WINNSBORO – For the second time in 12 months, federal
nuclear inspectors have noted defects in critical hardware at the V.C. Summer
nuclear plant in Fairfield County.
On October 4, the Nuclear Regulatory Commission (NRC)
informed Dominion Energy, which operates V.C. Summer, of an apparent violation
of “substantial safety significance.”
The NRC issued a preliminary “Yellow” assessment, the second
most serious level, involving an emergency diesel generator. The generators
provide emergency power during blackouts.
Red assessments are the most serious, followed by Yellow,
White, and Green.
Yellow assessments indicate a “substantial safety or
security significance finding,” according to the NRC.
NRC spokesman Dave Gasperson estimated the agency would
probably make a final determination sometime in November after holding a public
regulatory meeting.
V.C. Summer will have an opportunity to respond to the
Yellow assessment, he said.
“It’s up to V.C. Summer if they want to present information
during a conference or submit a written response,” Gasperson said.
In a prepared statement, Dominion acknowledged that backup
systems are critical in the operation of nuclear power plants.
“At Dominion Energy, safety is our top priority,” the
statement says. “Rigorous internal and external controls are in place to
ensure all equipment is maintained and operates as designed.”
According to the NRC report, federal inspectors found
defects that left the generator vulnerable to piping cracks. The report also
stated that pipe cracks had been detected during prior testing.
“Despite the challenge to maintain leak-tight connections
and repeat occurrences of cracked piping, no significant changes were made to
maintenance practices, procedures or system design, and the licensee continued
to reactively monitor for leakage even after vulnerabilities were identified,”
the report states.
Documented issues of cracking had been reported as far back
as 2003, the report continues.
“The licensee treated individual pipe failures as
‘broke/fix’ rather than identifying the system vulnerability,” the report
states. “The licensee fixed the cracked piping/fittings but failed to identify
and correct the failure mechanism that affected the fuel oil system piping.”
In its statement, Dominion said it would continue to work on
maintaining compliance with federal nuclear regulations.
“With a commitment to continued safe operations, we are
inspecting and maintaining our generator and related components,” the statement
said. “We will continue to keep the
NRC updated on our future strategy
to further enhance our diesel generators.”
The preliminary Yellow assessment comes almost exactly a
year after the NRC noted safety defects in another V.C. Summer emergency diesel
generator, prompting the federal agency to issue a White assessment, according
to documents obtained by The Voice.
White assessments are less serious than Yellow assessments.
They indicate a “low to moderate safety or security significance finding,”
according to the NRC.
Specifically, Dominion failed “to adequately assess erratic emergency diesel generator governor operation, which resulted in an inoperable [generator],” according to the 2022 violation.
“The [generator] was exhibiting other-than-expected and
non-routine conditions in the form of significant fuel rack and kilowatt
swings,” the violation letter states. “These conditions resulted in a condition
of the indeterminate cause and other-than expected equipment performance found
during surveillance testing.”
V.C. Summer has received at least two other White assessment
violations since 2000, according to the NRC database.
Both occurred when SCANA ran V.C. Summer.
In 2006, the NRC issued a violation notice when V.C. Summer received
a shipment of radioactive material “in a package with radiation levels on an
external surface that exceeded applicable regulatory requirements.”
The package was then taken from V.C. Summer to an unnamed
offsite waste processing vendor, according to the NRC.
The second White assessment was issued in 2000 after the NRC
discovered a turbine driven emergency feed water pump had become inoperable,
records show.
Emergency water pumps help to cool reactors in the event of
a shutdown.
