Nuclear data sensitivity/ uncertainty analysis for XT-ADS

XT-ADSの核データ感度/不確かさ解析

菅原 隆徳  ; Sarotto, M.*; Stankovskiy, A.*; Van den Eynde, G.*

Sugawara, Takanori; Sarotto, M.*; Stankovskiy, A.*; Van den Eynde, G.*

SCK/CENで進められているMYRRHAプロジェクトのXT-ADS炉心を対象に、感度係数と共分散データを用いた不確かさ解析を行った。解析コードにはSCALE, ERANOS, SAGEPコードを使用し、感度解析における計算モデルや解析コードの違いの影響,不確かさ解析における共分散データの違いの影響を検討し、XT-ADSの核設計精度について議論を行った。解析の一例として、SCALEコード用に整備された共分散データを用いた場合、XT-ADSの実効増倍率に対する不確かさは約1.0%との結果が得られた。0.3%dkを目標精度とした場合、この結果は目標精度に達しておらず、積分実験などによるさらなる核データの改善が必要である。

The XT-ADS, an accelerator-driven system for an experimental demonstration, has been investigated in the framework of IP EUROTRANS FP6 project. In this study, the sensitivity and uncertainty analyses were performed to comprehend the reliability of the XT-ADS neutronic design. For the sensitivity analysis, it was found that the sensitivity coefficients were significantly different by changing the geometry models and calculation codes. For the uncertainty analysis, it was confirmed that the uncertainties deduced from the covariance data varied significantly by changing them. The uncertainties deduced from the covariance data for the XT-ADS criticality were 0.94%, 1.9% and 1.1% by the SCALE 44-group, TENDL-2009 and JENDL-3.3 data, respectively. When the target accuracy of 0.3%dk for the criticality was considered, the uncertainties did not satisfy it. To achieve this accuracy, the uncertainties should be improved by experiments under an adequate condition.