Sato, Kentaro*; Ikeuchi, Kazuhiko*; Kajimoto, Ryoichi; Wakimoto, Shuichi; Arai, Masatoshi*; Fujita, Masaki*
Journal of the Physical Society of Japan, 89(11), p.114703_1 - 114703_7, 2020/11
Kusumoto, Tamon*; Matsuya, Yusuke; Baba, Kentaro*; Ogawara, Ryo*; Akselrod, M. S.*; Harrison, J.*; Fomenko, V.*; Kai, Takeshi; Ishikawa, Masayori*; Hasegawa, Sumitaka*; et al.
Radiation Measurements, 132, p.106256_1 - 106256_4, 2020/03
Internal radiation therapy with Cu-64 concentrates energy deposition in tumor cells by virtue of released Auger electrons with low energy. In our previous study, we have attached the solutions at the surface of Fluorescent Nuclear Track Detector (FNTD) and succeeded in measuring the absorbed doses of Auger electrons registered in FNTD. However, because there are several types of radiation emitted from the source, i.e., beta rays, positron etc., the contribution degree of Auger electron to energy concentration remain uncertain. In this study, we quantitatively analyzed the spatial dose distribution in the FNTD based on Monte Carlo simulation with PHITS and GEANT4, and evaluated high dose deposited by Auger electrons. The dose distribution calculated by the PHITS code is exactly equivalent to that by Geant4. Also, the simulations are well agreement with experimental results. If the contribution of Auger electrons is ignored, the significantly high absorbed dose proximal to the source is not properly reduced. These findings demonstrate that Auger electrons work very effectively to kill cancer cells proximal to Cu-64 source while minimizing damage effects on normal cells distal to the source.
Dupont, E.*; Astier, A.*; Petrache, C. M.*; Lv, B. F.*; Deloncle, I.*; Kiener, J.*; Orlandi, R.; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; et al.
Physical Review C, 101(1), p.014309_1 - 014309_6, 2020/01
Tanaka, Shoya; Aritomo, Yoshihiro*; Miyamoto, Yuya*; Hirose, Kentaro; Nishio, Katsuhisa
Physical Review C, 100(6), p.064605_1 - 064605_6, 2019/12
Fission fragment mass distributions of U, Np, and Pu are studied using the Langevin approach in the widely excitation energy range as = 15-55 MeV. In the present calculation, neutron emission before fission, so called multichance fission, was introduced. The calculated results well demonstrated the experimental data, which shows the double-peak structure up to the highest excitation energies and the clear dependence on the initial fissioning nuclides. The trend is nicely correlated with the neutron binding energy of the compound nucleus that dominates the neutron emission probability before fission.
Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Lguillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; Kster, U.*; Pollitt, A.*; Hambsch, F.-J.*; et al.
Physical Review C, 100(4), p.044610_1 - 044610_7, 2019/10
Xiao, Y.*; Go, S.*; Grzywacz, R.*; Orlandi, R.; Andreyev, A. N.; Asai, Masato; Bentley, M. A.*; de Angelis, G.*; Gross, C. J.*; Hausladen, P.*; et al.
Physical Review C, 100(3), p.034315_1 - 034315_8, 2019/09
Ito, Kei*; Ito, Daisuke*; Saito, Yasushi*; Ezure, Toshiki; Matsushita, Kentaro; Tanaka, Masaaki; Imai, Yasutomo*
Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.6632 - 6642, 2019/08
In this paper, a mechanistic model is proposed to calculate the entrained gas flow rate by a free surface vortex. The model contains the theoretical equation of transient gas core elongation and the empirical equation of critical gas core length for gas bubble detachment. Based on those two equations, the entrained gas flow rate is calculated as the portion of the gas core elongated beyond the critical gas core length per unit time. Then, the mechanistic model was applied to the calculation of the entrained gas flow rate in a simple water experiment. As a result, it is confirmed that the entrained gas flow rate grows rapidly when the liquid (water) flow rate, which determine the strength of a free surface vortex, exceeds a certain threshold value.
