Mitsubishi Heavy Industries Limited

Shinobu Tsubota

Daisuke Sato

Hideki Matsumoto

Hiroki Koike

Kazuya Yamaji

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

Resonance calculation program and analyzing apparatus

A nuclear-characteristic calculating program for calculating a nuclear characteristic of a fuel rod that contains nuclear fuel and burnable poison includes a first scattering model that can represent a simple scattering of the neutron and a second scattering model that can represent a complicated scattering of the neutron. The nuclear-characteristic calculating program includes step of calculating, when a burnup of the fuel rod is before a set burnup at which the burnable poison is considered to lose neutron absorption capability, the nuclear characteristic of the fuel rod by using the second scattering model, step of switching, when the burnup of the fuel rod is the set burnup, the scattering model from the second scattering model to the first scattering model, and step of calculating, after performing step of switching, the nuclear characteristic of the fuel rod by using the first scattering model.

Nuclear-characteristic calculating program and analyzing apparatus

[Problem to be Solved] To provide a resonance calculation program capable of evaluating a physical quantity such as an effective cross section in a radial direction of a circular region of a fuel rod by making a resonance calculation based on the equivalence principle. [Solution] A resonance calculation program for calculating an effective cross section by performing a resonance calculation based on an equivalence principle includes a radial-distribution calculation step Sof calculating a distribution of the effective cross section in a radial direction of a circular region by calculating the effective cross section defined by a predetermined calculation expression including a geographical coefficient for each of a plurality of annular regions while a neutron escape probability in a resonance region is expressed by a polynomial rational expression including the geographical coefficient serving as a factor representing geographical shapes of a plurality of annular regions that are circumferentially annular and that are obtained by radially dividing the circular region that is an axial cross section of a fuel rod at predetermined intervals.

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Tokyo, Japan

Shinobu Tsubota