REACTOR CORE CHARACTERISTIC EVALUATION AND ITS SYSTEM IN LONG TERM STOPPING OF NUCLEAR REACTOR

摘要

PROBLEM TO BE SOLVED: To provide a reactor core characteristic evaluation method and a reactor core characteristic evaluation system in which the evaluation accuracy of reactor core characteristics is increased by properly finding an assembly nuclear constant of reactor core calculation in the long term stopping of a nuclear reactor.SOLUTION: A reactor core characteristic evaluation method comprises an assembly calculation process of calculating an average assembly nuclear constant P of fuel assembly of each core fuel, and a reactor core calculation process of calculating reactor core characteristics for multiple nodes obtained by dividing the whole reactor core three-dimensionally and virtually. The assembly calculation process has (i) a step of calculating a fuel assembly nuclide composition C, (ii) a step of calculating an assembly nuclear constant P(E, C) after the elapse of an operation stop period t, and (iii) a step of calculating an assembly nuclear constant Pafter the re-operation. The reactor core calculation process has (iv) a step of finding an assembly nuclear constant P(E, C, ΔE) corresponding to an actual burnup Eof each node and an intended burnup increment ΔE, and calculating the reactor core characteristics for each node by using the assembly nuclear constant P.SELECTED DRAWING: Figure 5