Optimal Design of Spent Fuel Containment Impact Limiter by Response Surface Method

Impact limiters are attached near to the top and the bottom of a spent fuel containment body as shock absorbers to maintain the structural integrity of the containment not only in normal condition but also in hypothetical accident condition of 9m falling. Ellipsoidal-head-like metallic impact limiters are used for a spent fuel containment which is designed to carry 26 spent fuel assemblies. Main geometry dimensions of the limiters, such as diameter, thickness of the shell, length of straight flange and fillet radius, are design variables. The LS-DYNA software is applied to simulate the acceleration of containment in a falling accident. Sensitivity analyses of the variables on acceleration of spent fuel containment in the 9m falling accident are carried out. By response surface method, the best geometry dimensions which minimize the acceleration of the containment in falling accident are achieved. As showed in results, ellipsoidal head shaped metallic impact limiters work very well in the 9m falling accident. They could significantly decrease load factor and provide more safety margin.