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Murakami, Masashi; Yoshida, Yukihiko; Nango, Nobuhito*; Kubota, Shogo*; Kurosawa, Takuya*; Sasaki, Toshiki
no journal, ,
no abstracts in English
Futagami, Satoshi; Yamano, Hidemasa; Kurisaka, Kenichi; Ujita, Hiroshi*
no journal, ,
To create an innovation for efficient and effective social implementation of nuclear power plant PRA, automatic construction tool for fault tree architecture and automatic failure judgment tool to construct reliability database are developed by using AI and digitization technology. In this meeting, development plan of AI tools is reported.
Tada, Kenichi
no journal, ,
This presentation explains the overview and current status of the JAEA Advanced Multi-Physics Analysis platform for Nuclear Systems JAMPAN. Validation of nuclear reactor design codes requires comparison with experimental data. Though multi-physics experimental data are desired for it, it is difficult to measure such data for a wide range of operation conditions. The preparation of the high-fidelity multi-physics simulation results which are substitutes for experimental data is required to reduce the number of experimental data. JAEA started to develop the multi-physics platform JAMPAN in 2021 to provide high-reliability multi-physics calculation results.
Tada, Kenichi; Akie, Hiroshi; Kamiya, Tomohiro; Nagaya, Yasunobu; Yoshida, Hiroyuki
no journal, ,
We implemented the handling module for the subchannel analysis code NASCA on the multi-physics platform JAMPAN. This function is used for the neutronics/thermal-hydraulics coupling simulation. The MVP/NASCA coupling calculation on JAMPAN will be applied to the large-scale calculation e.g., a whole core analysis. The calculation results of JAMPAN were compared to those of the prototype simulation system IPACS. The calculation results of JAMPAN showed good agreement with those of IPACS.
Uesawa, Shinichiro; Yamashita, Susumu; Shibata, Mitsuhiko; Yoshida, Hiroyuki
no journal, ,
To evaluate the heat transfer of fuel debris in the primary containment vessel of the Fukushima Daiichi Nuclear Power Station, JAEA has developed a numerical simulation method with JUPITER. The previous work reported that JUPITER was appropriate for flow analysis of a porous medium. In this report, we report experimental and numerical results for natural convection in a system containing the porous medium to validate effective thermal conductivity models of the porous medium in JUPITER. The comparison result indicated that the use of a geometric mean model rather than a series model and a parallel model as an effective thermal conductivity model is appropriate for the natural convective heat transfer analysis in the systems containing the porous medium.
Kadowaki, Masanao; Nagai, Haruyasu; Yoshida, Toshiya*; Terada, Hiroaki; Tsuzuki, Katsunori
no journal, ,
We have developed a method for quantitatively estimating the uncertainty in the direction of radioactive material plume dispersion in atmospheric dispersion predictions using an analytical model obtained by applying Bayesian machine learning to a database of long-term prediction calculation results. In this method, atmospheric dispersion calculations using analytical outputs of meteorological fields were defined as true values, and the uncertainty using forecast outputs was evaluated based on the difference in plume centroid between analysis and forecast outputs and Bayesian machine learning. To test this method, atmospheric dispersion calculations were performed using WSPEEDI-DB, with a hypothetical atmospheric release of Cs-137 from the Nuclear Science Research Institute in Ibaraki Prefecture. The calculation result showed that this method can effectively estimate the uncertainty in the direction of plume dispersion predicted by the atmospheric dispersion model.
Nakayama, Shinsuke; Iwamoto, Osamu
no journal, ,
In molten salt reactors and small modular reactors (SMRs), the use of graphite and CaH
as moderators is being considered, respectively. Thermal neutron scattering law of moderator material has a large influence on the reactor core design. In addition, charged-particle emission reactions such as (n,p) and (n,a) on K-39 in molten salt and on Cu-63 in heat pipes of SMRs can produce nuclides that are problematic for waste management. Therefore, accurate data on thermal neutron scattering laws for graphite and CaH, and charged-particle emission reaction cross sections for K-39 and Cu-63 are important for the core design of these innovative reactors. Based on the above, we have been studying the evaluation method of these data. The progress to date will be presented.
Terada, Hiroaki; Nagai, Haruyasu; Tsuzuki, Katsunori; Kadowaki, Masanao
no journal, ,
no abstracts in English
Kimura, Atsushi; Endo, Shunsuke; Nakamura, Shoji; Rovira Leveroni, G.
no journal, ,
no abstracts in English
Kondo, Ryoichi; Nagaya, Yasunobu
no journal, ,
A functional expansion tally (FET) method expanded by numerical basis functions is under development for Monte Carlo transport simulation. In this work, a multi-group Monte Carlo calculation was performed to obtain the flux distribution with the FET method using numerical basis functions for one-dimensional whole core geometry. The numerical basis functions were generated by singular value decomposition of fluxes, which were calculated by a deterministic method in unit assembly with various calculation conditions. The whole core flux distribution was calculated by expanding the flux distribution of each assembly with the numerical basis functions. The accuracy of the proposed method was confirmed in comparison with the discrete tally method and the conventional Legendre polynomials based FET method.
