The integral SCOR design incorporates PWR technology proven by more than 40 years of experience, and adopts passive safety systems studied at CEA in the 1990s. The safety approach of SCOR strengthens the prevention of abnormal operation and acceptability of failures for a large set of conditions, thereby reducing the expected frequencies of accident initiators and consequences. The design approach reduces the number and complexity of the safety systems and simplifies the required operator actions compared to those of a standard loop type PWRs (Generation II).

Nuclear reactor characteristics described here are quite similar to well-known PWRs (core geometry and materials, reactor control type, etc.). The SCOR design is characterized by the following innovative solutions:

5 See, for example, the detailed description of the effect of ‘safety by design’ given in IAEA-TECDOC-1391 Status of Advanced LWR Designs: 2004 in the description of the IRIS design (p. 591-592).

• Suppression of the large diameter connections on the reactor pressure vessel;

• Passive and integrated emergency core cooling system, based only on natural circulation and using external air as ultimate heat sink;

• Reactor operating with a soluble boron-free core; the control rod mechanisms are integrated in the vessel;

• Choice of a small power density, enabling large operating margin on core power parameters (i. e. to DNBR);

• Easy testability and maintenance of all safety systems.

Consequences of a significant number of accidents are either outright eliminated or reduced by conception, i. e. without any need of active or passive systems. The major safety systems are passive; they require no operator action or off-site assistance for a long time after an accident. Moreover, core and containment cooling is provided for lasting a long time without alternative current power. This approach is generic for different reactor designs.