05000335/LER-2012-010, Regarding Degraded Manhole Conduit Seals Bypassed External Flood Protection

Regarding Degraded Manhole Conduit Seals Bypassed External Flood Protection

ML13004A096
Person / Time
Site:	Saint Lucie
Issue date:	12/27/2012
From:	Jensen J Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 12-010-00
Download: ML13004A096 (4)

LER-2012-010, Regarding Degraded Manhole Conduit Seals Bypassed External Flood Protection

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
3352012010R00 - NRC Website

text

FPLo December 27, 2012 L-2012-443 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re:

St. Lucie Unit 1 Docket No. 50-335 Reportable Event: 2012-010 Date of Event: November 2, 2012 Degraded Manhole Conduit Seals Bypassed External Flood Protection The attached Licensee Event Report 2012-010 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Respectfully, St. Lucie Plant JJ/KWF Attachment Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/201, (10-2010)

Estimated burden per response to comply with this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 LICENSEE EVENT REPORT (LER)

F52), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects@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.

3. PAGE St. Lucie Unit 1 05000335 1 OF 3

4. TITLE Degraded Manhole Conduit Seals Bypassed External Flood Protection

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED I

~"A"t"'

NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR na na I __

~~NUMBER NO. I OPRTN IFACILITY NAME DOCKET NUMBER 11 02 2012 2012 -

010 00 12 27 20121 na na

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)

El 20.2201(b)

El 20.2203(a)(3)(i)

El 50.73(a)(2)(i)(C)

[E 50.73(a)(2)(vii) 1] 20.2201(d)

El 20.2203(a)(3)(ii)

El 50.73(a)(2)(ii)(A)

El 50.73(a)(2)(viii)(A)

E-20.2203(a)(1)

El 20.2203(a)(4) 0 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)

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)

El 50.73(a)(2)(v)(A)

El 73.71(a)(4) 100%

El 20.2203(a)(2)(iv)

El 50.46(a)(3)(ii)

[I 50.73(a)(2)(v)(B)

El 73.71(a)(5) 1 % 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)

El 50.73(a)(2)(i)(B)

El 50.73(a)(2)(v)(D)

Specify in Abstract below or in Analysis of Safety Significance The degraded conduit flood seals in Unit 1 were within electrical manholes located below the 17.2 feet elevation design basis flood.

The analysis performed by Engineering concluded that RAE flooding resulting from a PMH event (due to the backflow of water through the flooded unsealed and degraded conduits seals) would exceed the internal flooding analysis of record.

This may have resulted in the loss of redundant safe shutdown equipment on the -0.5 feet elevation (e.g., boric acid makeup pumps).

FPL completed its assessment of this condition and concluded that this condition did not have a significant impact on the health and safety of the public.

The PMH is a

very low probability event.

In the unlikely event a PMH event occurred, procedurally pre-planned and spontaneous damage control actions would mitigate the impact on internal flooding, and diverse methods remained available and unaffected for maintaining safe shutdown conditions.

Corrective Actions

The completed Fukushima flooding walkdown effort encompassed the extent of condition for identifying configurations that could bypass external flood protection features.

All identified St. Lucie Unit 1 degraded conduit seals have been repaired.

Similar Events

None Failed Components None Other Information The Fukushima flood walkdowns performed at the St. Lucie site also identified missing and degraded conduit penetration seals on St. Lucie Unit 2.

However, the Engineering analysis concluded that RAB flooding resulting from the PMH event was bounded by the internal flooding analysis of record.

All identified St.. Lucie Unit 2 degraded conduit seals have been repaired.