[2O01-03] Statistical Model, Library, Covariance

[2O01] Estimation of Covariance of Neutron Cross Sections for Decommissioning

*Tatsuki Amitani¹, Tsunenori Inakura¹, Naoki Yamano¹, Ken-ichi Tanaka², Chikako Ishizuka¹, Satoshi Chiba¹ (1. Tokyo Tech, 2. IAE)

Keywords:Decommissioning, Clearance, Neutron cross section, Covariance, Bayesian Monte Carlo

To optimize disposal of low-level radioactive waste generated from decommissioning of nuclear facilities, required are 1) reliable assessment of radioactive level by calculation and measurement and 2) a good estimate of the uncertainty of those results for the classification of radioactive waste. We estimated the covariance of neutron cross sections of ⁵⁹Co and ⁶²Ni, which are important nuclides for decommissioning, to improve reliability of calculation previously. In this study, we evaluated that of two nuclides (¹⁵¹Eu, ¹⁵³Eu), which are contained in concrete, using a nuclear data evaluation code system T6 based on parameter distributions determined by a Bayesian Monte Carlo method.