ML20118A682
| ML20118A682 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 09/18/1992 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-92-001, IEB-92-1, TXX-92446, NUDOCS 9209240422 | |
| Download: ML20118A682 (2) | |
Text
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"JLS Log
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File # 10119 T U.AC 1 I C LE September 18, 1992
% illiam J. Cahllt. Jr, Group Vur freudent U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STE/,M ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 NRC BULLETIN 92-01, SUPPLEMENT 1:
FAILURE OF THERMO-LAG 330 FIRE BARRIER SYSTEM TO PERFORM ITS SPECIFIED FIRE ENDURANCE FUNCTION REF:
1)
NRC Bulletin 92-01: Failure of Thermo-Lag 330 Fire Barrier System to maintain cabling in wide cable trays and small conduits frie from fire damage,
Gentlemen:
TU Electric has evaluated the issues identified in the subject bulle~
n, and has concluded that reference 2 adequately addresses the issues /conce_ s identified in the subject bulletin.
Reference 2 and this letter satisfy the requested actions.
Should you require additional information or have any other questions please contact Obaid Bhatty at (817) 897-5839.
Sincerely,
/
William J. Cahill, Jr.
OS/tg Attachments c-Mr. J. L. Milhoan, Region IV Mr. T. A. Bergman, NRR Mr. B. E. Hollan, NRR l
Resident Inspectors, CPSES (2)
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PDR 400 N. Olive Street LB. 81 Dn!!as, Texas 75201
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, to TXX-92446 Page 1 of 1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of Texas Utilities Electric Company Docnet Nos. 50-445 50-446 (Comanche Peak Steam Electric Station, Units 1 & 2 AFFIDAVIT William J. Cahill, Jr. being duly sworn, hereby deposes and says that he is Group Vice President, Nuclear of TV Electric, that he is duly authorized to sign and file with the Nuclear Regulatory Commission this response to NRC Bulletin 92-01, Supplement 1; that he is familiar with the content thereof; and that the natters set forth therein are true and correct to the best of his knowledge, information and belief.
/
i WTiliam J. CMill, Jr.//
Group Vice President, Nuclear STATE OF TEXAS
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COUNTY OF SOMERVELL
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fM gbscribedandsworntobeforeme,aNotaryPublic,ont;11s day of c)C/ fWAUL
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903.9 TUELECTRIC July 9, 1992 WHilam J. Cahill. Jr.
Group 6 we bruarot U. S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 NRC BULLETIN 92-01: FAILURE OF THERMO-LAG 330 FIRE BARRIER SYSTEM TO MAINTAIN CABLING IN WIDE CABLE TRAYS AND SMALL CONDUITS FREE FROM FIRE DAMAGE REF:
1)
TU Electric letter logged TXX-92325 from W. J. Cahill, Jr. to NRC dated July 2, 1992.
Gentlemen:
TU Electric has evaluated the concerns of the subject bulletin. The requested actions specified in the bulletin and the corresponding TU Electric responses for Unit 1 and Unit 2 are presented below.
Reauested Action 1 For those plants that use either 1-or 3-hour pre-formed Thermo-Lag 330 panels and conouit shapes, identify the areas of the plant which have Thermo-Lag 330 fire barrier material installed and d9termine the plant areas which use this material for protecting either small diameter conduit or wide trays (widths greater that 14 inches) that provide safe shutdown capability.
TU Flectric Response Identification of the plant electrical raceways which have Thermo-Lag 330 fire barrier material installed to provide safe shutdown capability for Unit 1, were identified prior to implementation of the testing program described in the bulletin.
Reauested Action 2 In those plant areas in which Thermo-Lag fire barriers are used to protect in wide cable trays, small conduits, or both, the licensee should implement, accordance with plant procedures, the appropriate compensatory measures, L!
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P. O. tiot 1002 Glen Rose Texas 7NM3-1002
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TXX-92331 Page 2 of 2 such as fire watches, consistent with those which would be implemented by either the plant technical specifications or the operating license for an inoperable fire barrier.
TV Electric Response 3.s identified in Licensee Event Report (LER)-92-011-00 (Ref. 1), and the voluntary report made via the Emergency Notification System, CPSES has implemented fire watches as compensatory measures in accordance with the Fire Protection program.
