Experimental investigation of the fuel rod loading in an evaporating fuel element storage pool

Spent fuel elements are stored in a spent fuel storage pool until transport to the interim storage facilities. During outage of a nuclear power plant the fuel rods from the depleted reactor core are also stored in this storage pool. Hypothetical accident scenarios assume that the after-heat removal from the fuel elements in the storage pool fails due to evaporation and failure of water inlet systems. Experiments on these phenomena have been performed in the test facility ADELA. Wall temperatures at the fuel elements under extreme power conditions of 200 W and solely air cooling were always below 600 C. Assuming a fairly good geometric and thermohydraulic similarity between the experiment and the real fuel element storage pool the structural integrity of the fuel rods should be ensured in case of cooling failure phenomena. Further investigations on heat transfer mechanisms and flow behavior within the fuel rod bundles are required.