ML20077F079
| ML20077F079 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/05/1994 |
| From: | Broughton T GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C311-94-2307, GL-92-08, GL-92-8, NUDOCS 9412130261 | |
| Download: ML20077F079 (9) | |
Text
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GPU Nuclear Corporation a fl Nuclear ar=r" Middletown, Pennsylvania 17057-0480 (717) 944-7621 Writer's Direct Dial Number:
l7:7) 948-8005 December 5, 1994 C311-94-2307 l
U. S. Nuclear Regulatory Commission Attn: Document Control Desk I
Washington, D.C.
20555
Dear Sir:
Subject:
Three Mile Island Nuclear Station, Unit I (TMI-1)
Operating License No. DPR-50 l
Docket No. 50-289 Response to the Follow-up to the Request for Additional Information Regarding Generic Letter 92-08 Issued Pursuant to 10 CFR 50.54(f) dated September 19, 1994.
l The purpose of this letter is to up-date the previous GPUN response to the l
Request for Additional Information Regarding Generic Letter 92-08 "Thermo-Lag l
330-1 Fire Barriers," Pursuant to 10 CFR 50.54(f).
This action is necessary since a follow-up request for additional information has found specific answers to sections of the Generic Letter incomplete based on the reference to future NEI activity.
Letter C311-94-2012 dated February 10, 1994 conveyed the initial GPUN response.
At the time of that response, only the NEI Phase I testing of upgraded Thermo-Lag configurations was complete.
Both the testing and subsequent results had little applicability to plant baseline installation configurations.
The Phase II test program results and the Application Guide were commodities unavailable for reference but important to a complete
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response.
The attachment to this letter contains the TMI-1 response to the NRC follow-up request for additional information itemized by section.
It incorporates
>g information unavaliable at the time of the initial response.
00'
-o gg Sincerely, l
a LSu:Lu PQ bon /~
no T. G. Broug OS Vice President and Director, TMI s
WGH
~k Attachment
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cc:
Administrator, Region I TMI Senior Resident Inspector TMI Senior NRC Project Manager AOM NEI - Alex Marion FileG9403glear Corporation is a subsidiary of General Public U% ties Corporation g I~
C311-94-2307 Page 1 of 8 11.
Important Barrier Parameters B.
Required Information 1.
State whether or not you have obtained and verified each of the aforementioned parameters for each Thermo-Lag barrier installed in the plant.
If not, discuss the parameters you have not obtained or verified.
Retain detailed information on site for NRC audit where the aforementioned parameters are known.
Response
in the previous response, C311-94-2012 dated February 10, 1994 GPUN pro"ided the results of a documentation review which identified the gs
- Thermo-Lag barrier configurations and material amounts installed at THI-1. Since that time, a walkdown of fire area / zones was initiated to document the installed barrier configurations with digitized computer images.
At this point in the evaluation process, the parameters identified during the test programs and the determination of the relevent Application Guide sections have been confirmed.
The TSI configurations and performance parameter descriptions identified in the Application Guide were adapted by GPUN in a database matrix.
Data was collected during the walkdown and entered into the database to permit detailed comparisons with NEI data and fire endurance test results from the TU and TVA programs. As a result of the comparison, fire ratings are being established on a component by component basis.
The walkdown is complete in 17 of the 19 THI-1 fire area / zones with the two remaining delayed by industrial safety and ALARA considerations and will be performed while the plant is shutdown.
The comparison activity and barrier acceptability determinations are in progress.
The detailed information is being retained and will be available for NRC audit.
2.
For any parameter that is not known or has not been verified, describe how you will evaluate the in-plant barrier for acceptability.
Response
As a result of the plant walkdown, personnel were able to confirm all but one configuration parameter with the installation documentation.
The exception involves installation of preform clam shell over conduit and a conduit coupling.
The documentation shows banding at conduit couplings to conform with the 2" banding rule.
The banding detail cannot be verified without removing the portion above the coupling because of the overlap of the larger diameter preform over the banding on the smaller diameter material.
This will be done at
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i C311-94-2307 Page 2 of 8 random on a number of samples to verify the conformance with banding.
spacing requirements.
