Westinghouse Electric Co. and U.S. regulators are wrangling over statements made about the safety of the AP1000 nuclear reactor design, which could be used in at least 14 proposed reactors in the United States.
Attention to the approval process and nuclear safety has piqued in the aftermath of Japan's nuclear crisis triggered by the March 11 earthquake and tsunami that ripped through the Fukushima Daiichi plant.
Westinghouse, a subsidiary of Toshiba Corp., yesterday said statements the NRC made about safety issues with the design led to misinterpretation and speculation about the AP1000. In a release on May 20, NRC Chairman Gregory Jaczko called on the company to make certain safety changes to its design before the agency would consider the proposal, first submitted in December 2010.
"NRC statements regarding the discovery of new issues relating to the approval of design amendments for the AP1000 nuclear power plant are being misinterpreted and sensationalized," Ricardo Pérez, president of operations for Westinghouse, said in a statement yesterday. "NRC statements, including a news release issued May 20, do not reflect Westinghouse's transparent and cooperative approach to the handling of the discovery and severity of the few remaining issues that need to be resolved before receiving approval from the NRC."
The design calls for a 1,100-megawatt electric pressurized-water reactor that includes passive safety features to cool the reactor after an accident without the need for human intervention.
Jaczko said ongoing discussions revealed safety issues that had to be addressed, including questions about thermal and seismic stresses on the shield building and calculations for how much stress can be exerted on the passive containment cooling system, which holds water in case of emergencies.
But Westinghouse said both regulators and the company were aware of the three remaining issues, none of which were significant or will change the design.
Even so, Jaczko issued the release and again mentioned the issue in an op ed for the Huffington Post published yesterday. In the piece, Jaczko said that as a commissioner at the NRC for more than six years and chairman since 2009, he has seen the transparent and tremendous amount of work the agency has taken on. But he also notes that a "skewed picture" of the NRC has emerged in some stories that paint the agency as an ineffectual regulator.
Jaczko defended the agency, pointing directly to his order for staff to resolve significant design concerns with the Westinghouse AP1000 reactor design.
"This took place in full view of the public, including a dissenting opinion by one of our staff members," the chairman wrote. "Despite this transparency, there was little public recognition that this highlighted the NRC's commitment to safety."
Westinghouse expects to resolve the issues and receive final approval for the design this September, said Vaughn Gilbert, a company spokesman.
Westinghouse has been identified as the supplier for 14 U.S. reactors and has contracts for building six of those reactors. Significant pre-construction work is already under way for four of the plants, and Westinghouse is also building four plants -- although the design is slightly different -- in China that will come online in 2016.
The NRC and Westinghouse have agreed that the containment vessel internal pressure calculation needs to be revised, and that those calculations will be reviewed by the commission in a public forum on June 2, Westinghouse said.
In April, the NRC challenged Westinghouse's analysis of its shield building design report submitted in May 2010, specifically the amount of heat and light the structure could receive needed to be combined with seismic risks. Westinghouse agreed to perform detailed calculations to assure the NRC the structure was safe and presented the data to the agency last week.
The company says it also self-identified issues with a passive containment cooling system tank that holds water to be used during emergencies. The company hadn't used specific model outputs for one corner of the structure of the tank, but said preliminary conclusions indicate there is no reason to change the tank design.
But NRC spokesman Scott Burnell said the agency had expected to complete the certification process for the design by the end of the summer but will not be able to meet that deadline. The agency, he said, is working through thousands of comments on the design and will revise the timeline as soon as the safety issues are resolved.