Investigation of chemical additives for reactor containment sprays

A study has been conducted to evaluate certain chemical additives for use in a reactor containment spray to enhance the removal of fission product iodine. Sodium thiosulfate in boric acid solution, sodium thiosulfate in alkaline boric acid solution, and alkaline boric acid solution alone were each evaluated. Laboratory tests consisted of thermal stability studies of the conditions following a hypothetical loss of coolant accident, studies of radiation stability and radiolysis of the aqueous solutions, chemical reactions between the additives and iodine, and evaluations of the corrosiveness of the spray additive solution toward plant materials. Results of this testing and associated studies related to the reactor containment indicate alkaline boric acid solutions to be superior to sodium thiosulfate solutions owing to questions of the latter's chemical/thermal stability, possible solids formation in large quantity, radiation stability, and effects it may have on solution radiolysis. (auth)