for either reactor fixed incore detectors and/or core exit thermocouples to enhance core monitoring systems. The method uses a combination of both measured sensor signals and expected signal responses to develop a ratio of measured to expected signals. The ratios are evaluated by determining the expected ratios for each detector based on the behavior of the remaining collection of detectors, taking into account the geometry/location of the other detectors. The method also provides for automatic removal of invalid detectors from the core power distribution determination if sufficient detectors remain on line to adequately characterize the core's power distribution.

Abstract: A method and apparatus for the calibration of neutron flux monitoring devices used in a nuclear reactor core. The apparatus includes a transverse in-core probe (TIP) cable with a neutron absorber located a fixed distance apart from a TIP detector. The neutron absorber may be passed within close proximity of the neutron flux monitoring device such that a perceived drop in measured neutron flux occurs, whereupon the cable may be repositioned relative to the monitoring device to ensure that the TIP detector is within close proximity of the monitoring device for purposes of calibrating the monitoring device.

Abstract: Provided are a neutron detector detecting a neutron flux distribution of the inside of a reactor, a thimble guide tube provided being inserted from outside into inside of the reactor, for inserting the neutron detector, a drive apparatus connected to the thimble guide tube and inserting or extracting the neutron detector into or out of the thimble guide tube, a vacuum unit controlling the vacuum state in the thimble guide tube, a supply unit supplying carbon dioxide gas, a gas purge unit connected to the supply unit and conducting gas purge in the thimble guide tube by carbon dioxide gas, a gate valve provided between the thimble guide tube and the drive apparatus and performing open/close operation, and a control apparatus controlling the gate valve, the drive apparatus, the vacuum unit, the supply unit, and the gas purge unit.

Abstract: A method and apparatus for monitoring a parameter in an irradiated environment and communicating a signal representative of the monitored parameter to a less caustic environment that employs a wireless transmitter that is powered by the irradiated environment. The power for the wireless transmitter is derived from a self-powered radiation detector disposed within the radioactive environment.

Abstract: A method and apparatus for the calibration of neutron flux monitoring devices used in a nuclear reactor core. The apparatus includes a transverse in-core probe (TIP) cable with a neutron absorber located a fixed distance apart from a TIP detector. The neutron absorber may be passed within close proximity of the neutron flux monitoring device such that a perceived drop in measured neutron flux occurs, whereupon the cable may be repositioned relative to the monitoring device to ensure that the TIP detector is within close proximity of the monitoring device for purposes of calibrating the monitoring device.

Abstract: Disclosed herein is a method for constructing a pseudo hot pin power distribution using in-core detector signal-based planar radial peaking factors in a Core Operating Limit Supervisory System (COLSS). The method includes defining a planar radial peaking factor FxyK based on in-core detector signals in the COLSS, and expanding the planar radial peaking factor FxyK so that the planar radial peaking factor FxyK is suitable for a number of nodes of the COLSS. The planar radial peaking factor FxyK is calculated only for the in-core detector signals using a preset equation, rather than by using table lookup.

Abstract: The power monitoring system has: a local power range monitor (LPRM) unit that has a plurality of local power channels to obtain local neutron distribution in a nuclear reactor core; an averaged power range monitor (APRM) unit that receives power output signals from the LPRM unit and obtains average output power signal of the reactor core as a whole; and an oscillation power range monitor (OPRM) unit that receives the power output signals from the LPRM unit and monitors power oscillations of the reactor core. The output signals from the LPRM unit to the APRM unit and the output signals from the LPRM unit to the OPRM unit are independent.

Abstract: A pair of linear arrays of gamma thermometer (GT) sensors arranged in a nuclear reactor core including: a first linear array of GT sensors, wherein the GT sensors are arranged asymmetrically along a length of the first linear array; a second linear array of GT sensors, wherein the GT sensors are arranged asymmetrically along the second linear array and wherein the second linear array of GT sensors is asymmetrical with respect to the first linear array of GT sensors, and the first linear array positioned in the reactor core at a first core location and the second instrument housing positioned at a second core location, wherein a line of symmetry of the core extends through a center of the core and the first core location is the same horizontal distance from the line of symmetry as the second core location.

