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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 
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.
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：0.01(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 
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.
Ishitsuka, Etsuo; Sakamoto, Naoki*
Physical Sciences and Technology, 6(2), p.60 - 63, 2019/12
Tritium release into the primary coolant of the research and test reactors during operation had been studied, and it is found that the recoil release from chain reaction of Be is dominant. To reduce tritium concentration of the primary coolant, feasibility study of the tritium recoil barrier for the beryllium neutron reflectors was carried out, and the tritium recoils of various materials were calculated by PHITS. From these calculation results, it is clear that the thickness of tritium recoil barrier depends on the material and 20
40 
m is required for three orders reduction.
Ishitsuka, Etsuo; Kenzhina, I.*; Okumura, Keisuke; Ho, H. Q.; Takemoto, Noriyuki; Chikhray, Y.*
JAEA-Technology 2018-010, 33 Pages, 2018/11
JAEA-Technology-2018-010.pdf:2.58MB
As a part of study on the mechanism of tritium release to the primary coolant in research and testing reactors, tritium recoil release rate from Li and U impurities in the neutron reflector made by beryllium, aluminum and graphite were calculated by PHITS code. On the other hand, the tritium production from Li and U impurities in beryllium neutron reflectors for JMTR and JRR-3M were calculated by MCNP6 and ORIGEN2 code. By using both results, the amount of recoiled tritium from beryllium neutron reflectors were estimated. It is clear that the amount of recoiled tritium from Li and U impurities in beryllium neutron reflectors are negligible, and 2 and 5 orders smaller than that from beryllium itself, respectively.
Ishitsuka, Etsuo; Kenzhina, I. E.*; Okumura, Keisuke; Takemoto, Noriyuki; Chikhray, Y.*
JAEA-Technology 2016-022, 35 Pages, 2016/10
JAEA-Technology-2016-022.pdf:3.73MB
As a part of study on the mechanism of tritium release to the primary coolant in research and testing reactors, the calculation methods by PHITS code is studied to evaluate the recoil tritium release rate from beryllium core components. Calculations using neutron and triton sources were compared, and it is clear that the tritium release rates in both cases show similar values. However, the calculation speed for the triton source cases is two orders faster than that for the neutron source case. It is also clear that the calculation up to history number per unit volume of 2
10
(cm
) is necessary to determine the recoil tritium release rate of two effective digits precision. Furthermore, the relationship between the beryllium shape and recoil tritium release rate using the triton sources was studied. Recoil tritium release rate showed linear relation to the surface area per volume of beryllium, and the recoil tritium release rate showed about half of the conventional equation value.
Bi(
Zn,n)
113Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Koura, Hiroyuki; et al.
Journal of the Physical Society of Japan, 73(10), p.2593 - 2596, 2004/10
Times Cited Count：487 Percentile：99.22(Physics, Multidisciplinary)The isotope of the 113th element, 113, and its daughter nuclei, 
111 and 
Mt, were obserbed, for the first time, in the Bi + Zn reaction at a beam energy of 349.1 MeV with a total dose of 1.610
. The production cross section of 113 is deduced to be 
fb (
cm
).
Yoshizawa, Michio; Tanimura, Yoshihiko; Saegusa, Jun; Nemoto, Hisashi*; Yoshida, Makoto
Radiation Protection Dosimetry, 110(1-4), p.81 - 84, 2004/09
Times Cited Count：3 Percentile：23.52(Environmental Sciences)The facility of Radiation Standards (FRS) of JAERI has equipped with the concrete-moderated neutron calibration fields as simulated workplace neutron fields. The fields use an Am-Be (37GBq) neutron source placed in the narrow space surrounded by concrete wall and bricks to produce scattered neutrons. The neutron spectra of the fields were measured with Bonner multi-sphere spectrometer system (BMS), spherical recoil-proton proportional counters (RPCs), and a liquid scintillation counter (NE-213). The results were compared with each other, and the neutron spectra and the ambient dose equivalent rate, 
(10), were agreed well within the uncertainty. The angular distributions of neutron fluence were calculated by the MCNP-4B2 Monte Carlo code to obtain the reference personal dose equivalent rate, 
(10). The calculated results show that the scattered neutrons have a wide variety of incident angles. The reference (10) values considered the angular distribution were found to be 10-18% smaller than those without consideration.
