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Nakamura, Makoto; Tobita, Kenji; Gulden, W.*; Watanabe, Kazuhito*; Someya, Yoji; Tanigawa, Hisashi; Sakamoto, Yoshiteru; Araki, Takao*; Matsumiya, Hisato*; Ishii, Kyoko*; et al.
Fusion Engineering and Design, 89(9-10), p.2028 - 2032, 2014/10
Times Cited Count：13 Percentile：70.2(Nuclear Science & Technology)After the Fukushima Dai-ichi nuclear accident, a social need for assuring safety of fusion energy has grown gradually in the Japanese (JA) fusion research community. DEMO safety research has been launched as a part of BA DEMO Design Activities (BA-DDA). This paper reports progress in the fusion DEMO safety research conducted under BA-DDA. Safety requirements and evaluation guidelines have been, first of all, established based on those established in the Japanese ITER site invitation activities. The amounts of radioactive source terms and energies that can mobilize such source terms have been assessed for a reference DEMO, in which the blanket technology is based on the Japanese fusion technology R&D programme. Reference event sequences expected in DEMO have been analyzed based on the master logic diagram and functional FMEA techniques. Accident initiators of particular importance in DEMO have been selected based on the event sequence analysis.
Nakamura, Makoto; Tobita, Kenji; Someya, Yoji; Tanigawa, Hisashi; Gulden, W.*; Sakamoto, Yoshiteru; Araki, Takao*; Watanabe, Kazuhito*; Matsumiya, Hisato*; Ishii, Kyoko*; et al.
Plasma and Fusion Research (Internet), 9, p.1405139_1 - 1405139_11, 2014/10
Key aspects of the safety study of a water-cooled fusion DEMO reactor is reported. Safety requirements, dose target, DEMO plant model and confinement strategy of the safety study are briefly introduced. The internal hazard of a water-cooled DEMO, i.e. radioactive inventories, stored energies that can mobilize these inventories and accident initiators and scenarios, are evaluated. It is pointed out that the enthalpy in the first wall/blanket cooling loops, the decay heat and the energy potentially released by the Be-steam chemical reaction are of special concern for the water-cooled DEMO. An ex-vessel loss-of-coolant of the first wall/blanket cooling loop is also quantitatively analyzed. The integrity of the building against the ex-VV LOCA is discussed.
Takase, Hiroyasu*; Inagaki, Manabu*; Noguchi, Toshihide*; Shimaoka, Akiko*; Martin, A. J.*; Wakamatsu, Hisanori*; Takase, Kyoko*; Tabara, Michiko*; Matsui, Hiroya
JAEA-Research 2007-066, 215 Pages, 2007/08
JAEA-Research-2007-066-01.pdf:43.05MBJAEA-Research-2007-066-02.pdf:58.73MBJAEA-Research-2007-066-03.pdf:13.08MB
In this study a systematic approach to explicitly address type and size of uncertainties associated with safety assessment due mainly to incomplete knowledge on a spatially heterogeneous geological environment was developed. In this approach a wide range of model variations including the ones with relatively law plausibility are taken into account so that ambiguity remaining in the knowledge is illustrated, which is a distinctive feature of the approach compared with the conventional methodology where only a limited number of best plausible model variations are considered. The study also proposed an approach to assessing plausibility of each model variation based on multiple pieces of evidence by using evidential support logic (ESL). Furthermore the approach was applied to Horonobe area to demonstrate its applicability to the similar class of geological environment as an example.
Takase, Hiroyasu*; Noguchi, Toshihide*; Wakamatsu, Hisanori*; Martin, A. J.*; Yamada, Kazuhiro*; Takase, Kyoko*; Tabara, Michiko*
JNC TJ5400 2005-001, 200 Pages, 2005/03
JNC-TJ5400-2005-001.pdf:57.24MB
In the Horonobe deep geological formation research plan, in order to improve confidence in disposal technology and safety assessment methods, research is being done connected with disposal technology and safty assessment. This research concerns the geological environmental acquired during investigations from the surface to the deep sub-surface and the geological model constructed using these data.Inthe current study groundwater flow and mass transport analysis have been conducted taking into account uncertainties associated with the coceptual model for geological environment in Horonobe area that was constructed by using data acquired during the investigation from ground surface. In addition a number of scoping calculations were made to support planning of the in-situ experiments.
Takase, Hiroyasu*; Metcalfe, R.*; Inagaki, Manabu*; Noguchi, Toshihide*; Aoyama, Yuji*; Takase, Kyoko*; Tabara, Michiko*
JNC TJ5400 2003-006, 264 Pages, 2004/02
JNC-TJ5400-2003-006(errata).pdf:0.08MBJNC-TJ5400-2003-006-1.pdf:83.88MBJNC-TJ5400-2003-006-2.pdf:15.97MB
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