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Abe, Teruyoshi; Nogiwa, Kimihiro*; Onitsuka, Takashi*; Nakamura, Takahisa; Sakakibara, Yasuhide
E-Journal of Advanced Maintenance (Internet), 6(4), p.146 - 152, 2015/02
Thermal embrittlement of cast austenitic stainless steel components from the decommissioned advanced thermal prototype reactor Fugen has been characterized. Cast stainless steel materials were obtained from recirculation pump casing. The actual time at temperature for the materials was 138,000 h at 275
C. The "Fugen" material show modest decrease in Charpy-impact properties and a small increase in micro-Vickers hardness in ferrite phase because of thermal aging at relatively low service temperatures. The fracture toughness prediction method (H3T model) predicts slightly lower values for Charpy-impact energy obtained from the Fugen material. The results from microstructural analysis suggest that the prediction method have the potential to provide higher accuracy by considerations of the activation energy for embrittlement at low service temperatures.
Ando, Ryosuke; Abe, Teruyoshi; Nakamura, Takahisa
E-Journal of Advanced Maintenance (Internet), 6(4), p.153 - 164, 2015/02
Wall thinning of serviced carbon steel piping of the secondary cooling system after long term operation of Advanced Thermal prototype Reactor (ATR) Fugen power station has been investigated as a series of evaluation of validity and availability of utilization of serviced materials on research projects focused on aging management. Reliability of wall thinning rates of the steel piping has been examined referring the previous inspection data. Examinations also have been made on prediction of wall thinning rates, rationalization of management of pipe wall thinning and verification of countermeasures against wall thinning.
Nogiwa, Kimihiro; Onitsuka, Takashi; Abe, Teruyoshi; Sakakibara, Yasuhide; Horie, Kaoru; Nakamura, Takahisa
Journal of Nuclear Science and Technology, 50(9), p.883 - 890, 2013/09
Times Cited Count：2 Percentile：17.87(Nuclear Science & Technology)The degree of influence of thermal aging on cast stainless steels over a protracted time at low temperatures was investigated by means of a toughness test and microstructural characterization performed on components dismantled from the advanced thermal proto-type reactor "Fugen". The thermal embrittlement mechanism was examined using data obtained dismantled from the materials that had aged on site. The results of a Charpy impact test and microstructural characterization performed using 3DAP analysis reveal early signs of a thermal aging effect over a protracted period at low temperatures corresponding boiling-water reactor (BWR).
Ando, Ryosuke; Abe, Teruyoshi; Nakamura, Takahisa
no journal, ,
Wall thinning of the steel piping of secondary cooling system after long term operation using the served materials of "Fugen" Power Station has been investigated as a series of the evaluation of the validity and availability of the utilization of serviced materials on the research projects focused on the aging. Reliability of the wall thinning rate of the steel piping has been examined referring the previous inspection data. Besides, prediction of the wall thinning rate, rationalization of the management of pipe wall thinning and verification of the countermeasures against wall thinning, have been also examined.
Abe, Teruyoshi
no journal, ,
no abstracts in English
Nogiwa, Kimihiro; Onitsuka, Takashi; Abe, Teruyoshi; Sakakibara, Yasuhide; Nakamura, Takahisa
no journal, ,
Thermal embrittlement of cast austenitic stainless steel components from the decommissioned advanced thermal prototype reactor "Fugen" has been characterized. Cast stainless steel materials were obtained from recirculation pump casing. The actual time at temperature for the materials was 138,000 h at 275C. The Fugen material show modest decrease in Charpy-impact properties and a small increase in micro-Vickers hardness in ferrite phase because of thermal aging at relatively low service temperatures. The fracture toughness prediction method (H3T model) predicts slightly lower values for Charpy-impact energy obtained from the Fugen material. The results from microstructural analysis suggest that the prediction method have the potential to provide higher accuracy by considerations of the activation energy for embrittlement at low service temperatures.
Yuasa, Toyotaka; Abe, Teruyoshi; Nakamura, Takahisa; Myochin, Munetaka; Takagi, Hisatsugu
no journal, ,
Suffered SCC (stress corrosion cracking) at the primary cooling system in 1980, the Fugen power station introduced the three preventive technologies immediately. After the upgrade of the plant, no SCC occurred during the operation period. We have inspected the actual structural materials of the Fugen power station on its decommissioning stage to evaluate effectiveness of SCC management technologies, which are combining material replacement, induction heating stress improvement (IHSI) to reduce the welding residual tensile stress, and application of hydrogen addition to reduce oxygen in the water. No crack in the materials was found by metallurgical structure observation. Moreover, judging from the analysis of residual stress and the heat affected zone in the materials, the effectiveness of SCC management technologies was verified.
Nogiwa, Kimihiro; Onitsuka, Takashi; Abe, Teruyoshi; Sakakibara, Yasuhide; Nakamura, Takahisa; Horie, Kaoru
no journal, ,
no abstracts in English
Onitsuka, Takashi; Nogiwa, Kimihiro; Abe, Teruyoshi; Sakakibara, Yasuhide; Nakamura, Takahisa; Horie, Kaoru
no journal, ,
no abstracts in English
Onitsuka, Takashi; Nogiwa, Kimihiro; Abe, Teruyoshi; Sakakibara, Yasuhide; Nakamura, Takahisa; Horie, Kaoru
no journal, ,
no abstracts in English
Nogiwa, Kimihiro; Onitsuka, Takashi; Takeuchi, Tomoaki; Abe, Teruyoshi; Sakakibara, Yasuhide; Horie, Kaoru; Nakamura, Takahisa
no journal, ,
no abstracts in English
