RADIONUCLIDE RELEASE FROM AERO-SPACE NUCLEAR REACTOR FUELS. V. PHASE TWO: PULSED NEUTRON IRRADIATION OF FUEL IN WATER.
NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF
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Accidental seawater immersion of a NERVAROVER type core would result in a criticality excursion, releasing fission product radionuclides to the environment. In order to simulate the excursion situation and to study the resulting radionuclide release, specimens of NERVAROVER fuel were irradiated under different pulsed neutron conditions in a TRIGA Mark F reactor, the KEWB reactor, and the KIWITNT reactor excursion test. Most of these specimens were irradiated immersed in water. Under these conditions measurements were made of 1 the fission product inventories of fuel specimen and environmental water 2 internal capsule pressure generated, 3 fuel body and microstructure damage, and 4 leaching properties of irradiated fuel. Irradiation effects of greater than moderate significance occurred only in the fuel specimen irradiated most severely in the KIWI-TNT reactor excursion test. Release of fission products to the water appeared to be a function of exposed surface area of the fuel and was less dependent on specimen specific fissioning for both long term leaching after irradiation and during irradiation. Fission product fractionation in the fuel was a function of the specimen specific fissioning. All fission products which fractionated, except I131, have a volatile precursor. Author
- Nuclear Propulsion