05000446/LER-2005-003, Regarding Two Pressurizer Safety Valves Found with Unsatisfactory Lift Setpoints
| ML051880080 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 06/27/2005 |
| From: | Madden F TXU Generation Co, LP, TXU Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CPSES-200501345, TXX-05122 LER 05-003-00 | |
| Download: ML051880080 (8) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4462005003R00 - NRC Website | |
text
A TXU Power TXU Power Comanche Peak Steam Electric Station P.O. Box 1O02 (E01)
Glen Rose, TX 76043 Tel: 254 897 5209 Fax: 254 897 6652 mike.blevins~txu.com Mike Blevins Senior Vee President &
Chief Nuclear Officer Ref: #10CFR50.73(a)(2)(i)(B)
CPSES-200501345 Log # TXX-05122 June 27, 2005 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50-446 LICENSEE EVENT REPORT 446/2005-003-00 TWO PRESSURIZER SAFETY VALVES FOUND WITH UNSATISFACTORY LIFT SETPOINTS Gentlemen:
By means of this letter, TXU Generation Company LP (TXU Power) submits the enclosed Licensee Event Report (LER) 2005-003-00 for Comanche Peak Steam Electric Station Unit 2.
This communication contains no new licensing basis commitments regarding CPSES Units 1 and 2. Should you have any questions, please contact Bob Kidwell at (254) 897-5310.
Sincerely, TXU Generation Company LP By:
TXU Generation Management Company LLC Its General Partner Mike Blevins By: Ž1 2/Y)41-
/Fre'd W. Madden Director, Regulatory Affairs LI-e 0--L-D-A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
TXX-05122 Page 2 of 2 RJK Enclosure c -
B. S. Mallett, Region IV M. C. Thadani, NRR Resident Inspectors, CPSES
Enclosure to TXX-05122 NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 31504104 EXPIRES 06/30/2007 (6-2004)
Estunated the NRC may not conduct or sponsor. and a person is not requed to respond to. the infrmation coltlection Facilny Name (I)
Docket Number (2)
Page (3)
COMANCHE PEAK STEAM ELECTRIC STATION UNIT 2 05000446 1 OF 6 Tale (4)
TWO PRESSURIZER SAFETY VALVES FOUND WITH UNSATISFACTORY LIFT SETPOINTS Event Date l5)
LER Number (6 R
t Date 7\\
Other Faciliies Involved 81 blontb Day Year Year Sequential Revision Month I
Day Year Facility Name Docket Numbers I
Number Number N/A 05000 04 27 2005 2005 _
003 00 06 27 2005 05000 ope2 This rtissubmnstedpuratothe reurments of0CFR:(Cbeckalthatap)
(II) 20.2201(b) 20.2203(aX3Xi) 5 S0.73(aX2XiXC) 50.73(a)(2Xvii)
Lever 20.2201(d) 20.2203(aX3Xii) 50.73(aX2)(iiXA) 50.73(aX2XviiiXA)
Level 2%
20.2203(aXI) 20.2203(a)(4) 50.73(aX2)(iiXB) 50.73(aX2)(viiiXB) 20.2203(aX2Xi) 50.36(cX2XiXA) 50.73(aX2Xiii) 50.73(aX2XixXA) 20.2203(aX2Xii) 50.36(cXI XiiXA) 50.73(aX2XivXA) 50.72(aX2Xx) 20.2203(aX2Xiii) 50.36(cX2) 50.73(aX2XvXA) 73.71 (a)(4) 20.2203(aX2Xiv) 50.46(aX3Xii) 50.73(aX2XvXB) 73.71 (aXS) 20.2203(aX2Xv) 50.73(a)(2XiXA)
=
50.73(aX2XvXC)
OTHER 20.2203(aX2Xvi)
X 50.73(a)(2iXB) 50.73(aX2XvXD)
Specify in Abstract below or in =
(If morespace E reqUired.
ILe additional copes of SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On April 4,2005, the three (3) Pressurizer Safety Valves (PSVs) [EIIS: (AB)(PZR)(RV)]
on Unit 2 were removed from the system and were sent off-site to NWS Technologies for surveillance testing in support of the eighth refueling outage on Comanche Peak Unit 2.
Testing was performed using a procedure designed to comply with ASME OM Code Appendix I and Westinghouse Owner's Group guidance, using saturated steam as the test medium.
During as-found surveillance testing on April 7, 2005, the lift pressure of PSV 2-801 OA was found to be 2451 psig, approximately 1.4% below the Technical Specification (TS) 3.4.10 TS Limiting Condition for Operation (LCO) setpoint of >/=2460 psig and <1=2510 psig (2485 psig +/-10%). On April 11, 2005, the as-found lift pressure of PSV 2-8010B was found to be 2452 psig, which is approximately 1.3% below the TS LCO setpoint range. PSV 2-8010C was found with an acceptable lift pressure. Both of the unsatisfactory PSVs were reworked by the vendor and the as-left lift pressures were verified to be within TS limits.
(If more space is required. use additional copies of (If morepace isequre. use adiionil copies of (If more space is required. use additional copies of (If more spacc is equred, use addtiol copies of NRC Form 366A) (17)
IV. CAUSE OF THE EVENT
Based on an analysis of this event, performed by CPSES Engineering Programs personnel having experience with these valves, the root cause was determined to be the close tolerance required by the Technical Specification (TS) acceptance criteria (+/-1 % of setpoint) and the inability of the valves to repetitively perform within that tolerance during as-found surveillance testing.
A specific material condition cause of the setpoint drift could not be determined. The testing results were within the 3% acceptance range of ASME OM Code Appendix I. Per past discussions with the valve vendor, deviations within this range are within the design requirements of the valve and do not indicate a material problem with the valves. This conclusion is further supported by the fact that the valves demonstrated satisfactory as-left test results after adjustment.
V.
CORRECTIVE ACTIONS
In both cases, routine maintenance was performed by the vendor on both PSVs before retesting to restore them to the required lift setpoints. On October 24, 2003 for the prior instance and April 18, 2005 in the later, the required surveillances were completed with all three PSVs being as-left tested satisfactorily to state-of-the-art requirements.
The long term corrective action is for TXU Power to investigate revising the safety analysis to support a License Amendment for relaxation of the +/-1% TS Limiting Condition for Operation (LCO) requirement for the PSV as-found lift setpoint tolerance.
VI. PREVIOUS SIMILAR EVENTS
Three (3) previous similar events have been reported for CPSES pursuant to I OCFR50.73(a)(2)(i)(B) related to lift setpoint drift: LER 446/94-018 on Unit 2, LER 445/96-008 on Unit 1, and LER 445/02-004 on Unit 1.