Information Notice 2002-13, E-mail from H. Nieh, Oedo to A. Levin, Ocm, Et Al., Issuance of Information Notice 2002-13, Fwd: E-mail from D. Pickett T Davis-Besse Communication Plan

E-mail from H. Nieh, Oedo to A. Levin, Ocm, Et Al., Issuance of Information Notice 2002-13, Fwd: E-mail from D. Pickett T Davis-Besse Communication Plan

ML023570309
Person / Time
Site:	Davis Besse
Issue date:	04/04/2002
From:	Ho Nieh NRC/EDO
To:	Beall J, Croteau R, Gamberoni M, Hiltz T, Kerri Kavanagh, Levin A, Mccabe B, Sharkey J, Tschiltz M, Uhle J NRC/OCM
References
IN-02-013
Download: ML023570309 (7)

SýM-ichae'-Tschiitz - Fwd: Issuace

lof"/nformat'on Notice 2002-13 Pagei

From: Ho Nieh

To: Alan Levin; Brian McCabe; James Beall; Jeffry Sharkey; Jennifer Uhle; Kerri

Kavanagh; Marsha Gamberoni; Michael Tschiltz; Rick Croteau; Thomas Hiltz

Date: Thu, Apr 4, 2002 2:28 PM

Subject: Fwd: Issuance of Information Notice 2002-13 For your info.

Ho

clO0 -o 046

F-Micha'e Tschiltz - Issuance of Information Notice 2002-13 Page 1 From: Douglas Pickett

To: Davis-Besse Com Plan

Date: Thu, Apr 4, 2002 1:58 PM

Subject: Issuance of Information Notice 2002-13 To the Davis-Besse Communications Team:

For your information, Information Notice 2002-13, "Possible Indicators of Ongoing Reactor Pressure

Vessel Head Degradation," was issued today.

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iviicraei I scn11z - inTormation Noticeý~~~~~~~

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uu;-13 Ino I--_ - 2 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, DC 20555-0001 April 4, 2002 NRC INFORMATION NOTICE 2002-13: POSSIBLE INDICATORS OF ONGOING

REACTOR PRESSURE VESSEL HEAD DEGRADATION

ADDRESSEES

All holders of operating licenses for pressurized water nuclear power reactors, except those

who have permanently ceased operations and certified that fuel has been permanently removed

from the reactor.

PURPOSE

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice on recent

Davis-Besse experience to alert addressees to possible indicators of reactor coolant pressure

boundary degradation including degradation of the reactor pressure vessel (RPV) head

material. The NRC anticipates that recipients will review this information for applicability to their

facilities and consider taking appropriate actions. However, the suggestions contained in this

information notice do not constitute NRC requirements and, therefore, no specific action or

written response is required.

DESCRIPTION OF CIRCUMSTANCES

The Davis-Besse nuclear power plant recently discovered a significant cavity in the RPV head

on the downhill side of control rod drive nozzle number 3 and some head wastage behind

nozzle number 2. In response, the NRC issued Information Notice 2002-11, "Recent

Experience With Degradation of Reactor Pressure Vessel Head," on March 12, 2002, and

Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure

Boundary Integrity," on March 18, 2002. NRC also sent an Augmented Inspection Team (AIT)

to the plant to investigate the circumstances of the degradation of the RPV head material.

Through the AIT, several possible indicators of reactor coolant pressure boundary degradation

such as was observed at Davis-Besse were identified. These indicators include unidentified

reactor coolant system (RCS) leakage and containment air cooler (CAC) and radiation element

(RE) filter fouling.

Until 1998, RCS unidentified leakage at Davis-Besse was normally less than 0.1 gallons per

minute (gpm). In October 1998, the licensee removed the rupture disks downstream of the

pressurizer relief valves and bypassed a drain line that collected leakage from the relief valves

in the quench tank (identified leakage). As a result, all leakage past the relief valves was

vented directly into the containment atmosphere and collected in the sump, increasing the

unidentified leakage to approximately 0.8 gpm. In May 1999, the licensee reinstalled the

ML020930617 IN 2002-13

........... .

.LMicnael I-scni!iz - InTormation Notice 2002-13.wpd P*n* 9

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_  ! rupture disks and reconnected the drain line; however, the RCS unidentified leakage was only

reduced to approximately 0.2 gpm (or approximately 0.1 gpm higher than normal). This

elevated level of unidentified leakage was attributed by the licensee to control rod drive

mechanism (CRDM) flange leakage since the plant had a past history of flange leakage.

