Decay and Fission Yield Data Library for ORIGEN2 Code to Reproduce the Decay Heat Values Recommended by the Atomic Energy Society of Japan.

Abstract

The decay heat values calculated with ORIGEN2 code, which is widely used for the evaluation of radioactivity and the decay heat analysis of spent fuel, are not consistent with the "recommended decay heat values" by the Atomic Energy Society of Japan, the adoption of which to the safety assessment has been authorized by Japanese Atomic Energy Safety Commission. The discrepancy between them has caused perplexity in the use of ORIGEN2 code. In order to diminish the discrepancy, fission product decay data and fission yield data of ORIGEN2 code are replaced with the data contained in the JNDC Nuclear Data Library of Fission Products that was used for making the "recommended decay heat values". The decay heat calculation with ORIGEN2 code using the replaced data is able to obtain the decay heat values agreeing with the "recommended values" within nearly 1% for most of the cooling time region except for a limited region where the maximum discrepancy of 3% exists in the case of 1s irradiation. In the case of longer irradiation time (1 yr), the discrepancy is diminished to nearly 0.5% for whole range of the cooling time.