Resonance calculation program and analyzing apparatus

A computer-readable storage medium storing a resonance calculation program configured to execute a resonance calculation of calculating an effective cross section serving as an input value for neutron transport calculation on hardware at a time of calculating a neutron flux in a fuel assembly storing a fuel rod, wherein

• a cross section of the fuel assembly taken along an orthogonal plane orthogonal to an axial direction of the fuel rod is defined as an analysis target region in the resonance calculation, the analysis target region being divided into a plurality of detailed regions, a part of the detailed regions being a resonance region where a resonance phenomenon occurs,
• a neutron escape probability in the resonance region is expressed by a polynomial rational expression representing a gray range from a black body in which the resonance region absorbs all of neutrons to a white body in which the resonance region does not absorb all of the neutrons at all, the polynomial rational expression including a first rational coefficient and a second rational coefficient,
• the resonance calculation program uses:
• a fitting equation for calculating the first rational coefficient and the second rational coefficient, with the first rational coefficient and the second rational coefficient used as factors;
• a first calculation equation for calculating a background cross section for calculating the effective cross section, with the first rational coefficient used as a factor;
• a second calculation equation for calculating the neutron flux, with the background cross section used as a factor;
• and
• a third calculation equation for calculating the effective cross section, with the second rational coefficient and the neutron flux obtained by the second calculation equation used as factors, and wherein
• the resonance calculation program comprises:
• a calculation point setting step of setting a macroscopic cross section in the gray range, to the resonance region as a calculation point;
• a first neutron flux calculation step of calculating the neutron flux set at the calculation point and corresponding to the macroscopic cross section based on Method of Characteristics;
• a coefficient calculation step of fitting the fitting equation to the macroscopic cross section and the neutron flux so as to provide a function representing the macroscopic cross section and the neutron flux at the calculation point, and calculating the first rational coefficient and the second rational coefficient;
• a background cross section calculation step of assigning the calculated first rational coefficient to the first calculation expression, and calculating the background cross section;
• an effective cross section interpolation step of interpolating the effective cross section from a cross section storage unit storing the effective cross section made to correspond to the background cross section, with the calculated background cross section used as an argument;
• a second neutron flux calculation step of assigning the background cross section to the second calculation equation, and calculating the neutron flux;
• and
• an effective cross section calculation step of assigning the effective cross section obtained at the effective cross section interpolation step, the neutron flux obtained at the second neutron flux calculation step, and the second rational coefficient obtained at the coefficient calculation step to the third calculation equation, and calculating the effective cross section.