ML20082B730
| ML20082B730 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 07/09/1991 |
| From: | Beckham J GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| HL-1682, NUDOCS 9107160343 | |
| Download: ML20082B730 (6) | |
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001887 July 9. 1991 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 PLANT HATCH - UNIT 1 NRC DOCKET 50-321 OPERATING LICENSE DPR-57 SPECIAL REPORT l-91-005, REVISION 1 FIRE BARRIER ASSEMBLIES INOPERABLE FOR A PERIOD LONGER THAN 14 DAYS Gentlemen:
In accordance with Plant Hatch Unit 1 Technical Specifications section 6.9.2 and Appendix B of the Fire Hazards Analysis, Georgia Power Company is submitting the enclosed revision to a Special Report concerning fire barrier assemblies which were inoperable for a period greater than 14 days.
Sincerely,
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[J.T.Beckham,Jr.
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Enclosure:
Special Report 1-91-005, Revision 1 cc:
Georaia Power Company Mr. H. L. Sumner, General Manager - Nuclear Plant Mr. J. D. Heidt, Manager Engineering and Licensing - Hatch NORMS U.S. thttlear Reaulatory Commission. Washinaton. D.C2 Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Reaulatory Commission. Reaion 11 Mr. S. D. Ebneter, Regional Administrator Mr. L. D. Wert, Senior Resident inspector - Hatch 9107160343 910709
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I ENCLOSURE PLANT HATCH - UNIT 1 NRC DOCKETS 50-321 OPERATING LICENSE DPR-57 SPECIAL REPORT l-91-005, RFVISION 1 FIRE BARRIER ASSEMBLIES IN0PERtBLE FOR LONGER THAN 14 DAYS RESULTS IN A S1ECIAL REPORT AS RE0VIRED BY THE FIRE HAZARDS ANALYSIS A.
REQUIREMENT FOR REPORT This revised report is required by Unit 1 Technical Specifications section 6.9.2 which states that Special Reports shall be submitted as required by the Fire Hazards Analysis (FHA) and its Appendix B requirements.
This revision is also being submitted to report findings discovered as a result of corrective actions committed to in Revision 0.
Specifically, corrective action 4 committed the Company to review Nelson frames affected by Design Change Request (DCR)84-217.
The findings of that review are included in this report.
Appendix B of the FHA, section 1.1.1, states that fire-rated assemblies and sealing devices in fire-rated assembly 3enetrations separating fire areas must be operable. Action statement ()) requires that inoperable fire-rated assembly (s) and/or sealing device (s) must be restored to operable status within 14 days or prepare and submit a Special Report to the Commission within the next 30 days per Technical Specifications section 6.9.2.
In the event described in this report, two cable penetration seals were found to be inoperable.
Investigations showed that these conditions had existed for longer than 14 days; therefore, this Special Report is required.
B.
UNIT STATUS AT TIME OF EVENTS On 5/15/91, at 0900 CDT, Unit I was in the Run mode at a power level of 2436 CMWT (100 percent of rated thermal power).
On 6/13/91, at 1500 CDT, Unit I was in the Run mode at a power level of 2436 CMWT (100 percent of rated thermal power).
C.
DESCRIPTION OF EVENTS On 5/15/91, at approximately 0900 CDT, nonlicensed personnel reviewing DCR 84-217 determined that cable penetration seal IT54-Z2Al2 was inoperable.
Specifically, the cable penetration seal assembly, known as a Nelson frame, was not installed in accordance with the manufacturer's instructions.
The penetrations are sealed with Nelson blocks, mechanical devices which slip over the cables and seal the penetration.
In place of HL-1682 E-1
..i
9 ENCLOSURE (Continued)
SPECIAL REPORT l-91-005, REVISION 1 FIRE BARRIER ASSEMBLIES IN0PERABLE FOR LONGER THAN 14 DAYS RESULTS IN A SPECIAL REPORT AS RE0VIRED BY THE FIRE HAZARDS ANALYSIS four of thirty-five Nelson blocks, a silicone scalant known as RTV-lC6 was used in approximately a 0.4 square foot area of the penetration.
