Improvement of Validation Technique for Long Term Soundness of In-core Component Materials of Light Water Reactor Plant after Repair and Maintenance

轻水堆核电站维修保养后堆芯部件材料长期完好性验证技术的改进

• 批准号: 17360451
• 负责人: HASEGAWA Akira
• 金额: $ 10.43万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360451/
• 关键词: In-core component materials of light water reactor; Stainless steels; Soundness after welding; Transmutation Helium; Irradiation hardening; Cavity formation; 溶接健全性; 照射誘起偏析

The objective of this study is to investigate damage microstructure development including He bubble formation in the austenitic stainless steel for in-core components including transmutant He atoms due to heat treatment during re-welding and neutron irradiation after rewelding by means of the simulation experiments using light ion implantation/irradiation by using an accelerator. The formation of He atoms was simulated using He ion implantation. The heat treatment during re-welding was simulated using a static heat treatment in a furnace.Damage microstructure development including helium (He) bubble formation in solution annealed type 316L austenitic stainless steel due to heat treatment (850 and 1050_oC for 5-500 min) after He ion pre-implantation (10-1000 appm) at room temperature and hydrogen (H) ion irradiation (0-0.5 dpa) at the temperature of 300_oC after the heat treatment was investigated in order to evaluate the microstructural degradation in a HAZ (heat affected zone) region … More of in-core components of fission reactors during re-welding and post welding neutron irradiation. The growth of He bubbles was observed due to the increment of He concentration, annealing time and annealing temperature of heat treatment, and displacement damage by H irradiation. He bubbles formed during the heat treatment and after H ion irradiation were distributed both in the grain boundary and in the matrix. The significant growth of He bubbles in the grain boundary after H irradiation up to 0.5 dpa was observed.It was clarified by this study that the growth of He bubbles significantly occurred due to the increment of He-concentration, annealing time and temperature of heat treatment, and displacement damage followed by He-ion implantation and heat treatment. He bubble formation in the grain boundary is well known to cause an embrittlement, weld metal cracking and degradation of weldability. Thus, in order to keep the highly reliable operation of fission reactor plants, the identifying the He concentration before re-welding repair, re-welding under the precisely controlled conditions, and the operation term and inspection periods after re-welding repair would be significantly important. Moreover, thermal stress and its cycling occurring due to the re-welding are also considered to cause the growth of He bubble. Therefore, the effect of thermal stress level and cycling on the He bubble formation and growth behavior must be investigated in future work. Less

本研究的目的是通过利用加速器进行光离子注入/辐照的模拟实验，研究再焊过程中的热处理和再焊后的中子辐照对包括反变氦原子在内的芯内部件的损伤组织的发展，包括气泡的形成。用氦离子注入模拟了氦原子的形成过程。为了评价热影响区(…)热影响区的组织退化，研究了固溶退火型316L奥氏体不锈钢在室温(10-1000appm)氦离子预注入(10-1000appm)后进行热处理(850oC和1050oC，5-500min)和氢离子辐照(0-0.5dpa)后的损伤组织演变再焊和焊后中子辐照过程中，裂变反应堆堆芯部件较多。由于He浓度、热处理时间和热处理温度的增加，以及H辐照引起的位移损伤，观察到了He气泡的生长。热处理过程中和氢离子辐照后形成的气泡分布在晶界和基体中。H辐照至0.5 dpa后，晶界上的He气泡显著长大。研究表明，He浓度的增加、热处理时间和温度的增加以及He离子注入和热处理引起的位移损伤都会使晶界上的He气泡显著长大。众所周知，晶界中气泡的形成会导致脆化、焊缝金属开裂和焊接性退化。因此，为了保证裂变反应堆装置的高可靠运行，确定重焊修复前的氦气浓度、精确控制条件下的重焊条件、重焊修复后的运行时间和检查周期具有重要意义。此外，重新焊接引起的热应力及其循环也被认为是导致氦气泡长大的原因。因此，热应力水平和循环对氦气泡形成和长大行为的影响有待于进一步研究。较少

项目成果

Study on Damage Analysis of Austenitic Stainless Steel for In-core Components of Fission Reactor using Accelerator Irradiation Experiments

裂变反应堆堆芯部件奥氏体不锈钢的加速器辐照实验损伤分析研究

• 发表时间: 2008
• 作者: Masato Ito;Daigo Setoyama;Junji Matsunaga;Hiroaki Muta;Ken Kurosaki;Masayoshi Uno;Shinsuke Yamanaka;A. Hasegawa
• 通讯作者: A. Hasegawa

照射損傷を受けた原子力用オーステナイトステンレス鋼におけるナノレベルの微細組織と変形組織の挙動解析

核奥氏体不锈钢辐照损伤纳米级显微组织和变形组织行为分析

• 发表时间: 2007
• 作者: Masato Ito;Daigo Setoyama;Junji Matsunaga;Hiroaki Muta;Ken Kurosaki;Masayoshi Uno;Shinsuke Yamanaka;A. Hasegawa;A. Hasegawa;長谷川 晃
• 通讯作者: 長谷川 晃

水素イオン照射したオーステナイトステンレス鋼の照射誘起不均一変形挙動の評価

氢离子辐照奥氏体不锈钢辐照诱导异质变形行为评价

• 发表时间: 2008
• 作者: Kazuo Takahashi;Masayoshi Uno;Mihoko Okui;Shinsuke Yamanaka;長谷川 晃
• 通讯作者: 長谷川 晃

Study on microstructure and deformation behavior of irradiated austenitic stainless steel

辐照奥氏体不锈钢显微组织及变形行为研究

• 发表时间: 2007
• 作者: Masato Ito;Daigo Setoyama;Junji Matsunaga;Hiroaki Muta;Ken Kurosaki;Masayoshi Uno;Shinsuke Yamanaka;A. Hasegawa;A. Hasegawa;長谷川 晃;A. Hasegawa
• 通讯作者: A. Hasegawa

Study on Damage Microstructure Development of Re-welded Austenitic Stainless Steel of In-core Component Using Light-ion Irradiation

轻离子辐照核心部件重焊奥氏体不锈钢损伤微观组织发展研究

• 发表时间: 2007
• 期刊: Proc. of The 13th International Conference on Environmental Degradation of Materials in Nuclear Power Systems CD-ROM
• 作者: S.Nogami,