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Yokoyama, Kenji; Yamamoto, Akio*
no journal, ,
no abstracts in English
-ray irradiationMotooka, Takafumi; Nagaishi, Ryuji; Yamagishi, Isao
no journal, ,
We conducted ray irradiation test using simulated carbonate slurry to obtain the basic knowledge of the cause of stagnant water over the High Integrity Container. We observed a rise in water level, air bubbles in the slurry, a supernatant when the carbonate slurry with 95 g/L density was irradiated by ray at 8.5 kGy/h. The cause of the rise in water level was regarded as the volume expansion by the gas retention in the carbonate slurry.
Sasaki, Takayuki*; Akimoto, Yuji*; Seki, Kotaro; Nagano, Misato*; Ishimori, Kenichiro; Ueno, Takashi; Kameo, Yutaka
no journal, ,
no abstracts in English
-concrete system under randomizationUeki, Taro
no journal, ,
Analysis framework under indeterminate material distribution is investigated for the Monte Carlo (MC) criticality calculation of continuously mixed media formed via molten core concrete interaction. Randomized Weierstrass functions (RWF) are utilized to represent the volume fractions of constituent materials. The possibility of several percent fluctuation of effective multiplication factor is shown by the MC simulation with delta-tracking.
Furutachi, Naoya; Minato, Futoshi; Iwamoto, Osamu
no journal, ,
To establish the nuclear transmutation system for the long-lived fission products (LLFPs), it is desired to improve precision of the simulation calculation for the transmutation system. To achieve this, nuclear data of various nuclei produced via the nuclear transmutation of LLFPs are also important. However, it is expected that unstable nuclei with no available experimental data are produced via the nuclear transmutation. One of the physical quantity that is very difficult to predict with no experimental data is the thermal neutron capture cross section. The thermal neutron capture cross section is dominated by the energy and width of the first resonance, and slight variation of them can change the thermal neutron capture cross section drastically. While it is very difficult to determine them with high precision, it is known that a resonance width follows Porter-Thomas distribution because of complexity and randomness of a nuclear structure, and a resonance spacing follows Wigner distribution. In this work, we calculate the thermal neutron capture cross section by using the statistical property of the resonance parameters with Monte Carlo method. The calculation result is obtained as a probability distribution of the thermal neutron capture cross section. We calculated approximately 250 nuclei that have experimental data, and found that the dispersion of the experimental data is well explained by the calculated probability distribution.
Minato, Futoshi
no journal, ,
no abstracts in English
Kureta, Masatoshi; Koizumi, Mitsuo; Ozu, Akira; Tsuchiya, Harufumi; Seya, Michio
no journal, ,
The new program "Development of active neutron NDA techniques" has been started for non-proliferation applications collaborating with EC-JRC. The final purpose of this program is to establish the measurement techniques for the high radioactive special nuclear material such as MA-Pu fuel for transmutation of minor actinide. In this program, JAEA will conduct the R&D on active neutron non-destructive measurement techniques, DDA, NRTA, PGA/NRCA and DGS. The research and development plan is presented in this report.
Komeda, Masao; Maeda, Makoto; Shimofusa, Taichi; Tobita, Hiroshi; Ozu, Akira; Kureta, Masatoshi
no journal, ,
He-3 detectors are most popular for NDA systems of the active neutron method. However, the price of He-3 detectors is rising due to short supply of the He-3 gas, and it is concerned that the cost of fabricating a NDA system with many He-3 detectors is rising. A new hybrid detector called B-10 plus detector has been developed by GE Reuter-Stokes. The B-10 plus detector has higher detection efficiency than a B-10 detector while the usage of He-3 gas is reduced. We make a report on experimental results of performance comparison between He-3 detectors and B-10 plus detectors on the active neutron method.
Tsukimori, Kazuyuki; Ando, Masanori; Yada, Hiroki; Anoda, Yoshinari*; Ichimiya, Masakazu*; Uno, Masayoshi*
no journal, ,
no abstracts in English
Nakayama, Shinsuke; Kono, Hiroshi*; Araki, Shohei*; Watanabe, Yukinobu*; Iwamoto, Osamu; Ye, T.*
no journal, ,
Theoretical model analysis of deuteron-induced activation cross sections were performed using the calculation code system we have developed so far. In our previous works, we analyzed mainly double differential cross sections for the 
and 
reactions, and activation cross sections from the 
reactions in order to validate calculation method for the direct processes. In the present work, we analyzed activation cross sections from multi particle emission induced by high energy deuteron in order to validate calculation method for statistical decay processes. In the result of analysis, it was found out the calculation method adopted in our code system is valid.
