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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.
Yamashita, Susumu; Takase, Kazuyuki; Monji, Hideaki*; Yoshida, Hiroyuki
no journal, ,
no abstracts in English
4 bundleLiu, W.; Nagatake, Taku; Jiao, L.; Shibata, Mitsuhiko; Komatsu, Masao*; Takase, Kazuyuki; Yoshida, Hiroyuki
no journal, ,
To improve and validate the prediction accuracy of two - phase codes, Japan Atomic Energy Agency is working on the measurement of void faction distribution in rod bundles with using wire mesh sensors, under high pressure and high temperature conditions (2MPa, 212
C). The test section is a 44 rod bundle, in which two three - layer 99 wire mesh sensors are installed at two different axial positions. As the first step of the experiment, to validate the measuring system, we performed experiments in water - air system under atmospheric pressure, with using water and air flow rates as parameters. Void fraction distributions in the sub-channels of the rod bundle were derived in a wide flow pattern from bubbly flow to slug flow. The water flow rate, from the viewpoint of considering the natural circulation after reactor scrum, was lower than 600 kg/m
s. The data will be used to validate the void fraction correlations and two-phase evaluation codes.
Jiao, L.; Takase, Kazuyuki; Liu, W.; Nagatake, Taku; Uesawa, Shinichiro; Yoshida, Hiroyuki; Shibata, Mitsuhiko
no journal, ,
To construct a database for upwards air/water flows in a vertical pipe, extensive measurements of air/water flows in a vertical pipe using the wire-mesh sensor technology were conducted at the thermal fluid dynamic test facility TPTF of the Japan Atomic Energy Agency. The test section is 4m in length and 58mm in inner diameter, two sets of three-layers-WMS were set separately at the 1.15m and 1.65m elevation of the air injection position. Air was injected from the bottom of the pipe through 0.6mm/1mm/2mm diameter nozzles. The obtained data are characterized particularly by their quantity and their detailed information on important two-phase flow parameters (e.g. radial distribution of the void fraction, the gas velocity and the time and cross-section averaged bubble size distribution for different test section heights). In the near future, we would like to use the WMS to measure the detailed two-phase flow in sub-channels of a simulated bundle flow.
Nagatake, Taku; Takase, Kazuyuki; Yoshida, Hiroyuki
no journal, ,
no abstracts in English
Itakura, Mitsuhiro; Okita, Taira*
no journal, ,
Time to hydride precipitation in Zircalloy fuel cladding determines the lifetime of the fuel cladding of nuclear reactors. For the design of a new reactor with increased irradiation to transmute TRU elements and reduce waste, the effect of irradiation on the hydride formation must be evaluated. We carried out ab-initio calculations of vacancy cluster and the segregation of hydrogen to the cluster to deduce the fundamental parameters for the modeling of hydride formation. The results are indispensable for the design of the new reactor.
Hirouchi, Jun; Takahara, Shogo; Watanabe, Masatoshi; Munakata, Masahiro
no journal, ,
no abstracts in English
Watanabe, Masatoshi; Takahara, Shogo; Hirouchi, Jun; Munakata, Masahiro
no journal, ,
no abstracts in English
Fukano, Yoshitaka; Imaizumi, Yuya; Yoshioka, Naonori*; Akahori, Hisashi*
no journal, ,
no abstracts in English
Akahori, Hisashi*; Fukano, Yoshitaka
no journal, ,
no abstracts in English
Sugawara, Takanori; Nishihara, Kenji; Tazawa, Yujiro; Tsujimoto, Kazufumi
no journal, ,
This presentation shows fabrication and test results of a testing facility for fuel cooling that is a component of the testing facility for remote-handling of highly-radioactive MA fuels in the transmutation physics experimental facility (TEF-P) planned in the J-PARC. Evaluation formula of pressure drop and temperature increase used in the design of TEF-P was validated by the test, and, feasibility of cooling concept was confirmed.