Fission product aerosol behavior in the PRTR fuel rod failure of September 29, 1965

摘要

On September 29, 1965, at 0150 a purposely defected partially molten fuel rod in the rupture loop test facility of the PRTR reactor failed in an unexpected manner. The rupture which resulted in a loss of about 30% of the UO(sub 2)-PuO(sub 2) fuel from the rod was accompanied by the formation of a hole of approximately 1/2 inch diameter in the surrounding process tube. The subsequent flashing of the highly contaminated superheated water, released a fission product aerosol to the containment vessel atmosphere. This release resulted in about half of the noble gases reaching the containment vessel atmosphere. About 1 percent of the radioiodine and a somewhat smaller fraction of the solid fission products entered the containment vessel atmosphere. A subsequent radiochemical study provided detailed information on the behavior of some 15 fission products and of plutonium in their movement, following the rod failure, through the various liquid and gaseous systems of the reactor and its containment vessel. The ratios of the fission products (other than the noble gases) which were release to the containment vessel atmosphere were not far different from those in the fuel rod showing that relatively little fractionation occurred in the processes of dis- solution and aerosol formation. The observed deposition per unit area on metal surfaces was much higher than on painted surfaces. Much of the behavior of the radionuclides in this system was similar to what might be expected in the melt-down of any water cooled reactor and the information gained from the study should be applicable to the design of safeguards for such events.