The main control room (MCR) is also augmented by passive systems. The main control room habitability system (VES) will pressurize, cool, and provide fresh air to the MCR in the event of an accident. This system is initiated by a high radiation signal in the MCR. It isolates the MCR ventilation system and pressurizes the room to slightly higher than atmospheric pressure, thereby limiting infiltration by airborne contaminants.

V-5. Conclusions

The AP600 was the first passively safe nuclear plant to be certified in the United States. The certification was based on comprehensive integral system and separate effects testing conducted by Westinghouse and the U. S. Department of Energy at the SPES test facility in Italy and at the APEX test facility at Oregon State University. The U. S. Nuclear Regulatory Commission (NRC) conducted confirmatory tests at the ROSA-AP600 test facility in Japan and the APEX Facility at Oregon State University. The AP600 received Final Design Approval from the NRC in September, 1998 and Design Certification in December, 1999. The AP1000 received NRC Final Design Certification in January 2006.