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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: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 $$^{9}$$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

Feasibility study of tritium recoil barrier for neutron 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 $$^{9}$$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$$sim$$40 $$mu$$m is required for three orders reduction.

JAEA Reports

Calculations of Tritium Recoil Release from Li and U Impurities in Neutron Reflectors (Joint research)

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.

JAEA Reports

Calculation by PHITS code for recoil tritium release rate from beryllium under neutron irradiation (Joint research)

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$$times$$10$$^{4}$$ (cm$$^{-3}$$) 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.

Journal Articles

Experiment on the synthesis of element 113 in the reaction $$^{209}$$Bi($$^{70}$$Zn,n)$$^{278}$$113

Morita, 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:452 Percentile:99.19(Physics, Multidisciplinary)

The isotope of the 113th element, $$^{278}$$113, and its daughter nuclei, $$^{274}$$111 and $$^{270}$$Mt, were obserbed, for the first time, in the $$^{209}$$Bi + $$^{70}$$Zn reaction at a beam energy of 349.1 MeV with a total dose of 1.6$$times$$10$$^{19}$$. The production cross section of $$^{278}$$113 is deduced to be $$57^{+154}_{-47}$$ fb ($$10^{-39}$$ cm$$^2$$).

Journal Articles

Neutron spectra and angular distributions of concrete-moderated neutron calibration fields at JAERI

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:24.41(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, ${it H}$$$^{*}$$(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, ${it H}$$$_{p}$$(10). The calculated results show that the scattered neutrons have a wide variety of incident angles. The reference ${it H}$$$_{p}$$(10) values considered the angular distribution were found to be 10-18% smaller than those without consideration.

Journal Articles

Fuel and fission gas behavior during rise-to-power test of the High Temperature engineering Test Reactor (HTTR)

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:12 Percentile:63.5(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Experimental study on sequential reactions in fusion reactor materials by D-T neutron irradiation

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 $$^{56}$$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 $$^{56}$$Co will reach to 3-10 $$%$$ of that for primary neutron reaction product $$^{54}$$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.

Journal Articles

Radioactivity production around the surface of a cooling water pipe in a D-T fusion reactor by sequential charged particle reactions

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:17.46(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.

Journal Articles

Preliminary examination of the applicability of imaging plates to fast neutron radiography

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:16 Percentile:74.22(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Recent results from the JAERI recoil mass separator

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

Journal Articles

Effects of primary recoil (PKA) energy spectrum on radiation damage in FCC metals

Iwata, Tadao; Iwase, Akihiro

Radiat. Eff. Defect Solids, 144(1-4), p.27 - 61, 1998/00

no abstracts in English

JAEA Reports

Proceedings of Symposium on Nuclear Fusion and Fission of Heavy Elements, March 24$$sim$$25, 1997, JAERI, Tokai, Japan

Mitsuoka, Shinichi; Ikezoe, Hiroshi; Iwamoto, Akira; Nagame, Yuichiro

JAERI-Conf 97-009, 106 Pages, 1997/07

JAERI-Conf-97-009.pdf:4.02MB

no abstracts in English

Journal Articles

$$alpha$$-decay properties of the new neutron deficient isotope $$^{212}$$Pa

Mitsuoka, Shinichi; Ikezoe, Hiroshi; *; Nagame, Yuichiro; Tsukada, Kazuaki; ; Oura, Yasutsugu*

Physical Review C, 55(3), p.1555 - 1558, 1997/03

 Times Cited Count:27 Percentile:79.92(Physics, Nuclear)

no abstracts in English

Journal Articles

Design of radial neutron spectrometer array for the International Thermonuclear Experimental Reactor

Nishitani, Takeo; Kasai, Satoshi; Iguchi, Tetsuo*; *; Ebisawa, Katsuyuki*; *

Review of Scientific Instruments, 68(1), p.565 - 568, 1997/01

 Times Cited Count:5 Percentile:46.75(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Measurements of the response function and the detection efficiency of an NE213 scintillator for neutrons between 20 and 65 MeV

Meigo, Shinichiro

Nuclear Instruments and Methods in Physics Research A, 401, p.365 - 378, 1997/00

 Times Cited Count:56 Percentile:95.69(Instruments & Instrumentation)

no abstracts in English

Journal Articles

$$alpha$$ decay of a new isotope $$^{209}$$Th

Ikezoe, Hiroshi; *; Hamada, S.; Nagame, Yuichiro; ; Tsukada, Kazuaki; Oura, Yasutsugu*

Physical Review C, 54(4), p.2043 - 2046, 1996/10

 Times Cited Count:21 Percentile:73.58(Physics, Nuclear)

no abstracts in English

JAEA Reports

Design of radial neutron spectrometer for ITER

Nishitani, Takeo; Iguchi, Tetsuo*; Ebisawa, Katsuyuki*; *; Kasai, Satoshi

JAERI-Tech 96-038, 29 Pages, 1996/09

JAERI-Tech-96-038.pdf:1.17MB

no abstracts in English

Journal Articles

JAERI recoil mass separator

Ikezoe, Hiroshi; Nagame, Yuichiro; *; Hamada, S.; ; Otsuki, Tsutomu*

Nuclear Instruments and Methods in Physics Research A, 376, p.420 - 427, 1996/00

 Times Cited Count:38 Percentile:93.69(Instruments & Instrumentation)

no abstracts in English

58 (Records 1-20 displayed on this page)