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Tagami, Hirotaka; Ishida, Shinya; Tobita, Yoshiharu
Journal of Nuclear Science and Technology, 60(12), p.1548 - 1562, 2023/12
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)In a design of future Sodium-cooled Fast Reactor, there is a demand for evaluation of sequences and consequences of core disruptive accidents. Future SFRs include a unique core design with axially or horizontally heterogeneous core arrangement having complex fuel isotope distribution. A new model to flexibly represent fuel isotope distribution, called the Pu-vector model, has been developed in this study for inclusion in the SIMMER-III and SIMMER-IV codes (simply called as SIMMER). The model calculates movement of individual fuel isotopes, assuming they always accompany the convecting fuel in the fluid-dynamics model. The accuracy of the Pu-vector model was confirmed by comparing with the standard Monte Carlo static neutronics calculation. The new model can improve some of the limitations in the current SIMMER code, in which the fuel isotopes are represented only by two groups, fertile and fissile fuels. Assignment of a number of fuel isotopes to the two groups requires a detailed examination of different combinations of fuel isotopes to determine an optimized combination. The Pu-vector model can eliminate this complicated procedure to be performed prior to a SIMMER analysis, and more importantly provides accurate spatial distribution of fuel isotopes and thus will improve the applicability of SIMMER to the analyses of future large heterogeneous reactors.
Ishida, Shinya; Tagami, Hirotaka; Tobita, Yoshiharu; Okano, Yasushi; Yamano, Hidemasa; Kubo, Shigenobu
Dai-27-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 5 Pages, 2023/09
no abstracts in English
Ishida, Shinya; Fukano, Yoshitaka; Tobita, Yoshiharu; Okano, Yasushi
Proceedings of 2023 International Congress on Advanced in Nuclear Power Plants (ICAPP 2023) (Internet), 8 Pages, 2023/04
Ishida, Shinya; Fukano, Yoshitaka; Tobita, Yoshiharu; Okano, Yasushi
Journal of Nuclear Science and Technology, 13 Pages, 2023/00
Times Cited Count：1 Percentile：68.31(Nuclear Science & Technology)Aoyagi, Mitsuhiro; Sonehara, Masateru; Ishida, Shinya; Uchibori, Akihiro; Kawada, Kenichi; Okano, Yasushi; Takata, Takashi
Proceedings of Technical Meeting on State-of-the-art Thermal Hydraulics of Fast Reactors (Internet), 3 Pages, 2022/09
Ishida, Shinya; Fukano, Yoshitaka
Nihon Kikai Gakkai Rombunshu (Internet), 88(911), p.21-00304_1 - 21-00304_11, 2022/07
In previous studies, the reliability and validity of the SAS4A code was enhanced by applying Phenomena Identification and Ranking Table (PIRT) approach to the Unprotected Loss of Flow (ULOF). SAS4A code has been developed to analyze the early stage of Core Disruptive Accident (CDA), which is named Initiating Phase (IP). In this study, PIRT approach was applied to Unprotected Transient over Power (UTOP), which was one of the most important and typical events in CDA as well as ULOF. The phenomena were identified by the investigation of UTOP event progression and physical phenomena relating to UTOP were ranked. 8 key phenomena were identified and the differences in ranking between UTOP and ULOF were clarified. The code validation matrix was completed and an SAS4A model, which was not validated in ULOF, was identified and validated. SAS4A code became applicable to various scenarios by using PIRT approach to UTOP and the reliability and validity of SAS4A code were significantly enhanced.
Ishida, Shinya; Fukano, Yoshitaka
Dai-25-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2021/07
no abstracts in English
Ishida, Shinya; Kawada, Kenichi; Fukano, Yoshitaka
Mechanical Engineering Journal (Internet), 7(3), p.19-00523_1 - 19-00523_17, 2020/06
The Phenomena Identification and Ranking Table (PIRT) approach was applied to the validation of SAS4A code in order to indicate the reliability of SAS4A code sufficiently and objectively. Based on this approach, issue and objective were clarified, plant design and scenario were defined, FOM and key phenomena were selected, and the code validation test matrix was completed with the results of investigation about analysis models and test cases. The results of the test analysis corresponding to this matrix show that the SAS4A models required for the IP evaluation were sufficiently validated. Furthermore, the validation with this matrix is highly reliable, since this matrix represents the comprehensive validation that also considers the relation between physical phenomena. In this study, the reliability and validity of SAS4A code were significantly enhanced by using PIRT approach to the sufficient level for CDA analyses in SFR.
Ishida, Shinya; Kawada, Kenichi; Fukano, Yoshitaka
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 10 Pages, 2019/05
Core Disruptive Accident (CDA) has been considered as one of the important safety issues in the severe accident evaluation of Sodium-cooled Fast Reactor (SFR), and SAS4A code is developed for Initiating Phase (IP) of CDA. Phenomena Identification and Ranking Table (PIRT) approach was applied to the validation of SAS4A code in order to enhance its reliability in this study. SAS4A was validated in the following steps: (1) selection of the figure of merit (FOM) corresponding to Unprotected Loss Of Flow (ULOF) which is one of the most important and typical events in CDA, (2) identification of the phenomena involved in ULOF, (3) ranking the important phenomena, (4) development of the code validation test matrix, and (5) test analyses for validation corresponding to the test matrix. The reliability and validity of SAS4A code were significantly enhanced by this validation with PIRT approach.
Ishida, Shinya; Mizuno, Masahiro*
JAEA-Research 2015-002, 47 Pages, 2015/06
JAEA-Research-2015-002.pdf:7.22MB
An advanced safety analysis computer code, SIMMER-III and SIMMER-IV, has been developed to investigate the complex phenomena under the core disruptive accidents in LMFRs. Fuel slumping experiments performed in the Fast Critical Assembly (FCA) VIII-2 facility were analyzed by SIMMER-III (two dimensions) and SIMMER-IV (three dimensions) in order to validate the neutronics model of the code for the disrupted core analysis. The results of the SIMMER-III and SIMMER-IV analysis (70-group constants from the unified cross-section set ADJ2000R, multi-group transport approximation for the anisotropic scattering, S8 approximation for the discrete-ordinate order) indicated that the SIMMER-III and SIMMER-IV simulated the FCA VIII-2 experiments with sufficient precision. In addition, the parameter surveys showed that the simulation of the FCA VIII-2 experiments with sufficient precision can be performed with the 18-group constants and S4 approximation for the discrete-ordinate order.
Ishida, Shinya; Sato, Ikken
Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB Flash Drive), 9 Pages, 2013/05
Kawada, Kenichi; Ishida, Shinya; Onoda, Yuichi; Tobita, Yoshiharu
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Ishida, Shinya; Onoda, Yuichi; Kawada, Kenichi
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Ishida, Shinya; Kawada, Kenichi
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Kawada, Kenichi; Ishida, Shinya
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Kawada, Kenichi; Ishida, Shinya
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Ishida, Shinya; Tobita, Yoshiharu
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Ishida, Shinya; Kawada, Kenichi; Fukano, Yoshitaka
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Ishida, Shinya; Tagami, Hirotaka; Fukano, Yoshitaka; Yamano, Hidemasa; Kubo, Shigenobu
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JAEA has started developing a core disruptive accident analysis code for sodium-cooled fast reactors: SIMMER-V. As a main subject of the development, a prototype of detailed fuel pin model has been developed. This report presents an overview of this model and its verification plan.
Ishida, Shinya; Okano, Yasushi
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no abstracts in English
