Release of fission products from a fuel rod with an artificial hole through cladding irradiated in an in-pile water loop

Iodine spiking from a defective fuel rod into the primary coolant was measured, concerning main steam pipe breakage of a BWR plant. The fuel rod with an artificial pin hole was irradiated in the in-pile test section of water loop JMTR.OWL-1. Experimental conditions are depressurization and temperature drop of the primary loop coolant and diameter and position of the pin hole. The effect of coolant water flow through the pin hole on the fission products release was examined. The extrapolation of the results to BWR is made by way of the amount of fission products in free space of the fuel rod. (auth.)