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JAEA Reports

Activities of Working Group on Verification of PASCAL; Fiscal years 2016 and 2017

Li, Y.; Hirota, Takatoshi*; Itabashi, Yu*; Yamamoto, Masato*; Kanto, Yasuhiro*; Suzuki, Masahide*; Miyamoto, Yuhei*

JAEA-Review 2020-011, 130 Pages, 2020/09

JAEA-Review-2020-011.pdf:9.31MB

For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in Japan Atomic Energy Agency based on the latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressure thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to perform verification activities, and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL module and the source program of PASCAL was released to the members of working group. This report summarizes the activities of the working group on the verification of PASCAL in FY2016 and FY2017.

Journal Articles

Bayesian uncertainty evaluation of Charpy ductile-to-brittle transition temperature for reactor pressure vessel steels

Takamizawa, Hisashi; Nishiyama, Yutaka; Hirano, Takashi*

Proceedings of ASME 2020 Pressure Vessels and Piping Conference (PVP 2020) (Internet), 7 Pages, 2020/08

no abstracts in English

Journal Articles

Susceptibility to neutron irradiation embrittlement of heat-affected zone of reactor pressure vessel steels

Takamizawa, Hisashi; Katsuyama, Jinya; Ha, Yoosung; Tobita, Toru; Nishiyama, Yutaka; Onizawa, Kunio

Proceedings of 2019 ASME Pressure Vessels and Piping Conference (PVP 2019) (Internet), 8 Pages, 2019/07

no abstracts in English

JAEA Reports

User's manual and analysis methodology of probabilistic fracture mechanics analysis code PASCAL Ver.4 for reactor pressure vessel (Contract research)

Katsuyama, Jinya; Masaki, Koichi; Miyamoto, Yuhei*; Li, Y.

JAEA-Data/Code 2017-015, 229 Pages, 2018/03

JAEA-Data-Code-2017-015.pdf:5.8MB
JAEA-Data-Code-2017-015(errata).pdf:0.15MB

As a part of the structural integrity research for aging light water reactor components, a probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed in JAEA. The PASCAL code can evaluate the conditional failure probabilities and failure frequencies for core region in reactor pressure vessels under the pressurized thermal shock events. In this study, we improved many functions such as the stress intensity factor solutions, the fracture toughness models, or confidence level evaluation function by considering epistemic and aleatory uncertainties related to influence parameters in the structural integrity assessment. We also developed the analysis module PASCAL-Manager which calculates the failure frequency for the entire core region taking into consideration the failure probabilities obtained from PACAL-RV. Based on these improvements, the new analysis code is upgraded to PASCAL Ver.4. This report provides the user's manual and theoretical background of PASCAL Ver.4.

Journal Articles

Statistical analysis using the Bayesian nonparametric method for irradiation embrittlement of reactor pressure vessels

Takamizawa, Hisashi; Ito, Hiroto; Nishiyama, Yutaka

Journal of Nuclear Materials, 479, p.533 - 541, 2016/10

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

To understand neutron irradiation embrittlement in high fluence regions, statistical analysis using the Bayesian nonparametric (BNP) method was performed for the Japanese surveillance and material test reactor irradiation database. The BNP method is essentially expressed as an infinite summation of normal distributions, with input data being subdivided into clusters with identical statistical parameters (such as mean and standard deviation) for each cluster to estimate shifts in ductile-to-brittle transition temperature (DBTT). Clusters typically depend on chemical compositions, irradiation conditions, and the irradiation embrittlement. Specific variables contributing to the irradiation embrittlement include the content of Cu, Ni, P, Si, and Mn in the pressure vessel, neutron flux, neutron fluence, and irradiation temperatures. It was found through numerous examinations that the measured shifts of DBTT correlated well with calculated ones. Data associated with the same materials were subdivided into the same clusters even if neutron fluences were significantly disparate among the results. This indicates that slowly developing or late-onset embrittlement mechanisms were not evident in the present study.

