Irradiation test using foreign reactor, 1; Study of irradiation test with capsule temperature control system (Joint research)

Takabe, Yugo; Otsuka, Noriaki; Fuyushima, Takumi; Sayato, Natsuki; Inoue, Shuichi; Morita, Hisashi; Jaroszewicz, J.*; Migdal, M.*; Onuma, Yuichi; Tobita, Masahiro*; et al.

JAEA-Technology 2022-040, 45 Pages, 2023/03

JAEA-Technology-2022-040.pdf:6.61MB

Because of the decommission of the Japan Materials Testing Reactor (JMTR), the domestic neutron irradiation facility, which had played a central role in the development of innovative nuclear reactors and the development of technologies to further improve the safety, reliability, and efficiency of light water reactors, was lost. Therefore, it has become difficult to pass on the operation techniques of the irradiation test reactors and irradiation technologies, and to train human resources. In order to cope with these issues, we conducted a study on the implementation of irradiation tests using overseas reactors as neutron irradiation sites as an alternative method. Based on the "Arrangement between the National Centre for Nuclear Research and the Japan Atomic Energy Agency for Cooperation in Research and Development on Testing Reactor," the feasibility of conducting an irradiation test at the MARIA reactor (30 MW) owned by the National Centre for Nuclear Research (NCBJ) using the temperature control system, which is one of the JMTR irradiation technologies, was examined. As a result, it was found that the irradiation test was possible by modifying the ready-made capsule manufactured in accordance with the design and manufacturing standards of the JMTR. After the modification, a penetration test, an insulation continuity test, and an operation test in the range of room temperature to 300C, which is the operating temperature of the capsule, were conducted and favorable results were obtained. We have completed the preparations prior to transport to the MARIA reactor.

Advanced reactor experiments for sodium fast reactor fuels (ARES) project; Transient irradiation experiments for metallic and MOX fuels

Jensen, C. B.*; Wachs, D. M.*; Woolstenhulme, N. E.*; Ozawa, Takayuki; Hirooka, Shun; Kato, Masato

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 9 Pages, 2022/04

Feasibility study on tritium recoil barrier for neutron reflectors of research and test reactors

Kenzhina, I.*; Ishitsuka, Etsuo; Ho, H. Q.; Sakamoto, Naoki*; Okumura, Keisuke; Takemoto, Noriyuki; Chikhray, Y.*

Fusion Engineering and Design, 164, p.112181_1 - 112181_5, 2021/03

https://doi.org/10.1016/j.fusengdes.2020.112181

Tritium release into the primary coolant during operation of the JMTR (Japan Materials Testing Reactor) and the JRR-3M (Japan Research Reactor-3M) had been studied. It is found that the recoil release by Li(n,)H reaction, which comes from a chain reaction of beryllium neutron reflectors, is dominant. To prevent tritium recoil release, the surface area of beryllium neutron reflectors needs to be minimum in the core design and/or be shielded with other material. In this paper, as the feasibility study of the tritium recoil barrier for the beryllium neutron reflectors, various materials such as Al, Ti, V, Ni, and Zr were evaluated from the viewpoint of the thickness of barriers, activities after long-term operations, and effects on the reactivities. From the results of evaluations, Al would be a suitable candidate as the tritium recoil barrier for the beryllium neutron reflectors.

Irradiation growth behavior of improved Zr-based alloys for fuel cladding

Amaya, Masaki; Kakiuchi, Kazuo; Mihara, Takeshi

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.1048 - 1056, 2019/09

Irradiation test with silicon ingot for NTD-Si irradiation technology

Takemoto, Noriyuki; Romanova, N.*; Kimura, Nobuaki; Gizatulin, S.*; Saito, Takashi; Martyushov, A.*; Nakipov, D.*; Tsuchiya, Kunihiko; Chakrov, P.*

JAEA-Technology 2015-021, 32 Pages, 2015/08

JAEA-Technology-2015-021.pdf:3.15MB

Silicon semiconductor production by neutron transmutation doping (NTD) method using the JMTR has been investigated in Neutron Irradiation and Testing Reactor Center, Japan Atomic Energy Agency in order to expand the industry use. As a part of investigations, irradiation test with a silicon ingot was planned using WWR-K in Institute of Nuclear Physics, Republic of Kazakhstan. A device rotating the ingot made with the silicon was fabricated and was installed in the WWR-K for the irradiation test. And that, a preliminary irradiation test was carried out using neutron fluence monitors to evaluate the neutronic irradiation field. Based on the result, two silicon ingots were irradiated as scheduled, and the resistivity of each irradiated silicon ingot was measured to confirm the applicability of high-quality silicon semiconductor by the NTD method (NTD-Si) to its commercial production.

