الفهرس Only 14 pages are availabe for public view
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Abstract
During the irradiation of Uranium dioxide (UO2) fuel gaseous and volatile fission products (e.g.,noble gases and iodine) are produced in the fuel matrix.Small fraction of these fission gase diffuse from the spherical grains interior to the surface of fuel pellets and consequently transport to the fuel to cladding gap.A mathematical model is used to describe the release of stable and unstable volatile and gaseous fission products from UO2 fuel into the reactor cooling system through the gap and failed cladding. The proposed mathematical model simulates stable and unstable fission gases during steady state and transient conditions. The model calculates the fractional fission gas release to the gap over all the temperature range from low to high. Also, the activity release of unstable fission products in the reactor cooling system of an operating reactor which contains defective fuel rods is calculated. The transport of
unstable fission products is modeled by diffusion process while the migration
from the gap to the coolant is modeled by a first order rate process