05000289/LER-2011-002, Regarding Remote Shutdown Relay 69X1RR Contact Failure
| ML12053A013 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/20/2012 |
| From: | Newcomer M Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TMI-12-019 LER 11-002-00 | |
| Download: ML12053A013 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 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(b)(2)(ii) |
| 2892011002R00 - NRC Website | |
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Nuclear Three Mile Island Unit 1 Route 441 South, P.O. Box 480 Middletown, PA 17057 Telephone 717-948-8000 February 20, 2012 TMI-12-019 10 CFR 50.73 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 THREE MILE ISLAND NUCLEAR STATION, UNIT 1 (TMI, Unit 1)
RENEWED OPERATING LICENSE NO. DPR-50 DOCKET NO. 50-289 SUBJECT: LICENSEE EVENT REPORT (LER) NO. 2011-002-00 Enclosed is Licensee Event Report (LER) No. 2011-002-00: "Remote Shutdown Relay 69X1 RR Contact Failure." This report is being submitted in accordance with 10 CFR 50.73 (a)(2)(i)(B).
There are no regulatory commitments contained in this LER.
Should you have any questions concerning this report, please contact David Atherholt, Manager TMI, Unit 1 Regulatory Assurance at (717) 948-8364.
Sincerely, Mark Newco\\mer Plant Manager, Three Mile Island Unit 1 Exelon Generation Co., LLC RWL/mdf
Enclosure:
Licensee Event Report 2011-002-00 cc:
TMI, Unit 1 Senior Resident Inspector Administrator, Region I TMI, Unit 1 Project Manager 74~
NR" FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, 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 Three Mile Island, Unit 1 05000289 1 OF 4
- 4. TITLE:
Remote Shutdown Relay 69X1 RR Contact Failure
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACLDULNMEDOTETNUBE MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR N/A 05000 NUMBER NO.N/05 0
I I I
I I
FACILITY NAME DOCKET NUMBER 12 22 2011 2011 002 -
00 02 20 2012 N/A A0o0E
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
El 20.2201(b)
[I 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
N El 20.2201(d)
[I 20.2203(a)(3)(ii)
C3 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
[I 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
Dl 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
E] 50.36(c)(1)(ii)(A)
El-50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
[j 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
E] 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5) 100 E-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)
ED 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER FACILITY NAME TELEPHONE NUMBER (Include Area Code)
Michael Fitzwater, TMI Unit 1 Regulatory Assurance Engineer
- - L (717) 948-8228MANU-REPORTABLE MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT FACURE R
EPOA
CAUSE
SYSTEM COMPONENT FACTURER TO EPIX FACTURIER TO EPIX B
BI RLY Gould y
1 Inc.
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH IDAY IYEAR SUBMISSION El YES (if yes, complete 15. EXPECTED SUBMISSION DATE) 0 NO DATE 0,BSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On 12/22/11, the Reactor Building Emergency Cooling Water pump discharge valve "B" (RR-V-1 B) failed to open during performance of an Engineered Safeguards Actuation System (ESAS) quarterly surveillance test. RR-V-1 B was declared inoperable placing TMI-1 in an unplanned 72-hour Limiting Condition for Operation (LCO). RR-V-1 B was demonstrated to open and close via the control room console pushbutton. Troubleshooting determined a Remote Shutdown (RSD) transfer selector switch relay/contact was open. The open contact associated with the Remote Shutdown (RSD) transfer selector switch is in series with the ESAS signal to RR-V-1 B. Intermittent contact make-up was determined to be the cause of the failure. The RSD transfer switch was cycled several times, and the manual portion of ESAS testing was repeated successfully. Administrative controls were applied to ensure the switch contact closed properly if the RSD transfer switch was manipulated pending replacement. The relay was replaced on 1/6/12. Based upon the failure analysis the relay/contact was considered inoperable at the plant start up (reactor criticality 11/24/11) to the date of discovery (12/22/11). This is reportable under 10 CFR 50.73 (a)(2)(i)(B), "a condition prohibited by Technical Specifications" due to exceeding the allowable outage time and changing plant mode without satisfying the minimum conditions for criticality.
NRC FORM 366 (10-2010)U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE SEQUENTIAL REV YEAR NUMBER NO.
Three Mile Island, Unit 1 05000289 r2011 002 00 2
of 4
A.
EVENT DESCRIPTION
Plant Conditions before the event:
Babcock & Wilcox - Pressurized Water Reactor - 2568 MWth Core Power Date/Time: December 22, 2011 / 14:24 hours Power Level: 100% steady state power Mode: Power Operations There were no structures, systems, or components out of service that contributed to this event on the date of occurrence.
Event:
On 12/22/11 at 14:24, during the performance of quarterly Engineered Safeguards Actuation System (ESAS) surveillance ""B" Emergency Loading Sequence and HPI Logic Channel/Component Test",
Reactor Building Emergency Cooling Water pump discharge valve "B" (RR-V-1 B) failed to open, resulting in "B" Reactor Building Emergency Cooling Water Train being inoperable. The station entered a 72-hour Limiting Condition for Operation (LCO) in accordance with TMI, Unit 1 Technical Specifications 3.3.2, which states in part, "...Reactor Building Emergency Cooling Water... components shall not be removed from service1 so that th~eaffected system train is inoperable for more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />."
Following failure of RR-V-1 B to stroke via ESAS signal, operators demonstrated that RR-V-1 B would open and close via the control room console pushbutton. Troubleshooting determined that the Remote Shutdown (RSD) transfer selector switch relay/contact (69X1 RR) was open. The function of the RSD transfer selector switch and associated relay (69X1 RR) is to transfer control from the control room to the remote shutdown panel in the event that the control room is not habitable. The open contact was in series with the ESAS signal to RR-V-1 B, preventing operation of the valve via ESAS signal. The RSD transfer selector switch was operated several times to cycle the relay contact. Subsequent electrical testing of the circuit was performed validating the contact was closed. Operators performed the manual portion of ESAS testing demonstrating the ability of RR-V-1 B to open satisfactorily on an ESAS signal.
