ML020730547
| ML020730547 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 03/12/2002 |
| From: | Office of Public Affairs Region II |
| To: | |
| References | |
| Press Release-III-02-002 | |
| Download: ML020730547 (2) | |
See also: see also:Press Release-III-02-002
Text
NRC NEWS
U.S. NUCLEAR REGULATORY COMMISSION
OFFICE OF PUBLIC AFFAIRS, REGION III
801 Warrenville Road
Lisle IL 60532
Web Site: http://www.nrc.gov
No. III-02-002
March 12, 2002
CONTACT:
Jan Strasma (630) 829-9663
E-mail: opa3@nrc.gov
NRC TO CONDUCT AUGMENTED INSPECTION
OF DAVIS-BESSE REACTOR VESSEL DAMAGE
The Nuclear Regulatory Commission has begun a Augmented Team Inspection into damage to
a small area of the top of the reactor vessel, apparently caused by corrosion, at the Davis-Besse Nuclear
Power Station. The plant, located at Oak Harbor, Ohio, is operated by FirstEnergy Corporation.
The plant has been shut down since February 16 for refueling and maintenance.
The cavity in the top of the reactor vessel was discovered during inspection and repair activities
in the outage. It is about 4 inches by 5 inches and approximately 6 inches deep. The reactor vessel
head, fabricated of carbon steel with a stainless steel liner, is about 6 1/2 inches thick.
During the outage, plant personnel inspected 69 control rod tubes which pass through the
reactor vessel head. The NRC issued a bulletin last August requiring the detailed inspections at Davis-
Besse and other sites after cracking problems were found at several other nuclear plants.
Using ultrasonic techniques, FirstEnergy workers found cracks through the tube walls in three
tubes, and lesser cracks in two additional tubes.
During repairs to one of the tubes with through-wall cracks, workers discovered the void
adjacent to the tube.
The NRCs Augmented Inspection Team, comprised of metallurgical and engineering
specialists, will monitor the utilitys investigation and evaluation of the cavity and its determination of
the conditions causing the damage. The inspection is being conducted to better understand the
circumstances surrounding the corrosion and damage and to consider whether similar conditions might
exist at other plants.
The preliminary cause of the damage appears to be corrosion as a result of boric acid deposits.
Boric acid is a constituent of the water in the reactor cooling system and was apparently deposited on
the reactor vessel through the leaking crack in the control rod tube or some other source.
The utility is developing its plans for repair of the reactor vessel head. The NRC will review
the utilitys plans.
Following completion of the inspection, the NRC will hold a meeting in the plant vicinity to
discuss the inspection findings. The meeting will be open to public observation.
The inspection report, issued about four weeks after the inspection, will be available on the
agencys website and through its Electronic Reading Room at http://www.nrc.gov as an Agencywide
Document Access and Management System (ADAMS) document. Help in using ADAMS is available
through the NRC Public Document Room at 301/415-4737 or 800/397-4209.
The NRC has issued an Information Notice to operating nuclear plants to inform them of the
corrosion damage at Davis-Besse. The notice will be available online in the Electronic Reading Room
with the accession number of ML020700556.
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