SERAPHに期待される役割に関する検討; 実用化先導研究テーマに関する検討,1

A study on requested roles for SERAPH project; R&D themes for promoting FBR's commercialization,1

丹羽 元; 家田 芳明 

Niwa, Hajime; Ieda, Yoshiaki

本報告は、SERAPHに期待される役割を明確化するためにFBR安全研究専門委員会小委員会にて平成5年度上期に検討した結果を中間的に報告するものである。本小委員会では以下の方法により検討を行った。実用化時代の高速炉は従来型のNa冷却MOX大型炉から更に改良されたものとなることを踏まえて、そこで採用される可能性のある種々の安全性向上方策、設計オプションに関する研究テーマを新規の提案も含めて提示し、委員からの追加提案も加えてそれらの有効性、技術的成立性に関して小委員会委員に対してアンケート調査を実施した。アンケート結果、及び小委員会での議論を踏まえて、SERAPHを含む長期的な安全研究によって達成すべき目標としてリスク低減を指標として選択した。さらにリスク支配事象であるCDAにおける主要な現象(例えば再臨界)に対する防止、緩和方策を強化するとの観点から分析と評価を行った。それらの研究テーマに関して、新規の炉による炉内試験、実炉試験の必要性について検討を行い、以上に基づいて新規テーマをSERAPHに期待される役割として抽出した。本年度下期では、専門委員会におけるコメントを反映して検討を継続し、検討結果をまとめた上で、本年度の専門委員会において最終的に報告する予定である。

This is an interim report of a study on requested roles of the Safety Engineering Reactor for Accident Phenomenology (SERAPH) project which has been performed by the working group organized under the FBR safety research specialist committee. In this working group, the future requirements for SERAPH has been studied as follows: (1)Considering that the safety level of future FBRs would be much more improved from the present concept of sodium cooled mixed-oxide fueled large scale FBR, prevention and mitigation measures could be introduced or much more enhanced. Therefore currently proposed design measures have been widely reviewed and some were newly proposed, then the information was presented to the working group. An investigation was conducted by means of "questionnaire" to the working group members asking their effectiveness and technical feasibility. (2)Based on the results of the questionnaire and discussions in the working group, "risk reduction" has been selected as an index which should be pursued of through long-term safety research where SERAPH is expected to play an important role. The presented measures were analyzed and evaluated from the viewpoint of preventing and/or mitigating important phenomena in CDA (for example, recriticality) because CDA is a risk dominant event in FBRs. (3)R&D plans of each measure were drafted and needs of in-pile and reactor-scale experiments were examined including new experimental facilities. Based on this study, new R&D themes were preliminarily selected as future requirements for the SERAPH project. The final report will be presented at the end of the FY1993. This will include the results of the additional study reflecting the comments from the members of the FBR safety research specialist committee.