Thermal-hydraulic design calculations for JRR-3 cold neutron source with the new moderator cell

Tokunaga, Sho; Horiguchi, Hironori; Nakamura, Takemi

JAEA-Technology 2023-001, 37 Pages, 2023/05

JAEA-Technology-2023-001.pdf:1.39MB

The cold neutron source (CNS) of the research reactor JRR-3 converts thermal neutrons generated in the reactor into low-energy cold neutrons by moderating them with liquid hydrogen stored in the moderator cell. Cold neutrons generated by the CNS are transported to experimental instruments using neutron conduits, and are used for many studies of physical properties, mainly in life science, polymer science, environmental science, etc. Improvement of cold neutron intensity is essential to maintain competitiveness with the world's research reactors in neutron science, and we are developing a new CNS that incorporates new knowledge. The current moderator cell for the CNS of JRR-3 is a stainless-steel container which is a canteen bottle type, and the cold neutron intensity can be improved by changing the material and shape. Therefore, the basic specifications of the new moderator cell were changed to aluminum alloy which has a smaller neutron absorption cross section, and the shape was optimized using a Monte Carlo code MCNP. Since these changes in specifications will result in changes in heat generation and heat transfer conditions, the CNS of JRR-3 was re-evaluated in terms of self-regulating characteristic, heat transport limits, heat resistance and pressure resistance, etc., to confirm its feasibility in thermal-hydraulic design. This report summarizes the results of the thermal-hydraulic design evaluation of the new moderator cell.

Lattice parameters of austenite and martensite during transformation for Fe-18Ni alloy investigated through neutron diffraction

Gong, W.; Harjo, S.; Tomota, Yo*; Morooka, Satoshi; Kawasaki, Takuro; Shibata, Akinobu*; Tsuji, Nobuhiro*

Acta Materialia, 250, p.118860_1 - 118860_16, 2023/05

https://doi.org/10.1016/j.actamat.2023.118860

Photocatalytic unification of iodine species using platinum-loaded titanium dioxide

Sugita, Tsuyoshi; Mori, Masanobu*; Kozai, Naofumi

Journal of Photochemistry and Photobiology A; Chemistry, 438, p.114548_1 - 114548_6, 2023/04

https://doi.org/10.1016/j.jphotochem.2023.114548

Removal of iodine from water contaminated by nuclear accidents or the release of radioactive waste is complicated and costly because iodine exists in a variety of forms in the water. We investigated the unification of iodine species by photocatalysis as a pretreatment for removing radioactive iodine species from water. The effect of the TiO crystal phase of Pt-TiO and solution pH on the photocatalytic redox reactions of iodide (I), iodate (IO), and -iodobenzoic acid were evaluated. The choice of TiO crystalline phase and pH allowed the mixture of iodine species to be unified to only I or IO. Regardless of the type of Pt-TiO, the iodine in o-iodobenzoic acid was mineralized to I under alkaline conditions. Because the iodine species can be unified to a single species by selecting the photocatalyst and the solution pH, this photocatalytic treatment could be applied to remove iodine species with high efficiency.

Assessment report on research and development activities in FY2021 Activity; "Research and development in science and technology using neutron and synchrotron radiation" (Ex-post evaluation)

Materials Sciences Research Center

JAEA-Evaluation 2022-012, 87 Pages, 2023/03

JAEA-Evaluation-2022-012.pdf:9.58MB

Japan Atomic Energy Agency (hereafter referred to as "JAEA") consulted an assessment committee, "Evaluation Committee of Research Activities for Research and Development in Science and Technology Using Neutron and Synchrotron Radiation" (hereafter referred to as "Evaluation Committee") for ex-post evaluation of "Research and Development in Science and Technology Using Neutron and Synchrotron Radiation", in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and "Regulation on Conduct for Evaluation of R&D Activities" by JAEA. In response to the JAEA's request, the Committee assessed the research program and activities on Research and Development in Science and Technology Using Neutron and Synchrotron Radiation in Materials Sciences Research Center (MSRC) and Neutron Science Section (NSS) in Materials and Life Science Division (MLSD) of J-PARC Center during the period from April 2015 to October 2021. The Committee evaluated the management, research and development activities based on the explanatory documents prepared by MSRC and NSS and oral presentations with questions-and-answers by the Director General and the Division Heads of the MSRC and the Deputy Director General and the NSS Section Leader of J-PARC Center. This report summarizes the results of the assessment by the Evaluation Committee with the Committee report attached.