Controls were established for the RSD Selector Switch and associated relay (69X1 RR) to ensure it was maintained in the operable configuration until its replacement on 01/06/12.
At 22:36 on 12/22/2011, RR-V-1 B was declared operable and TMI-1 exited the 72-hour LCO time clock.
An extent of condition review was conducted that validated that there were no other failed open relay contacts associated with the remote shutdown panel. All ESAS/Heat Sink Protection System (HSPS) components that have remote shutdown contacts were tested satisfactorily following the last RSD panel relay manipulation.
The failed relay (69X1 RR) was replaced on 01/06/12. The failure analysis was completed on 02/02/12 on the failed relay/contact and concluded that the cause was due to intermittent contact closure. A pastU.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE SEQUENTIAL I REV YEA NUMER NO.
Three Mile Island, Unit 1 05000289 2011 002 --
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operability review was performed that identified surveillance procedure OP-TM-534-235, Remote Shutdown System Functional Test of RR-V-1 B was last satisfactorily performed on 11/10/11 during refueling outage 1 R1 9. This test cycled relay 69X1 RR. Review of evidence determined that the subject contact on 69X1 RR was not closing to its normally closed position once the RSD surveillance was completed. Based on this evidence, the operability of the 69Xl RR relay from 11/10/11 to 12/22/11 was not supported.
This event is reportable for two conditions under 10 CFR 50.73(a)(2)(i)(B) "operation or condition which was prohibited by the plant's Technical Specifications".
The first condition is a change in plant mode that occurred when the reactor was taken critical on 11/24/11 without satisfying the Technical Specification minimum conditions for operation. Technical Specification 3.3.1 states "The reactor shall not be made critical unless the following conditions are met:".
The following Technical Specification 3.3.1.5 states "Engineered Safeguards Valves and Interlocks Associated with the Systems in Specifications 3.3.1.1, 3.3.1.2, 3.3.1.3, 3.3.1.4 are OPERABLE.
Specification 3.0.1 applies." Both Reactor Building Emergency Cooling Water pumps are to be operable per T.S. 3.3.1.4. Relay 69Xl RR failed to provide a signal to Reactor Building Emergency Cooling Water pump discharge valve "B" (RR-V-1 B) which is an Engineered Safeguards valve associated with the system in TS 3.3.1.4 that was inoperable. Thus, the mode change was in violation of the unit Technical Specifications.
The second condition is the plant had a period of maintenance outage time that exceeded the Technical Specification allowable outage time. Based on past operability review, the period of time for relay 69X1 RR inoperability extended from 11/24/11 to 12/22/11 which is greater than the 72-hour allowable outage time provided in T.S. 3.3.2. The date of 11/24/11 began the period of inoperability based upon the time the reactor was taken critical.
The station is also evaluating the condition for reportability in accordance with 10 CFR 21 "Reporting of Defects and Noncompliance".
B.
CAUSE OF EVENT
The cause of this event was due to intermittent contact closure of a remote shutdown panel relay (69X1 RR) which prevented the Reactor Building Emergency Cooling Water pump discharge valve "B" (RR-V-1 B) from opening upon receipt of an ESAS signal.
C.
ANALYSIS / SAFETY SIGNIFICANCE The safety significance of the failed remote shutdown relay contact was minimal for actual and potential conditions.
During the period of time from plant start-up (reactor criticality on 11/24/11) until the failed Remote Shutdown Relay contact was satisfactorily tested and verified to return RR-V-1 B to operable status (on 12/22/11), no accidents or transients occurred. For twelve hours (12/19/11 - 12/20/11) while the plant was at full power, both the "A" train of the Reactor Building Spray (BS) system was not operable and theU.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE I
SEQUENTIAL I
REV YEAR NUMBER NO.
Three Mile Island, Unit 1 05000289 2011 002 --
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"A" train of Reactor Building Emergency Cooling Water system was not operable but remained available (during surveillance testing). The ability to manually open RR-V-1 B from the control room console was maintained at all times including when the "A" train of Reactor Building Emergency Cooling Water was not operable.
A risk evaluation was performed assuming the unavailability of the "A" train of Reactor Building Spray (BS) system, "A" train of Reactor Building Emergency Cooling Water (RR) system and, "B" train of Reactor Building Emergency Cooling Water system (RR). This configuration represents the most limiting case, since operator actions would likely result in restoring at least one train of Reactor Building Spray (BS) system or one train of Reactor Building Emergency Cooling Water system to service. The risk significance of this configuration results in a negligible risk increase.
D.
CORRECTIVE ACTIONS
O The relay was replaced and retested satisfactorily.
o Verified that all Remote Shutdown Relay contacts supporting safety related circuits were tested satisfactorily since their last manipulation.
o The station is reviewing this event for 10 CFR Part 21 applicability.
E.
PREVIOUS OCCURENCES
Industry and site OPEX search criteria used: Gould relay, J20A40, relay contact, contact seating yielded the following results.
o On 10/28/2009 when Clinton Power Station encountered problems during Emergency Diesel Generator operability surveillance testing when the diesel engine did not reach rated speed and voltage. This event was similar in that the same model relay contact failed due to light silver oxidation and minute surface contamination on the movable contact surfaces. The cause of this failure was not the same as the subject investigation.
Energy Industry Identification System (EIIS), System Identification (SI) and Component Function Identification (CFI) Codes are included in brackets, [SI/CFI] where applicable, as required by 10 CFR 50.73 (b)(2)(ii)(F).