The AP1000 is a 1,100 megawatt electric pressurized-water reactor that includes passive safety features that would cool down the reactor after an accident without the need for human intervention. Westinghouse submitted an application for certification of the original AP1000standard plant design on 28 March 2002; the NRC issued a rule certifying that design on 27 January 2006. Westinghouse submitted an application to amend the AP1000 on 27 May 2007. The NRC’s technical review of the amendment request focused on ensuring the agency’s safety requirements have been met.

Examples of significant design changes include the following:

• extension of seismic spectra to soil conditions
• revisions to buildings for enhanced protection (such as for aircraft impact)
• protection system instrumentation update
• revisions to the electrical system (additional auxiliary transformer; change in direct current (dc) voltage)
• turbine manufacturer change
• sump screen design and analysis
• control room ventilation system
• increased assembly capacity in the spent fuel pool (SFP) (change in rack design)
• updated load handling systems
• additional waste-water monitor tanks
• integrated head package (IHP) revision
• revision to loss-of-coolant accident (LOCA) methods
• reactor internal changes (flow skirt addition)
• pressurizer shape change
• reactor coolant pump design
• addition of containment vacuum relief system
• completion of human factors engineering commitments
• revision to closure logic for component cooling system isolation
• reactor vessel structural support

This process, including input from the Advisory Committee on Reactor Safeguards, led to the NRC issuing a final safety evaluation report on the amended AP1000 in August. The NRC issued a proposed rule for the amended design in January. Stakeholders provided more than 12,000 comments on the proposed rule; the NRC staff considered these comments in developing the final rule.

The NRC is currently reviewing six Combined License applications that reference the amended AP1000 design. The NRC has certified three other standard reactor designs: the Advanced Boiling Water Reactor, System 80+, and AP600. The agency is currently reviewing applications to certify the Economic Simplified Boiling Water Reactor, the US Advanced Pressurized Water Reactor and the EPR pressurized-water reactor.

The Commission is able to reach this final step in approving the amended AP1000 reactor design due to the staff’s dedicated work ensuring the design meets NRC’s safety requirements. The design provides enhanced safety margins through use of simplified, inherent, passive, or other innovative safety and security functions, and also has been assessed to ensure it could withstand damage from an aircraft impact without significant release of radioactive materials.

—NRC Chairman Gregory B. Jaczko

The Commission has also found good cause to make the rule immediately effective once it is published in the Federal Register; the rule is expected to be published within seven business days. NRC rules normally become effective 30 days after publication. The Federal Register notice and the Commission’s directions to the staff on publishing the approved rule will include a discussion on the good cause finding.

The design certification process provides for public participation and early resolution of safety issues for proposed reactor designs. NRC certification, in the form of a final rule, means the design meets the agency’s applicable safety requirements. If an applicant for a nuclear power plant license references a certified design, the applicant need not submit safety information for the design. Instead, the license application and the NRC’s safety review would address the remaining safety issues specific to the proposed nuclear power plant.

US Energy Secretary Steven Chu issued a statement in support of the Nuclear Regulatory Commission’s (NRC) decision to certify Westinghouse Electric’s AP1000 nuclear reactor design, a significant step towards constructing a new generation of U.S. nuclear reactors. In February 2010, the Obama Administration announced the offer of a conditional commitment for a $8.33 billion loan guarantee for the construction and operation of two AP1000 reactors at Alvin W. Vogtle Electric Generation Plant in Burke, Georgia.

The Administration and the Energy Department are committed to restarting America’s nuclear industry&madsh;creating thousands of jobs in the years ahead and powering our nation’s homes and businesses with domestic, low-carbon energy. Today’s decision certifying the AP1000 reactor design marks an important milestone towards constructing the first US nuclear reactors in three decades.

—Secretary Chu

Resources

• Design Certification Application Review - AP1000 Amendment