Utsuno, Yutaka; Yoshida, Sota*; Shimizu, Noritaka*; Otsuka, Takaharu*
no journal, ,
no abstracts in English
Sawamura, Masaru; Umemori, Kensei*; Sakai, Hiroshi*; Furuya, Takaaki*; Enami, Kazuhiro*; Egi, Masato*
no journal, ,
no abstracts in English
Tsuji, Tomoyuki; Sakamoto, Yoshiaki; Hoshino, Yuzuru; Suzuki, Yasuo*; Machida, Hiroshi*
no journal, ,
JAEA is planning a business for the disposal of low level radioactive wastes generated from research, industrial, and medical facilities. Because those wastes are generated from various facilities, it is important to develop reasonable confirmation methods based on the characteristics of radioactive wastes. As a model case of development of the evaluation method to determine the radioactivity concentration, the common method was studied to determine the radioactivity concentration of PIE wastes stored in NDC. The radioactivity concentrations of 17 nuclides (Sr-90, Tc-99, U-235, 238, Pu-238, 239+240, 241, Am-241, Cm-244 and so on) were calculated by ORIGEN-2 based on actual data such as initial contents and operation record of the spent fuel. From the comparison of the obtained data by radiological measurement with calculated values, it was studied that the theoretical method was applied to determine the radioactivity concentrations of 17 nuclides of PIE wastes.
Eguchi, Yuta; Sugawara, Takanori; Nishihara, Kenji; Tazawa, Yujiro; Tsujimoto, Kazufumi
no journal, ,
Transmutation Physics Experimental Facility (TEF-P) planned in the J-PARC project uses minor actinide (MA) fuel which has large decay heat. So it is necessary to consider the increase of the core temperature when the core cooling system is stopped. This change of the core temperature was evaluated by thermal conduction analysis. It was found that the impact of thermal insulation in the empty rectangular lattice matrix area was large. Testing equipment was fabricated to verify the accuracy of calculation model for the empty lattice matrix which was the free convection model of sealed fluid. By using this equipment, thermal distribution and one dimensional heat flow through the lattice were measured. It was observed that the actual equivalent thermal conductivity in the lattice was larger than the free convection model. It was also confirmed that the insertion of the aluminum block into the empty lattice could achieve the higher equivalent thermal conductivity. These results could be the useful data for the thermal conduction analysis.
Arai, Masaji; Takino, Kazuo
no journal, ,
The Department of Research Reactor and Tandem Accelerator began to discuss basic design concept of the new multipurpose research reactor succeeding to JRR-3.
Yamano, Hidemasa; Kawasaki, Nobuchika; Kubo, Shigenobu
no journal, ,
Tentative external hazard conditions assumed for a next-generation SFR design in 2011 were not reasonable because of an envelope range covering severe conditions. This report proposed a reasonable definition method of external hazard conditions and defined specific design basis and design extension conditions against various external hazards.
Gwon, H.; Tanigawa, Hisashi; Nakajima, Motoki; Hirose, Takanori; Kawamura, Yoshinori
no journal, ,
It is expected that the neutron wall loading in DEMO is larger than that in ITER, over 0.78 MW/m
. It is concerned that the decay heat due to the large neutron wall loading will lead to excessive temperature rising in blanket. In present study, the thermal response characteristics of blanket caused by the decay heat under LOCA were evaluated. In addition we considered how to effectively mitigate the excessive temperature rising based on the evaluation results.
Okano, Fuminori; JT-60SA Team
no journal, ,
no abstracts in English
Matsuda, Norihiro; Sato, Tatsuhiko; Niita, Koji*; Suyama, Kenya
no journal, ,
no abstracts in English
Ishimi, Akihiro; Katsuyama, Kozo; Akasaka, Naoaki; Misawa, Susumu*
no journal, ,
no abstracts in English