Kerri Kavanagh
Chief, Quality Assurance and Vending Inspection Branch
The NRC doesn’t just oversee how nuclear power plants operate. We
also oversee the quality of the important components that go into the
reactors. That’s why NRC staffers are working with the French Nuclear
Safety Authority and AREVA, a manufacturer of reactor components, to
determine if a quality assurance investigation underway in France has
implications for U.S. plants.
ASN – the acronym for the French regulator —
requested
the probe in early May after a flaw was discovered in the vessel of a
reactor under construction at Flamanville in France. So AREVA checked
the manufacturing records of the Le Creusot Forge, in central France.
They found anomalies in the records of about 400 parts manufactured
there since the plant opened in 1965. (Le Creusot Forge was purchased by
AREVA in 2006.)
ASN
says these are paperwork irregularities – inconsistencies,
modifications or omissions in production files concerning manufacturing
parameters or test results. The irregularities are troubling because
complete documentation provides assurance the components were forged to
the proper procedures and specifications.
They do not mean, however, that any parts or components manufactured at Le Creusot are defective.
AREVA
announced at the end of May
that it had completed two-thirds of its review and found no indications
of safety issues. The company told the NRC about 10,000 documents are
still under review. The company pledged to provide us with a list of
U.S. plants affected by these paperwork irregularities when the
investigation is completed around the end of July. We’ll continue to
engage with ASN and AREVA to make sure we have a complete picture of how
these irregularities may affect any components provided to U.S. nuclear
power plants.
NRC’s regulations in
10 CFR Part 21,
“Reporting of Defects and Noncompliance,” require any entity that
identifies reportable issues to evaluate them and inform the users of
any impacted components. The users then have 60 days to do their own
safety evaluations. If the users identify significant safety hazards,
they must report these to the NRC by phone within two days, and in
writing within 30 days.
AREVA and Le Creusot Forge are under contractual obligations to their
U.S. customers (who are NRC licensees) to follow these reporting
requirements. We’ll take appropriate regulatory and enforcement action
if we find issues of safety significance. At this time, there is no
indication of a safety issue with any components from Le Creusot covered
by this quality assurance audit.
Regarding new reactors, Westinghouse Electrical Co., the
architectural engineering firm for the AP1000 reactors under
construction at Vogtle and V.C. Summer, has confirmed that no components
at these plants were supplied by Le Creusot Forge.
Once AREVA completes its audit and we have a complete picture of the
situation, the NRC has several options. We may issue a generic
communication to keep the broader nuclear industry informed. We may also
perform inspections to ensure conformance and compliance with our
regulations.
More information will be coming on this issue. If the NRC determines
that Le Creusot Forge has provided components to U.S. nuclear power
plants, we’ll make sure those components are fully evaluated to
determine any impact the documentation irregularities might have on
their safety-related functions.
We’ve
talked before about how the uranium in nuclear fuel undergoes fission
during reactor operations. The fission process turns uranium into a
number of other elements, many of which are radioactive. These elements
continue to produce large amounts of radiation even when the fuel is no
longer supporting a chain reaction in the reactor. So shielding is
necessary to block this radiation, and protect workers and the public.
But
spent fuel also emits neutron radiation (particles from the nucleus
that have no charge) and gamma radiation (a type of electromagnetic ray
that carries a lot of energy). Both neutron and gamma radiation are
highly penetrating and require shielding.
The
NRC reviews spent fuel dry cask storage designs to ensure they meet
our limits on radiation doses beyond the site boundary, under normal and
accident conditions, and that dose rates in general are kept as low as
possible. Every applicant must provide a radiation shielding analysis as
part of the application for a new storage system, or an amendment to an
existing system. This analysis uses a computer model to simulate
radiation penetration through the fuel and thick shielding materials
under normal operating and accident conditions.
