Technical and economic conditions for increasing the burnup and extending the campaign of WWER-440 reactors

The results are presented of calculations of the dependence of the specific generation cost on the fuel burnup. For WWER type reactors, burnup of 30 MWd/kg is typical. Absolute savings are listed for cases of burnup increased to 45 and 60 MWd/kg U. Increased burnup is facilitated by increased fuel enrichment and is associated with problems of compensation for the increased reactivity at the beginning of the cycle, optimization of refuelling, extension of the campaign, use of burning-up absorbers, and some negative impacts. Special computer programs are developed and experiments performed for tackling those problems. Testing methods are also developed for monitoring the condition of the fuel element cans. No safety problems have so far arisen, and it is expected that the environmental impact of the nuclear cycle will be slightly positive. (M.D.). 4 figs., 3 tabs., 17 refs