Contrast dependence of scattering profiles for poly(ethylene glycol) in water; Investigation by small-angle neutron scattering with He spin filter and small-angle X-ray scattering

Ryoki, Akiyuki*; Watanabe, Fumi*; Okudaira, Takuya*; Takahashi, Shingo*; Oku, Takayuki; Hiroi, Kosuke; Motokawa, Ryuhei; Nakamura, Yo*

Journal of Chemical Physics, 160(11), p.114907_1 - 114907_9, 2024/03

https://doi.org/10.1063/5.0192680

Benchmark analysis of ductile fracture simulation for circumferentially cracked pipes subjected to bending

Kumagai, Tomohisa*; Miura, Yasufumi*; Miura, Naoki*; Marie, S.*; Almahdi, R.*; Mano, Akihiro; Li, Y.; Katsuyama, Jinya; Wada, Yoshitaka*; Hwang, J.-H.*; et al.

Journal of Pressure Vessel Technology, 144(1), p.011509_1 - 011509_18, 2022/02

https://doi.org/10.1115/1.4052852

To predict fracture behavior for ductile materials, some ductile fracture simulation methods different from classical approaches have been investigated based on appropriate models of ductile fracture. For the future use of the methods to overcome restrictions of classical approaches, the applicability to the actual components is of concern. In this study, two benchmark problems on the fracture tests supposing actual components were provided to investigate prediction ability of simulation methods containing parameter decisions. One was the circumferentially through-wall and surface cracked pipes subjected to monotonic bending, and the other was the circumferentially through-wall cracked pipes subjected to cyclic bending. Participants predicted the ductile crack propagation behavior by their own approaches, including FEM employed GTN yielding function with void ratio criterion, are FEM employed GTN yielding function, FEM with fracture strain or energy criterion modified by stress triaxiality, XFEM with J or delta J criterion, FEM with stress triaxiality and plastic strain based ductile crack propagation using FEM, and elastic-plastic peridynamics. Both the deformation and the crack propagation behaviors for monotonic bending were well reproduced, while few participants reproduced those for cyclic bending. To reproduce pipe deformation and fracture behaviors, most of groups needed parameters which were determined toreproduce pipe deformation and fracture behaviors in benchmark problems themselves and it is still difficult to reproduce them by using parameters only from basic materials tests.

Temporal change in radiological environments on land after the Fukushima Daiichi Nuclear Power Plant accident

Saito, Kimiaki; Mikami, Satoshi; Ando, Masaki; Matsuda, Norihiro; Kinase, Sakae; Tsuda, Shuichi; Sato, Tetsuro*; Seki, Akiyuki; Sanada, Yukihisa; Wainwright-Murakami, Haruko*; et al.

Journal of Radiation Protection and Research, 44(4), p.128 - 148, 2019/12

https://doi.org/10.14407/jrpr.2019.44.4.128

Detailed deposition density maps constructed by large-scale soil sampling for -ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident

Saito, Kimiaki; Tanihata, Isao*; Fujiwara, Mamoru; Saito, Takashi*; Shimoura, Susumu*; Otsuka, Takaharu*; Onda, Yuichi*; Hoshi, Masaharu*; Ikeuchi, Yoshihiro*; Takahashi, Fumiaki; et al.

Journal of Environmental Radioactivity, 139, p.308 - 319, 2015/01

https://doi.org/10.1016/j.jenvrad.2014.02.014

Development of Radiation Dose Assessment System for Radiation Accident (RADARAC)

Takahashi, Fumiaki; Shigemori, Yuji*; Seki, Akiyuki

JAEA-Data/Code 2009-008, 127 Pages, 2009/07

JAEA-Data-Code-2009-008.pdf:10.5MB

A radiation transport calculation can derive dose distribution in a heavily exposed person for the medical treatment at the case of an accident. Since the accident cannot be prospected, many complicated procedures are needed to make the input file soon after the accident and to inform radiation dose based upon the output files with much information concerning the calculation. Thus, ()diation ()ose ()ssessment system for ()adiation ()cident (RADARAC) was developed to derive effectively radiation dose by the MCNPX or the MCNP code. RADARAC consists of RADARAC_INPUT and RADARAC_DOSE. A user can interactively set up necessary resources to make input files with three programs in RADARAC_INPUT. The results of radiation doses are indicated with tables, graphs and figures depicting dose distribution by RADARAC_DOSE. It is confirmed that RADARAC can make input files with a few thousand lines and indicate more than 20,000 data dose within a few minutes.

