Principle of a Liquid Nitrogen Irradiation Device and Its Realization for Use in a Swimming-Pool Type Reactor

Abstract

The interesting characteristics of liquid nitrogen irradiation loops need not be demonstrated; but their use up to now has been largely limited by the occurrence of explosions in the liquid nitrogen submitted to pile radiations, These explosions are due to the presence of oxygen (0,5–1%) in commercial liquid nitrogen. This oxygen concentrates in the bath and is transformed into unstable ozone or oxygen-nitrogen compounds under the influence of γ -rays. Explosion occurs, for example, when their concentration is large enough or when the temperature is increased. This is at least true in piles with sufficiently high γ -fluxes, where many explosions have been reported, even though such devices may have operated successfully in graphite piles with low-γ-fluxes [1, 2].