Measurement and analysis of Np sample reactivity worth at TCA and FCA in JAEA

JAEAの臨界実験装置TCAとFCAにおけるNp-237サンプル反応度価値の測定と解析

櫻井 健 ; 森 貴正; 岡嶋 成晃  ; 谷 和洋*; 須崎 武則*; 齊藤 正樹*

Sakurai, Takeshi; Mori, Takamasa; Okajima, Shigeaki; Tani, Kazuhiro*; Suzaki, Takenori*; Saito, Masaki*

Reactivity worths of 22.87 grams of Np oxide sample were measured and analyzed in seven uranium cores in the Tank Type Critical Assembly (TCA) and two uranium cores in the Fast Critical Assembly (FCA) at the Japan Atomic Energy Agency. The TCA cores provided a systematic variation in the neutron spectrum between the thermal and resonance energy regions. The FCA cores, XXI and XXV, provided a hard neutron spectrum of the fast reactor and a soft one of the resonance energy region, respectively. Analyses were carried out using the JENDL-3.3 nuclear data library with a Monte Carlo method for the TCA cores and a deterministic method for the FCA cores. Ratios of calculation to experiment(C/E's) of the reactivity worth were between 0.97 and 0.91, and showed no apparent dependence on the neutron spectrum.