05000335/LER-2006-005, Regarding Internal Conduit Penetration Seals Outside Appendix R Design Basis
| ML070520159 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 02/09/2007 |
| From: | Johnston G Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2007-019 LER 06-005-00 | |
| Download: ML070520159 (5) | |
| 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)(ii) |
| 3352006005R00 - NRC Website | |
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FPL Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 February 9, 2007 L-2007-019 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Re:
St. Lucie Units 1 and 2 Docket No. 50-335, 50-389 Reportable Event: 2006-005-00 Date of Event: December 12, 2006 Internal Conduit Penetration Seals Outside Appendix R Design Basis The attached Licensee Event Report 2006-005-00 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event..
Very truly yours, Gordon L. Johnston Site Vice Presidentz St. Lucie Plant GLJ/dlc Attachment an FPL Group company
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/200' (6-2004)
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 conmaents regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission, LICENSEE EVENT REPORT (LER)
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. Ifa 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.
PAGE St. Lucie Unit 1 050001 OF
- 4. TITLE Internal Conduit Penetration Seals Outside Appendix R Design Basis.
- 5. EVENT DATE
- 6. LER NUMBER___
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MOTH DA YAR YER SEQUENTIAL REV MONTH DAY YEAR M
DANUMBER NO.
FACILITY NAME DOCKET NUMBER 12 12 2006 2006 -
005 0o0 02 09 2007
- 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)
El 50.73(a)(2)(vii)
[1 20.2201(d)
El 20.2203(a)(3)(ii)
E] 50.73(a)(2)(ii)(A)
[] 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
Z 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)
[] 50.73(a)(2)(iii)
Ej 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 21 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
E] 50.73(a)(2)(x)
Ej 20.2203(a)(2)(iii) 0 50.36(c)(2)
El 50.73(a)(2)(v)(A)
[_
73.71(a)(4) 10 20.2203(a)(2)(iv)
L] 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
Ej 73.71(a)(5) 100%
El 20.2203(a)(2)(v)
[] 50.73(a)(2)(i)(A)
[] 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
[] 50.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER Donald L.
Cecchett - Licensing Engineer 772-467-7155 El YES (Ifyes, complete 15. EXPECTED SUBMISSION DATE)
ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On December 12,
- 2006, St. Lucie Units 1 and 2 were in Mode 1 at 100 percent reactor power.
During the normal course of work FPL identified that the penetration seal configuration used for internal conduit penetration seals, although operable, were degraded due to inadequate qualification testing methods.
The documented test results do not provide an adequate basis for qualification of the internal conduit penetration seals to perform as a 3-hour fire barrier.
Approximately 1050 conduits at St. Lucie Unit 1 and approximately 2500 conduits at St. Lucie Unit 2 may be affected.
The apparent cause was determined to be a legacy issue occurring during the time of the Unit 1 Appendix R modifications, and the original construction of Unit 2.
The apparent cause was determined to be misinterpretation of fire test reports and guidelines from the NRC. At the time of discovery a condition report was initiated and general fire barrier impairments logged and issued in accordance with the Fire Protection Program.
Corrective actions completed or planned include the development and implementation of a fire test that will bound the as-installed internal conduit seal design, a
walkdown and documentation of the conduits requiring fire rated internal conduit seals, and incorporation of those seals into the inspection program.
RC FORM 366 (6-2004)
PRINTED ON RECYCLED PAPERU.S. NUCLEAR REGULATORY COMMISSION (7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION NUMBERT2 LER NUMBER (6)
PAGE (3)
FACILITY NAME (1)
IN 2LRNUMBER (6)PAE)3 YEAR SEQUENTIAL REVISION NUMBER NUMBER St. Lucie Unit 1 05000335 Page 2 of 4 2006 005 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
Description of the Event On November 28, 2006, St. Lucie Units 1 and 2 were in Mode 1 at 100 percent reactor power when FPL engineering identified that the penetration seal configuration being used for internal conduit penetration seals [EIIS:PEN] credited a test report that had not adequately demonstrated a 3-hour fire barrier.
Subsequent investigations also revealed that the documentation of the design basis of the seal configuration as installed was inadequate. On December 12, 2007, after an extensive investigation failed to identify a bounding test document, the station determined this issue was reportable pursuant to 10 CFR 50.73(a) (2) (ii)
(B).
Review of existing fire test documentation, used for qualification of the fire rated penetration seals, proved to be inconclusive in that the conduit used in the test, was capped on the fire side of the conduit.
This configuration prevented the non-fire side seal configuration from being challenged by either the fire or the hose stream.
A review of FPL plant drawings documenting conduits penetrating Appendix R barriers identified approximately 1050 conduits for St. Lucie Unit 1 and approximately 2500 conduits for St. Lucie Unit 2 that maybe affected.
The population of conduits in those totals requiring 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire rated seals is under investigation.
Cause of the Event
An Apparent Cause evaluation concluded this is a legacy issue stemming from the Unit 1 Appendix R modification, and Unit 2 original construction time frame, in which fire test reports and guidelines from the NRC were misinterpreted.
