Published: 1965
Total Pages: 15
Get eBook
Five monitor columns, containing some pre-irradiation weighed inner and outer fuel elements, were discharged under authorization of PT-NR-4, Sup A at tube average exposures in the range from 1554 to 1631 MWD/T. Uranium swelling values have been calculated from post-irradiation weight measurements and these swelling values have been compared with those swelling values obtained in the KER loop tests. There is acceptable agreement between KER and NPR results for swelling of inner uranium; there is acceptable agreement for outer fuel elements at higher exposures but ends-of-the-column elements (i.e. low-exposure values) are not in agreement. The current swelling values have been extrapolated to determine the tube-average exposure that will result in outer clad strains of one percent. At this conservative value of clad strain, one can predict entirely adequate performance of outer fuel elements to tube average exposures of 2200 MWD/T and inner fuel elements to 2700 MWD/T tube average exposure. Elements that will soon be discharged at tube average exposures ranging from 1900 to 2100 MWD/T, can be evaluated for swelling during the next outage and a much better prediction can be made on the relation of exposure vs swelling and hence exposure vs fuel element integrity. The continuing objective of this production test remains as the determination of fuel element performance vs exposure.
