The radiolysis of nitric acid solutions was investigated using gamma, beta and alpha radiation. Solutions were gamma-irradiated under various conditions and analyzed for all stable products. Solutions that were alpha-or beta-irradiated were analyzed for nitrite ion only.Nitrite ion, the major radiolysis product, was determined as a function of nitric acid concentration. A nitrite scavenger, p-nitroaniline, was added to prevent the nitrite ion from reacting prior to analysis. The nitrite yields from alpha irradiation were appreciably lower than the yields from gamma and beta irradiations at lower acid concentrations but continually increased with increasing acid concentration. The nitrite yields from gamma or beta irradiation increased with increasing acid concentration up to about 1 M but then decreased. Similarity of the gamma and beta yields substantiated this unusual trend. Previous investigations of neutral nitrate solutions have always shown an increase in yields at the higher nitrate concentrations. A mechanism, based on L.E.T. effects on three radiolytic reactions, has been postulated to explain the differences in yields between alpha and gamma (or beta) irradiation.The radiation chemistry of the aqueous nitrate system has been the subject of much s t~d y . l -~ However, most of the investigations have been in neutral or slightly basic solutions. The only reported works in acidic solutions have been by Savel'ev et al.,5 Mahlman,6 and Vashman et al . ' Savel'ev et al., using alpha radiation, were the only investigators to analyze for all of the stable radiation products. Mahlman analyzed directly only for hydrogen and oxygen yields from gamma irradiation, and Vashman et al. examined only OH, NO2, and NO3 radical formation in alpha-irradiated frozen nitric acid solutions by electron paramagnetic resonance.One reason for the lack of information in nitric acid solutions is the difficulty of analysis of the major radiolysis products, nitrite ion and hydrogen peroxide. Nitrite ion, or HN02, not only reacts with H202 but decomposes in acid solutions. In order to prevent these reactions and obtain meaningful analytical results, an analytical reagent was added to the solutions to react with or " scavenge" the nitrite ion as it is formed. p-Nitroaniline was the reagent used although other amines have been previously used.s* The reactions of Hz02 were not prevented prior to its analysis so that H202 yields were determined only in dilute acid solutions, and are not reported here.In this study, nitric acid solutions of varying concentrations were gamma-, alpha-and beta-irradiated. Solutions that were alpha-or beta-irradiated were analyzed for nitrite only ; solutions that were gamma-irradiated were irradiated under various conditions and analyzed for all stable products. The linear energy transfer (L.E.T.) effects on the mechanism of nitrite production are discussed and the interpretations may lead to greater understanding of the radiation chemistry of the aqueous nitrate system." Nitrite " will be used in this repor...

No abstract

Nitric acid solutions containing plutonium were prepared and stored for various periods. The amount and composition of the gases generated by the a-radiation were then determined. The G (total gas) decreased from 0.20 to 0.02 as the HNO, concentration was increased from 1 M to lOM. The main products were H a and Oe. Hydrogen is formed by the radiolysis of H,O; its yield decreases with increasing HNOs concentration because the H atoms are more effectively scavenged by nitrate ions. Oxygen is formed by the catalytic decomposition of H,O,. The reaction of H,O, with HNO?, the main radiolysis product in HNO, solution, takes precedence over the decomposition as the HNOs concentration increases, thereby decreasing the 0, yield.

Many plutonium contaminated waste materials decompose into gaseous products because of exposure to alpha radiation. The gases generated (usually hydrogen) over long-storage periods may create hazardous conditions. To determine the extent of such hazards, knowing the gas generation yields is necessary. These yields were measured by contacting some common Rocky Flats Plant waste materials with plutonium and monitoring the enclosed atmospheres for extensive periods of time. The materials were Plexiglas, polyvinyl chloride, glove-box gloves, machining oil, carbon tetrachloride, chlorothene VG@ solvent, Kimwipes@ (dry and wet), polyethylene, Dowex-1 resin, and surgeon's gloves. Both plutonium-239 oxide and plutonium-238 oxide were used as radiation sources. The gas analyses were made by mass spectrometry and the results obtained were the total gas generation, the hydrogen generation, the oxygen consumption rate, and the gas composition over the entire storage period. Hydrogen was the major gas produced in most of the materials. The total gas yields varied from 0.7 1 to 16 cubic centimetres (standard temperature pressure) per day per curie of plutonium. The oxygen consumption rates varied from 0.0088 to 0.070 millimoles per day per gram of plutonium oxide-239 and from 0.0014 to 0.005 I millimoles per day per milligram plutonium 238. ' A. A. Miller. "Radiation Chemistry of Polyvinyl Chloride."

This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission" includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor.