* NRC says Mitsubishi Heavy failed certain requirements
* SCE wants to restart Unit 2 at San Onofre
* NRC may approve of San Onofre 2 restart in March
* San Onofre reactors shut in January
Dec 19 California power company Southern
California Edison (SCE) said it did not rely on testing by
Japanese engineering firm Mitsubishi Heavy Industries Ltd
to develop its restart plan for Unit 2 at the San
Onofre nuclear plant in California.
Both reactors at the 2,150-megawatt (MW) San Onofre plant
shut in January due to tube wear problems in the units' new
steam generators. Mitsubishi Heavy built those steam generators
and installed them in 2010 and 2011.
The U.S. Nuclear Regulatory Commission (NRC) said in a
letter posted on its website that Mitsubishi Heavy failed to
meet certain requirements related to the mock-up and testing of
re-designed components for the steam generators that may be used
to repair the San Onofre steam generators.
But in a statement Tuesday night, SCE, a unit of California
power company Edison International, said it did not
consult or rely upon the Mitsubishi testing under review by the
NRC to create the utility's plan to restart Unit 2.
The NRC is also reviewing SCE's plan to restart Unit 2 and
may issue a decision on that plan in March. The reactor cannot
restart without the NRC's approval.
SCE's plan to restart Unit 2 includes preventive plugging of
tubes in the steam generators and operating the 1,070-MW unit at
70 percent power for a five-month period.
San Onofre is one of the biggest power plants in California
and its shutdown since January has caused reliability challenges
for the Southern California power grid.
SCE said its team of experts conducted three independent
operational assessments of tube wear. The assessments were done
by units of nuclear engineering firm Areva SA of
France, the Westinghouse Electric unit of Japan's Toshiba Corp
, and international testers at Intertek/Aptech.
SCE said none of its experts based their review and
recommendations on testing by Mitsubishi. SCE said this was
confirmed Tuesday at an NRC public meeting in Rockville,
SCE submitted technical information to the NRC in October in
support of its proposed restart plan for Unit 2. That plan did
not include a restart for Unit 3 in part because the steam
generators in Unit 3 suffered more tube wear.
The company shut Unit 2 on Jan. 9 for a planned outage. Unit
3 shut on Jan. 31 after station operators detected a leak in a
steam generator tube.
SCE operates San Onofre for its owners: SCE (78.21 percent),
Sempra Energy's San Diego Gas & Electric (20 percent)
and the city of Riverside (1.79 percent).