05000280/LER-2016-001, Regarding Emergency Service Water Pump Inoperable Due to Corrosion of Valve Support
| ML16216A150 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/11/2016 |
| From: | Lane N Virginia Power (Virginia Electric & Power Co) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 16-273 LER 16-001-00 | |
| Download: ML16216A150 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(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), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 2802016001R00 - NRC Website | |
text
July 11, 2016 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555-0001
Dear Sir or Madam:
10CFR50.73 Virginia Electric and Power Company Surry Power Station 5570 Hog Island Road Surry, Virginia 23883 Serial No.:
16-273 SPS:
TSC Docket No.: 50-280 50-281 License No.: DPR-32 DPR-37 Pursuant to 1 OCFR50.73, Virginia Electric and Power Company hereby submits the following Licensee Event Report applicable to Surry Power Station Unit 1 and Unit 2.
Report No. 50-28~, 5.0-281/2016;:.001-00 This report has been reviewed by the Station Facility Safety Review Committee and will be forwarded to the Management Safety Review Committee for its review.
Enclosure Commitment cont13ined in this letter: None Very truly yours,
/).~ f_z N. L. Lane~
Site Vice President Surry Power Station cc:
U.S. Nuclear Regulatory*Commission, Region II Marquis One Tower, Suite 1200
. 245 Peachtree Center Ave.; NE:
- Atlanta, GA 30303-1257
- NRG Senior Resident Inspector Surry Power Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMJSSl9~ APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (11-2015)
~lllou, 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 />.
l::J Reported lessons learned are incorporated into the licensing process and fed back to industry.
11
\\..... J LICENSEE EVENT REPORT (LER)
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and (See Page 2 for required number of Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC digits/characters for each block) 20503. If a means used to impose an information collection does not display a currently vaiid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Surry Power Station, Unit 1 05000 - 280 1 OF 4
- 4. TITLE Emergency Service Water Pump Inoperable Due to Corrosion of Valve Support
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO.
MONTH DAY YEAR Surry Power Station, Unit 2 05000 - 281 05 11 2016 2016 - 001 -
FACILITY NAME DOCKET NUMBER 00 07.
11 2016 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITIED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
D 20.2201(b)
D 20.2203(a)(3)(i)
D 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A)
N D 20.2201 (d)
D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(1)
D 20.2203(a)(4)
D so.13(a)(2)(iii)
D 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(i)
D 50.36(c)(1)(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(ii)
D 50.36(c)(1)(ii)(A)
D 50.73(a)(2)(v)(A)
D 13.11(a)(4)
D 20.2203(a)(2)(iii)
D so.36(c)(2)
[gj 50. 73(a)(2)(v)(B)
D 13.11ca)(s) 100 D 20.2203(a)(2)(iv)
D so.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73.11(a)(1)
D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 13.11ca)(2)(i)
D 20.2203(a)(2)(vi)
[gj 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 73.77(a)(2)(ii).
D 50.73(a)(2)(i)(C)
D OTHER Specify in Abstract below or in NRG Form 366A
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT I
TELEPHONE NUMBER (Include Area Code)
Barry Garber (757) 365-2725 CAUSE SYSTEM COMPONENT MANU-REPORTABLE I
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX x
Bl PSF B779 y
~
x Bl SPT H913 y
'{';
- 14. SUPPLEMENTAL REPORT EXPECTED 15.EXPECTED
~ONTH DAY YEAR D YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
[gj NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On April 7, 2016 at 0638 hours0.00738 days <br />0.177 hours <br />0.00105 weeks <br />2.42759e-4 months <br />, with Surry Power Station Units 1 and 2 operating at 100% power, the Emergency Service Water Pump (ESWP) 1 B cooling water discharge valve flange was found to be cracked, and the pump was declared inoperable. During flange and valve support repair activities, four bolts on the cooling water discharge valve support base plate were found to be failed due to corrosion. The flange was replaced and the support base plates were anchored with stainless steel bolts. ESWP 1 B was returned to operable status on April 9, 2016 at 1105 hours0.0128 days <br />0.307 hours <br />0.00183 weeks <br />4.204525e-4 months <br />. The cause of the flange and support failure was corrosion of the base plate and anchor bolts from repetitive exposure to service water. On May 11, 2016, an Engineering evaluation determined that the piping and support had been non-functional for prior operability based on the potential for lateral displacement during a seismic event. Therefore, this report is being submitted, pursuant to 1 O CFR 50. 73(a)(2)(i)(B), for operations prohibited by Technical Specifications, and pursuant to 1 O CFR
- 50. 73(a)(2)(v)(B), an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat. Based on the risk assessment of this event, the risk impact was determined to be of very low significance, and, as a result, the health and safety of the public were not affected.
NRG FORM 366 (11-2015)
Page 2 of4 1.0 DESCRIPTION OF THE EVENT Three diesel-driven vertical Emergency Service Water Pumps (ESWPs) [EllS-Bl-P] are provided at the James River intake structure [EllS-KE-NN] to deliver required service water makeup to the intake canal [EllS-KE-NN] in case of a total loss of station power. In the event of a Loss of Coolant Accident (LOCA) and a total loss of station power, with the requirement that the pon-LOCA unit must also be cooled down, two of the three ESWPs would be required to provide the design service water makeup. Technical Specification (TS) 3.14.A.4 states that when the reactor coolant system temperature or pressure exceeds 350°F or 450 psig, three emergency service water pumps shall be operable. TS 3.14.B allows one ESWP to remain inoperable for a period not to exceed 7 days.
