A more thorough inspection yesterday of the second, smaller
acid-created cavity on top of the reactor vessel head at the
Davis-Besse nuclear plant initially shows less corrosion than
expected, a FirstEnergy spokesman said.
Workers yesterday machined out a tight-fitting control rod nozzle
next to the small cavity to get a better look at the damage
apparently created by a boric acid leak. The 150-ton carbon steel
vessel head is a vital safety component that covers the radioactive
``It looks to be about what they thought it was earlier,'' plant
spokesman Richard Wilkins said. ``If anything, it's actually smaller
than we thought it was. They'll be taking a closer look at it over
the next few days.''
The nozzles allow special rods to be inserted into the reactor
chamber to control the fission process. A large, 6-inch-deep cavity
was found next to one of the reactor head's 69 nozzles in early
March after the plant was shut down in mid-February for refueling
and a safety inspection.
Boric acid, part of the reactor coolant, apparently leaked
through hairline fractures in what is called nozzle No. 3 and ate
entirely through the vessel head's carbon steel exterior. A thin
layer of stainless steel lining kept the acid from creating a bad
``loss of coolant'' accident inside the plant in Oak Harbor, about
25 miles east of Toledo.
The second, much smaller cavity was subsequently found at
adjacent nozzle No. 2.
Wilkins said nozzle No. 2 probably will be capped off and the
control rod device for that specific nozzle moved to a backup nozzle
at another location on the reactor vessel head.
The Nuclear Regulatory Commission will hold a public meeting
tomorrow at Oak Harbor High School to announce findings by its team
of inspectors. The meeting starts at 9 a.m. The school is at 11661
W. State Route 163.
The NRC will hold another meeting April 10 at its Rockville, Md.,
headquarters, where FirstEnergy will present plans to repair the
acid-created damage. The NRC can reject any repair plans and force
FirstEnergy to replace the damaged vessel head, a process that could
keep the plant closed for two years or longer. FirstEnergy has said
it expects repairs will cost between $5 million and $10 million and
keep the plant closed through at least the end of June.
Nozzle cracking became an industrywide issue after cracks were
found in nozzles at other power plants. But Davis-Besse is the first
nuclear plant found with cavities that apparently are related to the
nozzle cracking issue.
The NRC subsequently ordered the 68 other similar nuclear power
plants in the country to ensure that they don't have the same kind
of damage. Those reports were due at the NRC yesterday. An NRC
spokesman said a final tally on the reports won't be available for a
couple of days.