05000443/LER-2013-001, Regarding Failure to Enter Technical Specification Following Discovery of SW Leak
| ML13365A003 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 12/23/2013 |
| From: | Ossing M NextEra Energy Seabrook |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| SBK-L-13330 LER 13-001-00 | |
| Download: ML13365A003 (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)(v), Loss of Safety Function 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 |
| 4432013001R00 - NRC Website | |
text
'1 NEXTera December 23, 2013 10 CFR 50.73 Docket No. 50-443 SBK-L-13330 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Seabrook Station Licensee Event Report (LER) 2013-001 Failure to Enter Technical Specification Following Discovery of SW Leak Enclosed is Licensee Event Report (LER) 2013-001. This LER reports an event that was discovered at Seabrook Station on October 30, 2013. This event is being reported pursuant to the requirements of 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(v)(D).
Should you require further information regarding this matter, please contact me at (603) 773-7512.
Sincerely, NextEra Energy Seabrook, LLC Michael H. Ossing Licensing Manager
~Ž~-~$
cc:
W. Dean, NRC Region I Administrator J. G. Lamb, NRC Project Manager P. Cataldo, NRC Senior Resident Inspector NextEra Energy Seabrook, LLC.
626 Lafayette Rd, Seabrook, NH 03874
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the FOIA/Privacy Section (T-5 F53), U.S. Nuclear LICENSEE EVENT REPORT (LER)
Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects.resourse@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 13. PAGE Seabrook Station 05000443 1 of 4
- 4. TITLE Failure to Enter Technical Specification Following Discovery of SW Leak
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MNH DYYA I EUNIL RVFACILITY NAME DOCKET NUMBER MONTH DAY YEAR EAR NSEQUENTIAL REVR MONTH DAY YEAR N/A N/A FACILITY NAME DOCKET NUMBER 10 30 2013 2 013 001 00 12 23 2013 N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
[1 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1) 0l 20.2203(a)(4) 0l 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
[I 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL E] 20.2203(a)(2)(ii) 0l 50.36(c)(1)(ii)(A) 0l 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4) 1 % 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[E 50.73(a)(2)(v)(B)
El 73.71(a)(5) 100%
[I 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)
[
50.73(a)(2)(i)(B)
[
50.73(a)(2)(v)(D)
Specify in Abstract below or in Ocean and the cooling tower. The normal source of water for the SW system is the ocean through two tunnels, one tunnel from the submerged intake structure offshore and a second tunnel that discharges cooling water to the ocean.
The cooling tower serves as the ultimate heat sink during a seismic event that results in blockage of the ocean tunnels.
While the ocean serves as the normal supply of cooling water, heat loads can be automatically or manually transferred to the cooling tower.
Technical Specification 3/4.7.4 requires that the SW System be Operable in Modes 1 through 4. This includes An operable SW pump house and two service water loops with an operable SW pump in each loop and, An operable mechanical draft cooling tower and two cooling tower loops with one operable cooling tower pump in each loop, and A portable cooling tower makeup system stored in its design operational readiness state.
The SW strainer bypass line is located upstream of the Primary Component Cooling Water (PCCW) and Diesel Generator (DG) heat exchangers and is pressurized during ocean pump alignment and cooling tower operation. The line is not isolable with the system in service. If a leak at this location was large enough, cooling tower inventory and the ability to operate for seven days without makeup could be impacted. The calculated maximum acceptable boundary leakage for 7 day cooling tower operation is approximatelyl 37.25 gpm. The POD performed on August 8, 2013 for the leak discovered on August 7, 2013 concluded that the leak was estimated to be less than 10 drops per minute. A structural evaluation performed for the August 7, 2013 specifically addressed the UT indication and concluded that the structural integrity of the SW bypass line was not compromised and there was no structural impact on the service water system. The evaluation of the other SW safety functions (Cooling Tower inventory, Cooling supply to PCCW and EDG heat exchangers and PAB flooding) did not address the UT indication. Based on the leak rate of 10 dpm, both the preparer and reviewer of the POD were of the opinion that this leak was the same as previous pin hole leaks identified in service water piping. The POD documented the propagation of the leak was assumed to be a %" diameter hole based on the 10 dpm leak.
