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Rapid Response: Activists Claims Distort Facts About Advanced Reactor Design, April 21, 2010

Today, regional anti-nuclear organizations asked federal nuclear energy regulators to launch an investigation into what it claims are “newly identified flaws” in Westinghouse’s advanced reactor design, the AP1000. During a teleconference releasing a report on the subject, participants urged the Nuclear Regulatory Commission (NRC) to suspend license reviews of proposed AP1000 reactors.

In its news release, even the groups making these allegations provide conflicting information on its findings. In one instance, the groups cite “dozens of corrosion holes” at reactor vessels and in another says that eight holes have been documented. In all cases, there is another containment mechanism that would provide a barrier to radiation release.

Below, we examine why these claims are unwarranted and why the AP1000 design certification process should continue as designated by the NRC.


Myth: In the AP1000 reactor design, the gap between the shield building and reactor containment (which surrounds the reactor core to protect the public and the environment in the case of a radiation release) allows for “numerous locations where rust can develop on the steel containment.” This rust could create a hole large enough that, during an accident, the radiation dose to the public could be “ten times greater than the NRC allows.”

The Facts: Compared to the example cited in the report, the AP1000 containment vessel is more accessible for inspection and makes use of thicker, corrosion-resistant steel. NRC requirements for inspection and maintenance, as well as operational testing, would preclude an undetected corrosion of steel used in the reactor containment structure.


The report alleges that the gap between the plant shield building and containment creates an area that is “extraordinarily difficult to detect until the rust creates a hole completely through the steel.” In reality, unlike the example cited by the report, the AP1000 containment vessel is accessible for inspection.

Furthermore, the AP1000 containment vessel is made of high-quality, 1.75” thick steel. Water corrosion as specified in the critics’ report would require rates that simply are not credible. Operational testing and inspection would reveal any flaw, especially those significant enough that could lead to a hole of the hypothetical size stated.

Finally, the containment vessel itself is built to American Society of Mechanical Engineers codes that have more than 100 years of proven safety margin protection to the public.

For a copy of Arnold Gundersen's statement and visuals used in the report, see

For more on the AP1000’s safety features, click here.