Hierarchical aggregation in a complex fluid; The Role of isomeric interconversion

Massey, D.*; Williams, C. D.*; Mu, J.*; Masters, A. J.*; Motokawa, Ryuhei; Aoyagi, Noboru; Ueda, Yuki; Antonio, M. R.*

Journal of Physical Chemistry B, 127(9), p.2052 - 2065, 2023/03

https://doi.org/10.1021/acs.jpcb.2c07527

A Colossal barocaloric effect induced by the creation of a high-pressure phase

Jiang, X.*; Hattori, Takanori; Xu, X.*; Li, M.*; Yu, C.*; Yu, D.*; Mole, R.*; Yano, Shinichiro*; Chen, J.*; He, L.*; et al.

Materials Horizons, 10(3), p.977 - 982, 2023/03

https://doi.org/10.1039/d2mh00905f

As a promising environment-friendly alternative to current vapor-compression refrigeration, solid-state refrigeration based on the barocaloric effect has been attracting world wide attention. Generally, both phases in which a barocaloric effect occurs are present at ambient pressure. Here, instead, we demonstrate that KPF exhibits a colossal barocaloric effect due to the creation of a high-pressure rhombohedral phase. The phase diagram is constructed based on pressure-dependent calorimetric, Raman scattering, and neutron diffraction measurements. The present study is expected to provide an alternative routine to colossal barocaloric effects through the creation of a high-pressure phase.

Impact assessment for internal overflow in JRR-3

Tokunaga, Sho; Iguchi, Shintaro; Kawamura, Sho; Hirane, Nobuhiko

JAEA-Technology 2022-004, 74 Pages, 2023/02

JAEA-Technology-2022-004.pdf:2.46MB

In JRR-3, in response to the new regulatory standard for research reactors that is enforced December 2013, we submitted the application document of reactor installation license for the JRR-3 on September 2014, and acquired the permission on November 2018. Thereafter, we carried out impact assessment for internal overflow based on the design principles as described in the application document of reactor installation license for the JRR-3. There are two legal requirements for internal overflow. The first is to ensure that the necessary safety functions are not lost due to internal overflow that occur in the facility. The second is to prevent leakage of liquid containing radioactive materials outside the radiation controlled area in the event of an internal overflow. For these requirements, assuming each overflow source, it was confirmed that the necessary safety functions would not be lost and that liquid containing radioactive materials would not leak outside the controlled area. Regarding these assessments, design and construction plans were submitted in installments, and the approvals were obtained sequentially. This report shows the result that is impact assessment for internal overflow in JRR-3.

Evaluation of insertion property of control rod of JRR-3 at earthquake by time history response analysis method

Kawamura, Sho; Kikuchi, Masanobu; Hosoya, Toshiaki

JAEA-Technology 2021-041, 103 Pages, 2023/02

JAEA-Technology-2021-041.pdf:8.7MB

In response to new regulatory standard for research and test reactor which is enforced December 2013, JRR-3 got license in November 2018 by formulate new design basis ground motion. After that we evaluated for insertion property of control rod using that new design basis ground motion, and that evaluation results were accepted as approval of the design and construction method by Nuclear Regulation Authority. Now, we re-evaluated to insertion property of control rod about neutron absorber and follower fuel element by time history response analysis method. In this report, it shows that new results have sufficiency of margin compared with the past results that are accepted as approval of the design and construction method.

Tensile overload-induced texture effects on the fatigue resistance of a CoCrFeMnNi high-entropy alloy

Lam, T.-N.*; Chin, H.-H.*; Zhang, X.*; Feng, R.*; Wang, H.*; Chiang, C.-Y.*; Lee, S. Y.*; Kawasaki, Takuro; Harjo, S.; Liaw, P. K.*; et al.

Acta Materialia, 245, p.118585_1 - 118585_9, 2023/02

https://doi.org/10.1016/j.actamat.2022.118585

Magnetic structural analysis of nanocrystalline soft magnets by small-angle neutron scattering

Mamiya, Hiroaki*; Oba, Yojiro; Hiroi, Kosuke; Miyatake, Takayuki*; Gautam, R.*; Sepehri-Amin, H.*; Okubo, Tadakatsu*

IEEE Magnetics Letters, 14, p.7100105_1 - 7100105_5, 2023/02

https://doi.org/10.1109/LMAG.2023.3242108