Kwon, Saerom*; Konno, Chikara; Ota, Masayuki*; Ochiai, Kentaro*; Sato, Satoshi*; Kasugai, Atsushi*
Fusion Engineering and Design, 144, p.209 - 214, 2019/07
We performed a TENDL-2017 benchmark test with iron shielding experiments by using 40 and 65 MeV neutrons, in order to verify a nuclear data library above 20 MeV for neutronics analyses of A-FNS. We found out that the calculated neutron spectra with TENDL-2017 unnaturally increased near 30 MeV. We figured out that incorrect secondary neutron spectrum data in Fe, Fe and Fe at 30 MeV caused the increase of the neutron flux. Similar problems occurred in a lot of nuclei of TENDL-2017, TENDL-2015 and FENDL-3.1d from TENDL-2010 and TENDL-2011.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
BIO Web of Conferences (Internet), 14, p.03011_1 - 03011_2, 2019/05
Dose coefficients, which are committed effective dose per unit intake of radionuclides, are fundamental amounts for dose estimation and protection standards against internal exposures. In this study, we built a calculation function of dose coefficients using the latest dosimetric models and data as a part of development of internal dosimetry code in accordance with 2007 Recommendations of the International Commission of Radiological Protection (ICRP). Quality of the function was assured by comparing the results generated by the function to values recorded in a database of dose coefficients for workers provided by ICRP. In the presentation, we will report the results of quality assurance and the future plans of code development.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
Journal of Nuclear Science and Technology, 56(5), p.385 - 393, 2019/05
At high energy accelerator facilities, various radionuclides are produced by nuclear reactions of high energy particles with structure and/or ambient air of the facilities. Consequently, the radionuclides are potential sources of internal exposure for works of the facilities. However, the International Commission on Radiological Protection (ICRP) do not provide dose coefficients, which are committed effective doses per intake, for the short-lived radionuclides whose half-lives are shorter than 10 minutes in accordance with the ICRP 2007 Recommendations. Then, we estimated the dose coefficients for inhalation and ingestion of these short-lived radionuclides in accordance with the ICRP 2007 Recommendations. In addition, we compared the dose coefficients with those in accordance with the ICRP 1990 Recommendations. As a result, a decreasing tendency was shown in the dose coefficients for inhalation cases; an increasing tendency was observed in those for ingestion cases. It was found that these changes in dose coefficients were mainly caused by the revision of the dose calculation procedures, alimentary tract models. The result of this study will be useful for planning of radiation protection at the high energy facilities.
Miyamoto, Yuya*; Aritomo, Yoshihiro*; Tanaka, Shoya; Hirose, Kentaro; Nishio, Katsuhisa
Physical Review C, 99(5), p.051601_1 - 051601_7, 2019/05
Matsushita, Kentaro; Ito, Kei*; Ezure, Toshiki; Tanaka, Masaaki
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 9 Pages, 2019/05
A numerical simulation code named SYRENA has been developed in JAEA to analyze the behavior of entrained bubbles and dissolved gas in the primary coolant of sodium-cooled fast reactor (SFR). In the present study, a flow network model of SYRENA to a hypothetical pool type reactor was developed and the non-condensable gas behavior was investigated through the comparison with that in the loop type reactor. The effect of the dipped-plate (D/P) tentatively introduced into the pool-type reactor on the gas behavior was investigated through the parametric analyses about the sodium exchange flow rate through the D/P and the gas entrainment rate at the free surface. It was suggested that the increase in the exchange flow rate through the D/P doesn't always work to decrease the bubble volume in the primary coolant system.
Tsekhanovich, I.*; Andreyev, A. N.; Nishio, Katsuhisa; Denis-Petit, D.*; Hirose, Kentaro; Makii, Hiroyuki; Matheson, Z.*; Morimoto, Koji*; Morita, Kosuke*; Nazarewicz, W.*; et al.
Physics Letters B, 790, p.583 - 588, 2019/03
Manabe, Kentaro; Matsumoto, Masaki*
Journal of Nuclear Science and Technology, 56(1), p.78 - 86, 2019/01
If an insoluble cesium-bearing particle is incorporated into the human body, the radioactivity will move as a single particle. In this case, it is impossible to estimate the number of disintegrations by considering the average behavior of countless nuclei. Then, a method was developed to simulate the behavior of the particle stochastically; and a biokinetic model was constructed to consider the characteristics of insoluble particles. Combination of the method and the model enables to estimate the number of disintegrations, and consequently the internal doses considering the stochastic behavior of the single cesium particle. We evaluated a probability density function of committed equivalent and effective doses and its 99th percentile value and arithmetic mean by repeating the above described procedure, and compared them to the reference values based on the existing models. As a result, the 99th percentile value of committed effective doses was 70 times the reference value when the number of incorporated particles was one, and consequently the dose level was quite low. When the exposure level is 1 mSv in committed effective dose, the uncertainty originating in the insolubility of cesium particles was negligibly small.
