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Journal Articles

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

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 $$^{6}$$Li(n$$_{t}$$,$$alpha$$)$$^{3}$$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.

Journal Articles

Evaluation of tritium release into primary coolant for research and testing reactors

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

Journal of Nuclear Science and Technology, 58(1), p.1 - 8, 2021/01

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

The sources and mechanisms for the tritium release into the primary coolant in the JMTR and the JRR-3M containing beryllium reflectors are evaluated. It is found that the recoil release from chain reaction of $$^{9}$$Be is dominant and its calculation results agree well with trends derived from the measured variation of tritium concentration in the primary coolant. It also indicates that the simple calculation method used in this study for the tritium recoil release from the beryllium reflectors can be utilized for an estimation of the tritium release into the primary coolant for a research and testing reactors containing beryllium reflectors.

Journal Articles

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

Journal Articles

Irradiation test and post irradiation examination of the high burnup HTGR fuel

Ueta, Shohei; Aihara, Jun; Shaimerdenov, A.*; Dyussambayev, D.*; Gizatulin, S.*; Chakrov, P.*; Sakaba, Nariaki

Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.246 - 252, 2016/11

In order to examine irradiation performance of the new Tri-structural Isotropic (TRISO) fuel for the High Temperature Gas-cooled Reactor (HTGR) at the burnup around 100 GWd/t, a capsule irradiation test was conducted by WWR-K research reactor in the Institute of Nuclear Physics (INP) of Kazakhstan. The irradiated TRISO fuel was designed by Japan Atomic Energy Agency (JAEA) and fabricated in basis of the HTTR fuel technology in Japan. The fractional release of fission gas from the fuel during the irradiation shows good agreement with the predicted one released from as-fabricated failed TRISO fuel. It was suggested that unexpected additional fuel failure would not occur during the irradiation up to 100 GWd/t. In addition, the post-irradiation examination (PIE) with the irradiated fuel is planned to qualify TRISO fuel integrity and upgrade HTGR fuel design for further burnup extension.

JAEA Reports

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.

Journal Articles

Irradiation performance of HTGR fuel in WWR-K research reactor

Ueta, Shohei; Shaimerdenov, A.*; Gizatulin, S.*; Chekushina, L.*; Honda, Masaki*; Takahashi, Masashi*; Kitagawa, Kenichi*; Chakrov, P.*; Sakaba, Nariaki

Proceedings of 7th International Topical Meeting on High Temperature Reactor Technology (HTR 2014) (USB Flash Drive), 7 Pages, 2014/10

A capsule irradiation test with the high temperature gas-cooled reactor (HTGR) fuel is being carried out using WWR-K research reactor in the Institute of Nuclear Physics of the Republic of Kazakhstan (INP) to attain 100 GWd/t-U of burnup under normal operating condition of a practical small-sized HTGR. This is the first HTGR fuel irradiation test for INP in Kazakhstan collaborated with Japan Atomic Energy Agency (JAEA) in frame of International Science and Technology Center (ISTC) project. In the test, TRISO coated fuel particle with low-enriched UO$$_{2}$$ (less than 10% of $$^{235}$$U) is used, which was newly designed by JAEA to extend burnup up to 100 GWd/t-U comparing with that of the HTTR (33 GWd/t-U). Both TRISO and fuel compact as the irradiation test specimen were fabricated in basis of the HTTR fuel technology by Nuclear Fuel Industries, Ltd. in Japan. A helium-gas-swept capsule and a swept-gas sampling device installed in WWR-K were designed and constructed by INP. The irradiation test has been started in October 2012 and will be completed up to the end of February 2015. The irradiation test is in the progress up to 69 GWd/t of burnup, and integrity of new TRISO fuel has been confirmed. In addition, as predicted by the fuel design, fission gas release was observed due to additional failure of as-fabricated SiC-defective fuel.

JAEA Reports

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.

Journal Articles

Effects of irradiation and water temperatures on IASCC susceptibility of stainless steels

Miwa, Yukio; Tsukada, Takashi

Proceedings of 8th Japan-China Symposium on Materials for Advanced Energy Systems and Fission & Fusion Engineering, p.161 - 168, 2004/10

Irradiation assisted stress corrosion cracking (IASCC) is one of the environmental degradation problems of in-core structural materials for light water reactors. The effects of irradiation and water temperatures on the IASCC were studied using type 316(LN) stainless steels irradiated at 333-673 K to 1.1-16 dpa. IASCC did not occur at 513 K in oxygenated water for specimens irradiated below 573 K to 1.1-16 dpa, but IASCC occurred above 533 K in oxygenated water for all specimens. The irradiation temperature had a strong influence on IASCC susceptibility at 513 K in oxygenated water, so that the irradiation temperature dependence was compared with the temperature dependence of other radiation-induced phenomena.