Konno, Chikara; Kochiyama, Mami; Hayashi, Hirokazu
no journal, ,
We have produced ORIGEN and ORIGEN-S libraries from JENDL 5 released in 2021 in order to use JENDL 5 in the codes. Analysis results of the JPDR decommissioning data with these libraries were similar to those with the libraries bundled in ORIGEN and ORIGEN-S, which indicated that the produced libraries had no problem
Horiguchi, Naoki; Yoshida, Hiroyuki; Kitatsuji, Yoshihiro; Fukumori, Mai*; Hasegawa, Makoto*; Kishimoto, Tadafumi*
no journal, ,
A Li-7 enriched pH adjuster is essential for water quality control on PWRs. As the required Li-7 enrichment technology, we have developed the multi-channel counter-current electrophoresis (MCCCE) method. In this research, to understand the behavior of ions in the enrichment experiment, we developed a numerical simulation method of the long-time behavior of the ions based on the 3-dimensional field data of the electricity by commercial software and the flow by TPFIT-LPT. In this work, we applied it to the behavior of the ions in a simplified plate-type flow channel from the experimental one. Since the separation coefficient calculated from the simulation results of Li-7 and Li-6 ions agreed well with the experimental value, we confirmed the applicability of the method.
Sasaki, Yuji; Kaneko, Masashi; Suzuki, Hideya*; Ban, Yasutoshi
no journal, ,
ADAAM, which is a tridentate diamide including tertiary N atom and developed by JAEA, shows very high separation factor (SF=6) of Am/Cm in nitric acid-n-dodecane system. We tried to enlarge SF using masking agents, however, it is not successful up to now. Thus, the batchwise multi-stage extraction using solo ADAAM for Am/Cm separation is performed. One of the advantages for this technique is available to use small volumes of organic and aqueous phases. Calculation gives product of more than 95% Am with less than 5% Cm by 12 stages of solvent extraction. On the other hand, because of relatively low SF, volume of the raffinate solution may increase several times after multi-stage extraction. In this presentation, we discuss how to cut down their volumes.
Maeda, Makoto; Toh, Yosuke
no journal, ,
no abstracts in English
-emitting nuclides analysis of the stagnant water including sediments in Fukushima Daiichi NPS, 1; -emitting nuclides in the stagnant water at the unit 3 reactor of Fukushima Dai-ichi NPSOuchi, Kazuki; Oka, Toshitaka; Yomogida, Takumi; Morii, Shiori; Kitatsuji, Yoshihiro; Koma, Yoshikazu; Konno, Katsuhiro*
no journal, ,
To understand the existence of -nuclides in the particulate solids contained in the stagnant water in the unit 3 reactor of Fukushima Daiichi Nuclear Power Station, the stagnant water was classified by particle size using filters with pore diameters of 10, 1, 0.1, and 0.02~
m, and U and Np concentrations in the solid fraction and filtrate were investigated using ICP-MS. Both nuclides were present in large particles larger than 10~m, and some were present in the stagnant water on fine particles or ions smaller than 0.02~m.
-emitting nuclides analysis of the stagnant water including sediments in Fukushima Daiichi NPS, 2; Detection of fine particle containing -emitters by SEM-EDX and alpha TrackYomogida, Takumi; Ouchi, Kazuki; Morii, Shiori; Oka, Toshitaka; Kitatsuji, Yoshihiro; Koma, Yoshikazu; Konno, Katsuhiro*
no journal, ,
To investigate the morphology of -nuclides in solid fraction of the stagnant water in the Fukushima Dai-ichi nuclear Power Station's Unit 3 reactor, we tried to detect particles containing -nuclides by scanning electron microscopy-X-ray detection (SEM-EDX) and the alpha track method. As a result of SEM-EDX observation, several sub-m to 10 m size particles containing U were identified. The particles containing alpha emitters were identified by alpha-track method. These particles with few hundred m in diameter were mainly composed of iron.
Sugawara, Takanori; Sato, Takumi; Murakami, Tsuyoshi*; Nishihara, Kenji
no journal, ,
We propose Partitioning and Transmutation Complex (PTComplex) aiming for early realization of Partitioning and Transmutation technology. The PTComplex consists of the pyrochemical reprocessing facility and the high intensity proton accelerator. Molten salt in a tank of the pyrochemical reprocessing facility is irradiated with spallation neutrons generated by high intensity protons, and minor actinides in the molten salt are transmuted.
Np fission chamberIwamoto, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta*; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.
no journal, ,
no abstracts in English
-emitting nuclides analysis of the stagnant water including sediments in Fukushima Daiichi NPS, 4; Fe analysis of particulate solids in the contaminated water at Fukushima Daiichi NPS by M
ssbauer spectroscopyOuchi, Kazuki; Nakada, Masami; Yomogida, Takumi; Oka, Toshitaka; Koma, Yoshikazu; Kitatsuji, Yoshihiro
no journal, ,
In order to understand the chemical form of particulate solids contained in the retained water at three locations of Fukushima Daiichi NPS, the chemical species of Fe which is the main constituent element of solids were analyzed with Mssbauer spectroscopy. Most Fe was found to be 
-form Fe(III) oxyhydroxide. Small amounts of Fe(II) hydroxide and magnetic substance were also detected in the torus and tank samples, respectively.
Watanabe, Nao; Sugawara, Takanori; Nishihara, Kenji; Kaji, Yoshiyuki
no journal, ,
In the design of Accelerator-Driven System (ADS), a beam window is one of the structures used under severe conditions. Since the maximum temperature of the beam window at rated operation will be more than 500
C, a creep damage evaluation has been required. Therefore, we have developed a coupled analysis system on ANSYS Workbench to evaluate the creep strain quantitatively. In this system, temperature distribution of the beam window is calculated by the coupled analysis of particle transport and thermal hydraulics analyses, and then is used as an input data for a creep analysis. Calculation result by this analysis system showed that the creep strain after the rated operation was less than 0.1%.