RCS Characterization and SNM Accountability: Trace Fuel Circulation in the RCS, Reactor Building, and Auxiliary Building at TMI-2

Reactor coolant circulation following the Three Mile Island Unit 2 core destruction distributed fuel within the reactor coolant system and into the connected auxiliary systems. The collection sites generally were the low points, the horizontal surfaces, and, to a lesser extent, the vertical surfaces. The affected auxiliary systems included the reactor coolant drain tank, the letdown system, the makeup and purification system, the liquid waste systems, and the reactor coolant pump seal return lines. Steam flow to the steam generators could only move small particles (<1 mm). Smoke formation during core degradation accounted for much of the film formation in the upper elevations of the coolant system. Restart of the reactor coolant pumps accounts for the larger particles found in the steam generators.