Journal Articles

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

 Times Cited Count:30 Percentile:12.03(Materials Science, Multidisciplinary)

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 $$^{circ}$$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 $$times$$ 10$$^{25}$$ m$$^{-2}$$). The molybdenum and tungsten mirrors manufactured by sintering without melting the surface have a potential for plasma facing mirrors in ITER.

Journal Articles

Irradiation and penetration tests of boron-doped low activation concrete using 2.45 MeV and 14 MeV neutron sources

Morioka, Atsuhiko; Sato, Satoshi; Kinno, Masaharu*; Sakasai, Akira; Hori, Junichi*; Ochiai, Kentaro; Yamauchi, Michinori*; Nishitani, Takeo; Kaminaga, Atsushi; Masaki, Kei; et al.

Journal of Nuclear Materials, 329-333(2), p.1619 - 1623, 2004/08

 Times Cited Count:7 Percentile:52.58(Materials Science, Multidisciplinary)

The neutron penetration and the activation characteristics of the boron-doped low activation concrete were investigated for irradiation of 2.45 and 14 MeV neutrons. The shielding property of the 2 wt% boron-doped low activation concrete is superior to that of the 1 wt% boron for the thermal neutron, on the contrary to the no clear difference for the fast neutron. The total activity detected in the boron-doped low activation concrete was about one hundredth of that in the geostandard sample at more than 30 days cooling time. The total activity of the boron-doped concrete by major nuclei does not depend on the boron density for the 14 MeV neutron irradiation.

Journal Articles

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

 Times Cited Count:7 Percentile:52.58(Materials Science, Multidisciplinary)

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 3.5$$times$$10$$^{25}$$n/m$$^{2}$$ (E$$>$$1MeV), 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.

JAEA Reports

Proceedings of the 11th International Workshop on Ceramic Breeder Blanket Interactions; December 15 - 17, 2003, Tokyo, Japan

Enoeda, Mikio

JAERI-Conf 2004-012, 237 Pages, 2004/07

JAERI-Conf-2004-012.pdf:44.1MB

This report is the Proceedings of "the Eleventh International Workshop on Ceramic Breeder Blanket Interactions" which was held as a workshop on ceramic breeders Under the IEA Implementing Agreement on the Nuclear Technology of Fusion Reactors, and the Japan-US Fusion Collaboration Framework. In the workshop, information exchange was performed for designs of solid breeder blankets and test blankets in EU, Russia and Japan, recent results of irradiation tests, HICU, EXOTIC-8 and the irradiation tests by IVV-2M, modeling study on tritium release behavior of Li$$_{2}$$TiO$$_{3}$$ and other breeders, fabrication technology developments and characterization of the Li$$_{2}$$TiO$$_{3}$$ and Li$$_{4}$$SiO$$_{4}$$ pebbles, research on measurements and modeling of thermo-mechanical behaviors of Li$$_{2}$$TiO$$_{3}$$ and Li$$_{4}$$SiO$$_{4}$$ pebbles, and interfacing issues, such as, fabrication technology for blanket box structure, neutronics experiments of blanket mockups by fusion neutron source and tritium recovery system.

Journal Articles

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.

JAEA Reports

Evaluation report of capsule development for uniform irradiation

Kikuchi, Taiji; Ishikawa, Kazuyoshi; Matsui, Yoshinori; Itabashi, Yukio

JAERI-Tech 2004-043, 21 Pages, 2004/03

JAERI-Tech-2004-043.pdf:2.73MB

In the JMTR, the irradiation examinations for nuclear reactor material are usually requested high accurate irradiation temperature, neutron fluence and neutron spectrum. The general demands satisfy to choice the best irradiation hole in the JMTR. However, for more accuracy, it is necessary to produce capsule with special mechanisms. To get the expectant neutron spectrum (ratio of fast neutron and thermal neutron), the thickness of cadmium is calculated by nuclear calculation code. Cadmium is the material to absorb the thermal neutron. Therefore, the necessary thickness was plated the outside of the specimen container with the cadmium. This paper is reported (1) the various base examinations for the development, (2) the result of the evaluations and (3) the evaluation result of an actual irradiation examination about uniform irradiation capsule of the reversing mechanism.

JAEA Reports

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.

