Radiolytic organic iodide formation under nuclear reactor accident conditions

The radiological and environmental impacts of serious nuclear reactor accid ents are governed to a large extent by the release of airborne radioiodine to the environment. The post-accident volatilization of radioiodine can be significantly affected by organic impurities present in a reactor containme nt structure, in this research, the impact of organic compounds on iodine b ehavior was investigated under chemical conditions representative of those expected post-accident in a reactor containment structure. Gas chromatograp hy, mass spectrometry, and UV spectrophotometry were used to analyze the ga s and liquid phases of irradiated iodide solutions containing various alkyl halide, carbonyl, and aromatic compounds; the three classes of organic mol ecules most likely present in containment. Chloro-iodo organics and alkyl i odides were the major types of volatile iodo-organics formed in the presenc e of alkyl chlorides and carbonyls, respectively, while no volatile iodo-or ganics were formed in the presence of aromatics. The originally present l(- ) formed small amounts of l(2) in the presence of ionizing radiation. The q uasi-steady-state l(2) concentration increased in the presence of alkyl chl orides and decreased in the presence of carbonyls and aromatics. These resu lts indicate that using materials, such as paints, containing aromatics as opposed to alkyl halides and carbonyl compounds will provide a passive mean s to reduce iodine releases following reactor accidents.