Multiple mechanisms in proton-induced nucleon removal at 100 MeV/nucleon

Pohl, T.*; Sun, Y. L.*; Obertelli, A.*; Lee, J.*; Gmez-Ramos, M.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Cai, B. S.*; Yuan, C. X.*; Brown, B. A.*; et al.

Physical Review Letters, 130(17), p.172501_1 - 172501_8, 2023/04

https://doi.org/10.1103/PhysRevLett.130.172501

We report on the first proton-induced single proton- and neutron-removal reactions from the neutron deficient O nucleus with large Fermi-surface asymmetry at 100 MeV/nucleon. Our results provide the first quantitative contributions of multiple reaction mechanisms including the quasifree knockout, inelastic scattering, and nucleon transfer processes. It is shown that the inelastic scattering and nucleon transfer, usually neglected at such energy regime, contribute about 50% and 30% to the loosely bound proton and deeply bound neutron removal, respectively.

Temporal variability of Cs concentrations in coastal sediments off Fukushima

Suzuki, Shotaro*; Amano, Yosuke*; Enomoto, Masahiro*; Matsumoto, Akira*; Morioka, Yoshiaki*; Sakuma, Kazuyuki; Tsuruta, Tadahiko; Kaeriyama, Hideki*; Miura, Hikaru*; Tsumune, Daisuke*; et al.

Science of the Total Environment, 831, p.154670_1 - 154670_15, 2022/07

https://doi.org/10.1016/j.scitotenv.2022.154670

Study on the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute (FY2020)

Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi; Miyakoshi, Hiroyuki; Takamatsu, Misao; Sakamoto, Naoki; Isozaki, Ryosuke; Onishi, Takashi; et al.

JAEA-Review 2021-020, 42 Pages, 2021/10

JAEA-Review-2021-020.pdf:2.95MB

The disposal of radioactive waste from the research facility need to calculate from the radioactivity concentration that based on variously nuclear fuels and materials. In Japan Atomic Energy Agency Oarai Research and Development Institute, the study on considering disposal is being advanced among the facilities which generate radioactive waste as well as the facilities which process radioactive waste. This report summarizes a study result in FY2020 about the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute.

Think of issues for treatment various waste from nuclear plant

Suzuki, Masafumi*; Yoshinaka, Kazuyuki

Gijutsushi, (648), p.12 - 15, 2020/12

AA2020-0333.pdf:0.97MB

The site tour which is a part of CPD events regarding the issue concerning the radioactive waste from nuclear facilities was organized in autumn 2019, and we visited the facilities related to the specified waste due to the Fukushima-Daiichi Nuclear Power Plant accident in spring 2020. The tours made us reacknowledge the impact of radionuclides on environment at accident, the importance of the management of nuclear facilities under the basic premise of ensuring safety, the necessity of the discussion based on the common understanding, and that would be contributed to find the solution of those issues.

Shell structure of the neutron-rich isotopes Co

Lokotko, T.*; Leblond, S.*; Lee, J.*; Doornenbal, P.*; Obertelli, A.*; Poves, A.*; Nowacki, F.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Authelet, G.*; et al.

Physical Review C, 101(3), p.034314_1 - 034314_7, 2020/03

https://doi.org/10.1103/PhysRevC.101.034314

The structures of the neutron-rich Co isotopes were investigated via () knockout reactions at the Radioactive Isotope Beam Factory, RIKEN. Level schemes were reconstructed using the coincidence technique, with tentative spin-parity assignments based on the measured inclusive and exclusive cross sections. Comparison with shell-model calculations suggests coexistence of spherical and deformed shapes at low excitation energies in the Co isotopes.

Security by facility design for sabotage protection

Suzuki, Mitsutoshi; Demachi, Kazuyuki*

Journal of Nuclear Science and Technology, 55(5), p.559 - 567, 2018/05

https://doi.org/10.1080/00223131.2017.1417170

Facility design of nuclear power plant for a sabotage protection is investigated and an effect of the design change for damage control on reduction of sabotage risk is shown using the vital area identification methodology. The loss of offsite power leading to the station blackout is assumed to be a typical example for further evaluation. In this study, the vulnerability of target set is defined as the multiplication of the accessibility, the distribution of target and the degree of adversary's interference. The built-in measures for damage control are of vital importance in case of the existence of adversary's interference until neutralization. It is confirmed that not only the physical protection system but also the facility design play an important role in the effective and efficient sabotage protection. It is very important to introduce a security by design approach in an initial stage of the NPP construction while considering the interface between safety and security.

Engineering validation and engineering design of lithium target facility in IFMIF/EVEDA project

Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; Ida, Mizuho*; Ito, Yuzuru; Niitsuma, Shigeto; Edao, Yuki; et al.

Fusion Science and Technology, 66(1), p.46 - 56, 2014/07

https://doi.org/10.13182/FST13-770

Engineering design of contact-type liquid level sensor for measuring thickness validation of liquid lithium jet in IFMIF/EVEDA lithium test loop

Kanemura, Takuji; Kondo, Hiroo; Suzuki, Sachiko*; Hoashi, Eiji*; Yamaoka, Nobuo*; Horiike, Hiroshi*; Furukawa, Tomohiro; Ida, Mizuho; Nakamura, Kazuyuki; Matsushita, Izuru*; et al.

Fusion Science and Technology, 62(1), p.258 - 264, 2012/07

https://doi.org/10.13182/FST12-A14144

In the Engineering Validation and Engineering Design Activities (EVEDA) project of the International Fusion Materials Irradiation Facility (IFMIF), which is one of the Broader Approach (BA) activities, thickness variation of a liquid lithium (Li) jet simulating the IFMIF Li target is planned to be measured in the EVEDA Li Test Loop (ELTL). For this purpose, a contact-type liquid level sensor was developed, which can detect contacts between a probe and Li. Analysis of the contact signals yields average jet thickness and amplitude distribution. One of the key development requirements is to drive the probe by 0.1 mm step with positioning accuracy of 0.01 mm under the vacuum condition of 10Pa. To satisfy such a requirement, the sensor's own weight load and moment load were calculated, and based on those calculation results a powerful motor and a friction-reduced ball screw were selected and strong structure was adopted. We have successfully completed the design work of the sensor.

Characterization of the dissolver sludge of MOX spent fuel at the Tokai Reprocessing Plant

Suzuki, Kazuyuki; Hatanaka, Akira; Samoto, Hirotaka; Suwa, Toshio; Tanaka, Kosuke; Tanaka, Yukiyoshi

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 6 Pages, 2011/12

The properties of the sludge in dissolver vessels from the reprocessing of ATR-MOX and ATR-UO fuels were investigated on the pilot-plant scale at the Tokai Reprocessing Plant (TRP). This sludge is mainly composed of platinum-group elements, zircaloy fragments, and post-precipitates from the dissolver solution. The sludge deposited on the dissolver causes difficulties such as pipe clogging. The characteristics of the sludge collected from the dissolver vessels, which affect the reprocessing operation, were revealed through chemical composition analysis using ICP-AES, and XRD. It was confirmed that the major component of the sludge was zirconium molybdate, and no significant differences between ATR-MOX and ATR-UO fuels were observed in terms of the sludge compositions. In order to gain further understanding of the properties of the sludge, the distributions of Pu and other trace elements were EPMA.

Design of purification loop and traps for the IFMIF/EVEDA Li test loop; Design of cold trap

Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Iuchi, Hiroshi; Ida, Mizuho; Yagi, Juro*; Suzuki, Akihiro*; Fukada, Satoshi*; Matsushita, Izuru*; Nakamura, Kazuyuki

Fusion Engineering and Design, 86(9-11), p.2437 - 2441, 2011/10

https://doi.org/10.1016/j.fusengdes.2010.12.021

Engineering Validation and Engineering Design Activities (EVEDA) for The International Fusion Materials Irradiation Facility (IFMIF) were started from July 2007 under an international agreement called ITER Broader Approach. As a major Japanese activity, EVEDA Li test loop (ELTL) to simulate hydraulic and impurity conditions of IFMIF has already designed and is under construction, in which feasibility of hydraulic stability of the liquid Li target, the purification systems of hot traps are major key issues to be validated in this loop. This paper focuses on the purification systems of the ELTL. Design of a cold trap and hot traps are discussed in this paper.