[2M10-12] Experimental Analysis

[2M10] Practical gamma ray measurement of short half-life noble gas (¹³⁵Xe, ⁸⁸Kr) emitted by fuel debris for criticality estimation

*Eka Sapta Riyana¹, Ikuo Kanno¹, Masahiro Sakamoto¹, Taichi Matsumura¹, Kenichi Terashima¹, Keisuke Okumura¹ (1. JAEA)

Keywords:Fuel Debris, Subcritical System, Neutron Multiplication Factor, Short Half-life Fission Products, activity ratio of 88Kr to 135Xe.

Our previous study showed a linear relationship between the activity ratio of ⁸⁸Kr to ¹³⁵Xe and the effective multiplication factor, k_eff, in a primary containment vessel (PCV) and in a fuel debris canister. The accuracy of the activity ratio, which closely related to the accuracy of predicted k_eff , is estimated based on an existing gamma ray energy spectrum. Practical measurement method for the gamma ray from nuclides in the PCV and the fuel debris canister gas is proposed.