Mori, Masanobu*; Sugita, Tsuyoshi; Fujii, Kengo*; Yamazaki, Taiki*; Isaka, Mayu*; Kobayashi, Kentaro*; Iwamoto, Shinji*; Itabashi, Hideyuki*
Analytical Sciences, 34(12), p.1449 - 1453, 2018/12
The photocatalyst coating stainless-steel wire mesh (TiO-WM) was prepared by double-layer coating method. The TiO-WM was evaluated using flow analytical system, which included the reactor and conductimetric detector (FAS-CD). The DMSO decomposition test through the FAS-CD reveal that photocatalytst was stable coating on the stainless-steel wire mesh.
Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Lguillon, R.*; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; Ache, M.*; Astier, A.*; et al.
Nuclear Instruments and Methods in Physics Research A, 906, p.88 - 96, 2018/10
We have developed a new setup to measure prompt fission -ray spectra in neutron induced fission up to energies sufficient to reveal the structure associated with giant dipole resonances of fission fragments. The setup consists of multi-wire proportional counters, to detect both fission fragments in coincidence, and two large volume (101.6 mm in diameter and 127.0 mm in length) LaBr(Ce) scintillators, to measure the -rays. The setup was used to obtain the prompt fission -ray spectrum for thermal neutron induced fission of U at the PF1B cold-neutron beam facility of the Institut Laue-Langevin, Grenoble, France. We have successfully measured the -ray spectrum up to energies of about 20 MeV, what extends the currently known -ray spectrum limit to higher energies by approximately a factor of two.
Aratani, Hidekazu*; Nakatani, Yasuhiro*; Fujiwara, Hidenori*; Kawada, Moeki*; Kanai, Yuina*; Yamagami, Kohei*; Fujioka, Shuhei*; Hamamoto, Satoru*; Kuga, Kentaro*; Kiss, Takayuki*; et al.
Physical Review B, 98(12), p.121113_1 - 121113_6, 2018/09
Kajimoto, Ryoichi; Sato, Kentaro*; Inamura, Yasuhiro; Fujita, Masaki*
AIP Conference Proceedings 1969, p.050004_1 - 050004_8, 2018/05
Chimi, Yasuhiro; Iwata, Keiko; Tobita, Toru; Otsu, Takuyo; Takamizawa, Hisashi; Yoshimoto, Kentaro*; Murakami, Takeshi*; Hanawa, Satoshi; Nishiyama, Yutaka
JAEA-Research 2017-018, 122 Pages, 2018/03
Warm pre-stress (WPS) effect is a phenomenon that after applying a load at a high temperature fracture does not occur in unloading during cooling, and then the fracture toughness in reloading at a lower temperature increases effectively. Engineering evaluation models to predict an apparent fracture toughness in reloading are established using experimental data with linear elasticity. However, there is a lack of data on the WPS effect for the effects of specimen size and surface crack in elastic-plastic regime. In this study, fracture toughness tests were performed after applying load-temperature histories which simulate pressurized thermal shock transients to confirm the WPS effect. The experimental results of an apparent fracture toughness tend to be lower than the predictive results using the engineering evaluation models in the case of a high degree of plastic deformation in preloading. Considering the plastic component of preloading can refine the engineering evaluation models.
Kwon, Saerom*; Konno, Chikara; Ota, Masayuki*; Sato, Satoshi*; Ochiai, Kentaro*
JAEA-Conf 2017-001, p.123 - 128, 2018/01
The -version of ENDF/B-VIII, ENDF/B-VIII2, was released in August, 2016. Thus we studied whether the overestimation problems due to the O and Fe data of ENDF/B-VII.1 were corrected in the iron and concrete shielding experiments with 40 and 65 MeV neutrons at TIARA. We produced the ACE files of ENDF/B-VIII2 with the NJOY2012.50 code and used the MCNP-5 code for this analysis. The nuclear data libraries, ENDF/B-VII.1, FENDL-3.1b and JENDL-4.0/HE, were also used for comparison. The following results were obtained; (1) the drastic overestimation of around 40 MeV due to the 5Fe data was improved, (2) the overestimation for around 65 MeV due to the Fe data was also slightly improved, though it was worse than that with FENDL-3.1b, (3) the drastic overestimation due to the O data was not improved. The final version of ENDF/B-VIII should also be modified based on these results.