核燃料施設の事故影響評価手法に関する調査（Ⅰ）: 再処理施設における想定異常事象の種類と特徴

摘要

近年，我が国においても原子力施設の安全規制におけrnるリスク情報活用に向けた活動が原子炉施設を中心に進rnむ中で，核燃料施設を対象に確率論的安全評価（PSA：rnProbabilistic Safety Assessment）手法および基礎的データrnの整備も積極的に進められている。核燃料施設においてrnPSA等から導出されるリスク情報を安全規制に活用するrnには，核燃料施設の個々の安全上の特徴を反映したPSArn手法の整備および各施設におけるリスクの評価?分析を進rnめることが必要であることから，日本原子力学会の「核燃rn料施設事故影響評価手法調査専門委員会」では，平成16rn年度より（独）日本原子力研究開発機構からの委託を受けて，rn核燃料施設のPSA手法のうち，特に事故時の影響評価のrnための解析手法に重点をおいて調査検討を実施してきrnた。%A special committee on "Research on the analysis methods for accident consequence of nuclear fuel facilities (NFFs)" was organized by the Atomic Energy Society of Japan (AESJ) under the entrustment of Japan Atomic Energy Agency (JAEA). The committee aims to research on the state-of-the-art consequence analysis method for probabilistic safety assessment (PSA) of NFFs, such as fuel reprocessing and fuel fabrication facilities. The objective of this research is to obtain the useful information related to establishing quantitative performance objectives and to risk-informed regulation through qualifying issues needed to be resolved for applying PSA to NFFs. The research activities of the committee were mainly focused on the analysis method of consequences for postulated accidents with potentially large consequences in NFFs, e.g. events of criticality, leakage of molten glass, hydrogen explosion, boiling of radioactive solution and fire (including rapid decomposition of TBP complexes), resulting in release of radioactive materials to the environment. The results of the research were summarized in a series of six reports. This report aims to provide common backgrounds of the events studied in order to promote the understanding of the other five technical reports and shows overviews of abnormal events postulated in a reprocessing plant and their features.