Monitoring Krypton-85 During Three Mile Island Unit 2 Purging

The Penn State noble gas monitor played an important role in measuring environmental levels of ⁸⁵Kr during the purging of the Three Mile Island Unit 2 primary containment. It filled a gap in the U.S. Environmental Protection Agency monitoring program, which existed between their real time monitors and their cryogenic gas chromatographic separation technique. During the 15-day purging period, the system analyzed a total of 124 samples, of which 37 were quantified to contain ⁸⁵Kr in concentrations ranging from 3×10⁴ to 1.5×10⁶ pCi/m³. The maximum whole body beta dose rate was found to be 0.28 mrem/h.