Measurement of spent nuclear fuel burn-up using a new H method

Nauchi, Yasushi*; Sato, Shunsuke*; Hayakawa, Takehito*; Kimura, Yasuhiko; Suyama, Kenya; Kashima, Takao*; Futakami, Kazuhiro*

Nuclear Instruments and Methods in Physics Research A, 1050, p.168109_1 - 168109_9, 2023/05

https://doi.org/10.1016/j.nima.2023.168109

Measurement of neutrons from spent nuclear fuel is performed in this study using the H method, which detects 2.223 MeV rays from neutron capture reaction of hydrogen using a highly pure germanium (HPGe) detector. The detection of the 2.223 MeV ray is affected by intense ray emission from fission products (FPs) because the emission rate of rays from the FP is seven orders of magnitude higher than the emission rate of neutrons. To shield the intense ray from the FP, the HPGe detector is placed off the axis of a collimator, whereas a polyethylene block is placed on the axis. In this geometry, the detector is shielded from the intense rays from the FP, but the detector can measure 2.223 MeV rays from the H reactions in the polyethylene block. The measured count rate of the 2.223 MeV rays is consistent with the expected rate within the statistical error, which is calculated based on the nuclide composition, which is primary Cm, estimated via depletion and decay calculations. Accordingly, the H method is considered feasible to quantify the number of neutron leakage from spent nuclear fuel assembly, which is applicable to certify burn up of the assembly.

Innate immune genes including a mucin-like gene, , induced by ionizing radiation in

Kimura, Takafumi*; Takanami, Takako*; Sakashita, Tetsuya; Wada, Seiichi*; Kobayashi, Yasuhiko; Higashitani, Atsushi*

Radiation Research, 178(4), p.313 - 320, 2012/10

https://doi.org/10.1667/RR2989.1

Here, we found that exposure to ionizing radiation (IR) induce certain innate immune response gene of in the intestine. Pre-treatment with IR before seeding on lawn plate, significantly increased survival rate in the nematode. IR induction of gene was highly dependent on the ELT-2 transcription factor and p38 MAPK. Moreover, the insulin/IGF-1 signal pathway works as an enhancer of induction of this gene. Silencing of the gene led to growth retardation after IR irradiation. Finally, we describe the cross-tolerance between the responses to radiation exposure and innate immune system.

Fuel performance evaluation of rock-like oxide fuels

Shirasu, Noriko; Kuramoto, Kenichi; Nakano, Yoshihiro; Yamashita, Toshiyuki; Kimura, Yasuhiko; Nihei, Yasuo; Ogawa, Toru

Journal of Nuclear Materials, 376(1), p.88 - 97, 2008/05

https://doi.org/10.1016/j.jnucmat.2008.01.019

The concept of the rock-like oxide (ROX) fuel has been developed for the annihilation of excess plutonium in light water reactors. Irradiation tests and post-irradiation examinations were carried out on candidate ROX fuels. The ternary fuel of YSZ-spinel-corundum system, the single-phase fuels of YSZ, the particle dispersed fuels of YSZ in spinel or corundum matrix, and the blended fuels of YSZ and spinel or corundum matrix were fabricated and submitted to irradiation tests. The fuels containing spinel showed chemical instabilities with the vaporization of MgO component, which caused fuel restructuring. The swelling behavior was improved with the particle-dispersed fuels. However, the particle-dispersed fuels showed higher fractional gas release (FGR) than blended type fuels. The FGR of YSZ single-phase fuels were comparable to what would be expected for UO fuels. The YSZ single-phase fuel showed the best irradiation performance among the ROX fuels investigated.

Preparation of acellular arteries by irradiation

Fujisato, Toshiya*; Kikuchi, Masahiro; Sakashita, Tetsuya; Funayama, Tomoo; Kobayashi, Yasuhiko; Funamoto, Seiichi*; Kimura, Tsuyoshi*; Kishida, Akio*; Yamaoka, Tetsuji*

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 119, 2008/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2007-060.pdf

Synthetic materials, such as ePTFE or Dacron are not suitable for reconstructing the small-diameter arteries. In contrast, tissue engineering (TE) graft has been attracting great attention recently. One of the promising approaches of TE grafts is using acellular tissues. The acellular scaffold may have the same structure and characteristics as the natural tissue and can be replaced with the host tissues. In this study, we prepared the acellular scaffold using irradiation, which is expected to induce the apoptosis of the cells.

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

https://doi.org/10.1016/S0022-3115(03)00178-8

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.

Burn-up measurement of irradiated rock-like fuels

Shirasu, Noriko; Yamashita, Toshiyuki; Kanazawa, Hiroyuki; Kimura, Yasuhiko; Sudo, Kenji; Magara, Masaaki; Inagawa, Jun; Kono, Nobuaki; Nakahara, Yoshinori

JAERI-Research 2001-018, 23 Pages, 2001/03

JAERI-Research-2001-018.pdf:1.48MB

no abstracts in English

Behavior of actinides and fission products in mixed nitride fuels irradiated in JMTR; 88F-5A capsule

Iwai, Takashi; Nakajima, Kunihisa; Kikuchi, Hironobu; Kimura, Yasuhiko; Kanaitsuka, Fumio; Sekita, Noriaki; Arai, Yasuo

JAERI-Research 2000-009, p.36 - 0, 2000/03

JAERI-Research-2000-009.pdf:6.16MB

no abstracts in English

Behavior of plutonium and fission products in thermally stabilized mixed carbide fuel irradiated in JMTR

Iwai, Takashi; Arai, Yasuo; Nakajima, Kunihisa; Kimura, Yasuhiko; ;

JAERI-Research 96-066, 26 Pages, 1996/12

JAERI-Research-96-066.pdf:1.91MB

no abstracts in English

Technical report: Technical development on silicide plate-type fuel experiment at Nuclear Safety Research Reactor

Yanagisawa, Kazuaki; Soyama, Kazuhiko; Ichikawa, Hiroki; ; Hoshino, Osamu; ; ; ; Kanazawa, Hiroyuki; Kimura, Yasuhiko; et al.

JAERI-M 91-114, 67 Pages, 1991/08

JAERI-M-91-114.pdf:4.28MB

no abstracts in English

Confinement properties of pellet injected JT-60 plasmas

Kamada, Yutaka; Yoshino, Ryuji; ; Ozeki, Takahisa; Kawasaki, Kozo; Hiratsuka, Hajime; Miyo, Yasuhiko; Kimura, Haruyuki; Nishitani, Takeo; Yoshida, Hidetoshi; et al.

JAERI-M 89-050, 33 Pages, 1989/05

JAERI-M-89-050.pdf:1.05MB

no abstracts in English