GAMMA-RAY IRRADIATION EFFECTS ON CORROSION RATES OF STAINLESS-STEEL IN BOILING NITRIC-ACID CONTAINING IONIC ADDITIVES

Irradiation effects of gamma-rays on corrosion rates of type 304ULC st ainless steel in 9 x 10(-3) mol/m(3) boiling nitric acid containing an ionic additive of multivalence elements of Ce(IV), Cr(VI) or Ru(III) were studied by measuring weight losses of specimens immersed under th e Co-60 gamma-ray irradiation of 1 kC/(kg-h) (4 MR/h). Tests without i rradiation were carried out as well to obtain reference data. All the coexisting ionic species enhanced the corrosion in comparison with tho se in pure nitric acid, and the gamma-ray irradiation moderated the en hancement. The valence analyses of these additives and redox potential measurements before and after the immersion batch under the irradiati on suggested that the reduction of Ce(IV) and Cr(VI) induced by the ir radiation have moderated the corrosion environment.