Verification of the ORIGEN2 code analysis for the TMI-2 reactor core

Accurate definition of the fission product inventories produced in the TMI-2 reactor prior to the accident on March 29, 1979 are of considerable interest to many organizations including the Department of Energy which is shipping the damage reactor core to the Idaho National Engineering Laboratory and conducting the TMI-2 reactor examination program, and General Public Utilities which is defueling the reactor. Numerous fission product inventory calculations have been performed for the TMI-2 core, including an ORIGEN2 analysis by EG ampersand G which uses 1239 nodes to define burnup in the reactor core. To provide a verification of the predicted fission product inventories, a measurement study was performed using pellets from various core regions. Measurements were performed for transuranics, burnup monitors, noble gases, principal gamma ray emitters, 129I, and 90Sr. Comparisons between the experimental results and the code analyses are presented with an evaluation of the associated uncertainties. Also, a discussion is presented of the probable causes of the observed differences between the code and measured values. 10 refs., 1 fig., 2 tabs