A macroscopic cross-section model for BWR pin-by-pin core analysis

作者：Fujita Tatsuya^*; Endo Tomohiro; Yamamoto Akio

来源：Journal of Nuclear Science and Technology, 2014, 51(3): 282-304.

DOI：10.1080/00223131.2014.864248

• pin-by-pin
• fine mesh
• BWR core analysis
• cross section
• macroscopic depletion model
• instantaneous and history effects
• cross-term effect

A macroscopic cross-section model used in boiling water reactor (BWR) pin-by-pin core analysis is studied. In the pin-by-pin core calculation method, pin-cell averaged cross sections are calculated for many combinations of core state and depletion history variables and are tabulated prior to core calculations. Variations of cross sections in a core simulator are caused by two different phenomena (i.e. instantaneous and history effects). We treat them through the core state variables and the exposure-averaged core state variables, respectively. Furthermore, the cross-term effect among the core state and the depletion history variables is considered. In order to confirm the calculation accuracy and discuss the treatment of the cross-term effect, the k-infinity and the pin-by-pin fission rate distributions in a single fuel assembly geometry are compared. Some cross-term effects could be negligible since the impacts of them are sufficiently small. However, the cross-term effects among the control rod history (or the void history) and other variables have large impacts; thus, the consideration of them is crucial. The present macroscopic cross-section model, which considers such dominant cross-term effects, well reproduces the reference results and can be a candidate in practical applications for BWR pin-by-pin core analysis on the normal operations.

• 出版日期2014-3-4