ML023570333

E-mail from B. Gabriel to Chairman Meserve'S Office Staff, Fwd: PNO-II-02-006B, Davis-Besse

ML023570333
Person / Time
Site:	Davis Besse
Issue date:	04/05/2002
From:	Gabriel B NRC/OCM
To:	Meserve R NRC/Chairman
References
PNO-III-02-006B
Download: ML023570333 (4)

Text

,tMichael'Tschiltz - Fwd: PNO-111-02-006B - Davis Besse .T. Page

,I MicaeIshitz- wd:PN1II-2I06 avs..se .. ag From: Barbara Gabnel A --1/7o To: MESERVE Date: Fri, Apr 5, 2002 10:36 AM

Subject:

Fwd: PNO-III-02-006B - Davis Besse oc¶o-aq*

Michaer Tschiltz - PNO-1I1-02-006B - Davis Besse Page.

From: Adeline Saso To: A. Vicky Lewis; Alicia Penaherrera; Barbara Gabriel; Bradley Jones; Brenda Platchek; Brent Clayton; Brian McCabe; Bruce Berson; Bruce Burgess; Bruce Jorgensen; Catherine Poland; Cathy Jaegers; Chris Miller, Constance Yusko; Consuella Debnam; Cynthia Pederson; Diane Flack; Donna Smith; Gary Shear; Greta Dicus; Headquarters Operations Officer 2; Heather Astwood; J. Anita Summerour; Jan Strasma; Janet Kweiser; Jeannette M Whitaker; Jeffry Sharkey; Jo Carson; John Davidson; John Grobe; John Madera; John Thoma; Joseph Himes; Judy Ledbetter; Julie Crutchley, Karen Jackson; Kay Gallagher; Kenneth Clark; Kim Lee; Linda Herr; Linda Lewis; Lorna Pini; Maggalean Weston; Marc Dapas; McGaftmp McGaftmp; Melba Hawkes; Michael Markley; Michael Mayfield; Monte Phillips; Nancy Belmore; Noble Green; NRCWEB; OPA; Patrick Hiland; PN1; Rick Croteau; RidsSecyMailCenter; Roger Davis; Roger Hannah; Roland Lickus; Roy Caniano; Sandra Figueroa; Shirley Rohrer; Steven Reynolds; Susan Abrahams; Terry Agneu; Theresa Mayberry, Thomas Hiltz; Thomas Kozak; Tojuana Fortune; Tonya Russell; Vicki Boiling; Victoria Ibarra Date: Fri, Apr 5, 2002 10:25 AM

Subject:

PNO-1I1-02-006B - Davis Besse Please see attached PN which is going into Adams.

CC: John Jacobson; Ronald Langstaff

"Mical Tschiltz - PNO-III-02-006B.wpd Page M"ichael Tciltz PN-l-206 "p Pa April 5, 2002 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-111-02-006B This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.

Facility Licensee Emergency Classification Davis-Besse Notification of Unusual Event FirstEnergy Nuclear Operating Co. - Alert Oak Harbor OH - Site Area Emergency Docket: 50-346 - General Emergency x Not Applicable

SUBJECT:

REACTOR VESSEL HEAD DEGRADATION (SECOND UPDATE)

DESCRIPTION:

The NRC's Augmented Inspection Team presented the preliminary findings of its review of the reactor vessel head degradation at the Davis-Besse plant in a meeting with the licensee on April 5, 2002, in Oak Harbor, Ohio. The AIT began the inspection on March 12, 2002, after the utility reported that significant corrosion damage had been found while repairs were being made to a control rod drive nozzle in the reactor vessel head.

The team found that evidence of the corrosion damage was present at least as early as 1998 and that the utility missed several opportunities to identify the problem prior to the current refueling outage.

Beginning in 1999, the plant staff observed a gradual increase in the frequency of filter changes required for the containment radiation monitor filter from monthly to every other day. The filter changes were required because of clogging by material identified as corrosion products from reactor cooling system leakage. Boric acid and corrosion product deposits on the containment air coolers also increased.

The utility also failed to properly implement the NRC-required boric acid control program in that reactor vessel head boric acid deposits were not properly removed and indications of reactor vessel head corrosion were not recognized or evaluated. In the 2000 refueling outage significant deposits of boric acid -- different in color and consistency previously associated with reactor cooling system leaks -- were found on the reactor vessel head.

The utility is continuing its review of the root cause of the reactor vessel head damage. The Augmented Inspection Team concurred with the utility's preliminary evaluation that the reactor vessel wastage was caused by corrosion associated with leakage of primary cooling water containing boric acid due to cracks in the No. 2 and No. 3 control rod drive nozzles. Additional issues remain to be addressed, however, in the utility's root cause evaluation, including factors affecting the rate at which the cracks and corrosion progressed, the role of deposits left on the reactor vessel head, and a determination of the chemical process involved in the corrosion.

The utility's evaluation will be presented to the NRC and made publically available when it is completed.

. Michael Tschiltz - PNO-I I-02-006B.wpd Page .

PNO-II-02-006B The State of Ohio will be notified. The information in this preliminary notification has been reviewed by licensee management.

This information is current as of 9:00 a.m. (Eastern Time) on April 5, 2002.

CONTACTS:

Ron Gardner John Jacobson 630/829-9751 630/829-9736