大型高速増殖炉要素技術設計研究(II); 簡易熱応力評価線図(不連続応力の簡易解析)

Partitioning design study of large FBR; Diagram for thermal stress evaluation (Simplified analyses of discontinuity thermal stresses)

古橋 一郎*; 渡士 克己; 今津 彰

Furuhashi, Ichiro*; not registered; Imazu, Akira

FBR機器設計における熱応力計算費用の低減と計算期間の短縮を目的として、軸対称シエル理論を用い不連続熱応力の簡易解析を行なった。これにより(1)円筒端部、(2)材質および板厚の不連続部、異材継手部、(3)軸方向温度勾配、容器の液面近傍部、(4)容器とフランジの接続部、(5)ノズルと容器の接続部、(6)スカート構造部、ノズルのセーフエンド構造部、(7)補強リング部、等の定常および非定常熱応力が簡易かつ迅速に計算できる。さらに、(9)円筒に円周方向温度分布が生じた場合、(10)壁面近傍にサーマルストライピングが生じた場合の簡易熱応力評価式を求めた。これらの結果を用いることにより、種々の形状および寸法に対する熱応力が容易に計算でき、設計費用と設計期間の低減が期待できる。

Simplified analyses of discontinuity thermal stresses were performed using axisymmetrical shell theory for the purpose of saving cost and time of thermal stress calculations in the design of FBR's components. By these analyses, steady and unsteady thermal stresses are to be calculated easily and quickly for the following regions (1)edge of cylinder, (2)discontinuity of material properties and thickness, dissimilar metal pipe joint, (3)axial temperature distribution, cylinder near the liquid surface level, (4)junction of vessel & flange, (5)junction of nozzle and vessel, (6)skirt structures, nozzle safe end, and (7)ring reinforcement. Also, simple formulae were proposed for estimating thermal stresses caused by (9)circumferential temperature distribution of cylinder, (10)thermal striping near the structural wall. By using these results, one can easily evaluate thermal stresses for various shapes and dimensions, and saving of cost and time should be accomplished in the design of FBR's components.