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.

Unveiling spin-dependent unoccupied electronic states of CoMnGe (Ga) film via Ge (Ga) absorption spectroscopy

Yoshikawa, Tomoki*; Antonov, V. N.*; Kono, Takashi*; Kakoki, Masaaki*; Sumida, Kazuki; Miyamoto, Koji*; Takeda, Yukiharu; Saito, Yuji; Goto, Kazuki*; Sakuraba, Yuya*; et al.

Physical Review B, 102(6), p.064428_1 - 064428_7, 2020/08

https://doi.org/10.1103/PhysRevB.102.064428

Quick measurement of continuous absorption spectrum in ion beam pulse radiolysis; Application of optical multi-channel detector into transient species observation

Iwamatsu, Kazuhiro*; Muroya, Yusa*; Yamashita, Shinichi*; Kimura, Atsushi; Taguchi, Mitsumasa; Katsumura, Yosuke*

Radiation Physics and Chemistry, 119, p.213 - 217, 2016/02

https://doi.org/10.1016/j.radphyschem.2015.10.024

A quick measurement system of a continuous absorption spectrum covering a wide range from 200 to 950 nm was constructed by employing an optical multi-channel detector. Ion beam pulse radiolysis with 12.5 MeV/u He, 18.3 MeV/u C and 17.5 MeV/u Ne ions were performed with the measurement system. Transient absorption spectrum of (SCN) was clearly observed in KSCN aqueous solutions within a few minutes in spite of their very small absorbance, demonstrating high sensitivity of 0.001-0.003 in absorbance in the range from 260 to 660 nm as well as short measurement time of a few minutes. Two different absorption peaks attributed to Br and Br were observed simultaneously in NaBr aqueous solutions, showing powerfulness of the measurement system in overviewing chemical kinetics under ion beam irradiation especially in not well investigated chemical systems.

Linear energy transfer effects on time profiles of scintillation of Ce-doped LiCaAlF crystals

Yanagida, Takayuki*; Koshimizu, Masanori*; Kurashima, Satoshi; Iwamatsu, Kazuhiro*; Kimura, Atsushi; Taguchi, Mitsumasa; Fujimoto, Yutaka*; Asai, Keisuke*

Nuclear Instruments and Methods in Physics Research B, 365(Part B), p.529 - 532, 2015/12

https://doi.org/10.1016/j.nimb.2015.07.065

We measured temporal profiles of scintillation of Ce-doped LiCaAlF scintillator crystals at different linear energy transfers (LETs). Based on the comparison of the high-LET temporal profiles with those at low LET, we found that a fast component was observed only at low LET. The disappearance of the fast component at high LET is tentatively ascribed to quenching of excited states at defects owing to the interaction between excited states via Auger process. In addition, the rise and the initial decay behavior was dependent on the LET. This LET-dependent behavior is explained by a seeming acceleration process and a slowing down process in energy transfer at high LET. The LET-dependent temporal profiles provide a basis of discrimination technique of -ray and neutron detection events using these scintillators based on the nuclear reaction, Li(n,)t.

Occurrence and potential activity of denitrifiers and methanogens in groundwater at 140 m depth in Pliocene diatomaceous mudstone of northern Japan

Katsuyama, Chie*; Nashimoto, Hiroaki*; Nagaosa, Kazuyo*; Ishibashi, Tomotaka*; Furuta, Kazuki*; Kinoshita, Takeshi*; Yoshikawa, Hideki; Aoki, Kazuhiro; Asano, Takahiro*; Sasaki, Yoshito; et al.

FEMS Microbiology Ecology, 86(3), p.532 - 543, 2013/12

https://doi.org/10.1111/1574-6941.12179

Anaerobic microbial activity has a major influence on the subsurface environment, and should be considered in subsurface activities including the construction of radioactive waste repositories. We investigated denitrification and methanogenesis in anoxic groundwater from 140 m depth in two boreholes, where the redox potential fluctuated. The average maximum potential denitrification rates, measured under anaerobic conditions in the two boreholes using an N tracer. Methanogenesis candidates were detected by 16S rRNA gene analysis. Although the stable isotope signatures suggested that some of the dissolved methane was of biogenic origin, no potential for methane production was evident during the incubations. The groundwater at 140 m depth did not contain oxygen, had an Eh ranging from -144 to 6.8 mV, and was found to be a potential field for denitrification.