On August 20, 2013, the leak increased to 90 dpm. On August 21, 2013, a second UT examination was performed of the leak area. The UT examination confirmed the indication size had not changed, however a depression (concavity) in the UT indication area of approximately 1/2" in diameter was noted. The UT examination results were evaluated by Engineering; concluding that since the size of the indication had not changed the structural integrity of the pipe is maintained. Based on information obtained from Engineering, Operations concluded that the current leak rate was within the bounding allowable leakage as determined by the prompt operability.
On August 28, 2013 at 1900, during surveillance testing of the train-B cooling tower pump, it was determined that the previously identified leak had increased to approximately 25 gpm. During the swap to the cooling tower pumps SW header pressure typically increases. In this situation, the SW header pressure increased from 48 psi to 66 psi. Based on the increase in leakage and SW header pressure, the control room staff terminated the surveillance and restored train B SW to the ocean pumps. When returned to the ocean pumps, 'B' SW header pressure returned to 48 psi and leakage decreased to approximately 15 gpm. Assessment of operability at that time determined that the SW system remained operable with the increased leakage based on the operability determination performed previously for the August 7, 2013 SW leak. A housekeeping patch was placed on the pipe and discussions regarding a relief request for a noncode repair started with the NRC. The repair was completed on September 1, 2013.
On October 30, 2013, a review of the event determined that the POD performed for the August 7, 2013 leak did not provide reasonable assurance of continued operability of the SW system. Therefore, the SW leak rendered the ocean and cooling tower loops in SW train B inoperable. TS 3.7.4, action d applies to this condition and requires restoring at least one loop to operable status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or placing the plant in Mode 3 in the next six hours and in Mode 5 in the next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. The plant exceeded the allowed outage time and shutdown time of the TS action when it operated from August 8, 2013 until September 1, 2013, when the leak was repaired. The review of the event also found that concurrent with the unrecognized inoperability of SW train B, the train A SW train was rendered inoperable for testing and maintenance activities. On August 15, 2013, train A SW was rendered inoperable on two occasions for a total time
of approximately three hours. The concurrent inoperability of both trains of the SW system resulted in a condition that could have prevented fulfillment of the safety function of the SW system. Therefore, this event meets the reporting criteria of 10 CFR 50.73(a)(2)(i)(B) for an operation or condition prohibited by the TS and 10 CFR 50.73 (a)(2)(v)(D) for an event that could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident.
No adverse consequences resulted from this event, and this incident had no adverse impact on the health and safety of the public or the plant and its personnel. This event did involve a safety system functional failure because both trains of the SW system were inoperable for approximately three hours on August 15, 2013. Nonetheless, this event was of minimal risk significance, having no impact on core damage frequency or large early release frequency as during the time in question, the SW system remained functional. No inoperable structures, systems, or components contributed to this event.
Corrective Actions
The Root Cause Team identified the following corrective actions:
- 1.
Involved individuals involved in the POD preparation were coached and mentored on documentation requirements for POD preparation.
- 2.
Revise the Fleet procedure to add appropriate process barriers to ensure the engineering evaluation adequately documents consideration of field input information and assumptions for safety functions. Include an independent review or supervisory review and require assumptions be stated (including disposition of input data), i.e., UT, NDE inspection results and observations.
- 3.
Reinforce procedure requirement to initiate a condition report for unexpected UT results even if the UT is being performed as part of an already identified condition.
- 4.
Prepare and present a case study regarding this event and root cause evaluation to Engineering, Operations Shift Management and Station Leadership.
Similar Events
A review of the corrective action program and LERs in the past five years identified no similar events.
Failed Components None.
Additional Information
The Energy Industry Identification System (EIIS) codes are included in this LER in the following format: [EIIS system identifier].