Evaluation method of the verification test items for the transient analysis code of sodium cooled fast reactor

GEN-IV reactors as a kind of advanced reactors including SFRs (Sodium Fast Rectors) are now world-widely under development with the aims of highly economical advances and safety enhancement. Together with the development of the advanced reactors, transient and accident analysis method for water reactors has also progressed. However, since the advanced reactors are fundamentally different from the water reactors, regulatory tools (code, data, etc.) may not be further directly applicable to the advanced reactor designs. For the reliable regulatory decision in accident analysis the analysis code should be sufficiently verified and validated. Several code and standards have been applied to light water reactors, for example Reg. Guide 1.157, Reg. Guide 1.203, NUREG-1230, ASME V&V 10.1-2012, and so on. Recently CFD (Computational Fluid Dynamics) has been gradually adopted in nuclear safety analysis and guidelines on the usage have also been suggested such as ECORA (Evaluation of Computational fluid dynamic methods for reactor safety analysis). The critical review of such materials gives insights for the evaluation method for the transient analysis code and this will be discussed in this paper. The key words in these materials are PIRT (Phenomena Identification and Ranking Table) and uncertainty analysis including bias. Another one important feature is that the regulatory bodies do not have the same degree of data as are available for light water reactors. Some proposed an international cooperative research and exploration as only a practical way. KINS (Korea Institute of Nuclear Safety) has devoted much effort in such a problem because Korean nuclear industry are now under pursuance of construction of SFR. As a first research step for the licensing process in SFR accident analysis a phenomena identification table was developed from the intensive research and independent reviews. Ranking process was not performed yet but screening process was conducted. So each item in the table is believed to be worthy while to consider. Such items will be discussed together with the evaluation method of the verification test items for the transient analysis code. (author)