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Hirota, Noriaki; Nakano, Hiroko; Fujita, Yoshitaka; Takeuchi, Tomoaki; Tsuchiya, Kunihiko; Demura, Masahiko*; Kobayashi, Yoshinao*
The IV International Scientific Forum "Nuclear Science and Technologies"; AIP Conference Proceedings 3020, p.030007_1 - 030007_6, 2024/01
Dynamic strain aging (DSA) and intergranular stress corrosion cracking (intragranular SCC) occur in high temperature pressurized water simulating a boiling water reactor environment due to changes in dissolved oxygen (DO) content, respectively. In order to clearly understand the difference between these phenomena, the mechanism of their occurrence was summarized. As a result, it was found that DSA due to intragranular cracking occurred in SUS304 stainless steel at low DO 
1 ppb, while DSA was suppressed at DO 100 to 8500 ppb due to the formation of oxide films on the surface. On the other hand, when DO was increased to 20000 ppb, the film was peeled from the matrix, O element diffused to the grain boundary of the matrix, resulting in intergranular SCC. These results are indicated that the optimum DO concentration must be adjusted to suppress crack initiation due to DSA and intergranular SCC.
Liu, Q.; Homma, Toshimitsu; Nishimaki, Yuichiro*; Hayashi, Hiroko*; Terakado, Masato*; Tamura, Satoshi*
JAEA-Data/Code 2010-001, 57 Pages, 2010/03
JAEA-Data-Code-2010-001.pdf:16.81MB
For a risk assessment model of an engineering system, the uncertainties in the model inputs propagate through the model and lead to the uncertainty in the model output. In order to evaluate the model output uncertainty and the contribution of each model input to the output uncertainty, the computer code GSALab, which is based on Monte Carlo simulations, has been developed. It is composed of three parts, namely, random samples generation, uncertainty analysis and sensitivity analysis. In the part of sensitivity analysis, several global sensitivity indicators, including the popularly used variance-based indicators, are implemented. In addition, the GUI (Graphical User Interface) of GSALab has been developed for the user's convenience. In addition to risk assessment models, it is also possible to use GSALab for uncertainty and sensitivity analysis of a wide class of mathematical models.
Ishikawa, Noriko; Oka, Kiyoshi; Naganawa, Akihiro*; Yoshino, Junji*; Wakabayashi, Takao*; Watanabe, Shinya*; Naito, Takehito*
Nihon Kikai Gakkai Rombunshu, C, 75(756), p.2359 - 2361, 2009/08
Instruments for measuring the internal pressure of digestive organs are used for diagnosing functional diseases, judging how critical the condition is, and deciding the treatment method or determining the degree of alleviation. However, the technique wherein the internal pressure of the small intestine is measured is highly invasive and painful for patients, and the insertion of the catheter via transducers is not preferred because it involves the insertion of an electric instrument in the body. In this study, we developed a system that measures the pressure of the small intestine with an ileus tube, which is generally used for the treatment of ileus. The main feature of our system is that can be used to measure internal pressure without the insertion of electric instruments such as transducers into the body, allowing the assessment of ileus without causing pain to the patient being treated. In this note, we present a brief description of the structure and function of this instrument used to measure the internal pressure of the small intestine.
Amano, Hikaru; Takahashi, Tomoyuki*; Uchida, Shigeo*; Matsuoka, Shungo*; Ikeda, Hiroshi*; Hayashi, Hiroko*; Kurosawa, Naohiro*
Journal of Nuclear Science and Technology, 40(11), p.975 - 979, 2003/11
Times Cited Count：2 Percentile：19(Nuclear Science & Technology)MOGRA is a migration prediction code for toxic ground additions including radioactive materials in a terrestrial environment. MOGRA consists of computational codes that are applicable to various evaluation target systems, and can be used on personal computers. The computational code has the dynamic compartment analysis block, GUI for computation parameter settings and results displays, data bases. The compartments are obtained by classifying various natural environments into groups that exhibit similar properties. A hypothetical combination of land usage was supposed to check the function of MOGRA. The land usage was consisted from cultivated lands, forests, uncultivated lands, urban area, river, and lake. Each land usage has its own inside model which is basic module. Also supposed was homogeneous contamination of the surface land from atmospheric deposition of 
Cs (1.0 Bq/m
). The system analyzed the dynamic changes of Cs concentrations in each compartment, fluxes from one compartment to another compartment.
Amano, Hikaru; Takahashi, Tomoyuki*; Uchida, Shigeo*; Matsuoka, Shungo*; Ikeda, Hiroshi*; Hayashi, Hiroko*; Kurosawa, Naohiro*
JAERI-Conf 2003-010, p.32 - 36, 2003/09
MOGRA (Migration Of GRound Additions) is a migration prediction code for toxic ground additions including radioactive materials in a terrestrial environment. MOGRA consists of computational codes that are applicable to various evaluation target systems, and can be used on personal computers. The computational code has the dynamic compartment analysis block at its core, the graphical user interface (GUI) for computation parameter settings and results displays, data files and so on. The compartments are obtained by classifying various natural environments into groups that exhibit similar properties. MOGRA has varieties of databases, which consist of radionuclides decay chart, distribution coefficients between solid and liquid, transfer factors from soil to plant, transfer coefficients from feed to beef and milk, concentration factors, and age dependent dose conversion factors for many radionuclides. Here the status of development of MOGRA is presented.
