05000280/LER-2015-001, Regarding Inadequate Missile Protection Due to Failure to Procedurally Control Sliding Missile Shields
| ML15103A270 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 03/30/2015 |
| From: | Lane N Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 15-127 LER 15-001-00 | |
| Download: ML15103A270 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vi) |
| 2802015001R00 - NRC Website | |
text
10CFR50.73 Virginia Electric and Power Company Surry Power Station 5570 Hog Island Road Surry, Virginia 23883 March 30, 2015 U. S. Nuclear Regulatory Commission Serial No.:
15-127 Attention: Document Control Desk SPS:
JCP Washington, D. C. 20555-0001 Docket No.: 50-280 50-281 License No.: DRP-32 DPR-37 Pursuant to 10CFR50.73, Virginia Electric and Power Company hereby submits the following Licensee Event Report applicable to Surry Power Station Units 1 and 2.
Report No. 50-280, 50-281/2015-001-00 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.
Very truly yours, N. L. Lane Site Vice President Surry Power Station Enclosure Commitment contained in this letter: None cc: U.S. Nuclear Regulatory Commission, Region II Marquis One Tower, Suite 1200 245 Peachtree Center Ave., NE Atlanta, GA 30303-1257 NRC Senior Resident Inspector Surry Power Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 (02-2014)
(02-2014)
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 and Information Collections LICENSEE EVENT REPORT (LEBranch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by LE EP (LEmR) internet e-mail to lnfocol*eds.Resource@nrc.gov, and to the Desk Officer, Office of Information and (See Page 2 for required number of RegulatoryAffairs, 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 digits/characters for each block) 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 05000280 1 OF 3
- 4. TITLE Inadequate Missile Protection Due to Failure to Procedurally Control Sliding Missile Shields
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MO D
YEAR I SEQUENTIAL REV FACILITY NAME DOCKET NUMBER M NUMBER NO.
MONTH DAY YEAR Surry Power Station, Unit 2 05000281 FACILITY NAME DOCKET NUMBER 01 27 2015 2015-001
- - 00 3
30 2015 05000
- 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)
[1 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
N[
20.2201(d)
E] 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
N El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i)
El 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)
El 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)
El 50.36(c)(2)
[
50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[
50.73(a)(2)(v)(B) l 73.71(a)(5) 100 El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
ED 50.73(a)(2)(v)(C)
El OTHER [E
20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
[
50.73(a)(2)(v)(D) speciinAbsfact belowFor in
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT TELEPHONE NUMBER (Include Area Code)
N. L. Lane, Site Vice President (757) 365-2001CAUSE SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX D
XX DR N
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION El YES (Ifyes, complete 15. EXPECTED SUBMISSION DATE)
[ NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On January 27, 2015, with Units 1 and 2 operating at 100 percent power, it was identified that four sliding missile shields on the Main Steam Valve House (MSVH) were not included in the Abnormal Environmental Conditions procedure to be closed upon the threat of high winds. The shields are necessary to meet the design function of the MSVH for protection of the safety-related equipment and must be closed to perform their design function. A missile penetrating the MSVH could have prevented the MS and/or AFW systems from being able to mitigate the consequences of -an accident. Therefore, this event is reportable pursuant to 10 CFR 50.73(a)(2)(v). The shields were inappropriately excluded from the original revision of the procedure, which has now been revised to include the shields. This event posed no significant safety implications due to the low probability of missile damage inside the MSVH with the shields open. Therefore, the health and safety of the public were not affected by this event.
NRC FORM 366 (02-2014)
1.0 DESCRIPTION OF THE EVENT On January 27, 2015, with Units 1 and 2 operating at 100 percent power, it was identified that the sliding missile shields [EIIS XX-DR] for the four Main Steam Valve House (MSVH) access doors were not included in the Abnormal Environmental Conditions procedure to be closed upon the threat of high winds in the event of a hurricane or tornado watch or warning.
The shields are necessary to meet the design function of the MSVH for protection of the equipment inside the MSVH (e.g., auxiliary feedwater pumps [EllS BA-P] or other safety-related components in the Main Steam (MS) [EllS SB] and Auxiliary Feedwater (AFW) [EIIS BA] systems) from high wind generated missiles. These shields are normally maintained open and must be closed upon the threat of high winds from a hurricane or tornado in order to perform their design function.
This issue was discovered during a procedure revision walk-through.
There have been approximately ten instances in the past three years when the Abnormal Environmental Conditions procedure was entered and it was determined that closure of sliding missile shields would have been appropriate due to local weather conditions. During these times, a missile could have penetrated the unprotected access doors and interacted with the auxiliary feedwater pumps or other safety-related components in the MS and AFW systems located inside the MSVH.
10 CFR 50.73(a)(2)(vi) includes events caused by procedural inadequacies. Since the Abnormal Environmental Conditions procedure did not ensure sliding missile shield closure, a missile could have prevented the AFW and/or MS system from performing their safety functions and is therefore reportable pursuant 10 CFR 50.73(a)(2)(v).
2.0
SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS
The MSVH sliding missile shields are part of the Class 1 structure designed to protect safety-related components inside the MSVH from the effects of tornados and high winds. If the doors are not closed upon the threat of high winds, the potential exists for a tornado-generated missile to disable a combination of MS lines and AFW trains which would challenge the ability to remove decay heat. Contingencies exist in Surry's function restoration procedures to provide alternate means of Decay Heat Removal, such as establishing Bleed and Feed Cooling or operation of the AFW crosstie from the other Unit.
Based on an assessment of this event, the increase in risk was determined to be of low significance due to the low probability of a missile entering the MSVH and disabling Surry's ability to remove decay heat. As a result, the health and safety of the public were not affected.
3.0
CAUSE
The Main Steam Valve House sliding missile shields were not included in original version of the Abnormal Environmental Conditions procedure. No documentation could be identified that indicated the reason these doors were not included in the procedure.
No similar procedure could be identified to exist prior to issuance of the original revision of the current procedure.
4.0 IMMEDIATE CORRECTIVE ACTION(S)
The abnormal environmental conditions procedure has been revised to include the four MSVH sliding missile shields in the list of sliding missile shields to be closed upon the threat of high winds.
5.0
ADDITIONAL CORRECTIVE ACTIONS
An extent of condition review was completed and verified that the station sliding missile shields are included in the Abnormal Environmental Condition procedure.
6.0 ACTIONS TO PREVENT RECURRENCE No additional actions are required.
7.0
SIMILAR EVENTS
None 8.0 MANUFACTURER/MODEL NUMBER Not applicable 9.0
ADDITIONAL INFORMATION
None NRC FORM 366 (02-2014)