Dynamic response of fast-reactor core subassemblies

• Published in: Nuclear engineering and design 1974-01, Vol.28 (1), p.31-41
• Main Authors: Belytschko, T., Kennedy, J.M., Marchertas, A.H.
• Format: Article
• Language: English
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/0029-5493(74)90087-9

A program for predicting the behavior of the hexagonal fuel assembly duct when subjected to internally generated pressures in the LMFBR is described. To a large extent, studies have been made with two-dimensional models of the hexcan. In these problems, the loadings must be restricted to line loads of sufficient length so that axial effects can be neglected. The finite element models range from a single hexcan to models which include both the loaded hexcan, two adjacent rows of hexcans, the coolant layers between hexcans, and the fuel rod assemblies. A nonlinear, transient finite element program called STRAW is used for the analyses. The program accounts for both geometric and material nonlinearities, and has special features for treating the coolant layer between hexcans by a quasi-Eulerian description and vertical flow in the hexcans and layer so that motions of the coolant can be accurately analyzed. The model has been used with loadings ranging from 500 psi to the kilobar range, and has yielded significant results on damage in adjacent assemblies and the restraining effects of the coolant. For example, preliminary results have shown that deformations of the loaded hexcan are reduced by 25 to 50% when the role of the coolant is included and that corner ductility has very large effects on hexcan response.