05000446/LER-2005-001, Re Condition Prohibited by Technical Specification
| ML050810484 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 03/14/2005 |
| From: | Madden F TXU Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CPSES-200500312, TXX-05024 LER 05-001-00 | |
| Download: ML050810484 (9) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4462005001R00 - NRC Website | |
text
TXU Power TXU Power Comanche Peak Steam Electric Station P.O. Box 1002 (E01)
Glen Rose, TX 76043 Tel: 254 897 5209 Fax: 254 897 6652 mike.blevins@txu.com Mike Blevins Senior Vice President &
Chief Nuclear Officer Ref: 10CFR50.73(a)(2)(i)(B)
CPSES-200500312 Log # TXX-05024 March 14, 2005 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50-446 CONDITION PROHIBITED BY TECHNICAL SPECIFICATION LICENSEE EVENT REPORT 446/05-001-00 Gentlemen:
Enclosed is Licensee Event Report (LER) 05-001-00 for Comanche Peak Steam Electric Station Unit 2, "Containment Personnel Airlock Door Inoperable."
This communication contains the following new commitment which will be completed as noted:
Commitment Number 27335
Commitment
Operations will evaluate the post work test conditions for the containment personnel and emergency airlocks to determine when a barrel test is required to restore operability.
/.
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
TXX-05024 Page 2 of 2 Sincerely, TXU Generation Company LP By:
TXU Generation Management Company LLC, Its General Partner Mike Blevins By:
9t 772)Ua red W. Madden Director, Regulatory Affairs GLM Enclosures c -
B. S. Mallett, Region IV W. D. Johnson, Region IV M. C. Thadani, NRR Resident Inspectors, CPSES
Enclosure to TXX-05024 NRC FORPI 366 U.S. NUCLEAR REGULATORY COMNIISSION APPROVED BY O0IB NO. 3150-0104 EXPIRES 06/3012007 (6-2004)
Estimated hurden per response to comply v ith this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />.
Reported lessons leanted are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records and FOLAPrivacy Service Branch (T.S F52). U.S. Nuclear Regulatory Commsission.
DC 205355 0001 orby internet e-mail to infocollectsgnwc.gov. andtotheDeskc0.
fringOffice of LICENSEE EVENT REPORT (LER)
Information andRegultoryAffaict. NEOI3-10202 (3150-I004). Officeof Managenent LI E S E ]V N
R ET R
LE )
and Budget. Washington. DC 20503. If ameans used to impose an infonniation collection does not display a currently valid OMB control number. the NRC may not conduct or sponsor, and a person is not requited to respond to. the information collection Facility Name (I)
Docket Number (2)
Page (3)
COMANCHE PEAK STEAM ELECTRIC STATION UNIT 2 05000446 1 OF 7 Tale (4)
CONDITION PROHIBITED BY TECHNICAL SPECIFICATION Event Duate (5
LER Numbner (6)
Report Dte (7)
Other Facilities Involved (8)
Month Year Year Sequential Revnrion Month Day Year FacilityName Docket Numbe l
I Number Number N/A 05000 01 18 05 05 000 03 14 1 05 05000 OperatTn report is suhiatted pursuant to the requ ents of 10 CFR - (Check all that apply)
(I )
mode (9) 1 20.2201(b) 20.2203(aX3Xi) 50.73(aX2XiXC) l 50.73(aX2Xvii)
Power 20.2201(d) 20.2203(aX3Xii) 50.73(aX2XiiXA) 50.73(aX2XviiiXA)
(I n) 100 20.2203(aXI) 20.2203(aX4) 50.73(aX2XiiXB) 50.73(aX2XviiiXB) 20.2203(aX2)Xi) 50.36(cX2XiXA) 50.73(aX2Xiii) 50.73(aX2XixXA) 20.2203(aX2Xii) 50.36(cX I XiiXA) 50.73(aX2)(ivXA) 50.72(aX2Xx) 20.2203(aX2Xiii) 50.36(cX2) 50.73(aX2XvXA) 73.71 (aX4) 20.2203(aX2Xiv) 50.46(aX3Xii) 50.73(aX2XvXB) 73.71 (aX5) 20.2203(aX2Xv) 50.73(aX2XiXA) 50.73(aX2XvXC)
OTHER 20.2203(a)(2Xvi)
X 50.73(a)(2XiXB) 50.73(aX2Xv)(D)
Specify in Abstract below or in =
(If tore space required useaddilbonalcopies of SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On November 17, 2004, CPSES Unit 2 was in Mode 1 operating at approximately 100 percent power. On November 17, Maintenance personnel (utility, non licensed) replaced the door gaskets [EIIS:(DR)(SEAL)] in both of the Unit 2 containment personnel airlock doors [EIIS:(NH)(AL)(DR)] as part of a seven year preventive maintenance activity. There was no time or situational pressure present during the installation of the gaskets by Maintenance personnel. Post work testing was then performed which consisted of a seal test to determine the integrity of the door seal. The seal test is performed by closing the door, then applying pressure to the annulus between the "dog teeth" of the gasket and ensuring that pressure is maintained for a specific time period. Technical Specification (TS) SR 3.6.2.1 requires that a seal test be performed within 7 days of door operation. After replacement of the gaskets, the inner door seal test was satisfactory; however, the outer door seal test was initially unsatisfactory. A portion of the outer seal was cleaned and re-greased and the outer door seal was then retested satisfactorily.
