A pneumatic rabbit facility has greatly increased the flexibility of a graphite thermal column at a 5-MW pool research reactor by providing accessibility during full power reactor operation. Previously, sample insertions and removals were possible only during reactor shutdown periods. The unique feature of the pneumatic facility is that the rabbit track and vent line were machined in two standard graphite stringers which, when connected end-to-end, provided full penetration of the thermal column. The “S”-shaped contoured track precludes radiation streaming, and the graphite surface is ideal for rabbit travel, eliminating the necessity of a liner that could present flux perturbation and column contamination problems.