遮蔽設計基本データベースの整備(IV)

Preparation of a basic data base for shielding design (IV)

中尾 誠*; 竹村 守雄*

not registered; Takemura, Morio*

最新の核データライブラリーJENDL-3.2に基づき作成された遮蔽解析用標準群定数ライブラリーJSSTDLを用いて、JASPER実験の実験解析を実施した。新遮蔽材透過実験では、JSSTDLの熱群改訂効果を確認するためポリエチレン体系に再度と適用するとともに、ジルコニウム体系を新たにとりあげた。炉内貯蔵燃料遮蔽評価実験ではIVFSを模擬した増倍層のある実験体系に適用した。さらに中性子検出器応答実験およびギャップストリーミング実験の遮蔽体中のナトリウム窓あるいは狭い空隙からの中性子ストリーミングの模擬実験体系にも適用した。JENDL-2に基づき作成され従来のJASPER実験解析に適用されてきた群定数ライブラリーJSDJ2での、同じ解析手法・入力による実験解析結果と、このJSSTDLでの解析結果との比較検討を行った。ポリエチレン体系ではライブラリーの改訂によりJSSTDLの過大評価は幾分軽減されることを確認したが、前年度までに実施した径方向遮蔽、軸方向遮蔽、IHX等の各実験の実験解析と同様に、全般的にJSSTDLは、JSDJ2に比較し高めの結果をもたらす傾向がみられた。これらの実験解析と並行して、選定された代表的なJASPER実験体系について、その実験解析を再現するのに必要な解析入力等のデータの計算機上への集約・整備を引き続き行った。

With use of a standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the JASPER experiments were performed. In order to verify the new version of JSSTDL, whose cross setions of thermal energy region was updated, the polyethylene transmission experiments of the Special Materials Experiment was analysed again, and also zirconium transmission experiment of the Experiment was newly analysed. JSSTDL was applied to the analysis of neutron multiplicative region of the in-vessel fuel storage mockup configulations in the IVS Experiment. Also it was applied to the analyses of neutron streaming effect through the mockup of sodium window in BC shield in the Flux Monitor Experiment and also the mockup of narrow gaps in thick concrete shield in the Gap Streaming Experiment. The results were compared with those obtained by the same analysis method and input data using the JSDJ2 library that had been applied consistently to the JASPER experiment analyses. Although the analysis with the new version of JSSTDL resulted in a little reduction of overestimation in the polyethylene transmission configulation, the results obtained with JSSTDL are, in general, higher than those with JSDJ2 as had been found in analyses in preceding years for the Radial Shield Attenuation Experiment, the Axial Shield Experiment, the Intermediate Heat Exchager Experiment and so on. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments, that were selected at the first stage of this study, were continued and new data were added into the computer disk holding previously accumulated data.