Stress distribution and flexibility of the suction bend of the primary sodium/pump LMFBR - SNR 300

Hydrodynamic aspects lead to the design of a special smooth section bend for the primary sodium pump LMFBR-SNR 300. This bend is built up from two symmetrical halves, formed from plates by explosive forming. To investigate the linear elastic stress distribution and flexibility of this bend for mechanical loads, analyses are made based on two different methods: First method: The bend is schematized by various toroidal segments with bend parameter lambda ranging from 0.049 to 0.22. The second method deals with three dimensional stress analysis. This is necessary to investigate the influence of change of curvatures and cross sections (neglected in the first method). Modelling is done for the symmetry one half of the complete suction bend, applying the thick shell element QUABC9 of the ASKA system. Application of this element for thin shell problems requires reductions of number of integration points. For the considered modal 2 x 2 reduced integration scheme is chosen only for the transverse shear component. The results of both methods are compared. (orig.)