Rooms that contain firesafe shutdown small diameter conduits or wide cable trays, which are protected by Thermo-Lag, are included in the fire watch coverage.
Recuested Action 3 Each licensee, within 30 days of receiving this bulletin, is required to provide a written notification stating whether it has or does not have Thermo-Lag 330 fire barrier systems installed in its facilities.
Each licensee who has installed Thermo-Lag 330 fire barriers is required to inform the NRC, in writing, whetner it has taken the above actions and is required to describe the measures being taken to ensure or restore fire barrier operability.
TU Electric Response Reference 1 and this letter satisfy the requested action.
Should you require additional information or have any other questions contact Obaid Bhatty at (817) 897-5839.
Sincerely, f
William J. Cahill, Jr.
e OB/tg Attachments c-Mr. J. L. Milhoan, Region IV Mr. T. A. Bergman, NRR Mr. B. E. Holian, NRR Resident Inspectors, CPSES (2)
- to TXX-92331 Page 1 of 1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
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Texas Utilities Electric Company
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Docket Nos. 50-445
)
50-446 (Comanche Peak Steam Electric
)
Station, Units 1 & 2
)
AFFIDAVIT William J. Cahill, Jr. being duly sworn, hereby deposes and says that he is Group Vice President, Nuclear of TV Electric, that he is duly authorized to sign and file with the Nuclear Regulatory Commission this response to NRC Bulletin 92-01; that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best nf his knowledge, information and belief.
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William J. Cah(ll, Jr.
Group Vice President, Nuclear STATE OF TEXAS
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COUNTY OF SOMERVELL
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Subscribed and sworn to before me, a Notary Public, on this 9th day nf
.fuly 1992.
Notary Public PATRICIA WILSON thlil su ccumssen a mts V:. y,f' Abrch 16.1993 m -- - -.
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Voluntary TUELECTRIC July 2, 1992 wmi.= J. c.hm. Jr.
Grous vke Presearm U. S. Nuclear Regulatory Commission Attn:
Occument Control Desk Wasnington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50-445 REPORT OF EVENT WITH GENERIC INTEREST LICENSEE EVENT REPORT 92-011-00 Gentlemen:
Enclosea is Licensee Event Report 92-011-00 for Comanche Peak Steam Electric Station Unit 1, " Failure of Thermo-Lag Fire Barrier Endurance Test Results In Scme Raceways Declarea Inoperable".
Sincerely, William J. Cahill, Jr.
/ /
By:
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A. B. Scott, Jr.
Vice President Nuclear Operations 09/tg Enclosure c-Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (2)
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p P. O. Box L0tr. Clea Rose. Teus 76001002
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FAILURE OF THERMO. LAG FIRE BARRIER ENDURANCE TESTS RESULTS IN SOME RACEWAYS DECLARED INOPERABLE
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A fire encurance testing program was establiOed to qualify Thermo-Lag 330 electncal raceway tire bamer systems for Comanene Peak Steam Electnc Station (CPSES). The testing consisted of a senes of 1-hour fire endurance tests on a variety of cable tray and concuit mock up test specimens. Test failures occurred on small conduit and wide cable trays. The conclusion was that some Thermo-Lag fire bamer configurations do not provide the level of safety as required by the CPSES Fire Protection Plan.
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The root cause of the fire bamer matenal failure was inadequate vendor installation specifications and procedures. Fire watch routes were adjusted to cover the affected l
areas per the CPSES Fire Protection Plan. Additional tests will be performed. These l
tests willinclude modification techniques to increase the Thermo-Lag thickness on small conduits and enhance the structuralintegnty of Thermo-Lag installed on wide caDie trays.
l Modifications of installed Thermo Lag configurations on small conduits and wide cable trays will be implemented based on the results of these tests. This Licensee Event Report is suomitted as a voluntary report.
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DESCRIPTION OF THE REPORTABLE EVENT A.
REPORTABLE EVENT CLASSIFICATION This Ucensee Event Repon is suomitted as a voluntary report.
f B.
PLANT CONDITIONS PRIOR TO THE EVENT i
On June 18,1992, Comancne Peak Steam Electnc Station (CPSES) Unit 1 was in Moce 1. Power Operation, with the reactor at approximately 100 percent of rated thermal power.
