The Overall Source Range Monitor Response During the Three Mile Island Unit 2 Accident

The source range monitor (SRM) response during the first 25 h of the Three Mile Island Unit 2 (TMI-2) accident is analyzed. The response of the SRM was simulated by performing static neutron transport calculations on a variety of lower head core material distribution models. Using the previously derived core and lower head material configurations at 225 min and 3 yr after shutdown as starting points, the changing lower head material distribution during the period from 225 min to 25 h after shutdown was estimated. The estimated lower head material distribution derived from this transport analysis appears to be consistent with other studies performed under the auspices of the TMI-2 accident evaluation program.