(If morespace is required, use di&tional copsof (If more spacesrequrff ed. use additional copes of (If more spaceis requwd. use additional copies of (If morespace isrequired, us A tonal copies of NRC Fortm 366A) (17)
Leakage past the outer door would also have been minimal because the maximum gap between the door and the barrel is only 1/16 of an inch, and even with the seal installed backwards it would still have provided some level of sealing functionality. TXU Power determined that the maximum leakage rate with the gaskets installed backwards would have been much less than 100 % of the containment volume per day and as a result, using the guidance in Inspection Manual Chapter 609, Appendix H, this condition would have low safety significance.
There were short periods of time from November 17, 2004 to December 13, 2004 during which the containment boundary was not intact due to access through the operable (inner) door. The ability to open the operable door to perform repairs, even if it means the containment boundary is temporarily not intact, is acceptable as noted in the TS 3.6.2 bases due to the low probability of an event that could pressurize the containment during the short time in which the operable door was open. In the unlikely event of a small break LOCA during these periods of access, personnel would have quickly shut the operable (inner) door. The probability of a larger LOCA during these brief intervals is 5 orders of magnitude below the annual design basis.
In addition, in the event of an impending large LOCA it is reasonable to assume that monitoring instrumentation and the leak detection capabilities required by the TS and credited for GDC-4 "leak before break" would alert Control Room personnel to the condition, and additional controls would be placed on containment access thus assuring that the containment personnel airlock doors would remain closed. Also, any release from a LOCA that might have occurred during the brief periods that the containment personnel airlock inner door was open would be processed through the Primary Plant Ventilation System emergency filtration units which would reduce particulate and iodine releases by a factor of 20.
Based on this analysis it was concluded that this event did not represent a safety system functional failure and did not adversely affect the safe operation of CPSES Unit 2 or the health and safety of the public.
(If more space is required, use additional copies ofNRC Forn 366A) (17)
IV.
CAUSE OF THE EVENT
TXU Power believes that the cause of this event was the installation of the Unit 2 containment personnel airlock door gaskets in a backwards configuration due to an inadequate procedure. The procedure governing installation of the door gaskets did not provide instructions on the correct orientation of the gaskets, and the design of the gaskets is such that the correct orientation is not obvious.
In addition, the post work test did not identify that the gaskets were installed backwards.
Although the seal test does provide some assurance that the gasket can hold pressure, the gaskets could be installed backwards and still successfully pass the seal test. However, a barrel test would likely have detected a gasket that was installed backwards.
V.
CORRECTIVE ACTIONS
The gaskets in the Unit 1 containment personnel airlock doors were inspected and were found to be installed correctly. The gaskets in the Unit 1 and Unit 2 emergency airlock doors were also inspected and were found to be installed correctly. The procedures governing installation of the door gaskets were revised to provide more detailed instructions on the correct orientation of the gaskets. Operations will evaluate the post work test conditions for the containment personnel and emergency airlocks to determine when a barrel test is required to restore operability.
VI.
PREVIOUS SIMILAR EVENTS
There have been no previous similar reportable events in the last three years involving inoperable containment personnel airlock doors.
NRCtRRM 1366A(1-2001)