Groups Ask Nuclear Agency to Delay Certification of Flawed AP1000 Reactor

DURHAM, North Carolina, November 11, 2011 (ENS) – The U.S. Nuclear Regulatory Commission is being asked to withhold certification for the new Westinghouse-Toshiba AP1000 nuclear reactor until flaws in its design exposed by Japan’s nuclear disaster are resolved. Two utilities plan to install the untried reactor in Georgia and South Carolina.

Public interest groups Thursday filed a legal motion petitioning the NRC to require the resolution of design issues with the Westinghouse-Toshiba AP1000 nuclear reactor before the certification of the reactor’s design and operating procedures.

The AP1000 pressurized water reactor has been selected by Southern Company for installation at the Plant Vogtle site near Waynesboro in eastern Georgia near the South Carolina border.

South Carolina Electric and Gas also has chosen the AP1000 for its Virgil C. Summer site near Jenkinsville, 20 miles northwest of Columbia, South Carolina.

Artist’s rendition of two Westinghouse-Toshiba AP1000 nuclear reactors (Image courtesy SC Nuclear)

The utilities cannot obtain licenses to start reactor construction until the AP1000 is certified.

But NRC commissioners are considering a final vote on the plant design without responding to a long list of problems raised earlier by experts within and outside the industry, say the petitioning groups – the AP1000 Oversight Group, Friends of the Earth and the North Carolina Waste Awareness and Reduction Network, NC WARN.

The groups say federal regulations require correction of problems with the reactor design during the design certification phase – not after construction of the AP1000 begins in Georgia and South Carolina.

With their legal motion, the groups filed a report they commissioned from nuclear engineer Arnie Gundersen, which documents seven unreviewed safety concerns involving the AP1000 design.

Gundersen’s concerns are based on the ongoing disaster at Japan’s Fukushima Daiichi nuclear power plant where a magnitude 9.0 earthquake and tsunami on March 11 cut off outside power to the nuclear plant operated by Tokyo Electric Power Co, TEPCO.

Smoke rises from TEPCO’s Fukushima Daiichi Unit 3 with the damaged Unit 4 to the right, March 21, 2011 (Photo courtesy TEPCO)

In the five days following the quake, there were hydrogen gas explosions in three of the plant’s six reactors, and partial meltdown of nuclear fuel rods in three of the reactors caused by loss of cooling water functions.

Radiation releases caused more than 80,000 people to evacuate a 30 kilometer (20 miles) area around the power plant on Japan’s Pacific coast, and they are still displaced. The accident is rated at Level 7, the highest on the UN’s International Nuclear Event Scale, and is considered the world’s second most serious nuclear disaster, after Chernobyl.

Gundersen, of Fairewinds Associates in Burlington, Vermont, reports “at least seven failure modes that the NRC and Westinghouse have not considered … impacting the ability of the Westinghouse passive design to cool” the reactor and spent fuel pools.

A nuclear engineer and former nuclear industry senior vice-president, Gundersen says Westinghouse’s assumption of zero probability of reactor and/or spent fuel cooling failure “is a blatant manipulation of a safety code designed to protect public health and safety.”

“Fukushima Unit 4 released enormous amounts of radiation when its spent fuel pool cooling system was shut down during the tsunami – and the lessons learned from this disaster must be applied in the design phase of the AP1000,” said Gundersen at a news conference Thursday.

Nuclear engineer Arne Gundersen (Photo courtesy Fairewinds Associates)

“This same sequence is possible on the AP1000, but the NRC and Westinghouse-Toshiba have factored a zero percent chance of such an accident occurring,” he warned.

The AP1000 Oversight Group has already identified the inability of the AP1000 shield building to act as an effective ultimate heat sink and its containment system to prevent releases of radioactivity in the event of an accident.

Gundersen identifies further concerns. One is that the AP1000 containment system is “extraordinarily close to exceeding its peak post accident design pressure.”

“Given that three out of three Containment Systems have failed at Fukushima, such a pressure burden to the Containment System is too great a risk to public health and safety,” the groups warn.

They point to an admission by TEPCO on November 2 that melted nuclear fuel inside three of the Fukushima reactors was emitting traces of a radioactive gas that is a byproduct of nuclear fission.

This means the fuel is probably continuing to experience bursts of fission although the reactors have all been shut down since March 11, officials said.

Westinghouse-Toshiba’s analysis assumes that once a nuclear reactor is shut down after an accident has begun, the reactor stays shut down, the groups say.

Fukushima Daiichi Unit 3 (Photo courtesy International Atomic Energy Agency )

“Even though the Fukushima accidents have clearly proven the fallacy of this Westinghouse-Toshiba calculation, Westinghouse-Toshiba does not include any additional heat from a continuing nuclear fission reaction like the Fukushima atomic power plants are currently experiencing,” they warn.

Many other problems with the AP1000 design are outlined in the petition. A “significant and irreconcilable flaw” is that the Westinghouse-Toshiba analysis assumes zero probability that the reactor could not be cooled by emergency means if the onsite emergency service water pumps were knocked out.

That is known as “the loss of the ultimate heat sink” and it is exactly what occurred at the Fukushima Daiichi nuclear plant. TEPCO attempted to cool the reactors and spent fuel pools by spraying water over the units with pump trucks, but did not manage to avoid meltdowns of the fuel.

“The four nuclear power plant accidents at Fukushima confirmed that a Loss of the Ultimate Heat Sink accident has an astronomically high probability of occurring, as in four out of four accidents, or 100%, and not the zero probability assumption currently predicted by Westinghouse-Toshiba,” the petition warns.

“The Commission will be legally negligent if it certifies the AP1000 without a thorough analysis of the critical issues we have raised,” said Jim Warren of NC WARN.

While the legal motion was filed with the Nuclear Regulatory Commission, Warren indicated that the groups are prepared to take the NRC to court.

“It’s a shame if a federal court must order the NRC to protect public safety, and to protect the ratepayers from design corrections attempted once construction begins, when corrections will be far costlier,” he said.

But the NRC staff has signed off on the AP1000 certification and the certification package was submitted to the Commission on October 21, 2011.

The certification package was not available for public scrutiny until November 2, when it was placed in the NRC’s ADAMS database as “NRC Responses to Public Comments, ADAMS ML112212319.”

The groups said in their petition, “We are disappointed the staff did not respond to, or even analyze, most of the comments by the Oversight Group and others.”

Given these and other serious concerns, Gundersen concludes that “certification of the AP1000 should be delayed until the original and current unanswered safety questions raised by the AP1000 Oversight Group are resolved.”

On its website, Westinghouse says, “The AP1000 design saves money and time with an accelerated construction time period of approximately 36 months, from the pouring of first concrete to the loading of fuel. Also, the innovative AP1000 features 50% fewer safety-related valves and 80% less safety-related piping, the company says.

Yet, “AP1000 is 100 times safer than current plants,” the company says.

The groups maintain it is the construction schedule of the utilities to which the NRC has given paramount importance over a resolution of continuing safety issues, including lessons being learned from the Fukushima accident.

“The utilities don’t want their activities stalled. They want to put rebars in the hole and start pouring concrete, they want to continue forward momentum,” Warren told reporters. The NRC has some “disdain for public interest in these issues.”

Licenses for the AP1000 are also being sought by other southeastern utilities such as Duke Energy, Progress Energy and Florida Power and Light.

Click here to see the presentation by Westinghouse of the AP1000 reactor.

Copyright Environment News Service (ENS) 2011. All rights reserved.