JAEA Reports

Development of facility for in-situ observation during slow strain rate test for irradiated materials

Nakano, Junichi; Tsukada, Takashi; Tsuji, Hirokazu; Terakado, Shogo; Koya, Toshio; Endo, Shinya

JAERI-Tech 2003-092, 54 Pages, 2004/01

JAERI-Tech-2003-092.pdf:14.05MB

Irradiation assisted stress corrosion cracking (IASCC) is a degradation phenomenon caused by synergy of neutron radiation, aqueous environment and stress on in-core materials, and it is an important issue in accordance with increase of aged light water reactors. Isolating crack initiation stage from crack growth stage is very useful for the evaluation of the IASCC behavior. Hence facility for in-situ observation during slow strain rate test (SSRT) for irradiated material was developed. As performance demonstrations of the facility, tensile test with in-situ observation and SSRT without observation were carried out using unirradiated type 304 stainless steel in 561 K water at 9 MPa. The following were confirmed from the results. (1) Handling, observation and recording of specimen can be operated using manipulators in the hot cell. (2) In-situ observation can be performed in pressurized high temperature water and flat sheet type specimen is suitable for the in-situ observation. (3) Test condition can be kept constantly and data can be obtained automatically for long test period.

Journal Articles

Assessment of irradiation temperature stability of the first irradiation testi rig in the HTTR

Shibata, Taiju; Kikuchi, Takayuki; Miyamoto, Satoshi*; Ogura, Kazutomo*

Nuclear Engineering and Design, 223(2), p.133 - 143, 2003/08

 Times Cited Count:1 Percentile:88.34(Nuclear Science & Technology)

The High Temperature Engineering Test Reactor (HTTR) can provide very large spaces at high temperatures for irradiation tests. The I-I type irradiation equipment was developed as the first irradiation rig. It will be served for an in-pile creep test on a stainless steel with large standard size specimens. It uses the ambient high temperature of the core for the irradiation temperature control. The target irradiation temperatures are 550 and 600$$^{circ}$$C with the target temperature deviation of $$pm$$3$$^{circ}$$C. In this study, the irradiation temperature changes at transient conditions were analyzed by an FEM code and the temperature controllability of the equipment was examined by a mockup test. The controllability was evaluated with the measured temperature transient data at the core graphite components in the Rise-to-Power tests of the HTTR. The result indicates that the temperature control method of the equipment is effective to keep the irradiation temperature stable in the irradiation test.

Journal Articles

Irradiation behavior of rock-like oxide fuels

Yamashita, Toshiyuki; Kuramoto, Kenichi; Shirasu, Noriko; Nakano, Yoshihiro; Akie, Hiroshi; Nagashima, Hisao; Kimura, Yasuhiko; Omichi, Toshihiko*

Journal of Nuclear Materials, 320(1-2), p.126 - 132, 2003/07

 Times Cited Count:10 Percentile:41.3(Materials Science, Multidisciplinary)

Two irradiation tests on the rock-like oxide (ROX) fuels, small disk-shape fuel targets and pellet-type fuels, were performed in order to clarify in-pile irradiation stabilities. Swelling, fractional fission gas release (FGR) and phase change were examined by puncture test, profilometry and ceramography. YSZ single-phase fuel showed an excellent irradiation behavior, ie. low fission gas release (less than 3%), negligible swelling and no appreciable restructuring. The particle dispersed fuels showed lower swelling and higher fission gas release than those of mechanically blended fuels. Spinel decomposition and subsequence restructuring in the spinel matrix fuels was observed for the first time in the present investigation. It would be possible to reduce the FGR of the spinel matrix fuels, if the maximum fuels temperature is limited below 1700 K where neither spinel decomposition nor restructuring was observed. Damaged area of spinel matrix due to fission fragment irradiation seemed to be confined to thin layers around the surface of YSZ particles.

JAEA Reports

IFMIF-KEP; International Fusion Materials Irradiation Facility key element technology phase report

IFMIF International Team

JAERI-Tech 2003-005, 559 Pages, 2003/03

JAERI-Tech-2003-005.pdf:48.89MB

The International Fusion Materials Irradiation Facility (IFMIF) is an accelerator-based D-Li neutron source designed to produce an intense neutron field that will simulate the neutron environment of a D-T fusion reactor. IFMIF will provide a neutron flux equivalent to 2 MW/m$$^{2}$$, 20 dpa/y in Fe, in a volume of 500 cm$$^{3}$$ and will be used in the development and qualification of materials for fusion systems. The design activities of IFMIF are performed under an IEA collaboration which began in 1995. In 2000, a three-year Key Element Technology Phase (KEP) of IFMIF was undertaken to reduce the key technology risk factors. This KEP report describes the results of the three-year KEP activities in the major project areas of accelerator, target, test facilities and design integration.

Journal Articles

Development of a non-destructive testing technique using ultrasonic wave for evaluation of irradiation embrittlement in nuclear materials

Ishii, Toshimitsu; Ooka, Norikazu; Hoshiya, Taiji; Kobayashi, Hideo*; Saito, Junichi; Niimi, Motoji; Tsuji, Hirokazu

Journal of Nuclear Materials, 307-311(Part.1), p.240 - 244, 2002/12

 Times Cited Count:3 Percentile:75.36(Materials Science, Multidisciplinary)

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