Uranium chelating ability of decorporation agents in serum evaluated by X-ray absorption spectroscopy

Uehara, Akihiro*; Matsumura, Daiju; Tsuji, Takuya; Yakumaru, Haruko*; Tanaka, Izumi*; Shiro, Ayumi*; Saito, Hiroyuki*; Ishihara, Hiroshi*; Homma-Takeda, Shino*

Analytical Methods, 14(24), p.2439 - 2445, 2022/06

https://doi.org/10.1039/D2AY00565D

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

https://doi.org/10.1038/s41550-020-01271-2

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Utilization of rock-like oxide fuel in the phase-out scenario

Nishihara, Kenji; Akie, Hiroshi; Shirasu, Noriko; Iwamura, Takamichi*

Journal of Nuclear Science and Technology, 51(2), p.150 - 165, 2014/02

https://doi.org/10.1080/00223131.2014.846834

Utilization of rock-like oxide (ROX) fuel in light water reactors for plutonium (Pu) burning was studied by material balance analysis for a case of Japanese phase-out scenario under investigation after the Fukushima accident. For the analysis, the nuclear material balance analysis (NMB) code was developed with features of accurate burn-up calculation, flexible combination of reactors and fuels and an ability to estimate waste and repository. Three scenario-groups of once-through, Pu burning in mixed oxide (MOX) fuel and in ROX fuel were analyzed. By construction of two full MOX- or ROX- reactors, Pu amount is reduced to about a half and isotopic vector of Pu is deteriorated as nuclear weapon especially in terms of spontaneous fission neutron. Effects by ROX are more significant than MOX in both amount and vector. Repository footprint and potential radio-toxicity is not reduced by MOX and ROX because heat and toxicity of MOX and ROX spent fuel is considerably high.

Development of Mo-Tc domestic production with high-density MoO pellets by (n,) reaction

Tsuchiya, Kunihiko; Tanase, Masakazu*; Takeuchi, Nobuhiro*; Kobayashi, Masaaki*; Hasegawa, Yoshio*; Yoshinaga, Hideo*; Kaminaga, Masanori; Ishihara, Masahiro; Kawamura, Hiroshi

Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 10 Pages, 2012/10

http://www.murr.missouri.edu/ismtr/papercall/Papers/JAEA/Tsuchiya_K=PAPER_Dev%20of%20Mo99-Tc99m%20Domestic%20Prod%20with%20HighDens%20MoO3%20Pellets.pdf

As one of effective uses of the JMTR, JAEA has a plan to produce Mo by (n, ) method, a parent nuclide of Tc. In case of Japan, the supplying of Mo depends only on imports from foreign countries. The R&D on production method of Mo -Tc has been performed with Japanese industrial users under the cooperation programs. The main R&D items for the production are (1) Fabrication of irradiation target such as the sintered MoO pellets, (2) Separation and concentration of Tc by the solvent extraction from Mo solution, (3) Examination of Tc solution for a medicine, and (4) Mo recycling from Mo generator and solution. In this paper, the status of the R&D is introduced for the production of Mo -Tc.

Managing beryllium in nuclear facility applications

Longhurst, G. R.*; Tsuchiya, Kunihiko; Dorn, C.*; Folkman, S. L.*; Fronk, T. H.*; Ishihara, Masahiro; Kawamura, Hiroshi; Tranter, T. N.*; Rohe, R.*; Uchida, Munenori*; et al.

Nuclear Technology, 176(3), p.430 - 441, 2011/12

https://doi.org/10.13182/NT11-A13318

Beryllium has important roles in nuclear facilities such as fission reactors and fusion reactors. Its neutron multiplication capability and low atomic weight make it very useful as a reflector in fission reactors. In both applications, the beryllium and the impurities in it become activated by neutrons transmutating to radionuclides, some of which are long-lived and difficult to dispose of. Also, gas production, notably helium and tritium, results in swelling, embrittlement, and cracking, which means that the beryllium must be replaced periodically, especially in fission reactors where dimensional tolerances must be maintained. It has long been known that neutron activation of inherent iron and cobalt in the beryllium results in significant Co activity. In 2001, it was discovered that activation of naturally occurring contaminants in the beryllium creates sufficient C and Nb to render the irradiated beryllium "Greater-Than-Class-C" for disposal in US radioactive waste facilities. In this paper we review the extent of the disposal issue, processes that have been investigated or considered for improving the disposability of irradiated beryllium, and approaches for recycling.