On April 7, 2016, during a walk-down of the ESWP house [El IS-Bl-MK], the ESWP 1 B cooling water discharge valve piping flange [EllS-81-LB-PSF] was found to be cracked. A follow on Engineering and Maintenance inspection confirmed the cracked flange and observed a cooling water discharge valve support [EllS-81-LB-SPT] was raised due to corrosion buildup under the support base plate.
With Units 1 and 2 operating at 100% power, ESWP 1 B was declared inoperable as of 0638 hours0.00738 days <br />0.177 hours <br />0.00105 weeks <br />2.42759e-4 months <br />, based on the deteriorated condition of the flange.
During flange repair activities, the valve support, consisting of two stanchions and two base plates, was removed to install stainless steel anchor bolts. On the north base plate, the existing carbon steel anchor bolts were found to be failed due to corrosion. The cracked flange was repaired, the valve support base plate anchor bolts were replaced, and ESWP 1 B was returned to operable status on April 9, 2016 at 1105 hours0.0128 days <br />0.307 hours <br />0.00183 weeks <br />4.204525e-4 months <br />. The elapsed time from discovery until the ESWP 1 B was returned to service was 52 hours6.018519e-4 days <br />0.0144 hours <br />8.597884e-5 weeks <br />1.9786e-5 months <br /> and 27 minutes.
On May 11, 2016, an engineering review determined that the piping and support were non-functional for prior operability based on the potential for lateral displacement during a seismic event.
If this were to occur, cooling water would discharge to the ESWP house. It is expected that since ESWPs are operated locally, the ESWP 1 B would be shut down to minimize water intrusion into the ESWP pump house. Based upon the as-found conditions of the failed valve support anchor bolts, the condition of the ESWP 1 B was determined to be present for a time greater than the 7 day limiting condition. Therefore, this report is being submitted pursuant to 10 CFR 50.73 (a)(2)(i)(B),
an operation or condition that was prohibited by the plant's Technical Specifications. In addition, during the prior 7-day period when ESVVP 18 was determined to be inoperable, ESWP 1C was removed from service for maintenance. Therefore, this report is also being submitted pursuant to 10 CFR 50. 73(a)(2)(v)(B), an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat.
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS
The duration of the ESWP 1 B flange and valve support failure is undetermined due to the nature of (11-2015)
- 1. FACILITY NAME Surry Power Station, Unit 1 Page 3 of 4 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET
- 2. DOCKET NUMBER YEAR 05000 - 280 2016
- 6. LER NUMBER SEQUENTIAL NUMBER 001 REV NO.
00 corrosion progression. The engineering review determined that the degraded condition was present for a period longer than the 7-day allowed outage time. A review of surveillance testing conducted since 2014 found no leakage observed from the cooling water discharge. Based upon the successful completion of the operability tests, ESWP 1 B could have performed its design function in the event of a Design Basis Large Break LOCA coincident with a loss of offsite power.
However, if a seismic event were also to occur, the cooling water discharge pipe could fail, due to the degraded support, and ESWP 1 B would be shutdown to prevent water intrusion into the ESWP house.
Seismic Reliability evaluations indicate that ESWPs do not play a significant role in Seismic Core Damage Sequences. The probability of a Design Basis Large Break LOCA coincident with a loss of offsite power and a seismic event is low. Therefore, based on the assessment of this event, the risk impact was determined to be of very low significance, and, as a result, the health and safety of the public were not affected.
3.0 CAUSE
The preliminary cause of the ESWP 1 B cooling water discharge valve support and flange failure was due to corrosion of the base plate and anchor bolts from repetitive exposure to service water.
The carbon steel support base plates and carbon steel anchor bolts were located in a low spot on the concrete floor and were subjected to wet conditions. The base plate corrosion caused the support to elevate, applied stress to the joint, and cracked the flange.
~
4.0 IMMEDIATE CORRECTIVE ACTIONS
Repairs to the ESWP 1 B cooling water discharge piping and support were completed, and the ESWP 1 B was returned to operable status April 9, 2016 at 1105 hours0.0128 days <br />0.307 hours <br />0.00183 weeks <br />4.204525e-4 months <br />. ESWP 1 A and 1 C cooling water discharge valves, piping, and supports were inspected and found to be unaffected.
5.0 ADDITIONAL CORRECTIVE ACTIONS
An apparent cause evaluation was initiated for this event.
An extent of condition was performed in the ESWP house and corrosion was identified on other support base plates. These conditions were evaluated and no further operability concerns were identified. The additional items were entered into the corrective action program.
s~o ACTIONS TO PREVENT RECURRENCE The ESWP 1 B cooling water discharge valve support anchor bolts were replaced with stainless steel anchor bolts to limit the vulnerability to corrosion.
The corrective actions from the approved apparent cause ~valuation will be entered into the corrective action program. (11-2015)
- 1. FACILITY NAME Surry Power Station, Unit 1 7.0 SIMILAR EVENTS Page 4 of 4 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET
- 2. DOCKET NUMBER YEAR 05000 - 280 2016
- 6. LER NUMBER SEQUENTIAL NUMBER 001 REV NO.
00 In 2015, corroded floor anchor bolts on a service water pipe support In Mechanical Equipment Room (MER) #3 were observed but the design function was not affected. Corrective actions extent of condition was limited to other supports in MER #3 and #4 (CR1012368).
8.0 MANUFACTURER/MODEL NUMBER Flange - 3 inch fiberglass; support foundation base plate material carbon steel; concrete anchor bolts - carbon steel Hilti Kwik Bolt
9.0 ADDITIONAL INFORMATION
None