検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年

Development of probabilistic fracture mechanics analysis codes for reactor pressure vessels and piping considering welding residual stress

溶接残留応力を考慮した原子炉圧力容器及び配管溶接部の確率論的破壊力学解析コードの開発

鬼沢 邦雄; 西川 弘之; 伊藤 裕人

Onizawa, Kunio; Nishikawa, Hiroyuki; Ito, Hiroto

原子炉圧力容器に関して、確率論的破壊力学解析コードPASCAL2における肉盛溶接部に関する評価機能の改良を行い、確率論的解析を実施した。具体的には、肉盛溶接部内ではき裂が進展しないようにき裂進展モデルを改良し、肉盛溶接に伴う残留応力を考慮して加圧熱衝撃時における原子炉圧力容器の破損確率解析を行った。解析結果から、肉盛溶接部の存在が条件付破壊確率に及ぼす影響を評価した。また、国内外の最新の知見に基づき、応力腐食割れ(SCC)を考慮して配管溶接部の破損確率を評価する確率論的破壊力学解析コードPASCAL-SPを開発した。配管溶接継手部における溶接残留応力分布の不確かさや、供用期間中検査におけるSCC検出性及びサイジング精度をモデル化し、PASCAL-SPに導入した。このPASCAL-SPを用いて、溶接残留応力の不確かさ及び供用期間中検査の検査程度が配管の破断確率に及ぼす影響を評価した。

Probabilistic fracture mechanics (PFM) analysis codes for reactor pressure vessels (RPVs) and piping, called as PASCAL series has been developed at JAEA. The PASCAL2 code can evaluate the conditional probability of flaw initiation and fracture of an RPV under transient conditions such as pressurized thermal shock considering neutron irradiation embrittlement of the materials surrounding the reactor core of the RPV. Recent improvements of PASCAL2 are related to the treatment of weld-overlay cladding. The results of PFM analysis using the improved code have indicated that the residual stress by weld-overlay cladding affects the fracture probability of RPV. The results also indicate that the fracture toughness of cladding should be taken into consideration for the evaluation of realistic through-wall cracking probability. The PASCAL-SP code has been developed recently. The PASCAL-SP evaluates the probabilities of failures such as leakage and break of safety-related piping complying with Japanese regulation and rules. Effects of welding residual stress distribution as well as inspection accuracy are focused in this study. Residual stress distributions, which affect SCC behavior, have been determined by parametric FEM analyses verified through comparisons with welding experiments and incorporated to the code.

Access

:

- Accesses

InCites™

:

パーセンタイル:8.19

分野:Engineering, Multidisciplinary

Altmetrics

:

[CLARIVATE ANALYTICS], [WEB OF SCIENCE], [HIGHLY CITED PAPER & CUP LOGO] and [HOT PAPER & FIRE LOGO] are trademarks of Clarivate Analytics, and/or its affiliated company or companies, and used herein by permission and/or license.