05000443/LER-2006-003, Re Voluntary LER for Deficient Hydrostatic Barriers
| ML061520345 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 05/23/2006 |
| From: | St.Pierre G Florida Power & Light Energy Seabrook |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| SBK-L-06109 LER 06-003-00 | |
| Download: ML061520345 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2) 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 |
| 4432006003R00 - NRC Website | |
text
0FPL Energy Seabrook Station FPL Energy Seabrook Station P.O. Box 300 Seabrook, NH 03874 (603) 773-7000 MAY 2 3 M06 Docket No. 50-443 SBK-L-06109 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Seabrook Station Licensee Event Report (LER) 2006-003-00 Voluntary LER for Deficient Hydrostatic Barriers Enclosed is Licensee Event Report (LER) 2006-003-00. This is a voluntary LER that reports an event that occurred at Seabrook Station on February 5, 2006.
Should you require further information regarding this matter, please contact Mr. James M.
Peschel, Regulatory Programs Manager, at (603) 773-7194.
Very truly yours, FPL Energy Seabrook, LLC Gene St. Pierre Site Vice President cc:
S. J. Collins, NRC Region I Administrator G. E. Miller, NRC Project Manager, Project Directorate I-2 G. T. Dentel, NRC Senior Resident Inspector
--I ---
6-; )-
an FPL Group company I
ENCLOSURE TO SBK-L-06109
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06130/2007 6r>2004)
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, the NRC may digits/characters for ea6h block) o and a person Is not required to respond to, the
- 3. PAGE Seabrook Station 05000443 I OF 3
- 4. TITLE Voluntary LER for Deficient Hydrostatic Barriers
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQTU__TIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEUENTIAL REV MONTH DAY YEAR N/A 05000 FACILITY NAME DOCKET NUMBER 02 05 2006 2006 - 003 -
00 05
- 23.
2006 N/A 05090
- 9. OPESTING MODE 11,THISREPORTISSUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check llthat apply)
O 20.2201(b) 0 20.2203(a)(3)(i) 0 50.73(a)(2)(i)(C) 0 50.73(a)(2)(v0i) 0 20.2201(d) 0 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A) 0 50.73(a)(2)(viii)(A) 0 20.2203(a)(1) 0 20.2203(a)(4) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B) 0 20.2203(a)(2)0) 0 50.36(c)(1)(i)(A) 0 50.73(a)(2)(iii) 0 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 0
20.2203(a)(2)11) 0 50.36(c)(1)(ii)(A)
D 50.73(a)(2)(iv)(A)
[
50.73(a)(2)(x)
O 20.2203(a)(2)(iii) 0 50.36(c)(2) 0 50.73(a)(2)(v)(A) 0 73.71 (a)(4) o0 20.2203(a)(2)(iv) 0 50.46(a)(3)(ii) 0 50.73(a)(2)(v)(B) 0 73.71(a)(5) 100 0 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A)
O 50.73(a)(2)(v)(C) 0 OTHER.
o 20.2203(a)(2Xvi) 0 50.73(a)(2)(i)(B) 0 50.73(a)(2)(v)(D)
Specify In Abstract below
___or In (If more space Is required, use additional copies of (If more space Is required, use additional copies of NRC Form 366A) (17)
A review of structural drawings and specifications revealed that the cable spreading room floor was not designed or constructed with features that would ensure its intended watertight Integrity. A review of concrete placement drawings revealed a construction Joint above a known leak location. Water could leak through this joint and follow the Q-decking to the wall Inside the electrical switchgear room.
Seal Maintenance and Inspection Procedures Station procedures were originally developed to inspect fire rated penetration seals and barriers in accordance with Technical Requirement 11-4.7.9.5. The inspection attributes specified In these procedures addressed only fire rated qualifications of the barriers and seals. An evaluation performed In 1991 concluded that the procedures used for fire barrier and seal Inspections would also demonstrate seal/barrier integrity for other safety-related applications, such as hydrostatic, air, and tornado barrier functions. However, the fire seal acceptance criteria allowed for certain defects to remain without repairs while, for hydrostatic seals, these allowable defects may not be sufficient to ensure a watertight seal. Although the procedures that provide administrative controls for the repair, removal, modification, and installation of the fire barrier penetration seals require a dedicated work order for penetration seal repairs and modifications, the guidance does not consider penetration seals In the cable removal steps. In addition, the post-maintenance and modification Inspection attributes apply the fire rated seal inspection criteria and do not consider the hydrostatic barrier function.
Safety Consequences
No consequences resulted from this event and, therefore, the event had no adverse impact on the plant or on the health and safety of the public. The degraded seals did not present a safety hazard and would not have prevented the fulfillment of any safety function. In the event of a fire, the seals will tend to expand as they are subjected to the heat of the fire, improving their effectiveness as a water barrier. The amount of leakage experienced during the deluge actuation was minimal and resulted in no adverse Impact on equipment in the essential switchgear room. Further, although the equipment in the essential switchgear room is not designed to be waterproof; a certain amount of protection Is provided by the inherent design of the metal enclosures. Most of the enclosures have solid tops with entry by conduit, and most vents, where provided, on the sides of the equipment have small hoods to prevent water intrusion. Vents on the top of inverters have drip shields covering the vents, and equipment mounted on the walls is offset by attachments to unistrut, preventing damage from water trickling down the walls. A fire in the cable spreading room is an extremely unlikely event due to the flame qualification of the cables, the absence of permanent combustibles in this area, and the rigid controls on transient combustible material in this area. From a PRA perspective, this area is one of the lowest risks of any fire areas with regard to fire frequencies. A conservative estimate of the frequency of loss of both buses from a fire deluge is I E-7/yr.
Additionally, there have been hourly fire watches going into the cable spreading room since early 2005.
IV. Corrective Actions
The corrective actions taken to address this event include:
- 1. The deficient seals were repaired.
- 2. Design changes were developed to upgrade the cable spreading room seals and floor joints.
Planned corrective actions will provide a detailed barrier and seal basis document and revise the administrative controls for maintenance and configuration control of barriers and seals.
V. Similar Events
LER 89-010 reported that three piping penetrations in the condensate storage tank enclosure did not contain the required hydrostatic seals. The cause of the condition was attributed to a failure to transform the sealing requirements into field fabrication and Installation drawings. Following this event, an inspection verified that all required hydrostatic seals were Installed.