A thermal and structural conceptual design and an analysis of tritium permeation are presented for the grid tubes and collector plate of the interim MARS tandem mirror reactor. Designs are presented for two thermal recovery concepts, a water coolant with low outlet temperature and gaseous coolant with high outlet temperature. System analyses were conducted for the grids. For the grids both radiative and actively cooled schemes were investigated. Three water cooled grid tube point designs were studied. For the liquid cooled collector, five coolant channel configurations were considered. A reference design was chosen for the grids and collecter plates.