Studies into the thermal behaviour of WWR-M/M2 fuel assemblies

For assessment of the potential hazards in spent fuel tanks of the Rossendorf research reactor, experimental data were to be acquired describing the behaviour of the fuel assemblies in the event of a kerosine-fuelled fire. The accident model describing the most severe effects on the environment assumes fuel assemblies to be uncovered, rising above the water level, with the kerosine fire burning on the water surface. The heat capacity and the thermal conductivity of the fuel assemblies play an important part in assessment of the magnitude of fission product release in the course of this worst but still realistic variant of the possible accident scenario. These two properties determine the time after which the fuel assemblies reach temperatures above the melting temperature of their cladding material, then inducing major fission product releases. (orig.)