Feasibility of uranium spallation target in accelerator-driven system

Ismailov, K.*; Saito, Masaki*; Sagara, Hiroshi*; Nishihara, Kenji

Progress in Nuclear Energy, 53(7), p.925 - 929, 2011/09

https://doi.org/10.1016/j.pnucene.2011.05.019

A feasibility study on natural uranium spallation target in accelerator-driven system (ADS) for minor actinide (MA) transmutation was performed. As a result of comparative study of uranium and lead-bismuth (PbBi) targets in the bare case without blanket surrounding, it was found that uranium target had better neutron generation performance, but limited by the geometrical size due to high neutron absorption in U. In ADS for MA transmutation, uranium used as target instead of PbBi also absorbs neutrons passing the target area. More realistic concept of pin type uranium spallation target cooled by liquid PbBi was considered aiming at enhancing spallation target performance in terms of neutron generation efficiency and operation temperature. The uranium pin target design had nothing better effects on neutron balance of such system than a conventional PbBi target in ADS and it was concluded that uranium target was not suitable for the full-scale ADS.

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.

Conceptual study for new Mo-production facility in JMTR

Kimura, Akihiro; Iimura, Koichi; Hosokawa, Jinsaku; Izumo, Hironobu; Hori, Naohiko; Nakagawa, Tetsuya; Kanno, Masaru; Ishihara, Masahiro; Kawamura, Hiroshi

JAEA-Review 2009-072, 18 Pages, 2010/03

JAEA-Review-2009-072.pdf:9.29MB

JAEA has a plan to produce Mo, a parent nuclide of Tc. At present, radioisotopes are indispensable for a diagnosis and treatment in the medical field. Demand of Tc (half life 6h) used as a radiopharmaceutical increases up year by year. Moreover, the expansion of demand will be expected in future. However, the supply of Mo in Japan depends fully on the import from foreign countries. Therefore, it is necessary to supply Mo stably by the domestic production. There are two methods of Mo (half life 65.9h) production; the one is the nuclear fission (n,fiss) method, and the other is the (n,) method using the Mo target. Mo production in the JMTR with the (n,) method was studied and evaluated. As a result, it was found that the partial amount of Mo demand is possible to supply stably if a new hydraulic-rabbit-irradiation-facility (HR) is used.

Refurbishment status and future program of Japan Materials Testing Reactor (JMTR)

Ishihara, Masahiro; Kawamura, Hiroshi; Niimi, Motoji; Kaminaga, Masanori; Hori, Naohiko; Nagao, Yoshiharu

Proceedings of 12th International Group on Research Reactors (12th IGORR) (USB Flash Drive), 10 Pages, 2009/10

The JMTR is a light water cooling tank typed reactor with first criticality in March 1968. The JMTR has been applied to fuel/material irradiation tests for LWRs, HTGR, fusion reactor and RI production. However, the JMTR operation was once stopped at August 2006, and the refurbishment works are now conducting. The reactor facilities will be renewed taking four years from the beginning of FY 2007, and necessary examination and works are carrying out on schedule. The renewed JMTR will be started from FY 2011, and be operated for a period of about 20 years until around FY 2030. The usability improvement of the JMTR, e.g. higher reactor availability-factor, shortening turnaround time to get irradiation results, attractive irradiation cost, business confidence, is also discussing with users as the preparations for re-operation. In the paper, status of the refurbishment of reactor facilities are introduced, moreover the future program using the JMTR will be prescribed.

Handling of HTTR second driver fuel elements in assembling and storage working

Tomimoto, Hiroshi; Kato, Yasushi; Owada, Hiroyuki; Sato, Nao; Shimazaki, Yosuke; Kozawa, Takayuki; Shinohara, Masanori; Hamamoto, Shimpei; Tochio, Daisuke; Nojiri, Naoki; et al.

JAEA-Technology 2009-025, 29 Pages, 2009/06

JAEA-Technology-2009-025.pdf:21.78MB

The first driver fuel of the HTTR (High Temperature Engineering test Reactor) was loaded in 1998 and the HTTR reached first criticality state in the same year. The HTTR has been operated using the first driver fuel for a decade. In Fuel elements assembling, 4770 of fuel rods which consist of 12 kinds of enrichment uranium are loaded into 150 fuel graphite blocks for HTTR second driver fuel elements. Measures of prevention of fuel rod miss loading, are employed in fuel design. Additionally, precaution of fuel handling on assembling are considered. Reception of fuel rods, assembling of fuel elements and storage of second driver fuels in the fresh fuel storage rack in the HTTR were started since June, 2008. Assembling, storage and pre-service inspection were divided into three parts. The second driver fuel assembling was completed in September, 2008. This report describes concerns of fuel handling on assembling and storage work for the HTTR fuel elements.