Excited Species of Gases Produced in the Nuclear Reactor

Abstract

For many years we have been investigating the chemical effects in gases of mixed pile radiation and fission fragment radiation produced in a nuclear reactor (1). Mixed pile radiation consists in y-radiation, fast neutrons, some-radiation, and, in gases containing nitrogen, proton recoil radiation produced by the N14 (n, p)C14 reaction. Fission fragment radiation is obtained by placing U235 glass fibers in the vessel or flow system containing the gas and subjecting the U235 to thermal neutrons. When 0.1 mg of U235 or more is present per cubic centimeter of gas, the fission fragment radiation produced is the predominant radiation acting on the gas. Our investigations have shown that the chemical effects produced by mixed pile radiation are similar to those caused by fission fragment radiation. For example, when nitrous oxide is irradiated with either fission fragments or pile radiation, the same relative amounts of N2, 02, and NO2 are formed. Also, when gases are irradiated with either a, 3, or 7 ionizing radiation, the M/N values obtained are the same (within the limit of error) and the primary processes are probably similar or even identical. On the other hand, if fission fragments are used (which initially have charges up to +20), then many of the primary formed ions will have charges exceeding unity. Under our experimental conditions these doubly (for example, helium3), triply, or even higher ionized particles will instantaneously react with surrounding uncharged particles, forming ions of lower charge. Therefore, it is possible for the distribution of ions, excited ions, and excited neutral species to be