05000287/LER-2009-001

LER-2009-001, Duke Energy Corporation
ONO1VP/7800 Rochester Highway
Seneca, SC 29672
864-885-4460
864-885-4208 fax
February 10, 2009 dabaxter@dukeenergy.com
U.S. Nuclear Regulatory, Commission
Document Control Desk
Washington, D.C. 20555
Subject: Oconee Nuclear Station
Docket No. 50-287
Licensee Event Report 287/2009-01, Revision 0
Problem Investigation Process No.: 0-08-8339
Gentlemen:
Pursuant to 10 CFR 50.73 Sections (a)(1) and (d), attached is
Licensee Event Report 287/2009-01, Revision 0, regarding
inoperability of two containment isolation valves in the Post-
Accident Liquid Sampling System. This report is being submitted
in accordance with 10 CFR 50.73 (a)(2)(i)(B).
This event is considered to be of no significance with respect
to the health and safety of the public.
There are no regulatory commitments contained in this report.
Any questions regarding the content of this report should be
directed to Russ Oakley at 864-885-3829.
Very truly yours,
Dave Baxter, Vice President
Oconee Nuclear Site
Attachment
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www.duke-energy.corn i2A
Document Control Desk
Date: February 10, 2009
Page 2
cc: Mr. Luis Reyes
Administrator, Region II
U.S. Nuclear Regulatory Commission
61 Forsyth Street, S. W., Suite 23T85
Atlanta, GA 30303
Mr. John Stang
Project Manager
U.S. Nuclear Regulatory Commission
Office of Nuclear Reactor Regulation
Washington, D.C. 20555
Mr. Andy Hutto
NRC Senior Resident Inspector
Oconee Nuclear Station
INPO (Word File via E-mail)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION
(9-2007)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of
digits/characters for each block)
1. FACILITY NAME
Oconee Nuclear Station, Unit 3
4. TITLE
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not conduct or sponsor, and a person is not required to respond to, the
information collection.
2. DOCKET NUMBER 3. PAGE
05000 287 1 OF 4
Two PALS CIVs Inoperable Due to Use of Unqualified Seat Material

Oconee Nuclear Station, Unit 3
Event date:	12-12-2008
Report date:	02-10-2009
2872009001R00 - NRC Website

BACKGROUND

The Post-Accident Liquid Sampling System (PALS) [KN] contains a line which runs from the Reactor Coolant System (RCS)[AB], through a containment penetration, to the sampling panel in the Auxiliary Building. The line contains two normally-closed solenoid-operated valves [SMV] inside containment (3RC-162 and 3RC-163) and two normally-closed manual valves (3RC-164 and 3RC-165) [ISV] outside containment. The two manual valves outside containment are credited as containment isolation valves (CIVs). This line is used to obtain boron samples following certain design basis events.

was operated in a condition prohibited by Technical Specifications (TS) for a period of time prior to recognition of the condition.

Prior to this event Unit 3 was operating at 100% power. Other.

safety systems and/or components were out of service at various times during the period of CIV inoperability. However, no plant evolutions or other inoperable equipment contributed to this event.

EVENT DESCRIPTION

On December 12, 2008, Oconee Nuclear Station (Oconee) discovered a design deficiency with containment isolation valves 3RC-164 and 3RC-165. The deficiency was discovered by Duke personnel during reviews of the preventive maintenance activities for these valves.

The valves were declared inoperable, and operators entered TS 3.6.3 Conditions A and B at 2000 hrs. These conditions require that the containment penetration be isolated within'one hour by use of at least one closed and de-activated automatic valve, one closed and de-activated non-automatic power operated valve, closed manual valve, or blind flange. TS required actions were satisfied by de­ activating (removing power from) two normally-closed solenoid­ operated valves (3RC-162 and 3RC-163) in the same sampling line at 2057 hrs.

Unit 3 has been operated at 1003 power for several fuel cycles between installation of 3RC-164 and 3RC-165 in 1996 until the time of discovery in 2008. Therefore, the unit was in the mode of applicability for LCO 3.6.3 upon entry into Mode 4 on startup from each refueling outage and TS 3.6.3 Conditions A and B were applicable during the entirety of each operating cycle. Also, Condition D was applicable one hour after Condition B, since the required actions of Conditions A and B were not completed.

Condition D requires shutdown to Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and shutdown to Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Since operators were unaware of the condition until years after the TS conditions became applicable, the required actions for these conditions were not taken within-the required completion times prescribed by TS.

CAUSAL FACTORS

The cause of the inoperability and subsequent reportable condition was a design deficiency involving the use of soft seat materials in containment isolation valves 3RC-164 and 3RC-165. These seats were made of a polymeric material which was not rated for pressure and temperature conditions to which it might have been exposed during post-accident sampling service. Therefore, the valve seats might have been damaged by exposure to these fluid conditions during sampling activities,.causing the valves to be subsequently incapable of performing their containment isolation function.

A contributing causal factor was the human error of selecting materials for use in an application for which they were not qualified. However, since this application error was made more than three years ago, it is considered a historical error.

CORRECTIVE ACTIONS

Immediate:

1) Upon discovery of the condition, 3RC-164 and 3RC-165 were declared inoperable. TS 3.6.3 Conditions A and B were entered, and power was removed from (normally-closed) valves 3RC-162 and 3RC­ 163.

Subsequent:

1) Confirmed that the condition did not exist on equivalent valves installed in the Unit 1 and 2 PALS system. These valves (1&2RC­ 164&165) are hardseated designs which are not susceptible to the same failure modes as the soft-seated design.

Planned:

1) Oconee plans to replace 3RC-164 and 3RC-165 with metal-seated valves.

SAFETY ANALYSIS

This event did not include a loss of'safety system function. Since 3RC-162 and 3RC-163 have hard seat materials which would not be degraded by exposure to high temperature and pressure conditions associated with sampling activity, these valves would have been capable of performing the containment isolation safety function.

These are normally-closed valves which are re-closed by procedure following post-accident sampling evolutions. Since there was no loss of safety function, there was no impact on core damage frequency.

No fission product barriers were compromised by this event.

Therefore, there was no actual impact on the health and safety of the public due to this event.

ADDITIONAL INFORMATION

A search of Oconee's corrective action database found no similar occurrences of this type of event with same cause.

There were no releases of radioactive materials, radiation exposures or personnel injuries associated with this event.

Energy Industry Identification System (EIIS) codes are identified in the text within brackets [1. This event is not considered reportable under the Equipment Performance and Information Exchange (EPIX) program.