Two methodologies for computing neutron sources from (alpha, n) and spontaneous fission reactions in vitrified waste.

摘要

The disposal of high-level defense waste in a geologic repository necessitates conversion of the waste to a stable form. For this purpose, the Hanford Waste Vitrification Plant (HWVP) will be constructed. In this facility the waste will be converted into 6.3 (times) 10(sup 5) cm(sup 3) glassified cylinders, 59 cm in diameter and 230 cm in height, which will be placed in steel containers and buried. The waste packages must be adequately shielded to ensure the safety of personnel handling them. To calculate the shielding necessary, the radiation source term must be determined. Although the (gamma)-ray source term does not present a problem, the neutron source term is a concern. Because the glass matrix is composed of light elements, the presence of any (alpha)-particle emitting radionuclides in the waste will contribute to the neutron flux. This paper attempts to ascertain the neutron flux and spectrum from ((alpha),n) reactions and add it to the flux resulting from spontaneous fission.