Even though the RTV-106 has fire resistive characteristics, the material has not been tested as a substitute for the Nelson blocks in the seal assembly.
Consequently, the three-hour fire rating of the penetration seal assembly was jeopardized.
Investigations into the event revealed that a walkdown of Nelson frame penetration seal assemblies had been performed in November of 1983 at which time deviations regarding the installation of Nelson frame penetration seal assemblies were identified. At that time, appro>riate compensatory actions were taken in accordance with the plant's Tec1nical Specifications.
These deviations were noted by the Commission during an inspection in August of 1984 and addressed in Report 50-321, 366/84-32, dated 9/17/84. One of the deviations noted in the 1983 walkdown involved the improper use of silicone in the Nelson frame for penetration IT54-22A12.
DCR 84-217 was developed to address the noted discrepancies including that associated with penetration IT54-22Al2. The DCR was implemented during the Fall 1984 Unit 1 Refueling outage.
During implementation of the DCR. it was determined that a permanent repair to penetration IT54-Z2Al2 seal assembly could not be completed by the end of the outage. The number of cables being routed through the penetration was more than the Nelson assembly could accommodata using the Nelson insert blocks.
Four of the thirty-five Nelson blocks could not be properly installed without one of the cables being removed and rerouted through another penetration. Consecuently, a temporary resolution was incorrectly approved and implementec. The Nelson frame was reassembled and RTV-106 was used to provide a fire barrier around five of the cables routed through the penetration.
The RTV was used to fill an area of approximately 0.4 square feet. A permanent repair was planned for the following Unit 1 Refueling outage; however, actions were not taken to en:ure the change was implemented.
,pon discovery of the condition on 5/15/91, Deficiency Card (DC)
- -91-2262 was written and licensed personnel were notified.
Subsequently, an hourly fire watch was established for the affected areas in accordance with the requirements of FHA, Appendix B, section 1.1.1.
To restore the three-hour fire rating of the penetration, a thermolag fire barrier was installed around the penetration.
HL-1682 E-2 1
ENCLOSVRE (Continued)
SPECIAL REPORT 1-91-005, REVISION 1 FIRE BARRIER ASSEMBLIES IN0PERABLE FOR LONGER THAN 14 DAYS RESULTS IN A SPECIAL REPORT AS RE0VIRED BY THE FIRE HAZARDS ANALYSIS On 6/13/91, as closecut activities were continuing on DCR 84-217, a second Nelson asserably in the same cable penetration, IT54-Z2A15, was found to have been left in an untested configuration.
Specifically, the Nelson assembly had been installed using a different silicone sealant, RTV-103, instead of Nelson insert blocks.
This involved approximately 15 cables in the assembly.
Deficiency Card 1-91-2742 was written to document this condition. No compensatory actions were required at that
- time, however, because the thermolag fire barrier, installed following the discovery of the problem with IT54-Z2Al2, covered both Nelson assemblies.
Therefore, tie three-hour fire rating of the renetration had l
been restored prior to discovering that IT54-22A15 had Laen left in an t
untested configuration.
in this case, investigation revealed that Maintenance Work Order (MWO) 1-84-7032 had been wri'. ten to remove silicone sealant RTV-103 and to reroute cables as necessary using the proper Nelson insert blocks.
Engineering personnel prepared work instructions on Work Process Sheet (WPS) 84-217-E007 on 11/9/84 to direct work activities. Under the administrative controls which existed at the
- time, each item on the WPS required an engineer's signature to disposition the work activity (i.e., as to whether it was satisfactorily completed).
In this particular case, the engineer who prepared the WPS deleted the line item addressing Nelson assembly IT54-Z2A15, and initialled the deletion en 12/18 No explanation was given in the i
documentation as to why work was n/84.
ot performed on this assembly.
D.
CAUSE OF EVENT The cause of the first event was cognitive personnel error on the part of l
nonlicensed personnel in that they failed to adequately evaluate the temporary repair to penetration IT54-Z2A12 seal to ensure that the three-hour fire rating of the seal was not jeopardized.