Fabrication of inert-matrix nitride fuel pins for the irradiation test at JMTR

Nakajima, Kunihisa; Iwai, Takashi; Kikuchi, Hironobu; Serizawa, Hiroyuki; Arai, Yasuo

JAERI-Research 2005-027, 42 Pages, 2005/09

JAERI-Research-2005-027.pdf:4.15MB

Nitride fuel pins containing inert matrix such as ZrN and TiN were fabricated for the irradiation test at JMTR, aiming at understanding irradiation behavior of nitride fuel for transmutation of minor actinides. Minor actinides are surrogated by plutonium in the present fuel pin. This report describes the preparation and characterization of fuel pellets, and fabrication of fuel pins. The irradiation for 11 cycles from May 2002 to November 2004 at JMTR was completed without any failure of fuel pins.

Irradiation test on Mo- and W-mirrors for ITER by low energy deuterium ions

Sugie, Tatsuo; Kasai, Satoshi; Taniguchi, Masaki; Nagatsu, Masaaki*; Nishitani, Takeo

Journal of Nuclear Materials, 329-333(2), p.1481 - 1485, 2004/08

https://doi.org/10.1016/j.jnucmat.2004.04.248

In ITER, the effect of lower energy particle bombardment is important for mirrors located near the divertor where the low temperature plasma is formed. The test pieces of molybdenum mirrors and a tungsten mirror were irradiated by high flux and low energy (67-80 eV) deuterium ions using SLEIS (Super Low Energy Ion Source with High Ion Flux) facility at the temperature of around 100 C. The molybdenum mirror manufactured by sintering and melting the thin layer of the surface by electron beam in order to eliminate holes on the surface has a higher reflectivity before irradiation than the mirrors without melting the surface, but the reflectivity decreases rapidly with the irradiation fluence due to the generation of blisters on the mirror surface. The reflectivity of molybdenum mirror manufactured by sintering only did not decrease so significantly (less than 10 % at the fluence of 1.3 10 m). The molybdenum and tungsten mirrors manufactured by sintering without melting the surface have a potential for plasma facing mirrors in ITER.

Effects of silicon, carbon and molybdenum additions on IASCC of neutron irradiated austenitic stainless steels

Nakano, Junichi; Miwa, Yukio; Koya, Toshio; Tsukada, Takashi

Journal of Nuclear Materials, 329-333(Part1), p.643 - 647, 2004/08

https://doi.org/10.1016/j.jnucmat.2004.04.098

To study effects of minor elements on the irradiation assisted stress corrosion cracking (IASCC), high purity Type 304 and 316 stainless steels (SSs) were fabricated and added minor elements, Si or C. After neutron irradiation to 3.510n/m (E1MeV), the slow strain rate tests (SSRT) for the irradiated specimens was conducted in oxygeneted high purity water at 561 K. Fracture surface of the specimens was examined using the scanning electron microscope (SEM) after the SSRT. Fraction of intergranular stress corrosion cracking (IGSCC) on the fracture surface after the SSRT increased with netron fluence. Suppression of irradiation hardening and increase of peiod to SCC fracture as benefitical effects of the additional elements, Si or Mo, were not observed obviously. In high purity SS added C, fraction of IGSCC was the smallest in the all SSs, although irraidiation hardening level was the largest in the all SSs. Addition of C suppressed the susceptibility to IGSCC.

Correlation between cleavage fracture toughness and charpy impact properties in the transition temperature range of reactor pressure vessel steels

Onizawa, Kunio; Suzuki, Masahide

JSME International Journal, Series A, 47(3), p.479 - 485, 2004/07

In the structural integrity assessment of reactor pressure vessel, fracture toughness values are estimated by assuming that the radiation effect on fracture toughness is equivalent to that on Charpy properties. Therefore, it is necessary to establish the correlation between both properties especially on irradiation embrittlement. In this paper, we present the fracture toughness data obtained by applying the master curve approach that was adopted recently in the ASTM test method. Materials used in this study are five ASTM A533B class 1 steels and one weld metal. Neutron irradiation for Charpy-size specimens as well as standard Charpy-v specimens was carried out at the Japan Materials Testing Reactor. The shifts of the reference temperature on fracture toughness due to neutron irradiation are evaluated. Correlation between the fracture toughness reference temperature and Charpy transition temperature is established. Based on the correlation, the optimum test temperature for fracture toughness testing and the method to determine a lower bound fracture toughness curve are discussed.

Development of sealing plug for sweep gas line

Kikuchi, Taiji; Yamada, Hirokazu*; Saito, Takashi; Nakamichi, Masaru; Tsuchiya, Kunihiko; Kawamura, Hiroshi

JAERI-Tech 2004-026, 28 Pages, 2004/03

JAERI-Tech-2004-026.pdf:2.06MB

Iirradiation capsule for irradiation test of tritium breeder and inner capsule for pebble bed of tritium breeder is inserted. Post irradiation examination of tritium breeder will be performed after irradiation test. On cutting of irradiation capsule, sweep gas line should be sealed to prevent the tritium gas release or inflow of water to sweep gas line. However, general valve and plug cannot apply to sweep gas line sealing because of the effect of neutron irradiation or limited space in irradiation capsule. Therefore, sealing plug for sweep gas line sealing has to be developed. This report shows the development of sealing plug for sweep gas line sealing and operating procedure of sealing plug in irradiation capsule.