Abstract: In a neutron flux detector guiding apparatus, a cylindrical support column is erected on an upper core support plate of a nuclear reactor container main body, a plurality of guide thimble guiding tubes is provided inside the upper core support column between the upper core support plate and an upper core plate, a plurality of guide thimbles is extended from the support column into the guide thimble guiding tubes, the plurality of guide thimbles is supported by a support plate supported at one end part by the support column and erected at the other end part by a support leg above the upper core support plate, and an upper end part of the support plate is inclined downward from the support column side toward the support leg side, thereby realizing simplification of a structure.

Abstract: A core monitoring system including: a TIP measuring a neutron amount in a nuclear reactor; a TIP drive device; a TIP panel; a neutron monitoring panel; and a process computer. The TIP panel includes: a TIP level processor and a TIP position processor that process a TIP level signal and a TIP position signal input from the TIP drive device, respectively; a time setting section synchronizing the TIP level signal and the TIP position signal; and a TIP level data storage section storing synchronized TIP level data. The neutron monitoring panel includes a time setting section setting collecting time of a LPRM level signal and an APRM level signal. The process computer compares the time and stores the TIP level data from the TIP panel and the LPRM and APRM level signals from the neutron monitoring panel corresponding in time, and calculates core performance based on the TIP level data.

Abstract: A pressure vessel includes upper and lower vessel sections joined by a flanged connection. A nuclear reactor core includes an array of fuel assemblies comprising fissile material. The nuclear reactor core is disposed in the lower vessel section. A side-entry vessel penetration is located at a side of the pressure vessel and passes through one of (i) a flange of the flanged connection and (ii) the lower vessel section. An incore instrument routing tube extends from the side-entry vessel penetration and enters the reactor core from above the reactor core. The incore instrument routing tube extends from the side-entry vessel penetration with a declination angle AE and includes a 90°?AE downward turn to enter the reactor core from above. The declination angle AE may be zero so that the routing tube extends horizontally from the side-entry vessel penetration and includes a 90° downward turn.

Abstract: A tool for use in servicing an LPRM assembly of a nuclear reactor vessel includes a structural member having a first bore that is structured to receive an LPRM device associated with the LPRM assembly, a headpiece provided at a first end of the structural member, and a nut engaging assembly slideably mounted on the structural member. The headpiece has a plurality of projections structured to mate with a plurality of bores provided in a seal of the LPRM assembly to enable the seal to be removed, and the nut engaging assembly has a housing that defines a second bore and that has first and second nut engaging portions. The nut engaging assembly is free to slide along the structural member and over the headpiece to a position wherein the engaging portions extend beyond the headpiece so that they may be used to remove the assembly nut.

Abstract: A method for providing a boron-lined neutron detector. The method includes providing a boron-containing material and providing water. The method includes mixing the boron-containing material into the water to create a water-based liquid mixture and providing a substrate of a cathode of the neutron detector. The method includes applying the water-based liquid mixture to the substrate of the cathode and removing water from the water-based liquid applied to the substrate to leave a boron-containing layer upon the substrate that is sensitive to neutron impingement. The step of providing a boron-containing material may be to provide the material to include B-10.

Abstract: A system for monitoring a state of a reactor core in a nuclear reactor may include an internal monitoring device located inside the reactor core, the internal monitoring device including one or more internal sensor arrays configured to take measurements of conditions of the reactor core at different vertical regions within the reactor core to generate internal measurement data; an external monitoring device located in the reactor structure outside the reactor core, the external monitoring device including one or more external sensor arrays configured to take measurements of conditions of the reactor core at positions outside the reactor core corresponding the plurality of different vertical regions within the reactor core to generate external measurement data, and a transmitter configured to wirelessly transmit the external measurement data; and a receiver station configured to determine a state of the reactor core based on the external and internal measurement data.

Abstract: A traveling reactor power monitoring system includes a traveling reactor power monitoring system including a drive control unit configured to move a traveling probe in a guide tube by rotating a motor, and a proximity switch that generates a 1st preventing retraction signal when the travelling probe is detected by the proximity switch to exist at a predefined stop range in a shielding vessel. The drive control unit stops retracting the travelling probe when the 1st preventing retraction signal is generated by the proximity switch, and wipes out the 1st preventing retraction signal by detecting that the probe exists outside the predefined stop range on the basis of a probe information as a substitute for the 1st preventing retracting signal output by the proximity switch.