Amano, Hikaru; Takahashi, Tomoyuki*; Uchida, Shigeo*; Matsuoka, Shungo*; Ikeda, Hiroshi*; Hayashi, Hiroko*; Kurosawa, Naohiro*
JAERI-Conf 2003-010, p.112 - 121, 2003/09
The functionality of MOGRA is being verified by applying it in the analyses of the migration rates of radioactive substances from the atmosphere to soils and plants and flow rates into the rivers. This has been achieved by also taking their mode classifications into consideration. In this report, a hypothetical combination of land usage was supposed to check the function of MOGRA. The land usage was consisted from cultivated lands, forests, uncultivated lands, urban area, river, and lake. Each land usage has its own inside model which is basic module. Also supposed was homogeneous contamination of the surface land from atmospheric deposition of Cs-137 (1.0 Bq/m). The system can analyze the dynamic changes of Cs-137 concentrations in each compartment, fluxes from one compartment to another compartment.
Hayashi, Hiroko*; Matsuoka, Shungo*; Takahashi, Tomoyuki*; Amano, Hikaru
JAERI-Conf 2003-010, p.122 - 130, 2003/09
Two dynamic compartment models were constructed as basic river models for MOGRA (Migration Of GRound Additions), an environmental-load effect predicting code. One is 1 component river model, in which radionuclides in particulate form and dissolved form are considered to be in equilibrium in the river water. Another one is 2 component river model, in which particulate form and dissolved form are considered to be different component and are separately compartmentalized. In each model the river sediment is set in a compartment, and the sedimentation of particulate form and resuspension of radionuclides in the river sediment are taken into account.To verify the analysis function of the constructed models, calculation conditions were set using data of Cs-137 concentration in the river water derived from Kuji river, Japan, and analysis was carried out. Comparing two models, almost no difference is seen when sedimentation velocity is low, while there is apparent difference when sedimentation velocity is high.
Takahashi, Tomoyuki*; Amano, Hikaru; Uchida, Shigeo*; Ikeda, Hiroshi*; Matsuoka, Shungo*; Hayashi, Hiroko*; Kurosawa, Naohiro*
Kankyo Eisei Kogaku Kenkyu, 17(3), p.340 - 344, 2003/07
no abstracts in English
Kinase, Sakae; Takahashi, Tomoyuki*; Sato, Satoshi; Saito, Kimiaki; Kurosawa, Naohiro*; Ryufuku, Susumu*; Hayashi, Hiroko*; Ishibashi, Kazufusa*
no journal, ,
no abstracts in English
Sato, Satoshi; Kinase, Sakae; Saito, Kimiaki; Takahashi, Tomoyuki*; Kurosawa, Naohiro*; Ryufuku, Susumu*; Hayashi, Hiroko*; Ishibashi, Kazufusa*; Sakamoto, Ryuichi*; Nemoto, Hisashi*
no journal, ,
no abstracts in English
Sato, Satoshi; Kinase, Sakae; Saito, Kimiaki; Takahashi, Tomoyuki*; Kanno, Mitsuhiro*; Hayashi, Hiroko*; Ishibashi, Kazufusa*; Kurosawa, Naohiro*; Sakamoto, Ryuichi*; Nemoto, Hisashi*
no journal, ,
no abstracts in English
Ryufuku, Susumu*; Ishibashi, Kazufusa*; Hayashi, Hiroko*; Kurosawa, Naohiro*; Sato, Satoshi; Kinase, Sakae; Saito, Kimiaki; Takahashi, Tomoyuki*
no journal, ,
no abstracts in English
Takemiya, Hiroshi; Nemoto, Miho*; Hayashi, Hiroko*; Seki, Akiyuki; Saito, Kimiaki
no journal, ,
no abstracts in English
Hayashi, Hiroko*; Kido, Hiroko*; Kurosawa, Ryohei*; Sone, Koichiro*; Nogami, Mitsuhiro*; Kitayama, Yoshiharu; Hitomi, Keitaro*; Torii, Tatsuo*
no journal, ,
no abstracts in English
Hirota, Noriaki; Kondo, Keietsu; Nakano, Hiroko; Fujita, Yoshitaka; Takeuchi, Tomoaki; Ide, Hiroshi; Tsuchiya, Kunihiko; Kobayashi, Yoshinao*
no journal, ,
Dynamic strain aging (DSA) has been identified in shrouds of boiling water reactors and recirculation system piping of pressurized water reactors in the nuclear field. This phenomenon increases the work hardening rate of the material and causes a reduction in ductility. Rodriguez reported that using stainless steel, this work hardening increases with grain refinement, making DSA more likely to occur. The objective of this study is to evaluate the effect of grain refinement on DSA in a high temperature pressurized water (HTPW) simulating nuclear reactor environment utilizing ultrafine grained SUS304L (UFGS). UFGS was heat treated to adjust the grain size from 0.59 
m to 68.6 m, and Hall-Petch relationship for 0.2 % yield stress was arranged. The k values obtained in this study were almost the same as the reference values previously obtained for SUS304L. Regarding the effect of grain size on fracture strain, a comparison of fracture strain between tensile test under air and slow strain rate test (SSRT) under 598 K / 15 MPa at dissolved oxygen 1 ppb showed that the fracture strain was lower than that under air as the grain size became coarser. The micrograph after fracture in a HTPW showed that ductile fracture surfaces were observed for materials with grain sizes less than 28.4 m. However, when the grain size coarsened to 68.6 m, more than half of all fracture surfaces were brittle fractured. For the material with a grain size of 0.59 m under HTPW, many correspondence grain boundaries of {111}/
3 boundaries were observed in the fracture cross-section of the sample. But these distributions were rarely observed when the grain size was coarsened to 68.6 m. Therefore, the suppression of crack propagation by DSA to the fine grains in a HTPW can be attributed to the relaxation of dislocation accumulation by the {111}/3 boundaries.
