05000390/LER-1917-005, Re Isolation of the 1B-B Safety Injection Pump Leads to a Condition Prohibited by Technical Specifications
| ML17191A430 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 07/10/2017 |
| From: | Simmons P Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 17-005-00 | |
| Download: ML17191A430 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2) |
| 3901917005R00 - NRC Website | |
text
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381 July 10, 2017 10 cFR 50 73 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390
Subject:
Licensee Event Report 39012017-005-00, lsolation of the 1B-B Safety lnjection Pump Leads to a Condition Prohibited by Technical Specifications This submittal provides Licensee Event Report (LER) 39012017-005-00. This LER provides details concerning the isolation of a Safety lnjection pump leading to a condition prohibited by Technical Specifications and an event that could have prevented the fulfillment of a safety function. This report is being submitted in accordance with 10 CFR 50.73(aX2)(i)(B) and 10 CFR 50.73(a)(2)(vXD).
There are no regulatory commitments contained in this letter. Please direct any questions concerning this matter to Kim Hulvey, WBN Licensing Manager, at (423) 365-7720.
Respectfully, Paul Simmons Site Vice President Watts Bar Nuclear Plant Enclosure cc: see Pag e 2
U.S. Nuclear Regulatory Commission Page 2 July 10, 2017 cc (Enclosure):
NRC Regional Administrator - Region ll NRC Senior Resident lnspector - Watts Bar Nuclear Plant
NRC FORM 366 (04-2o17)
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APPROVED BY oMB: NO. 3150-0104 ExptREs: 03t31t2020
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection,
- 1. FACILITY NAME Watts Bar Nuclear Plant, Unit 1
- 2. DOCKET NUMBER 05000390
- 3. PAGE 10F5 TITLE lsolation of the 4.
1B-B Safety lnjection Pump Leads to Condition Prohibited by Technical Specifications
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTHI DAY T YEAR YEAR I tt-t'rtJJf' REV NO MONTH I DAY YEAR FACITITYNAME N/A losooo 05 10 I 2017 2017 005 00 07 10 2A17 FACITIry NAME 105000
- 9. OPERATING MODE
- 11. THIS REPORT lS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR g: (Ctrec k all that appty) 1 tr zo z2o1 (b) tr zo zzo3(aX3Xi) n 50 73(aX2Xii)(A) n 50 73(a)(2XviiiXA) tr 20 zzo1 (d) tr zo 2zo3(aX3)(ii) f] 50 73(aX2XiixB) n 50 73(a)(2Xviii)(B) tr 20 2zo3(aX1) tr zo z2o3(a)(4) tr 50 73(a)(2xiii) tr 50 73(a)(2)(ixXA) tr 20 2zo3(aX2Xi) tr 50 36(cxlxixA) tr 50 73(aX2XivXA) n 50 73(aX2Xx)
- 10. POWER LEVEL 46 tr zo 2zo3(a)(2Xii) tr so 36(cxl xiixA) tl 50 73(a)(2)(vXA) n n T1 (a)(4) n 20 z2o3(a)(2Xiii) tr 50 36(cX2) tr 50 73(a)(2)(v)(B) tr rc T1 (aXs)
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X 50 73(aX2)(vXD) tr B 7T(aX2Xi)
I 20 zzas(a)(2)(vi)
X 50 73(aX2XiXB) tr 50 73(a)(2)(vii) tr fi T7(aX2Xii) tl 50 73(ax2xi)(c) tr OTHER Specify in Abstract betow or in
Other Systems or Secondary Functions Affected
No other systems or secondary functions were affected.
Method of discovery of each component or system Failure or Procedural Error
This valve misposition was discovered by an operator performing routine operator rounds.
Failure Mode and Effect of Each Failed Component Not applicable.
Operator Actions
Upon discovering valve 1-lSV-63-527 isolated, the operator promptly opened the valve.
Automatically and Manually lnitiated Safeg System Responses Not applicable.
CAUSE OF THE EVENT
A. The cause of each component or system failure or personnel error, if known.
The test director for the EDG Blackout Test failed to follow procedure use and adherence requirements related to the application of Not Applicable (N/A), and did not obtain Section Manager concurrence for the use of N/A.
B. The cause(s) and circumstances for each human performance related root cause.
The test director for the EDG Blackout Test failed to follow procedure use and adherence requirements related to the application of Not Applicable (N/A), and did not obtain Section Manager concurrence for the use of N/A.
ANALYSIS OF THE EVENT
On April 11,2017, WBN Unit 1 was in Mode 6 during the Unit 1 fourteenth refueling outage (U1R14). The station was making preparations to perform 0-Sl-824, 1B EDG Blackout Test. Blackout testing is normally conducted with the unit in Mode 5, however, due to a delay in the U1R14 schedule, the decision was made to conduct the testing in Mode 6. 0-Sl-824 Appendix B aligns the Sl System for the blackout testing to ensure that water is not inadvertently injected into the core. Section 3.1 of Appendix B accomplishes this
!a9k by ensuring that the Cold Overpressure Mitigation System (COMS) clearance is in place. Normally, a COMS clearance places a hold order on the breakers and hand switches of the system pumps with th6 capability to inject high pressure water into the core. Appendix B, Section 3.1, Step [2] assumes this clearance for COMS is in place. Appendix B, Section 3.1, Step [3] takes the additional step of ensuring that the 1B-B Sl Pump discharge valve (1-lSV-63-527-B) is closed and tagged. This is accomptished by E.
