Nonlinear seismic response of a series of interacting fuel columns consisting of stacked elements

A theoretical model for studying the seismic response of HTGR core has been developed by considering a series of interacting fuel columns placed in a vertical plane. The solution is made tractable by using the rigid body displacements for each block together with discrete spring and damper forces to represent surface deformations. Included in the model is the capability to treat problems varying in complexity from single block free rocking response through multicolumn response to two dimensional arbitrary inputs. Flexibility of the locating dowels as well as varying dowel appearances is treated as is the Coulomb friction resulting from relative motion between adjacent blocks. Finally, spring rates resulting from flat to flat or line to line contacts are included in the model. (Auth.)