Journal Articles

Bayesian statistical analysis on chemical composition contributing to irradiation embrittlement at high fluence region

Takamizawa, Hisashi; Nishiyama, Yutaka

Proceedings of 2016 ASME Pressure Vessels and Piping Conference (PVP 2016) (Internet), 5 Pages, 2016/07

It has been accepted that neutron irradiation embrittlement of reactor pressure vessel is caused by irradiation-induced formation of solute clusters (SCs) and matrix damages (MDs). In the present study, to analyze the contribution of chemical composition contained in SCs to irradiation embrittlement at high fluence region, statistical analysis using the Bayesian nonparametric (BNP) method was performed for Japanese PWR surveillance data. The significance of P, Si and Mn contents, which are not necessarily included in embrittlement correlations unlike the Cu and Ni content, was evaluated. The BNP method can learn the complexity of the statistical model itself from the input data and infer the predicted data with individual probability distribution of predict condition. The result suggested that irradiation embrittlement was most affected by the Si content at high fluence region.

Journal Articles

Radiation hardening and -embrittlement due to He production in F82H steel irradiated at 250 $$^{circ}$$C in JMTR

Wakai, Eiichi; Jitsukawa, Shiro; Tomita, Hideki*; Furuya, Kazuyuki; Sato, Michitaka*; Oka, Keiichiro*; Tanaka, Teruyuki*; Takada, Fumiki; Yamamoto, Toshio*; Kato, Yoshiaki; et al.

Journal of Nuclear Materials, 343(1-3), p.285 - 296, 2005/08

 Times Cited Count:40 Percentile:6.64(Materials Science, Multidisciplinary)

The dependence of helium production on radiation-hardening and -embrittlement has been examined in a reduced-activation martensitic F82H steel doped with $$^{10}$$B, $$^{11}$$B and $$^{10}$$B+$$^{11}$$B irradiated at 250$$^{circ}$$C to 2.2 dpa. The total amounts of doping boron were about 60 massppm. The range of He concentration produced in the specimens was from about 5 to about 300 appm. Tensile and fracture toughness tests were performed after neutron irradiation. 50 MeV-He$$^{2+}$$ irradiation was also performed to implant about 85 appm He atoms at 120$$^{circ}$$C by AVF cyclotron to 0.03 dpa, and small punch testing was performed to obtain DBTT. Radiation-hardening of the neutron-irradiated specimens increased slightly with increasing He production. The 100 MPam$$^{1/2}$$ DBTT for the F82H+$$^{11}$$B, F82H+$$^{10}$$B+$$^{11}$$B, and F82H+$$^{10}$$B were 40, 110, and 155$$^{circ}$$C, respectively. The shifts of DBTT due to He production were evaluated as about 70$$^{circ}$$C by 150 appmHe and 115$$^{circ}$$C by 300 appmHe. The DBTT shift in the small punch testing was evaluated as 50$$^{circ}$$C.

Journal Articles

Microstructure property analysis of HFIR-irradiated reduced-activation ferritic/martensitic steels

Tanigawa, Hiroyasu; Hashimoto, Naoyuki*; Sakasegawa, Hideo*; Klueh, R. L.*; Sokolov, M. A.*; Shiba, Kiyoyuki; Jitsukawa, Shiro; Koyama, Akira*

Journal of Nuclear Materials, 329-333(1), p.283 - 288, 2004/08

 Times Cited Count:18 Percentile:23.46(Materials Science, Multidisciplinary)

Reduced-activation ferritic/martensitic steels (RAFs) were developed as candidate structural materials for fusion power plants. In a previous study, it was reported that ORNL9Cr-2WVTa and JLF-1 (Fe-9Cr-2W-V-Ta-N) steels showed smaller ductile-brittle transition temperature (DBTT) shifts compared to IEA modified F82H (Fe-8Cr-2W-V-Ta) after neutron irradiation up to 5 dpa at 573K. This difference in DBTT shift could not be interpreted as an effect of irradiation hardening, and it is also hard to be convinced that this difference was simply due to a Cr concentration difference. To clarify the mechanisms of the difference in Charpy impact property between these steels, various microstructure analyses were performed.

