Abstracts and Available Papers Presented at the
1995 International RERTR Meeting

PHOTON DOSE RATES FROM SPENT FUEL ASSEMBLIES
WITH RELATION TO SELF-PROTECTION*

R. B. Pond and J. E. Matos
Argonne National Laboratory
Argonne, IL USA

Presented at the1995 International Meeting on
Reduced Enrichment for Research and Test Reactors
September 18-21, 1995
Paris, France

*Work supported by the US Department of Energy
Office of Nonproliferation and National Security
under Contract No. W-31-109-38-ENG

ABSTRACT

Photon dose rates as a function of fission product decay times have been calculated for spent fuel assemblies typical of MTR-type research and test reactors. Based upon these dose rates, the length of time that a spent fuel assembly will be self-protecting (dose rate greater than 100 rem/h at 1 m in air) can be estimated knowing the mass of fuel burned, the fraction of fuel burned, and the fuel assembly specific power density.

The calculated dose rates cover 20 years of fission product decay, spent fuel with up to 80% U-235 burnup and assembly power densities ranging from 0.089 to 2.857 MW/kg U-235. Most of the results are unshielded dose rates at 1 m in air with some shielded dose rates at 40 cm in water. Dose rate sensitivity estimates have been evaluated for a variety of MTR fuel assembly designs and for uncertainties in both the physical and analytical models of the fuel assemblies.

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