F.
G.
H ilt tv.
V.
verifying that the COMS clearance in Step [2] already holds 1-lSV-63-527-B closed and tagged or that the clearance is modified to include this valve.
0-Sl-824 is written with the assumption that the unit will be in Mode 5 during the performance of the surveillance. An appendix to the procedure restores system alignment following conduct of the testing.
That appendix does not contain restoration steps for 1-lSV-63-527-B because the procedure assumes configuration control for this valve is maintained under the COMS clearance. The surveillance essentially transfers responsibility for configuration control to the COMS clearance, which was not required in this case due to the test being performed in Mode 6. This lack of configuration control in 0-Sl-82-4 was a latent error introduced in the procedure in 2004.
The test director recognized that the unit was in Mode 6 and that the COMS clearance was neither required nor hanging at the time of the test. 0-Sl-82-4 Appendix B, Section 3.1, Step [2] and [3] were marked N/A during the preparation. Step [2] is marked with a note that states "COMS not required in Mode 6". Step [3] is marked with a note that states "Valve verified closed but not tagged. Mode 6 does not require valve to be tagged for COMS". The test director failed to follow procedure use and adherence requirements. Specifically, the Section Manager concurrence was not obtained prior to moving to the next step in the procedure. Additionally, the test director did not consider the effect of N/A on these steps with regard to configuration control. The system restoration appendix was not reviewed to ensure adequate restoration steps were in place to restore 1-lSV-63-527-B to its required open position for normal operation.
Contributing to the event, while not required, performance of an 18 month locked valve verification and a system alignment verification were waived during the outage.
ASSESSMENT OF SAFEry CONSEQUENCES Both trains of Slwere required to be in service to comply with TS 3.5.2 following re-entry into Mode 3 on April 26, 2017. During the time until the valve misposition was identified on May 10,2017, the 1A-A Sl was operable except for a2l minute period when its associated EDG was inoperable while it was checked to confirm water was not present in the engine cylinders. Therefore, during this 21 minute period, both Sl trains were considered inoperable. An evaluation concluded the change in core damage probability from the 1B-B Sl pump being isolated for 14 days considering the brief period where the 1A-A Sl pump was also unavailable, was less than 1E-7 during this time period, and the risk significance of this event was very small.
A. Availability of systems or components that could have performed the same function as the components and systems that failed during the event The 1A-A Sl pump was operable during the period in question except for a21 minute period.
B. For events that occurred when the reactor was shut down, availability of systems or components needed to shutdown the reactor and maintain safe shutdown conditions, remove residual heat, control the release of radioactive material, or mitigate the consequences of an accident Not applicable.
C. For failure that rendered a train of a safety system inoperable, an estimate of the elapsed time from the discovery of the failure until the train was returned to service The isolated 1B-B Sl pump was returned to service seven minutes after discovery. The 1B-B Sl pump was out of service from April 26, 2017 until May 10, 2017, or just over fourteen days.
VI. CORRECTIVE ACTIONS
This event was entered into the Tennessee Valley Authority (WA) Corrective Action Program and is being tracked under Condition Report (CR) 1294133.
A. lmmediate Corrective Actions Upon discovering the 1B-B Sl pump discharge isolation valve closed, the valve was immediately opened.
B. Corrective Actions to Prevent Recurrence or to Reduce Probability of Similar Events Occurring in the Future The EDG blackout procedures will be revised to ensure the Sl pump discharge valves are reopened at the completion of testing. Additional management focus has been applied since this event related to procedure use and adherence, particularly in the application of N/A associated with procedure use.
VII. PREVIOUS SIMILAR EVENTS AT THE SAME SITE
LER 390/2017-002 describes a condition prohibited by TS 3.6.3, Containment lsolation Valves, where a clearance was placed on the wrong fuses for a containment purge valve. This led to the purge valve not having power removed to its actuator while leak testing was being performed. While this configuration control issue was also associated with human performance (failure to identify the proper fuse location), it was not associated with procedural compliance.
LER 390/2016-002-00 describes a condition where by misinterpreting the requirements of TS 3.6.3, the containment penetration was not isolated within four hours. The event described in this LER is different in that the correct actions to comply with the TS were understood, but a human performance error resulted in the correct actions not being performed.
Concerns with procedural use and adherence are a station focus area and are described in Section Vl.B of this LER.
VIII. ADDITIONAL INFORMATION
None.
IX. COMMITMENTS None.Page 5 of 5