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Millstone first US reactor to exam at-risk Creusot component but avoids conclusive testing

Dominion Energy’s Millstone Unit 2 in Waterford, CT became the first and still only of seventeen U.S. reactors with at-risk Creusot Forge components to voluntarily inspect its reactor pressurizer manufactured at France’s controversial Creusot Forge.  An Utrasonic Test (UT) enhanced visual examination found no signs of defects or cracking on the 11-year old replacement part.  The Creusot Forge, owned by AREVA, is under investigation for the manufacture and global marketing of reactor components weakened by excess carbon contamination and falsifying quality assurance documentation.  Beyond Nuclear has been pushing US operators and the U.S. Nuclear Regulatory Commission (NRC) through an emergency enforcement petition to do the enhanced visual inspections and more important material testing to determine the carbon content in the steel of the Creusot components.   Dominion is not planning to do any material testing that would provide a quantitative measure of the carbon content which can weaken the component and potentially fail during operation.

Media attention and public concern in part generated by the Beyond Nuclear petition prompted the State of Connecticut’s Department of Energy and Environmental Protection (DEEP) to request that Dominion hire an independent contractor to conduct an Ultrasonic Test (UT) to conduct an enhanced visual inspection for cracking and defects on the reactor component. The UT results, announced April 11, 2017, found no evidence of cracking or a defect in the stainless-steel component. However, Beyond Nuclear and it co-petitioners are arguing that the UT exam would not have provided any data on the controversial root cause, excess carbon contamination or “carbon macrosegregation,” that can only be detected by material testing samples of the components’ elemental chemistry.  The presence of excessive carbon in steel once under the harsh operational environment of a nuclear power plant leaves it vulnerable to rapid tearing and cracking of the large forged reactor vessels, reactor vessel replacement heads, steam generators and pressurizers resulting in a potentially catastrophic loss of coolant accident.

Newly surfaced documents authored in 2005 and 2006 by France’s nuclear safety agency (ASN) publicly released by a French news agency reveal that the French nuclear industry, EdF and AREVA, knew that the Creusot Forge had  serious manufacturing discrepancies coupled with loss of control of quality assurance and proceeded with the manufacturing and global marketing of suspected at-risk components anyways. The director of ASN was "blown away" by the negligence he witnessed during his personal inspection of the forge.  Millstone 2 received and installed its replacement reactor pressurizer from Creusot in 2006. 

A January 2017 ASN-led multinational inspection report as described by its head of nuclear equipment, Remy Catteau, found that the AREVA-Creusot Forge was “Ill-equipped” to manufacture nuclear-grade components for the industry. In a Reuter news service interview, Catteau explained that the Creusot Forge’s limited technology had resulted in manufacturing errors (carbon macrosegregation) and "One of the ways to resolve problems was to hide things, and that was the wrong way."