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ionsShiina, Yoko*; Kinoshita, Ryo*; Funada, Shuhei*; Matsuda, Makoto; Imai, Makoto*; Kawatsura, Kiyoshi*; Sataka, Masao*; Sasa, Kimikazu*; Kaneko, Toshiaki*; Tomita, Shigeo*
Physical Review A, 110(6), p.062826_1 - 062826_7, 2024/12
Times Cited Count：0 Percentile：0.00(Optics)Sogabe, Joji; Ishida, Shinya; Tagami, Hirotaka; Okano, Yasushi; Kamiyama, Kenji; Onoda, Yuichi; Matsuba, Kenichi; Yamano, Hidemasa; Kubo, Shigenobu; Kubota, Ryuzaburo*; et al.
Proceedings of International Conference on Nuclear Fuel Cycle (GLOBAL2024) (Internet), 4 Pages, 2024/10
In the frame of France-Japan collaboration, the calculational methodologies were defined and assessed, and the phenomenology and the severe accident consequences were investigated in a pool-type sodium-cooled fast reactor.
Yamagishi, Isao; Hato, Shinji*; Nishihara, Kenji; Tsubata, Yasuhiro; Sagawa, Yusuke*
JAEA-Data/Code 2024-002, 63 Pages, 2024/07
JAEA-Data-Code-2024-002.pdf:2.91MB
JAEA-Data-Code-2024-002-appendix(CD-ROM).zip:9.42MB
Adsorption columns filled with zeolite are used to treat contaminated water containing radioactive cesium generated by the Fukushima Daiichi Nuclear Power Station accident. As the contaminated water treatment progresses, the radioactive cesium in the adsorption column becomes highly concentrated, and the adsorption column becomes a high radiation source. To evaluate the radiation effects such as decay heat and radiolytic hydrogen production in the adsorption column, the concentration of radioactive cesium in the adsorption column is necessary, but since it is difficult to evaluate the concentration by measurement, it is estimated by simulation. In this research, a zeolite column adsorption dynamics simulation (Zeolite Adsorption Column: ZAC) code was developed to calculate the concentration of radioactive materials such as radioactive cesium in a zeolite filled adsorption column when they are injected into the column. The code was validated through comparison of calculation results with existing codes and experimental results of small column tests. This report presents the details of the model, the handling of the code, and the validity of the results for the developed code.
Konno, Chikara
Journal of Nuclear Science and Technology, 61(1), p.121 - 126, 2024/01
Times Cited Count：1 Percentile：23.64(Nuclear Science & Technology)The JENDL-4.0/HE neutron and proton ACE files were produced in 2017 and those of 22 nuclei for neutron and 25 nuclei for proton were bundled in the PHITS code. Recently it was found that the following five data in the JENDL-4.0/HE neutron and proton ACE files had any problems; ACE files for 
N and 
O, heating numbers, damage energy production cross sections, secondary neutron multiplicities and fission cross sections. Thus new JENDL-4.0/HE neutron and proton ACE files were produced with the problems fixed. This paper describes the problems and how to produce the new neutron and proton ACE files in detail.
Kato, Tomoaki; Yamagishi, Isao
JAEA-Technology 2023-018, 53 Pages, 2023/11
JAEA-Technology-2023-018.pdf:2.6MB
In the decommissioning of Fukushima Daiichi Nuclear Power Station, radioactive carbonate slurry waste was generated using the Advanced Liquid Processing System (ALPS) pretreatment and temporarily stored in a high integrity container (HIC). In 2015, overflow of supernatant from HIC estimate as bubble retention in the carbonate slurry was discovered, increasing the need for a safety assessment of the carbonate slurry stored the HIC (HIC slurry). In this study, a carbonate slurry (simulated slurry) was prepared according to the Mg/Ca mass ratio in the ALPS inlet water of the HIC slurry which overflew the HIC. The effects of reaction time during the pretreatment process, suspended solids concentration (SS concentration), and settling time on the particle composition, morphology and rheological properties of the slurry were investigated. Evaluating the effect of reaction time and concentration process on chemical properties in slurry production, the effect of the reaction time was not confirmed in the simulated slurry that had undergone the concentration process, and slurry prepared at SS concentration of 150 g/L was composed of formless particles have a particle diameter of 0.4 
m or less. We also investigate the effect of SS concentration on sedimentability, decrease in SS concentration by dilution with processing solution contributed to an increase in the initial slurry settling velocity. Furthermore, two different flow characteristics were observed depending on the settling time, suggesting that the slurry at the initial settling time has non-Bingham flow properties, whereas it changes to Bingham flow properties as the settling time becomes longer. In addition, yield stress was increased with settling time, and this yield stress was found to be exponentially proportional to the density of the slurry. These results provide knowledge to estimate the current state of HIC slurry and are expected to contribute to the safety assessment.
Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; Hanakawa, Hiroki; Ide, Hiroshi
JAEA-Technology 2022-029, 55 Pages, 2023/02
JAEA-Technology-2022-029.pdf:2.77MB
Japan Materials Testing Reactor (JMTR) was decided as a one of decommission facilities in April 2017. The activation activity of secondary radioactive contamination remaining in the reactor facility was evaluated in order to submit the decommissioning plan to the Nuclear Regulation Authority. Total activation activity was 2.73
10
Bq after 12 years, 1.4610Bq after 21 years, respectively. The system with high activation activity was the primary cooling system in JMTR. The relatively large radionuclide was H-3, Fe-55, Co-60, Ni-63, Sr-90 and Cs-137. The radioactivity level was classified based on the values of the obtained radioactivity concentration. As a result, the primary cooling system and the drain system was classified as L2, and others was classified as L3. The nuclide that affected classification result was only Co-60 in irradiation facility of HR-1 and OSF-1. H-3, Co-60, Sr-90, Cs-137 and so on were affected classification in other system. When treating and disposing of radioactive waste, evaluation will be carried out based on appropriate methods.
Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*
Radiation Physics and Chemistry, 166, p.108493_1 - 108493_9, 2020/01
Times Cited Count：2 Percentile：17.49(Chemistry, Physical)In this work, when radiation sources of 
Cs, 
Sr and Y were assumed to be put in the front of a plain SUS304 plate as a typical material submerged in water, energy spectra of secondary photons and electrons at the front and back sides of plate were simulated with changing the thickness of plate, and spacing between the source and plate by using a Monte Carlo calculation code of PHITS. In the case of Cs gamma-ray (monochromatic 662 keV), the energy spectra at the front side was smaller than those at the back side due to the existence of plate. Then the dependence of spectra on the plate thickness was observed more clearly at the back side than at the front side. It was clearly shown how the energy spectra of photons and electrons varied with the incident radiation type, the spacing, and the thickness.
ionsShiina, Yoko*; Kinoshita, Ryo*; Funada, Shuhei*; Matsuda, Makoto; Imai, Makoto*; Kawatsura, Kiyoshi*; Sataka, Masao*; Sasa, Kimikazu*; Tomita, Shigeo*
Nuclear Instruments and Methods in Physics Research B, 460, p.30 - 33, 2019/12
Times Cited Count：3 Percentile：27.77(Instruments & Instrumentation)Shibata, Atsuhiro; Koma, Yoshikazu; Oi, Takao
Journal of Nuclear Science and Technology, 53(12), p.1933 - 1942, 2016/12
Times Cited Count：20 Percentile：84.80(Nuclear Science & Technology)
ionsNakajima, Kaoru*; Nagano, Kengo*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Hirata, Koichi*; Kimura, Kenji*
Applied Physics Letters, 104(11), p.114103_1 - 114103_4, 2014/03
Times Cited Count：7 Percentile：28.98(Physics, Applied)Yamamoto, Kazami; Shibata, Takeo*; Ogiwara, Norio; Kinsho, Michikazu
Vacuum, 81(6), p.788 - 792, 2007/02
Times Cited Count：14 Percentile：48.13(Materials Science, Multidisciplinary)The J-PARC 3GeV Rapid-Cycling Synchrotron (RCS) is required to provide 1MW pulsed protons to the spallation neutron target and the 50 GeV main ring. Since the acceleration period is set at a repetition rate of 25Hz, the eddy current effect due to such rapid repetition magnetic field is a big issue (i.e. the perturbation of the magnetic field and the heating owing to the ohmic loss) in the metal duct. Therefore, we choose the ceramics duct in the magnets in order to avoid the eddy current effect. But the total secondary electron emission yield (SEY) from the ceramics surface is larger than the metal one. In order to reduce these undesirable electron emitted from the chamber surface, Titanium Nitride (TiN) is coated on the inside surface of the chambers. We measured SEY from TiN coating surface with various conditions. We further investigated Diamond Like Carbon coating to search the possibility of another coating. The results of these measurements are shown.
