Increase of discharge burnup - a possibility of improving nuclear fuel utilization in pressurized water reactors

The relatively poor fuel utilization in PWRs and the limited resources of natural uranium call for improving the fuel economy of this type of reactor. A promising possibility is to increase the mean discharge burnup from 30 up to 40...50 GWd/t U and thus to reduce the natural uranium consumption by maximally 15 %. The central problem of increasing burnup is the fuel element behaviour under the condition of prolonged in-core time. It is to be expected that burnup values of about 40 GWd/t U will internationally be achieved in the mid eighties. Values of 50 GWd/t U, requiring burnup-resistent fuel elements, may be realized at the end of the eighties or beginning of the nineties. (author)