France Proposal of Applied Generation IV SFR Safety Design Criteria

The following criteria is only a proposal to initiation discussion. Currently appplied to the ASTRID project: The reactor core shall be self-stable for normal operation, with its three reactivity coefficients of flow-rate, temperature and power feedback to be negative. 2. The existence of two diversified automatic shutdown systems shall be complemented by a third independent and passive shutdown level that do not rely on active detection and control systems. 3. In case where automatic shutdown systems are not activated by the control process during any of the design accident conditions, the core shall not melt down on the short term, and sufficient time shall be available before any collapse of the reactor structures. 4. In case of inadvertent withdrawal of one or more control rod, demonstrate that there is no partial melting of a sub-assembly. 5. Demonstrate that a credible flow of gas or fluid that can vaporize, like oil, through the core is not sensitive on the core reactivity. 6. In case of a loss of decay heat removal systems, connections to link additional external systems shall be available. 7. Structures that are important for safety, of the main vessel, the safety vessel, their support and the core support structures shall be periodically inspected.