Suzuki, Mitsuhiro; Takeda, Takeshi; Asaka, Hideaki; Nakamura, Hideo
Journal of Nuclear Science and Technology, 43(1), p.55 - 64, 2006/01
Times Cited Count：10 Percentile：55.89(Nuclear Science & Technology)Effects of non-condensable gas from the accumulator tanks on secondary depressurization, as one of accident management (AM) measures in case of high pressure injection system failure, are studied at the ROSA-V/LSTF experiments simulating a ten instrument-tube break LOCA at the PWR vessel bottom. In an experiment with no gas inflow, the secondary depressurization at -55 K/h initiated by SI signal with 10 minutes delay succeeded in the LPI actuation. On the other hand, the gas inflow in another experiment degraded the primary depressurization and resulted in core uncovery before the LPI start. The third experiment with rapid secondary depressurization and continuous auxiliary feedwater supply, however, showed a possibility of long-term core cooling by the LPI actuation. RELAP5/MOD3 code analyses well predicted these experiment results and clarified that condensation heat transfer was largely degraded by the gas in the U-tubes. In addition, a primary pressure - coolant mass map was found to be useful for indication of key plant parameters of AM measures.
Suzuki, Mitsuhiro; Takeda, Takeshi; Asaka, Hideaki; Nakamura, Hideo
Nihon Kikai Gakkai 2005-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.223 - 224, 2005/09
Shown below are experimental results on characteristics of reactor instrumentations including a coolant mass tracking method and core exit thermocouples (CETs) which are necessary to precise operator actions for accident management (AM) during a loss-of-coolant accident (LOCA) at a pressurized water reactor (PWR). The experiments at the ROSA-V/LSTF facility of the Japan Atomic Energy Research Institute simulated small break LOCAs at the PWR vessel bottom and clarified effects of secondary depressurization as one of the AM measures in case of high pressure injection system failure and non-condensable gas inflow from the accumulator injection system. It was shown that the coolant mass tracking method based on three types of water level instruments could detect most of the primary coolant mass change between the initial state and core-heatup starting condition. The CET characteristics to detect the core heatup conditions were significantly degraded by the condensed water fall-back during the secondary depressurization action.
Suzuki, Mitsuhiro; Takeda, Takeshi; Asaka, Hideaki; Nakamura, Hideo
JAERI-Research 2005-014, 170 Pages, 2005/06
JAERI-Research-2005-014.pdf:7.64MB
A small break LOCA (SBLOCA) experiment was conducted at the LSTF of ROSA-V program to study effects of accident management (AM) on core cooling, which is important in case of high pressure injection (HPI) system failure during an SBLOCA at a PWR. The experiment, SB-PV-03, simulated ten instrument-tube break LOCA at the PWR vessel bottom equivalent to 0.2% cold leg break, total HPI failure, non-condensable gas inflow from accumulator injection system (AIS) and AM actions on secondary depressurization at -55 K/h and auxiliary feedwater (AFW) supply for 30 minutes. It was clarified that the AM actions were effective on primary depressurization until AIS injection end at 1.6 MPa, but thereafter became less effective by the gas inflow, resulting in low pressure injection (LPI) delay and whole core heatup under continuous water discharge at the break. The report describes these phenomena including core heatup related with primary coolant mass and AM actions, primary-to-secondary heat transfer analysis and estimation of gas in the primary loops.
