An apparatus for holding radioactive objects includes a base and a central pillar extending upwardly between a bottom end coupled to the base and a top end above the base. A plurality of inner segments are spaced around the central pillar, and a plurality of outer segments are spaced around the inner segments to form pairs. The inner segments, the outer segments and the central pillar may be coupled together to permit limited radial movement of at least one of the segments of each pair. Each pair may define a generally vertical, object-receiving channel arranged between the inner and outer segment of the pair. The segments of each pair may be adapted to bear against an object in the channel of the pair to laterally restrain the object and facilitate heat transfer from the object.