Gamma spectroscopic examination of the Peach Bottom HTGR Core

Fission product distributions were established for individual core components after the final shutdown of the Peach Bottom High-Temperature Gas-Cooled Reactor (HTGR). The purpose was to provide information on relative axial and radial power distributions, thorium absorption rates, fuel stack length, and fission product release

Gamma spectroscopic examination of Peach Bottom HTGR core components

During discharge of Core 2 from the Peach Bottom High-Temperature Gas-Cooled Reactor (HTGR), 55 driver elements, 21 test elements, three reflector elements, and one control rod with sleeve were axially gamma scanned with a high-resolution Ge(Li) detector. The purpose of the exercise was to determine fission product distributions for use in burnup calculations, power profile determinations, and fission product release and redistribution studies. The results showed that the predicted and measured burnups had a +-7 percent root mean square deviation on an element-to-element basis and were within +-0.7 percent (1 sigma) on a core average basis. The element-to-element variation of +-7 percent is within the generally stated +-3 percent to 8 percent accuracy for nuclear predictions