AP1000 - Safety Concerns

Safety Concerns

In April 2010, Arnold Gundersen, a nuclear engineer commissioned by several anti-nuclear groups, released a report which explored a hazard associated with the possible rusting through of the containment structure steel liner. In the AP1000 design, the liner and the concrete are separated, and if the steel rusts through, "there is no backup containment behind it" according to Gundersen. If the dome rusted through the design would expel radioactive contaminants and the plant "could deliver a dose of radiation to the public that is 10 times higher than the N.R.C. limit" according to Gundersen. Vaughn Gilbert, a spokesman for Westinghouse, has disputed Gundersen’s assessment, stating that the AP1000's steel containment vessel is three-and-a-half to five times thicker than the liners used in current designs, and that corrosion would be readily apparent during routine inspection.

Edwin Lyman, a senior staff scientist at the Union of Concerned Scientists, has challenged specific cost-saving design choices made for both the AP1000 and ESBWR, another new design. Lyman is concerned about the strength of the steel containment vessel and the concrete shield building around the AP1000. The AP1000 containment vessel does not have sufficient safety margins, says Lyman.

Potentially the most damaging critique of the AP1000 comes from John Ma, a senior structural engineer at the NRC.

In 2009, the NRC made a safety change related to the events of September 11, ruling that all plants be designed to withstand the direct hit from a plane. To meet the new requirement, Westinghouse encased the AP1000 buildings concrete walls in steel plates. Last year Ma, a member of the NRC since it was formed in 1974, filed the first "non-concurrence" dissent of his career after the NRC granted the design approval. In it Ma argues that some parts of the steel skin are so brittle that the "impact energy" from a plane strike or storm driven projectile could shatter the wall. A team of engineering experts hired by Westinghouse disagreed...

In 2012, Ellen Vancko, from the Union of Concerned Scientists, said that "the Westinghouse AP1000 has a weaker containment, less redundancy in safety systems, and fewer safety features than current reactors".