Journal Articles

Evaluation of neutron irradiation embrittlement in structural materials for reactor pressure vessel

Ooka, Norikazu*; Ishii, Toshimitsu

Hihakai Kensa, 52(5), p.235 - 239, 2003/05

no abstracts in English

Journal Articles

Irradiation behavior of low-copper reactor pressure vessel steels

Suzuki, Masahide; Nishiyama, Yutaka

Kinzoku, 71(8), p.42 - 45, 2001/08

no abstracts in English

Journal Articles

Development of a diagnostic technique using ultrasonic wave for evaluation of irradiation embrittlement in reactor pressure vessel materials

Ishii, Toshimitsu; Ooka, Norikazu; Niimi, Motoji; Kobayashi, Hideo*

Kinzoku, 71(8), p.20 - 24, 2001/08

no abstracts in English

Journal Articles

Comparison of transition temperature shifts between static fracture toughness and Charpy-V impact properties due to irradiation and post-irradiation annealing for Japanese A533B-1 steels

Onizawa, Kunio; Suzuki, Masahide

Effects of Radiation on Materials: 20th International Symposium (ASTM STP 1405), p.79 - 96, 2001/07

no abstracts in English

Journal Articles

Aging degradation of light water reactor materials; Reactor internal and pressure vessel materials

Tsukada, Takashi; Ebine, Noriya

Nippon AEM Gakkai-Shi, 9(2), p.171 - 177, 2001/06

no abstracts in English

Journal Articles

Evaluation of nuclear reactor pressure vessel integrity by magnetic interrogation and problems of relevant magnetic field analysis

Ara, Katsuyuki*; Ebine, Noriya

Denki Gakkai Magunetikkusu Kenkyukai Shiryo (MAG-01-55), p.1 - 6, 2001/03

no abstracts in English

Journal Articles

Development of a diagnostic technique using ultrasonic wave for evaluation of irradiation embrittlement in reactor pressure vessel materials

Ishii, Toshimitsu; Ooka, Norikazu; Hoshiya, Taiji; Kobayashi, Hideo*

KURRI-KR-62, p.29 - 41, 2001/03

no abstracts in English

JAEA Reports

PIE technology on mechanical tests for HTTR core component and structural materials developed at research hot laboratory

Kizaki, Minoru; Honda, Junichi; Usami, Koji; Ouchi, Asao*; Oeda, Etsuro; Matsumoto, Seiichiro

JAERI-Tech 2000-087, 50 Pages, 2001/02

JAERI-Tech-2000-087.pdf:2.78MB

no abstracts in English

Journal Articles

Investigation on methodology of fracture toughness evaluation for reactor pressure vessel steels

Onizawa, Kunio; Suzuki, Masahide

Nippon Kikai Gakkai Heisei-12-Nendo Zairyo Rikigaku Bumon Koenkai Koen Rombunshu, p.431 - 432, 2000/10

no abstracts in English

Journal Articles

Nondestructive magnetic measurements to evaluate material degradation of nuclear reactor structure; The Present state of research activities

Ara, Katsuyuki*; Ebine, Noriya

Denki Gakkai Magunetikkusu Kenkyukai Shiryo (MAG-00-182), p.23 - 31, 2000/09

no abstracts in English

Journal Articles

Effect of irradiation on fracture toughness in the transition range of RPV steels

Onizawa, Kunio; Tobita, Toru; Suzuki, Masahide

Effects of Radiation on Materials (ASTM STP 1366), p.204 - 219, 2000/00

no abstracts in English

69 (Records 1-20 displayed on this page)