05000483/LER-2006-008, Regarding Coms Inoperability, RHR Suction Relief Valve Failure
| ML063110580 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 10/30/2006 |
| From: | Thibault L Union Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| ULNRC05340 LER 06-008-00 | |
| Download: ML063110580 (13) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 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)(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 |
| 4832006008R00 - NRC Website | |
text
Union Electric Callaway Plant PO Box 620 Fulton, MO 65251 October 30, 2006 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 MIAmeren iff7 U LNRC05340 Ladies and Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.
FACILITY OPERATING LICENSE NPF-30 LICENSEE EVENT REPORT 2006-008-00 COMS Inoperabilitv, RHR Suction Relief Valve Failure The enclosed licensee event report is submitted in accordance with 10CFR50.73(a)(2)(i)(B), 10CFR50.73(a)(2)(v)(A) and 10CFR50.73(a)(2)(vii) to report a failure of a RHR suction relief valve while the pressurizer power operated relief valves were inoperable for cold overpressure protection.
Sincerely, L. E. Thibault Director Plant Operations LET/CSP/slk Enclosure a subsidiary of Ameren Corporation
ULNRC05340 October 30, 2006 Page 2 Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)
Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O-7D 1 Washington, DC 20555-2738 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360 Records Center Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, GA 30339
ULNRC05340 October 30, 2006 Page 3 bcc:
C. D. Naslund A. C. Heflin C. R. Younie K. D. Young G. A. Hughes D. E. Shafer (470)
S. L. Gallagher (100)
L. M. Belsky (NSRB)
K. A. Mills P. M. Bell in sp Qanrc. gov ded@nrc.gov LEREventsk~inpo.org babrookgwcnoc.com A160.0761 Certrec Corporation 4200 South Hulen, Suite 630 Fort Worth, TX 76109 (Certrec receives ALL attachments as long as they are non-safeguards and public disclosed).
Send the following without attachments:
Ms. Diane M. Hooper Supervisor, Licensing WCNOC P.O. Box 411 Burlington, KS 66839 Mr. Scott Bauer Regulatory Affairs Palo Verde NGS P.O. Box 52034, Mail Station 7636 Phoenix, AZ 85072-2034 Mr. Scott Head Supervisor, Licensing South Texas Project NOC Mail Code N5014 P.O. Box 289 Wadsworth, TX 77483 Mr. Dennis Buschbaum TXU Power Comanche Peak SES P.O. Box 1002 Glen Rose, TX 76043 Mr. Stan Ketelsen Manager, Regulatory Services Pacific Gas & Electric Mail Stop 104/5/536 P.O. Box 56 Avila Beach, CA 93424 Mr. John O'Neill Pillsbury Winthrop Shaw Pittman LLP 2300 N. Street N.W.
Washington, DC 20037
ULNRC05340 October 30, 2006 LIST OF COMMITMENTS The following table identifies those actions committed to by AmerenUE in this document. Any other statements in this document are provided for information purposes and are not considered commitments. Please direct questions regarding these commitments to:.
COMMITMENT COMMITMENT Due Date/Event Due Date/Event
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Callaway Plant Unit 1 05000483 1 OF 9
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE 1
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
IFACILITY NAME DOCKET NUMBER 8
30 2006 2006 008 -
00 10 30 20061
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
[E 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
ED 50.73(a)(2)(vii) 100 El 20.2201(d)
L] 20.2203(a)(3)(ii)
L] 50.73(a)(2)(ii)(A)
L] 50.73(a)(2)(viii)(A)
[3 20.2203(a)(1)
El 20.2203(a)(4)
[: 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
[_1 20.2203(a)(2)(i)
[E 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 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)
[] 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
El 50.36(c)(2) 0 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
[1 73.71(a)(5) 100 El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
El 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 SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES EJ8708B, Residual Heat Removal (RHR) B suction relief was inoperable for the cold overpressure mitigation system (COMS) function at the same time the pressurizer power-operated relief valves (PORVs) were not operable for the COMS function. Inoperability of the RHR suction relief valve was discovered during surveillance testing on August 30, 2006, after Refuel Outage 14 (Fall 2005). Relief valve EJ8708B lifted at approximately 146 pounds per square inch (psi) high during surveillance testing. Relief valve EJ8708A, RHR A suction relief, lifted within the proper range during surveillance testing. EJ8708A was considered operable but degraded (refer to section I.E., Method of discovery of each component, system failure or personnel error). Inoperability of the pressurizer PORVs for COMS was previously reported in Licensee Event Report (LER) 2006-001-00.