Water experiments on thermal striping in reactor vessel of Japan Sodium-cooled fast reactor; Countermeasures for control rods and radial blanket assemblies

Kobayashi, Jun; Kimura, Nobuyuki; Tobita, Akira; Kamide, Hideki; Watanabe, Osamu*; Oyama, Kazuhiro*

Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 10 Pages, 2011/10

Design study of an advanced loop-type sodium-cooled fast reactor, JSFR, has been carried out in a frame work of Fast Reactor Cycle Technology Development Project (FaCT) in Japan. As the temperature differences among the control rod channels, blanket assemblies and the core fuel assemblies are 100C centigrade in the maximum, temperature fluctuation due to the fluid mixing at the core outlet may cause high cycle thermal fatigue at the bottom of Upper Internal Structure (UIS). In this investigation, a water experiment was conducted using a 1/3 scale 60 sector model of the core and reactor upper plenum. Characteristics of temperature fluctuations near the cold fluid outlets were obtained and it was confirmed that several countermeasures can reduce temperature fluctuations at the bottom of UIS.

Horonobe Underground Research Laboratory Project; The Results of the pilot borehole investigation of the ventilation shaft (PB-V01); Geophysical loggings

Funaki, Hironori; Asamori, Koichi; Sanada, Hiroyuki; Hatsuyama, Yoshihiro*; Yamamoto, Takuya*; Ijiri, Yuji*; Matsuoka, Kiyoyuki*; Kimura, Kazuhiro*; Lin, S.*; Kumagai, Toshifumi*

JAEA-Data/Code 2010-002, 151 Pages, 2010/06

JAEA-Data-Code-2010-002.pdf:43.13MB

JAEA is implementing Horonobe URL Project as research and development of geological disposal. The investigation of the pilot boring was carried out around the Ventilation shaft in order to decide grouting plan and plant of effluent treating. This report summarize as data-code results of geophysical loggings.

Progress of the IFMIF/EVEDA prototype accelerator in the Broader Approach activities for fusion energy in FY2008

Shinto, Katsuhiro; Vermare, C.*; Asahara, Hiroo; Sugimoto, Masayoshi; Garin, P.*; Maebara, Sunao; Takahashi, Hiroki; Sakaki, Hironao; Kojima, Toshiyuki; Ohira, Shigeru; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.668 - 670, 2010/03

http://www.pasj.jp/web_publish/pasj6/papers/tpopa26.pdf

Progress of the IFMIF/EVEDA prototype accelerator in fiscal year of 2008 is described. All the sub-systems of the prototype accelerator have started to design, settled the plan of the manufacturing and component tests and fixed the design parameters. As a result of the analysis of planning for the engineering validation of the IFMIF accelerator system, the project duration to be prolonged to the end of 2014 including some months for contingency was approved by the BA Steering Committee. In this article, the design status of each accelerator component, the interface between the accelerator components and the IFMIF/EVEDA Accelerator Building settled in International Fusion Energy Research Centre (IFERC) in Rokkasho and the proposed accelerator commissioning plan for the engineering validation will be presented.

Preparation and evaluation of Re-labeled antibody (A7) for radioimmunotherapy with rhenium(I) tricarbonyl core as a chelate site

Ogawa, Kazuma*; Kawashima, Hidekazu*; Kinuya, Seigo*; Shiba, Kazuhiro*; Onoguchi, Masahisa*; Kimura, Hiroyuki*; Hashimoto, Kazuyuki; Odani, Akira*; Saji, Hideo*

Annals of Nuclear Medicine, 23(10), p.843 - 848, 2009/12

https://doi.org/10.1007/s12149-009-0319-4

Rhenium is one of the most valuable elements for internal radiotherapy because Re have favorable physical characteristics. However, there are problems when proteins such as antibodies are used as carriers of Re. Labeling methods require the complicated processes. Therefore, we planned the preparation by a simple method and evaluation of a stable Re-labeled antibody. For this purpose, we selected Re(I) tricarbonyl complex as a chelating site. A7 was used as a model protein. Re-labeled A7 was prepared by directly reacting a Re(I) tricarbonyl precursor with A7. Re-(CO)-A7 were prepared with radiochemical yields of 23-28%. After purification, Re-(CO)-A7 showed a radiochemical purity of over 95%. In biodistribution experiments, Re-labeled A7 showed high uptakes in the tumor.

Study on thermal striping at UIS of advanced loop type fast reactor; Water experiment using a 1/3 scale 60 degree sector model

Kobayashi, Jun; Kimura, Nobuyuki; Tobita, Akira; Kamide, Hideki; Watanabe, Osamu*; Oyama, Kazuhiro*

Proceedings of 17th International Conference on Nuclear Engineering (ICONE-17) (CD-ROM), 10 Pages, 2009/06

An advanced loop type sodium cooled fast reactor, JSFR, has been investigated in the frame work of Fast Reactor Cycle Technology Development Project (FaCT). As the temperatures difference between the control rod channels and the core fuel subassemblies is around 100 C, temperature fluctuation due to the fluid mixing at the core outlet may cause high cycle thermal fatigue at the bottom of Upper Internal Structure (UIS). Then, a water experiment was conducted using an 1/3 scale 60 degree sector model. Temperature and its fluctuation intensity distributions around the control rod were measured and an effect of the improved structure against the thermal fatigue was examined.