05000311/LER-2008-001, Regarding As-Found Pressurizer Safety Valve Lift Setpoint Exceeds Technical Specification Allowable Limits
| ML081490320 | |
| Person / Time | |
|---|---|
| Site: | Salem  (DPR-075) |
| Issue date: | 05/19/2008 |
| From: | Braun B Public Service Enterprise Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LR-N08-0116 LER 08-001-00 | |
| Download: ML081490320 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3112008001R00 - NRC Website | |
text
PSEG Nuclear LLC P.O. Box 236,, Hancocks Bridge, NJ 08038-0236 o PSEG Nuclear L.L. C.
MAY 1 9 2008 1 0CFR50.73 LR-N08- 0116 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington DC 20555-001 LER 311/08-001 Salem Nuclear Generating Station Unit 2 Facility Operating License No. DPR-75 NRC Docket No. 50-311
SUBJECT:
As-Found Pressurizer Safety Valve Lift Setpoint Exceeds Technical Specification Allowable Limits This Licensee Event Report, "As-Found Pressurizer Safety Valve Lift Setpoint Exceeds Technical Specification Allowable Limits" is being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR5O.73(a)(2)(i)(B).
The attached LER contains no commitments. Should you have any questions or comments regarding this submittal, please contact Mr. Howard Berrick at 856-339-1862.
Sincerely, Robert Braun Site Vice President - Salem Attachments (1)
J q
NRC-ORM 366 (9-2007)
U.S. NUCLEAR REGULATORY COMMISSION IAPPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 LICENSEE EVENT REPORT (LER)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME
- 12. DOCKET NUMBER
- 13. PAGE Salem Generating Station - Unit 2 05000311 1 of 3
- 4. TITLEAs-Found Pressurizer Safety Valve Lift Setpoint Exceeds Technical Specification Allowable Limits
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL R
NO.
MONTH DAY YEAR DOCKET NUMBER 03 20 08 2008 001 00 05 19 2008
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
El 20.2201(b)
El 20.2203(a)(3)(i) 0- 50.73(a)(2)(i)(C)
[I 50.73(a)(2)(vii) 6 El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
[] 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
[] 50.36(c)(1)(i)(A)
C3 50.73(a)(2)(iii) 0l 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
[] 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
C3 50.73(a)(2)(x)
[E 20.2203(a)(2)(iii)
[1 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71 (a)(4)
El 20.2203(a)(2)(iv)
C] 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5) 0%
[1 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
C3 50.73(a)(2)(v)(C) 0l OTHER El 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in
PLANT AND SYSTEM IDENTIFICATION
Westinghouse - Pressurized Water Reactor Pressurizer/Safety Valves {AB/RV}*
- Energy Industry Identification System (EIIS) codes and component function identifier codes appear as {SS/CC}
CONDITIONS PRIOR TO OCCURRENCE The plant was in the shutdown condition for refueling outage 2R16. No structures, systems, or components were inoperable at the time of discovery that contributed to the event.
DESCRIPTION OF OCCURRENCE On March 20, 2008, with Unit 2 in Mode 6 (Refueling) one of the three Pressurizer Safety Valves (PSV) 2PR3 {AB/RV) failed the as-found actuation pressure surveillance test, required by Technical Specification (TS) 4.4.2 and ASME OM-1987, Part 1, Requirements for Inservice Performance Testing of Nuclear Power Plant Pressure Relief Devices. The TS acceptance band for the as-found actuation pressure is +/-3% of the nameplate setpoint pressure. The first (as-found) actuation pressure for PSV 2PR3 was below the lower limit of minus 3% of the nameplate setpoint. The removed 2PR3 valve passed a second (informational) pressure test with a lift pressure of 2440 psig (-1.8%). The valve remained leak tight following reseating after each lift test.
The actual test results of valve 2PR3 are:
Test #
As found (psig)
TS Setpoint (psig)
Acceptable band (psig)
% Difference 1
2402 2485 2410.45 - 2559.55
- - 3.30 2
2440 2485 2410.45 - 2559.55
- - 1.80 Because the first as-found lift set point of the 2PR3 was not within 3% of set point, expanded testing scope was performed in accordance with the In-Service Test (IST) program. The two remaining PSVs were removed and replaced with pre-tested spares. The removed valves were subsequently tested and found to lift within TS tolerances.
CAUSE OF OCCURRENCE The 2PR3 valve was disassembled and all components were inspected. Valve critical dimensions were measured and all were within OEM tolerances. Three load tests were performed on the 2PR3 valve spring; the spring was found to be within OEM tolerance. A review of valve test data revealed that this was the first test of valve 2PR3 since it was received from the manufacturer in 1998. This valve was installed in the 2PR3 position in November 2003. Springs in a highly compressed state are known to relax over time. Other valves from this group of relief valves also lifted on the low side of the setpoint following their first installed operational cycle. This was the last valve of the group to complete its initial operational cycle.
NRC FORM 366 (9-2007)
PRINTED ON RECYCLED PAPER
(If more space is required, use additional copies of NRC Form 366A)The apparent cause of the 2PR3 setpoint drifting low was due to valve spring relaxation during its first operational service cycle, possibly compounded by the time between valve tests.
PRIOR SIMILAR OCCURRENCES A review of Salem LERs since 2001 identified one occurrence where PSVs exceeded the TS setpoint
.acceptance criteria of +/-3%. The cause for that occurrence was that the valve internals were not lapped in place. The corrective actions associated with that LER would not have prevented this event.
SAFETY CONSEQUENCES AND IMPLICATIONS
Pressurizer safety valves are typically credited in the UFSAR Chapter 15 safety analyses for their pressure relief benefits, and these valves are modeled at the setpoint plus +/-3% tolerance. Having one of these valves out of tolerance in the negative direction would be a direct benefit to all analyses that credit these valves for protection. For the UFSAR Chapter 15 safety analysis of Spurious Operation of the Safety Injection System at Power, an early lift of a safety relief could have the potential of liquid relief through the pressurizer safety valves. A review of this transient determined that the lower lift-pressure of 2402 psig on the one out-of-tolerance PSV would have no affect on the calculated results, since it will not open given a spurious operation of the safety injection system. It was concluded that there were no safety consequences or implications involved as a result of the 2PR3 valve being below the lower limit of minus 3% by 0.3%. Therefore, the public health and safety was not affected.
A review of this condition determined that a Safety System Functional Failure (SSFF) did not occurred as defined in Nuclear Energy Institute (NEI) 99-02.
CORRECTIVE ACTIONS
- 1. All Unit 2 PSVs were replaced with pre-tested valves.
- 2. The PSV testing was expanded to include the additional two PSVs in accordance with the IST Program, and both additional valves tested satisfactorily.
- 3. The tracking and scheduling basis for relief valve testing is being revised to assure that storage and shelf times, as well as service time, are factored into the ASME OM code testing periodicity of the valves.
COMMITMENTS
The corrective actions cited in this LER are voluntary enhancements and do not constitute commitments.