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
| 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 From:
To:
Kavanagh;
Date:
Subject:
Alan Levin; Brian McCabe; James Beall; Jeffry Sharkey; Jennifer Uhle; Kerri
Marsha Gamberoni; Michael Tschiltz; Rick Croteau; Thomas Hiltz
Thu, Apr 4, 2002 2:28 PM
Fwd: Issuance of Information Notice 2002-13 For your info.
Ho
clO0 -o 046 Pagei
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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iviic raei I scn11z - inTormation Notice uu;-13 .wDd
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
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.LMicnael I-scni!iz - InTormation Notice 2002-13.wpd 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.
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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:
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
.'Mic~hael Tschiltz -* Info~rmration No1tice 2026515.w.pdi
Page "I
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
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 nuclear
Protection Sprinkler Heads
Submerged Safety-Related
Electrical Cables
Recent Experience with
Degradation of Reactor
Pressure Vessel Head
Nonconservative Water Level
Setpoints on Steam
Generators
Potential for Top Nozzle
Separation and Dropping of
Certain Type of Westinghouse
Fuel Assembly
Pump Shaft Damage Due to
Excessive Hardness of Shaft
03/21/2002
03/12/2002
03/07/2002
02/13/2002
01/30/2002 power, research, and test
reactors and fuel cycle facilities.
All holders of operating licenses
or construction permits for
nuclear power reactors
All holders of operating licenses
for pressurized-water reactors
(PWRs), except those who have
permanently ceased operations
and have certified that fuel has
been permanently removed from
the reactor.
All holders of operating licenses
for nuclear power reactors, except those who have
permanently ceased operations
and have certified that fuel has
been permanently removed from
the reactor.
All holders of operating licenses
for nuclear power reactors, and
non-power reactors and holders
of licenses for permanently
shutdown facilities with fuel
onsite.
All holders of operating licenses
for nuclear power reactors, 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
2002-12
2002-11
2002-10
2002-09
2002-08 t*Mi~hah~l Ttchilt'Z - Information Notice 20"0"2-13.wpdl
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