Analysis of the Event
In accordance with NUREG-1022, "Event Reporting Guidelines 10 CFR 50.72 and 50.73,"
Revision 2, Section 3.2.4, a missing fire barrier, such that the required degree of separation for redundant safe shutdown trains is insufficient, is reportable as an unanalyzed condition that significantly degraded plant safety.
At the time of discovery 1-hour roving fire watches for the affected areas were already in place for unrelated reasons.
Therefore, this event was not reportable under 10 CFR 50.72, but is reportable under 10 CFR 50.73(a)
(2)
(ii)
(B).
Analysis of Safety Significance The potentially deficient conduit seals are located in the St. Lucie Unit 1 and St.
Lucie Unit 2 Reactor Auxiliary Building and penetrate various fire barriers.
The fire areas which are located on either side of each affected barrier were reviewed to determine the need for initial compensatory measures.
As a minimum the Fire Protection Plan requires operable detection on one side of the affected barrier when a barrier feature is inoperable.
Those areas where there was no detection present on either side of the barrier were reviewed and it was identified that there were no combustibles located adjacent to the affected conduits or there was a very low or negligible combustible loading in one or both of the affected rooms.
Walkdowns of all conduits will be completed to determine the need for fire rated seals internal to the conduits or the ability to screen out those which do not require a fire rated seal.
FPL's initial assessment of the conduit seals as installed concluded they are expected to be capable of providing a degree of fire resistance based on the materials used in the seal configuration.
Considering the active detection on one side of the affected barrier, or analyzed as adequate without detection, and theU.S. NUCLEAR REGULATORY COMMISSION (7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION DOCKET FACILITY NAME (1)
NUMBERT2 LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL REVISION YEA NUMB ER NUMBER St. Lucie Unit 1 05000335 Page 3 of 4 2006 005 00 TEXT (if more space is required, use additional copies of NRC Form 366A) (17) presence of a one hour roving fire watch, FPL considers that the safety significance of this issue as low.
An extent of condition was conducted and concluded that there is a unique set of conditions that applies only to internal conduit seals, however, corrective action will be taken that will address the entire population of conduits penetrating Appendix R fire barriers in both units. Electrical penetration seals in fire rated barriers have already been the subject of previous LERs and modifications and were upgraded/replaced with qualified fire rated configurations.
Corrective Actions
The proposed corrective actions and supporting actions listed below are entered into the site corrective action program.
Any changes to the proposed actions will be managed under the commitment management change program.
The following actions will be tracked within the St. Lucie Corrective Action Program:
l.Develop and perform a fire test to determine the fire rating for the existing conduit seal design.
2.Review results of fire test of the existing conduit seal design (2 inches of cerafiber and 1/."
of mastic) to determine appropriate corrective actions.
3.Perform walkdowns of Unit 1 and Unit 2 to determine the type of seal the conduits require and identify any additional actions to remediate seals based on this review.
4.Prepare engineering document(s) to revise plant documents/drawings as required to address internal conduit seals.
5.Corrective actions to implement fire watches for fire barrier impairments have been completed.
Similar Events
Although electrical and mechanical penetration seals in fire rated barriers have been the subject of previous
- LERs, this event is the first occurrence of any issues associated with internal conduit seals in fire rated barriers.
This is because electrical and mechanical penetration seals were clearly identified as 3-hour rated fire seals, i.e.,
identified on penetration schedules and included in the 18-month surveillance program.
The current PSL FSARs do not clearly identify internal conduit seals as rated seals but rather fire seals which prevent the passage of flames,
- smoke, and/or hot gases.
Therefore, this issue is not considered a repeatable issue.
A review of PSL's Condition Reports for the past 2-3 years identified one event, LER 2003-03-001," Fire Seals Inoperable Due to Inadequate Qualification Testing," dated April 5, 2004 (L-2004-073) in which cable tray fire penetration seals (not internal conduit seals) did not have an adequate basis as three-hour fire barriers. Beyond 3 years two additional LERs were identified i.e.,
LER 97-08, "Inoperable Mechanical Fire Penetrations Outside Appendix R Design Bases" dated August 27, 1997 (L-97-221),
involving incomplete corrective actions associated with NRC Information Notice (IN) 94-28, and LER 97-004, "Incorrect Original Cable Tray Fire Stop Assembly Outside Appendix RU.S. NUCLEAR REGULATORY COMMISSION (7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET LER NUMBER (6)
PAGE (3)
FACIITYNAME(1)NUMBER (2)
YEAR SEQUENTIAL REVISION St. Lucie Unit 1 05000335 Page 4 of 4 2006 005 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
Design," dated July 11, 1997(L-97-179),
which involved double-sided cable tray fire stops not being installed in accordance with the design drawings.
Failed Components Manufacturer:
Equipment:
Grace Co.
(previous owners of the product are International Protective Coatings, and Thomas Betts Corp).
Mastic Seal (Flame Safe, formerly Quelcor)