Fuel cycle development at Dukovany nuclear power plant

The development of the fuel cycle at the Dukovany nuclear power plant is described. The first step in upgrading the fuel cycle consisted in placing the partly spent fuel at the reactor core periphery. In the next step, the lifetime of the least spent fraction of the fuel was extended to the fourth cycle. A higher degree of burnup, without measurable occurrence of damaged fuel, was attained by introducing fuel charges with reduced leaks and by using fourth-cycle fuel. The nil occurrence of damaged fuel is compared with experience gained at the Loviisa and Bohunice nuclear power plants. The modifications of the WWER-440 fuel cycle have brought about considerable real fuel cost savings (at least 10%). In the 3-cycle system, 104 assemblies (on average) were replaced after each cycle. After adopting the system of using 24 assemblies in the 4th cycle, 96 working assemblies will be replaced, and the required overall period will be preserved. Additional, and more significant, savings are associated with the reduction of the number of spent assemblies removed from the reactor. (Z.S.). 3 figs., 4 refs