Sato, Hiroyuki; Ohashi, Hirofumi; Inaba, Yoshitomo; Maeda, Yukimasa; Takeda, Tetsuaki; Nishihara, Tetsuo; Inagaki, Yoshiyuki
JAERI-Tech 2005-014, 89 Pages, 2005/03
JAERI-Tech-2005-014.pdf:7.25MB
In a hydrogen production system using HTTR, it is required to control a secondary helium gas temperature within an allowable value at an intermediate heat exchanger (IHX) inlet to prevent a reactor scram. To mitigate thermal disturbance of the secondary helium gas caused by the hydrogen production system, a cooling system of the secondary helium gas using a steam generator(SG) and a radiator will be installed at the downstream of the chemical reactor. In order to verify a numerical analysis code of the cooling system, numerical analysis has been conducted. The pressure controllability in SG is highly affected by the heat transfer characteristics of air which flows outside of the heat exchanger tube of the radiator. In order to verify a numerical analysis code of the cooling system, the heat transfer characteristics of air has been investigated with experimental results of a mock-up model test. It was confirmed that numerical analysis results were agreed well with experimental results, and the analysis code was successfully verified.
He for neutron detectionNakamura, Tatsuya; Masaoka, Sei; Yamagishi, Hideshi; Tanaka, Hiroki; Soyama, Kazuhiko; Aizawa, Kazuya
Nuclear Instruments and Methods in Physics Research A, 539(1-2), p.363 - 371, 2005/02
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)We evaluated the neutron-detection performance of a capillary plate under high-pressure helium-3 in terms of the gas gain and the distribution of pulse heights, with the aim of using the device as a neutron detector and a gas preamplification device. The capillary plate exhibited a gas gain of more than 1000 up to a gas pressure of 6 atm with a 5% mixture of ethane, confirming an adequate gas gain as a neutron detector. It was also found that the rise times of the signal pulses were correlated with the range and the emission angle of the secondary particles, protons and tritons, thereby providing useful information for developing a system with position-sensitive readouts with a high spatial resolution and a low background.
Nishitani, Takeo; Ochiai, Kentaro; Maekawa, Fujio; Shibata, Keiichi; Wada, Masayuki*; Murata, Isao*
IAEA-CN-116/FT/P1-22 (CD-ROM), 8 Pages, 2004/11
no abstracts in English
Ida, Masato
Journal of the Physical Society of Japan, 73(11), p.3026 - 3033, 2004/11
Times Cited Count：8 Percentile：47.63(Physics, Multidisciplinary)The theoretical results regarding the "transition frequencies" of two acoustically interacting bubbles have been verified numerically. The theory provided by Ida [Phys Lett A (2002)] predicted the existence of three transition frequencies per bubble, each of which has the phase difference of 
between a bubble's pulsation and the external sound. In a subsequent paper [Phys Rev E (2003)], it was shown theoretically that transition frequencies may cause the sign reversal of the secondary Bjerknes force. In this paper, we employ a DNS technique to verify those results. The numerical results reproduce the theoretical predictions, validating the existence of the transition frequencies.
Suzuki, Mitsuhiro; Takeda, Takeshi; Asaka, Hideaki; Nakamura, Hideo
Proceedings of 6th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operations and Safety (NUTHOS-6) (CD-ROM), 14 Pages, 2004/10
no abstracts in English
Nishitani, Takeo; Ochiai, Kentaro; Yoshida, Shigeo*; Tanaka, Ryohei*; Wakisaka, Masashi*; Nakao, Makoto*; Sato, Satoshi; Yamauchi, Michinori*; Hori, Junichi; Wada, Masayuki*; et al.
Journal of Nuclear Science and Technology, 41(Suppl.4), p.58 - 61, 2004/03
no abstracts in English
