Verification of a Three-dimensional Multi-energy Group Kinetic Analysis Model by Using BWR Critical Operation Data

Abstract

A time-dependent diffusion model of a three-dimensional, multi-energy group kinetic analysis program STAND has been verified by using neutron detector responses in the subcritical condition. The responses were obtained from a BWR start-up examination. STAND is based on a polynomial nodal expansion method and an improved quasi-static model. It can simulate transients and reactivity accidents of boiling water reactors in critical and subcritical conditions, and works efficiently on a vector computer.

This paper describes the core neutronic model including treatment of external neutron sources and verification results tracing about a 10-min control rod operation during the BWR start-up examination. Calculated transient detector responses had good agreement with experimental ones. The CPU time necessary to calculate Is of behavior for a full core (460 radial meshes×30 axial meshes) with three energy groups was about 13 s on the HITACHI S-3800 vector computer when the shape function time step was set to 0.1–0.2 s.

KEYWORDS:

• three-dimensional calculations
• multi-energy group
• kinetic equations
• nodal method
• external neutron sources
• neutron detectors
• control rods
• BWR type reactors
• subcriticality
• vector computer