The following information is provided as background material to aid in understanding the event.
Technical Specification (TS) 3.4.12, COMS is applicable in Mode 4 with reactor coolant system (RCS) temperature less than or equal to 275F, Mode 5 and Mode 6 with the head on the reactor vessel. To meet the COMS requirements, TS 3.4.12 allows using one of the following pressure relief capabilities:
a. Two power operated relief valves (PORVs) with lift settings within the limits specified in the PTLR, or b. Two residual heat removal (RHR) suction relief valves with setpoints >/= 436.5 psig and </= 463.5 psig, or c. One PORV with a lift setting within the limits specified in the PTLR and one RHR suction relief valve with a setpoint >/= 436.5 psig and </= 463.5 psig, or d. The RCS depressurized and an RCS vent of >/= 2.0 square inches.
During a plant outage (generally a refueling outage), an RHR suction relief valve is removed from the RHR system and replaced with a pretested valve. Following the end of the outage, the relief valve that was removed from the system is sent to an offsite vendor for testing. The results are then evaluated for impact for the time the valve had been installed.
(If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of logs, watch relief checklists, plant computer data, and work control system data.
C. SAFETY CONSEQUENCES AND IMPLICATIONS OF THE EVENT.
From February 11, 2004 until they were replaced in October 2005 during Refuel 14, the RHR suction relief valve EJ8708B was inoperable for COMS and RHR suction relief valve EJ8708A was operable but degraded for COMS. During Refuel outages 13 and 14, various combinations of RHR suction relief valves and pressurizer PORVs were credited for COMS.
Concurrent with the inoperability of EJ8708B and the degraded condition of EJ8708A, the Pressurizer PORVs were discovered inoperable for COMS as described in LER 2006-001-00. The Pressurizer PORVs were inoperable for COMS for the entire period the B RHR suction relief was inoperable.
Coincident with the degraded condition of the COMS relief paths, both CCPs were capable of injection into the RCS below 2750F for approximately 20 minutes as described in inspection reports 05000483/2005004 and 05000483/2005005, and apparent violation 05000483/2005004-01.
Determination that the one RHR suction relief valve (EJ8708B) was inoperable and the other (EJ8708A) was degraded was made after both valves were removed from the system during Refuel Outage 14.
Determination that the pressurizer PORVs were inoperable for COMs was also an after the fact determination, which was made after Refuel 14. RHR suction relief valve EJ8708A did relieve within the proper range when it was tested. Valve EJ8708B relieved approximately 146 psi high when tested. The pressurizer PORVs were capable of providing some cold overpressure protection for the RCS when they were aligned for that purpose. As discussed in LER 2006-001-00, the response time to a pressure transient had not been tested to verify that it was within the time assumed in the accident analysis. As documented in LER 2006-001-00, the expected pressure increase was approximately 11 psi. During the period the RHR suction relief valves were inoperable or degraded for COMS, RCS pressure did not exceed 436.5 psig (the lower range of the lift pressure) with the RHR loop suctions open. Additionally, (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)
IV. PREVIOUS SIMILAR EVENTS
On February 13, 1988 (CAR 198800045), a Low Steam Line Pressure Safety Injection was inadvertently automatically initiated after a plant trip when RCS temperature was allowed to cool down to 491 degrees Fahrenheit (F), 615 psig steam pressure. The Safety Injection flow caused the pressurizer steam bubble to compress, resulting in the Pressurizer PORVs to lift 12 times. The transient in the PRT common relief valve discharge header caused by the lifting of the Pressurizer PORVs damaged the A Train RHR suction relief valve. The damage was not discovered until 1994 during the investigation of CAR 199301774 - EJ8708A lifted at 350 psig causing RCS pressure to lower to 100 psig.
V.
ADDITIONAL INFORMATION
The system and component codes listed below are from the IEEE Standard 805-1984 and IEEE Standard 803A-1984 respectively.
System:
BP. Residual Heat Removal/Low-Pressure Safety Injection (PWR)
Component:
RV, valve, relief