Criticality safety analysis for a core catcher designed in Korea

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• 作者：Song Hyun Kim^a ; Chang Ho Shin^a ; Hong-Chul Kim^b ; Jong Kyung Kim^a ; ^{jkkim1@hanyang.ac.kr} ; Jin Ho Song^b ; Tae Woon Kim^b
• 关键词：Core catcher ; Corium ; Core melting accident ; Criticality safety ; Criticality evaluation procedure
• 刊名：Progress in Nuclear Energy
• 出版年：2012
• 出版时间：August, 2012
• 年：2012
• 卷：59
• 期：Complete
• 页码：66-74
• 全文大小：1178 K

文摘

Corium is a molten mixture of portions of a reactor core generated by a core melting accident. Corium includes fissionable materials; therefore, a criticality safety analysis must be performed for the core catcher design. This study analyzes the criticality safety of corium arranged in a core catcher developed in Korea. The corium composition was calculated for a 1400 MW_e nuclear power plant. There are several variables involved in the criticality evaluation of corium, thus conservative assumptions were used to reduce the number of variables. A criticality evaluation procedure was employed to assess the operational failure of the core catcher under different accident scenarios. Four kinds of scenarios were selected, and criticality evaluations were pursued for each case. The multiplication factors in each condition were calculated with MCNP5 code. Also, the code bias was calculated with the benchmark problems of 262 LEU experiments to account for the uncertainty of MCNP code. All evaluation results for the assumed scenarios showed that the core catcher satisfies the regulatory guidelines for criticality safety. The calculation results will be used in the design of a core catcher being developed in Korea. It is expected that the data calculated in this study can be used as reference data for criticality safety evaluations of core melting accidents. Also, the procedure for criticality safety evaluation proposed in this study can be utilized to establish regulatory guidelines in Korea.