DECONTAMINATION STUDIES FOR HAPO HIGH TEMPERATURE REACTOR RECIRCULATION SYSTEMS PROGRESS REPORT:JUNE 1959 TO JANUARY 1960

摘要

An intensive decontamination program is currently in progress at the Hanford Atomic Products Operation. This program is being conducted to determine the effectiveness of several prospective decontamination processes for high temperature, recirculating water cooled, nuclear reactor systems. Candidate processes are also being evaluated to determine their corrosion characteristics.nTwo distinct types of contamination are encountered in nuclear reactors:(1) fission products and uranium dioxide from ruptured fuel elements, and (2) activated corrosion product films on piping surfaces. Acidic solutions preceded by a highly alkaline, potassium permanganate solution can usually be employed to remove the corrosion product contamina¬tion, but this procedure is not effective in removing uranium dioxide and fission products associated with fuel element ruptures. A solution of hydrogen peroxide, sodium carbonate and sodium bicarbonate plus wetting and stabilizing agents has been developed. This solution is highly effective in removing these materials.nSeveral acidic solutions have been evaluated during corrosion product removal studies;including sodium bisulfate, ammonium citrate, oxalic acid, phosphoric acid and nitric acid. In general, all of the solutions tested were reasonably effective as decontaminating agents and were compatible with the metals they were designed to decontaminate. In some cases the amount of corrosion observed was higher than the specified maximum allowable corrosion loss. However, in most cases it should be possible to remedy this situation by using different corrosion inhibitors.