C.
STATUS OF STRUCTURES, SYSTEMS OR COMPONENTS THAT WERE INOPERABLE AT THE START OF THE EVENT AND THAT CONTR!BUTED TO THE EVENT There were no inoperable strLctures, systems or components that contnbuted to the event.
D.
NARRATIVE
SUMMARY
OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES-A fire endurance testing program was established to qualify Thermo-Lag 330 electncal raceway fire barner systems (Ells:(ISL)(FA)) for CPSES. This testing was in response to Nuclear Regulatory Commission (NRC) Information Notice 91-47 and 91-79. These information Notices desenbed problems with Thermo-Lag 330 fire barner systems and assocrated failures. The testing was performed dunng the weeks of June 15 and June 22,1992 at an independent laboratory.
The testing consisted of a series of 1-hour fire endurance tests on a variety of cable tray (Ells:(TY)(FA)) ano conduit (Ells:(CND)(FA)) mock-up test specimens. The test specimens were constructed by plant personnel (utility, non-licensed) using stock matenal to give an accurate representation of the existing plant configuration. The fire carner systems for the test scecimens were constructed using pre-formed,1-hoy Thermo-Lag 330 panels and conouit shapes. The fire barner systems were installed using CPSES installation procecures.
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TEXT CONTINUATION DC. ::SSE ANO TO TWE P APERwoR4 REDUCTON PROJECT (315401046-OFFCE OF WANAGEMENT ANO BLOGET.WASHINGTOrt DCL aG fit.
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.I w COMANCHE PEAK-UNIT 1 01510101014l415 9 21 LO 111 010 03 ce 06 On June 17,1992, a 1-hour fire enourance test was conducted on a test specimen inat consisted of 3/4,1, and 5-inen conduit entering and exiting a junction box.
C;rcuit continuity was monitored dunng the test, with no recorded lost of circuit integnty. Temperatures were recorced on the 3/4-inch and 1-inch conduit and the ancuan 00x which exceeoed the 325 degree F threshold desenbed by Genenc Letter 86-10, wnereoy analysis would be recuired to justify elevated cable temoeratures. Cable jacket ano some insulation detenoration was found on the cac:es inside the 3/4-inen and 1-inen conouits.
On June 18,1992, e 1-hour fire enourance test was performeo on a 12-inch wide caole tray test specimen. rhe temperatures throughout the test were below the 325 cegree F threshold and no visible evidence of cable detenoration was found. This test was, therefore, successful.
On June 19,1992, a 1-hour fire enourance test was conducted on a 30 inch ladder back cacle tray test specimen. At 17 minutes into the test, the Thermo Lag nams seoarated across the bottom. At 18 minutes, a joint between a tray support and the tray snowed signs of weakening ano separation. At 25 minutes, internal temperatures inside the cable tray exceeded 325 degrees F. The joint fully separated at 41 minutes and circuit integnty was lost. The test was consicered, therefore, a failure. It should be noted that the 30-inen vertical runs did not appear to be atfected: however, the test was terminated prior to determining acceptability, As a result of the initial ter.t. the condition was reported to the CPSES Unit 1 Shift Sucervisor (utility, licensed) at 1430, June 18,1992. Fire watch routes were adjusted to cover the affected areas per the CPSES Fire Protection Program by 1500, June 18,1992. A voluntary report was made via the Emergency Notification System at 0139 on June 20,1992, pending further fire endurance test results and evaluation.
E.
THE METHC7 OF DISCOVERY OF EACH COMPONENT OR SYSTEM FAILURE, On PROCEDURAL OR PERSONNEL ERROR Discovery was made during Thermo-Lag fire enourance tests conducted at OMEGA Point Labs, San Antonio, Texas.
._ to TXX-92331 Page 5 of 7 Enclosure to TXX-92325
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COMPONENT OR SYSTEM F AILURES A.
FAILURE MODE, MECHANISM, AND EFFECT OF EACH FAILED COMPONENT Elevated temoeratures en caoles installed in conduit test specimen was due to mermal degracation at Thermo-Lag matenal dunng fire test conaitions. This failure resulteo in caole insulation detenoration. Failure of the Thermo Lag matenal on the 30-inen caote tray test specimen was oue to loss of structuralintegnty dunng fire test conottiens. Failures wer9 to test specimens dunng 1-hour fire encurance tests.