Accurate dose assessment system for an exposed person utilising radiation transport calculation codes in emergency response to a radiological accident

Takahashi, Fumiaki; Shigemori, Yuji*; Seki, Akiyuki

Radiation Protection Dosimetry, 133(1), p.35 - 43, 2009/01

https://doi.org/10.1093/rpd/ncp002

A system has been developed to assess radiation dose distribution inside a body of exposed persons in a radiological accident by utilizing radiation transport calculation codes - MCNP and MCNPX. The system mainly consists of two parts, pre-processor and post-processor of the radiation transport calculation. Programs for the pre-processor are used to set up a "problem-dependent" input file, which defines the accident condition and dosimetric quantities to be estimated. The developed program for the post-processor part can effectively indicate dose information based upon the output file of the code. All of the programs in the dosimetry system can be executed with a generally used personal computer and accurately give the dose profile to an exposed person in a radiological accident without complicated procedures. An experiment using a physical phantom was carried out to verify the availability of the dosimetry system with the developed programs in a -ray irradiation field. The dosimetry system with the developed programs can appropriately assess dose distribution inside or on the human body, if the user exactly define the source and human models and their geometric relationship.

Development of precise dose analysis system in a radiation accident, 2

Takahashi, Fumiaki; Shigemori, Yuji*; Seki, Akiyuki

no journal, , 

no abstracts in English

Study on distribution of radioactive substances around Fukushima Dai-ichi Nuclear Power Plant, 4; Enhancement of databases for contamination maps

Seki, Akiyuki; Takemiya, Hiroshi; Saito, Osamu; Saito, Kimiaki; Tanaka, Kei*; Takahashi, Yutaka*; Takemura, Kazuhiro*; Tsuzawa, Masaharu*

no journal, , 

The system for saving and providing the data which are related to the radionuclides in Fukushima prefecture and the neighboring prefectures has been developed. The data mainly include the dose-rate and the analysis result of the soil and water samples. The Center for Computational Science and e-Systems developed the system under the study on distribution of radioactive substances around Fukushima Dai-ichi Nuclear Power Plant founded by MEXT. Proceeding with the installation of the data which are collected by MEXT and Fukushima prefecture, the system are being enhanced more.

Current status of the database for radioactive material monitoring data

Seki, Akiyuki; Suzuki, Kenta; Takahashi, Yoshitomo; Matsubara, Takeshi; Suto, Shigeo; Saito, Kimiaki; Takemiya, Hiroshi; Murakami, Haruko*

no journal, , 

After the Fukushima Daiichi Nuclear Power Plant accident, a lot of monitoring studies had been conducted to collect the precious data which are important for the estimation and prediction of the radionuclide distribution. However, those monitoring databases were not convenient for users because their formats were not unified and they are provided as PDF files. Moreover those databases ware published on the independent websites operated by each organization. JAEA developed the database which provides the monitoring data in an unique format on the same website. The database provides not only numerical data but also visualization data following users' needs.

Current status of the site for radioactive substance monitoring data

Seki, Akiyuki; Suzuki, Kenta*; Takahashi, Yoshitomo*; Matsubara, Takeshi*; Suto, Shigeo*; Saito, Kimiaki; Takemiya, Hiroshi

no journal, , 

JAEA had collected and published radioactive monitoring data provided individually by government offices and local governments and so on. The amount of those data which were unified in same display format and accuracy had become enormous by six years after the accident had passed. To understand how much the radionuclide distribution changed, new contents which were prepared in maps and graphs were added in the site for publishing.