The Davis-Besse CACs control containment temperature and humidity. In November 1998, the

licensee identified increased CAC fouling caused by boron deposits. The licensee attributed

the increase in CAC fouling to the venting of the pressurizer relief valve leakage directly to

containment caused by the October 1998 modification discussed previously. The CACs were

cleaned many times between November 1998 and May 1999. In May 1999, the licensee

reinstalled the rupture disks and reconnected the drain line. After that modification, the

licensee cleaned the CACs again in June and July 1999. At that time, the licensee noticed that

the boric acid deposits removed from CAC number 1 exhibited a rust-like color. The licensee

attributed the discoloration to migration of the surface corrosion on the CACs into the boric acid

deposits and to the aging of the boric acid deposits. After the spring 2000 refueling outage, deposits again began to form on the CACs. Between June 2000 and May 2001, the licensee

cleaned the CACs eight times. No further CAC cleaning was needed until the current outage

when the licensee reported that fifteen 5-gallon buckets of boric acid were removed from the

CAC ductwork and plenum. A flow from the CACs also resulted in boric acid deposits

elsewhere within containment including on service water piping, stairwells, and other areas of

low ventilation.

Davis-Besse also has REs that are two identical air sampling systems in containment. The RE

filters accumulate particulates and may need to be changed to ensure acceptable system

operation. Licensee records correlate RE filter changes with past RCS leakage increases. In

March 1999, RE filter clogging from boric acid deposits was identified and attributed to the

pressurizer relief valve modification discussed previously. In November 1999, after identifying

yellowish brown deposits in the filters, the licensee obtained a chemical analysis of the filter

particulates which identified the presence of ferric oxide in addition to boric acid crystals.

Around this time, the licensee began changing the filters every one-to-three weeks. By

November 1999, the frequency of filter changes had again increased.

DISCUSSION

RCS leakage, boron deposits, and corrosion products like ferric oxide in CACs and RE filters

may indicate degradation of the reactor coolant pressure boundary materials. These indicators

do not provide clear evidence of the degradation; however, they may provide an opportunity for

licensees to suspect that degradation is ongoing. The NRC understands that the indications at

Davis-Besse were sometimes complicated by other events (e.g., flange leaks). Nonetheless, in

combination with other indicators, they may provide insights into whether degradation of the

reactor coolant pressure boundary materials is occurring.

The information in this notice is, in part, based on preliminary information. The safety

significance and generic implications of the information justify NRC's urgency to issue this

information notice.

.'Mic~hael Tschiltz -*Info~rmration No1tice 2026515.w.pdi Page "I

Michae! Tschiltz Information Notice 2002-1 3.wpd

-

Pace 3 This information notice does not require any specific action or written response. If you have

any questions about the information in this notice, please contact one of the technical contacts

listed below or the appropriate project manager from the NRC's Office of Nuclear Reactor

Regulation.

IRA!

William D. Beckner, Program Director

Operating Reactor Improvements Program

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contacts: Ian Jung, NRR John Jacobson, Region III

(301) 415-1837 (630)829-9736 E-mail: ixi@nrc..qov E-mail: iml3@nrc..ov

Attachment: List of Recently Issued NRC Information Notices

ML020930617 TEMPLATE #: NRR-052 OFFICE RSE Tech Editor BC:EMCB (A)SC:RORP:DRIP PD:RORP:DRIP

NAME ICJung PKleene* WHBateman TKoshy WDBeckner

DATE 04/ /2002 04/04/2002 04/04/2002 04/04/2002 04/04/2002

t*Mi~hah~l Ttchilt'Z - Information Notice 20"0"2-13.wpdl Page 5 Micha.l Thchiltz information Notice 2002-1 3.wpd Pace 5 Attachment 1 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

99-28, Supp 1 Recall of Star Brand Fire 03/22/2002 All holders of licenses for nuclearr

Protection Sprinkler Heads power, research, and test

reactors and fuel cycle facilities.

2002-12 Submerged Safety-Related 03/21/2002 All holders of operating licenses

Electrical Cables or construction permits for

nuclear power reactors

2002-11 Recent Experience with 03/12/2002 All holders of operating licenses

Degradation of Reactor for pressurized-water reactors

Pressure Vessel Head (PWRs), except those who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor.

2002-10 Nonconservative Water Level 03/07/2002 All holders of operating licenses

Setpoints on Steam for nuclear power reactors, Generators except those who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor.

2002-09 Potential for Top Nozzle 02/13/2002 All holders of operating licenses

Separation and Dropping of for nuclear power reactors, and

Certain Type of Westinghouse non-power reactors and holders

Fuel Assembly of licenses for permanently

shutdown facilities with fuel

onsite.

2002-08 Pump Shaft Damage Due to 01/30/2002 All holders of operating licenses

Excessive Hardness of Shaft for nuclear power reactors, Sleeve except those who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor.

OL =Operating License

OP = Construction Permit