Analysis of international standard problem No. 45, QUENCH06 test at FZK by detailed severe accidents analysis code, IMPACT/SAMPSON

摘要

The QUENCH06 test at Forschungszentrum Karlsruhe (FZK) selected to be the international standard problem (ISP) No. 45 by OECD/NEA has been analyzed by the IMPACT/SAMPSON code, a detailed analysis code for severe accidents in an LWR. The code has been used to perform blind and open phase analyses of the quench phenomenon and Zr/water reaction on the actual PWR cladding. Conclusions obtained from the analyses are as follows: (1) Overall, the blind phase analysis predicted relatively well the results of QUENCH06 test with respect to thermal hydraulics in the test bundle and its degradation due to Zr/water reaction. (2) The difference in the final accumulated hydrogen generation between the blind phase analysis and the test was 19% under parabolic rate constants by Cathcart-Pawel and Urbanic-Heidrick with a transition temperature of 1,853 K. (3) Embrittlement failure criteria for Zircaloy cladding against quenching adopted from the SCDAP/RELAP5 (MATPRO) predicted almost correctly the failure time of the QUENCH06 test. (4) The open phase analysis has traced the temperature change of the inner fuel cladding very well and has yielded almost the measured hydrogen release, considering inner surface oxidation after cladding failure. (5) The IMPACT/SAMPSON code has been validated against the quench phenomenon and the Zr/water reaction observed in the QUENCH06 test at FZK. [References: 18]