Abstract: The present invention relates to a computational system and method to analyze a radiation field in a light water nuclear reactor. The system and method include a radiation transport module for performing a neutron and gamma transport calculation of a reactor geometry model of the light water nuclear reactor for at least one fuel cycle; a material analysis module for analyzing flux data calculated by the radiation transport module for materials and/or components within the light water nuclear reactor; and a mobile component tracking module for calculating radiation exposure for components within the light water nuclear reactor which have more than one different location during or between the at least one fuel cycle.

Abstract: A method of determining the spatially corrected inverse count ratio (SCICR) used to determine reactor criticality, which subtracts a background noise signal from the source range detector output. The method monitors the source range detector signal at two different core temperature levels during a transient portion of the detector output as the power output of the reactor is increased in the source range. This information is employed to analytically determine the background noise signal, which is then subtracted from the detector outputs to obtain the SCICR reactivity measurement.

Abstract: A method of determining the spatially corrected inverse count ratio (SCICR) used to determine reactor criticality, which subtracts a background noise signal from the source range detector output. The method monitors the source range detector signal at two different core temperature levels during a transient portion of the detector output as the power output of the reactor is increased in the source range. This information is employed to analytically determine the background noise signal, which is then subtracted from the detector outputs to obtain the SCICR reactivity measurement.

Abstract: Prompt Gamma Neuteon Activation Analysis (PGNAA) is employed to determined in situ the content of nickel, copper, or other embrittlement-enhancing elements within the weld metal joints of nuclear reactor pressure vessels.

Abstract: A neutron dosimeter and a method for neutron dosimetry involving a two-layer structure, one layer being a fissile material, and the other being a material which changes its conductivity in accordance with a density of implanted ions. Neutrons striking the fissile material result in the production of energetic ions, a determinable number of which implant themselves in the second layer and so alter its conductivity. Measurements of the conductivity of the second layer provide information from which neutron dose may be inferred.

Abstract: A reactor cavity dosimetry system and method in a nuclear power plant having a reactor vessel and a primary biological shield substantially surrounding the reactor vessel thereby forming a reactor cavity between the vessel and the shield, the system and method providing for remotely and repeatedly positioning a plurality of neutron dosimeters at preselected locations within the cavity, and for withdrawing the dosimeters for analysis thereof and replacing them at the same preselected positions. Assessment of the long-term effects of neutron irradiation on the vessel is enhanced by accurate and repetitive placement of the dosimeters.

Abstract: A reactor cavity dosimetry system and method for deploying the system which includes a top access support stand. Having a generally rectangular frame assembly formed by a pair of cross members and a pair of frame tubes, the support stand holds the dosimetry in place as part of a continuous loop. The continuous loop is first fed through a U-shaped tube situated beneath the support stand, and coupled together by a chain support plug which is adapted for insertion within a hole formed in an upper one of the cross members to fix the position of the dosimetry axially with respect to the core of a nuclear power plant within which the system is deployed. Each of the frame tubes has mounted thereon a pivotable arm assembly with a spring-loaded slide. After insertion within the cavity, the arm assemblies are pivoted out from the plane of the frame assembly, and disposed locked in place perpendicularly across the cavity.

Abstract: A method and apparatus for measuring a neutron flux in which the neutrons induce fission reactions in the layer of fissile material, the fission reactions in turn inducing light pulses in a scintillator material. A photomultiplier tube detects the light pulses and emits an electrical pulse in response. The electrical pulses are summed, checked for coincidence, stored, and otherwise manipulated in order to detect and measure neutron flux. In one advantageous embodiment of the invention, several different fissile materials or coated and uncoated fissile materials are used in order to obtain a spectral distribution of the incident neutron flux. At another embodiment, opposed detectors are used in order to discriminate between actual neutron-induced fission events and background events.