Specifically, per the manufacturer's instructions, RTV-106 is recommended for use as a sealant between Nelson blocks and cable conduit with irregular surfaces.
It is apparent that the involved engineering personnel concluded from this that it was acceptable to uso RTV-106 as a fire barrier material in place of the Nelson blocks. Consequently, the involved personnel did not perform an adequate evaluation to ensure that RTV-106 itself actually had a three-hour fire rating.
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HI-1682 E-3 I
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4 s
ENCLOSURE (Continued)
SPECIAL REPORT l-91-005, REVISION 1 flRE BARRIER ASSEMBLIES IN0PERABLE FOR LONGER THAN 14 DAYS RESULTS IN A SPECIAL REPORT AS RE0VIRED BY THE FIRE HAZARDS ANALYSIS The cause of the second event is cognitive personnel error on the part of the engineer who deleted the repair from the WPS.
In this case, the engineer who wrote the WPS, apparently acting on his own initiative, authorized the penetration to :>e left in its untested configuration.
Hence, no work was performed on it, and the RTV-103 was left in place.
E.
ANALYSIS OF EVENT Fire-rated cable penetration seal assemblies are designed to prevent the propagation of a fire from one fire area to another.
In the event described in this report, two fire-rated penetration assemblies were rendered inoperable because they were assembled in an untested configuration.
When the first deficiency was discovered, licensed shift personnel implemented the compensatory actions of FHA, Appendix B, section 1.1.1, which requires verification that the applicable fire detection equipment was operable end the establishment of an hourly fire watch.
When the second deficiency was found, compensatory actions were not required because corrective actions carried out following the first event had restored the three-hour fire rating of the penetration.
Both of these fire-rated assemblies are located on the west wall of the l
Unit 1 Reactor Building, and separate the Reactor Building (fire area 1104) from the east cableway (fire area 1205F) of the Unit 1 Turbine Building.
Both fire areas are equipped with fire detection and suppression systems.
Fire area 1205F is equipped with both linear thermal detectors and smoke detectors, and fire area 1104 is equipped with smoke detectors.
Both fire areas are equipped with wet pipe automatic fire suppression systems, water hoses, and portable carbon dioxide fire extinguishers.
In the unlikely event of a fire in either of these areas, it would be promptly detected and subsequently extinguished by the automatic fire suppression systems and/or the site's trained fire brigade.
Based on the above analysis, it is concluded that this event had no adverse affect on nuclear safety.
F.
CORRECTIVE ACTIONS
- 1) When the firr.t penetration was identified, it was declared inoperable and the required hourly fire watch for the appropriate fire area was initiated.
When the second penetration was identified, it had already been sealed per corrective action 2, and no further action was required.
HL-1682 E-4 I
t l
ENCLOSURE (Continued)
SPECIAL REPORT l-91-005, '!EVISION 1 FIRE BARRIER ASSEMBLIES INOPF ABLE FOR LONGER j
THAN 14 DAYS RESULTS IN / iPECIAL REPORT AS REQUIRED BY THE E10' iZARDS ANALYSIS
- 2) The affected penetrations have been covered with a thermolag fire barrier material in accordance with approved plant procedures.
The material provides a three-hour fire rated barrier for the penetration.
- 3) The Nelson frame seal assemblies for the affected penetrations will be restored in conformance with the manufacturer's instructions which i
will restore-their three-hour fire rating. -This will be performed during the next Unit I refueling outage. At that time, the thermolag j
fire wrap will be removed.
This t.ction is currently scheduled to be completed by 12/10/91.
- 4) GPC will visually inspect the Nelson frame seal assemblies modified l
during implementation of DCR 84-217 and will submit a revision to this special report if further problems are identified - This action i
is currently sr.heduled to be completed by 12/10/91.
No disciplinary action will be taken within Georgia Power Company because the engineers involved in the personnel errors which caused these events are no longer employed by the Company.. Current administrative controls governing the design change process and the fire protection program should be sufficient to help preclude a recurrence of this event.
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