B.
CAUSE OF EACH COMPONENT OR SYSTEM FAILURE Circuit failure on the 30-inen cable tray test specimen occurred due to structural integoty tailure of the Thermo Lag fire barner system. Failure occurred to a test specimen curing 1-hour fire encurance test.
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C.
SYSTEMS OR SECONDARY FUNCTIONS THAT WERE AFFECTED BY FAILURE OF COMPONENTS WITH MULTIPLE FUNCTIONS Not applicaole this event was the failure of test specimens in 1-hour fire encurance tests and cid not involve actual plant components.
D.
FAILED COMPONENT INFORMATION Thermo-l ag 330 fire barner system Thermal Science. Inc.
111.
ANALYSIS OF THE EVENT A.
SAFETY SYSTEM RESPONSES THAT OCCURRED Not applicable - this event was the failure of test specimens in 1-hour fire endurance tests and cid not involve plant components or systems.
B.
DURATION OF SAFETY SYSTEM TRAIN INOPERABILITY Not aopticable - this event was the failure of test specimens in 1-hour fire endurance tests and did not involve plant components.
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C.
SAFETY CONSEQUENCES AND IMPLICATIONS OF THE EVENT CPSES is required to have a fire protection plan that satisfies 10CFR50 Appendix A, General Design Critena 3," Fire Protection." This design enteria requires structures, systems, ano components imponant to safety be d9 signed and located to minimize, in a,nanner consistent with other safety reauirements, the probability and effects of fires and explosions. The CPSES Fire Protection Plan recuires that one train of systems necessary to acnieve anc maintain hat chutdown conditions from either the control room or emergency control stations to be free from fire damage. In accorcance with the Plan, the separation of safe shutdown trains is ensured by separation of cables and equipment and associated circuits of redundant trains by a fire barner having a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rating or the enclosure of cable, eauipment, and ssociated non safety circuits of one redundant train in a fire bamer having a 1-hour rr6ng. In addition to providing the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> barner, fire detection and automatic fire suppression systems are installed in designated fire areas.
i The fire endurance testing program that was established to qualify Thermo-Lag 330
' ire carner systems was in response to NRC Information Notice 91-47 and 91-79
.vnicn desenbed problems with the Thermo Lag 330 fire barner system. The testing failures on small conouit and wide cable trays has demonstrated that they do not provice the level of safety as required by the CPSES Fire Protection Plan. Under tire conoitions. the failure of an electncal raceway fire barrier system, such as the Thermo Lag system, could lead to both trains of safe shutdown systems bs ng -
damaged by fire. This may affect the plant's ability to achieve and maintain -
shutcown conditions.
Compensatory measures, such as a fire watches, along with the low probability of an undetected fire of sufficient intensity and location to damage both trains of
. equipment, ensures that the continued safe operation of CPSES Unit 1 and the hat.ith and safety of the public are not adversely affected.
IV. CAUSE OF V3 EVENT Inaceauate performance of the fire barner matenal when installed in accordance with the venoors published installation specifications and procedures.
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COMANCHE PEAK UNIT 1 OL510101014l415 9 2 011 00 06 cr 06 V.
CORRECTIVE ACTIONS A.
CPSES is using fire watches as compensatory measures in accordance with the Fire Protection Program. All rooms that contain fire-safe shutdown conduits or cable trays, of all sizes and protected by Thermo-Lag, are included in the fire watch coverage.
B.
Adcitional tests will be performed. These tests willinclude modification / upgrade tecnnicues :o increase the Thermo Lag thickness on small conduits and enhance the structural integnty of Thermo Lag installed on wide cable trays.
C.
Based on the results of the additional testing desenbed above, modification / upgrade of installed Thermo Lag configurations on small conduits and wide cable trays will be implemented to provide the level of protection required by the CPSES Fire Protection Plan as applicable.
VI. PREVIOUS SIMIL A R EVENTS There nave been no previous similar events at CPSES.
Vll. ADDITIOt1AL INFORMATION This report satisfies the reporting requirements of 10CFR21 and 10CFR50.55e for CPSES Unit 2. The times listed in the report are approximate and Central Daylight Time.
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