Overcoming severe accidents in French PWR'S

Accident management brings an essential contribution in the overcoming of severe accidents in French PWR's. Without consideration of probability, the essential concern is to provide the operator with the means for controlling the situation up to the end of the accident situation, whatever the level of accident gravity-almost all potentially conceivable accidents are thus covered- and, in extreme situation, to limit radioactive release to the environment. It quickly became clear, without relaxing respect of the general design rules applicable to the installation as a whole, that the means to be implemented could be very modest in scope (including a filtered containment venting system) with the result that any criteria of the cost/benefit type would serve no purpose. Almost all the equipment required for the implementation of the corresponding operating procedures, regarding both prevention of degraded core situations and the limitation of the consequences of such situations, are now installed on the reactors in French nuclear power plants. The required level of technical competence, which has sometimes to be inculcated from scratch but also maintained over a long period of time, leads to the undertaking of tasks of various kinds, regarding teaching and hands-on practice, but also research and development activities with particular reference to accident phenomenology. The level of technical competence and know-how is almost certainly linked to a feeling of confidence which is essential, in the event of crisis, for implementation of procedures of the kind