Stress mitigation design of a tubesheet by considering the thermal stress inducement mechanism

熱応力発生機構に基づく管板設計法

安藤 勝訓 ; 高正 英樹*; 川崎 信史 ; 笠原 直人*

Ando, Masanori; Takasho, Hideki*; Kawasaki, Nobuchika; Kasahara, Naoto*

有限要素法解析により球形管板の応力発生機構について検討し、その結果をまとめた。一連の応力発生機構の検討結果に基づき平管板と球形管板を組合せたハイブリッド管板モデルを提案した。またこのハイブリッド管板モデルにおける応力発生機構についても分析した。

The stress generation mechanism of a tubesheet was revealed through finite element analysis. Semi-spherical tubesheet models were investigated for the first survey of the thermal stress mechanism. The calculated results of the semi-spherical tubesheet model indicated an extensive peak stress around the outermost hole. The recognized thermal stress mechanism of a semi-spherical tubesheet is summarized, and on the basis of the stress generation mechanism, we proposed a stress-mitigated tubesheet, a center-flattened spherical tubesheet (CFST), as an improved configuration. The stress generation mechanism of the CFST was also desicibed.