Backfitting requirements in nuclear power plants in Eastern Europe

The IAEA has analyzed the safety status of reactors of Soviet design and made proposals about improving it. The safety features were contrasted with those of Western reactor lines. Despite many deficits in safety, especially the WWER-440 reactors have a number of advantages as well. Thus, e.g., the low fuel temperature ensures good retention of fissile materials in the fuel. The use of high-grade materials was felt to obviate the need for provisions against failure of the primary system pipes in the WWER line of reactors. Instead, the safety concept was aimed at avoiding initiating events. With the participation of Wano, an EC crash program of assistance to Bulgaria has been launched. At present, an international project of assessing the safety RBMK reactors is being considered. Similar programs for other reactor lines are under discussion. (orig./HP)