Ueta, Shohei; Sumita, Junya; Emori, Koichi; Takahashi, Masashi*; Sawa, Kazuhiro
Journal of Nuclear Science and Technology, 40(9), p.679 - 686, 2003/09
Times Cited Count：13 Percentile：64.66(Nuclear Science & Technology)no abstracts in English
Hori, Junichi; Sato, Satoshi; Yamauchi, Michinori*; Ochiai, Kentaro; Nishitani, Takeo
JAERI-Research 2003-002, 50 Pages, 2003/03
JAERI-Research-2003-002.pdf:2.21MB
D-T neutron irradiation experiments have been performed with F82H and ODS ferritic steels and the effective cross sections for 
Co productions in those materials via the sequential reactions were measured. The effective cross sections for F82H and ODS ferritic steels were about 1.5 times larger than that for iron. The distributions of effective cross sections were measured for 6 materials (iron, copper, vanadium, titanium, tungsten and lead) and F82H. The sequential reaction rates in the region close to hydrogen compound became over 20 times larger than that in material itself. In the case of F82H, the increase ratio was about 50. It was indicated that the activity for the sequential reaction product Co will reach to 3-10 
of that for primary neutron reaction product 
Mn aound the surface of a cooling pipe in a fusion reactor. The effective cross sections were estimated by using (n,xp), (p,n) reaction cross sections, proton emission spectra, proton stopping power in the material. The estimated values were compared with experimental results.
Hori, Junichi; Maekawa, Fujio; Wada, Masayuki*; Ochiai, Kentaro; Yamauchi, Michinori*; Morimoto, Yuichi*; Terada, Yasuaki; Klix, A.; Nishitani, Takeo
Fusion Engineering and Design, 63-64, p.271 - 276, 2002/12
Times Cited Count：2 Percentile：17.03(Nuclear Science & Technology)In order to the waste management method and the safety design of future D-T fusion reactor, it is important to consider the radioactivity productions via not only primary neutron reactions but also sequential charged particle reactions (SCPR). Especially, on the surface of a coolant channel many recoiled protons are generated by the neutron irradiation with coolant water, so it is apprehensive that the undesirable radioactive nuclide production yields via SCPR are enhanced. In this work, the laminated sample pieces of fusion material foils (V, Fe, W, Ti, Pb, Cu) were made and attached on a polyethylene board to simulate water flowing inside a coolant channel. They were irradiated with D-T neutrons. The effective radioactivity cross section and the depth distribution of the radioactivity production yields due to SCPR were obtained for each material. On the other hand, the estimated values were compared with the experimental ones.
Matsubayashi, Masahito; Hibiki, Takashi*; Mishima, Kaichiro*; Yoshii, Koji*; Okamoto, Koji*
Nuclear Instruments and Methods in Physics Research A, 463(1-2), p.324 - 330, 2001/05
Times Cited Count：17 Percentile：73.21(Instruments & Instrumentation)no abstracts in English
Mitsuoka, Shinichi; Ikezoe, Hiroshi; Ikuta, T.*; Hamada, Shingo; Nagame, Yuichiro; Tsukada, Kazuaki; Nishinaka, Ichiro; Otsuki, Tsutomu*
Journal of Radioanalytical and Nuclear Chemistry, 239(1), p.155 - 157, 1999/00
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)no abstracts in English
Iwata, Tadao; Iwase, Akihiro
Radiat. Eff. Defect Solids, 144(1-4), p.27 - 61, 1998/00
no abstracts in English
25, 1997, JAERI, Tokai, JapanMitsuoka, Shinichi; Ikezoe, Hiroshi; Iwamoto, Akira; Nagame, Yuichiro
JAERI-Conf 97-009, 106 Pages, 1997/07
no abstracts in English
-decay properties of the new neutron deficient isotope 
PaMitsuoka, Shinichi; Ikezoe, Hiroshi; *; Nagame, Yuichiro; Tsukada, Kazuaki; Nishinaka, Ichiro; Oura, Yasutsugu*
Physical Review C, 55(3), p.1555 - 1558, 1997/03
Times Cited Count：28 Percentile：80.18(Physics, Nuclear)no abstracts in English
Nishitani, Takeo; Kasai, Satoshi; Iguchi, Tetsuo*; *; Ebisawa, Katsuyuki*; *
Review of Scientific Instruments, 68(1), p.565 - 568, 1997/01
Times Cited Count：5 Percentile：46.16(Instruments & Instrumentation)no abstracts in English
Meigo, Shinichiro
Nuclear Instruments and Methods in Physics Research A, 401, p.365 - 378, 1997/00
Times Cited Count：60 Percentile：95.79(Instruments & Instrumentation)no abstracts in English
decay of a new isotope ThIkezoe, Hiroshi; *; Hamada, S.; Nagame, Yuichiro; Nishinaka, Ichiro; Tsukada, Kazuaki; Oura, Yasutsugu*
Physical Review C, 54(4), p.2043 - 2046, 1996/10
Times Cited Count：21 Percentile：73.01(Physics, Nuclear)no abstracts in English
Nishitani, Takeo; Iguchi, Tetsuo*; Ebisawa, Katsuyuki*; *; Kasai, Satoshi
JAERI-Tech 96-038, 29 Pages, 1996/09
no abstracts in English
Ikezoe, Hiroshi; Nagame, Yuichiro; *; Hamada, S.; Nishinaka, Ichiro; Otsuki, Tsutomu*
Nuclear Instruments and Methods in Physics Research A, 376, p.420 - 427, 1996/00
Times Cited Count：38 Percentile：93.32(Instruments & Instrumentation)no abstracts in English
