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Kamikawa, Yutaka; Suzuki, Makoto; Agake, Toshiki; Murakami, Takahiko; Morita, Yusuke; Shiina, Hidenori; Fukushima, Manabu; Hirane, Nobuhiko; Ouchi, Yasuhiro
JAEA-Technology 2023-030, 57 Pages, 2024/03
Owing to the publication of the latest data about aircraft crashes by Nuclear Regulation Authority (NRA), it was necessary to re-evaluate the probabilities of aircraft crashes for Nuclear Science Research Institute (NSRI). By using of the assessment method provided in "Regulatory Guide of the Assessment Standard for Probability of Airplane Crash on a Nuclear Power Reactor Facility", we re-evaluated the probabilities of aircraft crashes against the nuclear facilities in NSRI. As a result of the evaluations, the sum of the probabilities of aircraft crashes against Waste Treatment Facilities (maximum probability among all nuclear facilities in NSRI) is 5.6810
(times/(reactor
year)) which is lower than 10
(times/(reactor
year)) that is the assessment criterion whether aircraft crashes is considered to be "anticipated external human induced events" in design basis or not.
Araki, Shohei; Murakami, Takahiko; Kamikawa, Yutaka; Arakaki, Yu; Tada, Yuta; Aizawa, Eiju; Ishii, Junichi; Seki, Masakazu; Izawa, Kazuhiko; Gunji, Satoshi
no journal, ,
We conducted thermal power measurements and thermal power calibration for a performance test in the modified STACY. The activation method was adopted in the thermal power measurements. The core for the measurements consisted of 253 fuel rods and a sample driver. The gold foils used for the activation foil method were installed in the sample driver. The operation was carried out twice, at 20-W and 50-W. The neutron flux in the core and the response of the gold foil were calculated using MVP and PHITS, respectively, with JENDL-5 as the nuclear data. In each measurement, the integrated power was 4.2-Wh and 8.9-Wh, respectively. The indicated power with default setting was found to be about 50% higher than the evaluated value.
Araki, Shohei; Arakaki, Yu; Maekawa, Tomoyuki; Murakami, Takahiko; Hasegawa, Kenta; Yoshikawa, Tomoki; Tada, Yuta; Kamikawa, Yutaka; Sumiya, Masato; Seki, Masakazu; et al.
no journal, ,
In the TEPCO's Fukushima Daiichi Nuclear Power Plant accident, fuel debris was formed by fuel melting and mixing with in-core structures. Although the detailed properties of the fuel debris are still unknown, it is thought to contain materials such as iron and concrete. Then, in order to understand the criticality characteristics of fuel debris, JAEA is conducting a comprehensive numerical analysis assuming the composition of fuel debris containing concrete and iron. However, integral experimental data including these materials are scarce, and the validation of the analytical results has not been fully investigated. Thus, JAEA modified the criticality facility STACY in order to obtain experimental data that will contribute to the validation. This report describes the outline and status of the modified-STACY, and the plan is also presented.