Improved method to demonstrate the structural integrity of high density fuel storage racks

Reracking of existing fuel pools to the maximum extent is desirable from an economical point of view. This goal can be achieved by minimizing the gaps between the spent fuel storage racks. Since the rack design is aimed at en abling consolidated fuel rod storage, additional requirements arise with re spect to the design and the structural analysis. The loads resulting from s eismic events are decisive for the structural analysis and require a specia lly detailed and in-depth analysis for high seismic loads. The verification of structural integrity and functionality is performed in two phases. In t he first phase the motional behavior of single racks, rows of racks and, wh ere required, of all racks in the pool is simulated by excitation with disp lacement time histories under consideration of the fluid-structure interact ion (FSI). The displacements from these simulations are evaluated, while th e loads are utilized as input data for the structural analysis of the racks and the pool floor. The structural analyses for the racks comprise substan tially stress analyses for base material and welds as well as stability ana lyses for the support channels and the rack outside walls. The analyses are performed in accordance with the specified codes and standards. (C) 2001 E lsevier Science B.V. All rights reserved.