* Reactor shut for refuelling Oct. 22
* Oyster Creek reports new pinhole leak
* NRC monitoring company response to new leak
* Exelon did not say when reactor would exit refuel
By Scott DiSavino
Nov 27 U.S. power company Exelon Corp
completed repairs on a reactor vessel nozzle at the Oyster Creek
nuclear power plant in New Jersey, federal nuclear regulators
"The company's weld overlay repairs to a reactor vessel
nozzle found recently to have two "indications" (flaws or
defects) are now completed," Neil Sheehan, a spokesman for the
U.S. Nuclear Regulatory Commission (NRC) said in an email.
"Our inspectors will review the final ultrasonic testing
data to ensure we are satisfied with the repair work," he said.
On Monday, Exelon said the 615-megawatt (MW) plant was in a
safe shutdown mode and it would fix the nozzle before the
reactor could exit a refuelling outage.
The company however did not say when the 43-year old unit -
the oldest operating reactor in the United States - would exit
the outage, which began on Oct. 22.
Separately, Exelon told the NRC in an event report early
Tuesday it found a pinhole leak of about 2 to 3 drops per minute
during testing of the reactor head spray line. The leak is
through an earlier weld.
The NRC said the line was part of a reactor vessel head
cooling system, which is only used when the plant is shutting
down. Its purpose is to assist in reactor vessel head cooling
The company said it was investigating the cause of the leak
and developing a plan to fix the problem.
The NRC said its specialists will engage Exelon on the leak
and review the company's investigation into the flaw and its
Earlier, the NRC said it had a metallurgist at Oyster Creek
to make sure the agency was satisfied with the nozzle overlay
Exelon said the indication in the nozzle was found during a
dye inspection of the reactor.
The NRC said the nozzle is used for the control rod drive
mechanism. Control rods are made of materials that absorb
neutrons and are used to control the power output or shut a
To fix the indication, which the NRC said was not a crack
but could grow into a crack if left unaddressed; Exelon ground
down the metal around the indication and welded a metal overlay
on top of the site to keep it within engineering standards for
All refuelling outages are busy, but this one was especially
active for Oyster Creek.
The plant declared an alert on Oct. 29 as water rose in the
plant's water intake structure due to the rising tide, and wind
and storm surge from Hurricane Sandy.
The NRC said there were no safety concerns because the plant
did not have to contend with a reactor shutdown since Sandy
passed through the area when the unit was already shut for
The NRC however on Nov. 13 said it started a special
inspection to gain a better understanding of how the intake
water level information was monitored and communicated during
the Sandy event.
STATE: New Jersey
TOWN: Forked River about 60 miles (96 km) east of
OPERATOR: Exelon Nuclear
OWNER(S): Exelon Nuclear
CAPACITY: 615 MW
UNIT(S): General Electric boiling water reactor
1965 - Construction started
1969 - Plant enters service, making it the oldest
operating nuclear plant in the United States
1999 - GPU Inc agreed to sell reactor to AmerGen for $10
2003 - Exelon bought AmerGen in 2003
2005 - Exelon applied with the NRC to extend the
operating license before the license was to
expire in 2009
2009 - NRC renewed the reactor's original 40-year
operating license for another 20 years
2010 - Exelon agreed with New Jersey to shut reactor
in 2019 to avoid building cooling towers
2019 - Oyster Creek reactor to shut
2029 - Operating license expires