The quality of the barrier installation was verified by installation process step sign-offs and final inspections performed by Quality Control and the Fire Protection Engineers. Since there has been no rework of the barriers and Maintenance barrier inspection procedures have been in effect and implemented since their initial installation, no significant deviations from the original design are expected.
3.
To evaluate NEI's application guidance, an understanding of the types and extent of the unknown parameters is needed.
Describe l
the type and extent of the unknown parameters at your plant in-this context.
Response
GPUN Fire Protection Engineers have been using the Application Guide to compare THI-1 plant-specific data with the test program results.
With the exception of plant-specific configurations which are currently unbounded by testing as identified in the response to question III.B.1 below, the plant walkdown/ documentation review results have resulted in the identification of no unknown parameters with the exception of those identified in II.B.2 which was not verifiable by the walkdown activity.
Ill.
Thermo-l.aq Fire Barriers Outside the Scope of the NEI Program B.
Required Information 1.
Describe the barriers discussed under item 1.B.1 that you have determined will not be bounded by the NEI test program.
Response
While it could not be determined which of the TMI-1 electrical raceway fire barriers would not be bounded by NEI's test program at the time of the response to the initial request for additional information, completion of both Phase I and II testing and the Application Guide by NEI have made a nearly complete comparison with installed plant configurations possibic.
The following specific plant installation configurations are not bounded by the NEI test programs to date:
a.
A pre-form conduit section is butted hard up to a concrete wall.
The protected conduit passing through a wall / conduit is embedded.
The barrier is pre-buttered and placed against the wall.
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C311-94-2307 Page 3 of.8 b.
A barrier passes through a wall and uses the " Picture Frame" TSI board anchored to the wall to extend the barrier to the wall.
c.
A barrier has been constructed in the corner of two concrete walls.
The barrier uses TSI Panels (1 HR) to build two sides of the barrier and the concrete walls to make the other two sides.
The TSI sides are secured to the wall by anchoring a " Picture Frame" strip on the concrete walls.
d.
In areas where the TSI barrier (Cable Tray) stops, a silicone foam fire seal has been insta110d.
This was used in areas where the cable tray stopped and the cables continued to another tray and only one or two of the multiple cables required protection.
For instance, where tray or conduit penetrate a TSI barrier as a heat sink, the open end was filled with foam.
The foam seal used in this manner has a depth consistent with that qualified by fire tests for the silicone foam seal configurations.
2.
Describe the plant-specific corrective action program or plan you expect to use to evaluate the fire barrier configurations particular to the plant. This description should include a discussion of the evaluations and tests being considered to resolve the fire barrier issues identified in GL 92-08 and to demonstrate the adequacy of existing in-plant barriers.
Response
Where the acceptability of a fire barrier system cannot be established based on comparison with test results, the Application Guide or adequately justified so as to permit approval of an exemption, the noncompliance will be eliminated through one or more of the following options: modification or upgrade of the barrier, rerouting circuits, complete replacement of the barrier or by additional testing.
3.
If a plant-specific fire endurance test program is anticipated, describe the following:
a.
Anticipated test specimens.
b.
Test methodology and acceptance criteria including cable functionality.
Response
No plant-specific fire endurance test program is anticipated for the unbounded GPUN configurations. NEI has requested that plants identify those configurations that cannot be evaluated against configurations tested to date. NEI is proposing to complete tests remaining from Phase II and possibly include additional testing to address those currently unbounded installation configurations common to the greatest number of utilities.
GPUN identified the
C311-94-2307 Page 4 of 8 configurations listed in response to 1 above in its answer to NEI and is also considering participation in a test effort with other utilities having equivalent unbounded configurations should the NEI tests not be performed or not include configurations specific to THI-1.
IV. Ampacity Deratina B.
Required Information 1.
For the barriers described under Item I.B.1, describe those that you have determined will fall within the scope of the NEI program for ampacity derating, those that will not be bounded by the NEI program, and those for which ampacity derating does not apply.
Response
As early as 1986, GPUN engineers were concerned with the heat retentive characteristics of Thermo-Lag barriers and the resultant effect on cable life and aging during normal plant operation.
The low ampacity derating values used by TSI for small diameter conduit protection schemes was questioned. A field test was initiated which monitored the internal temperatures of Thermo-Lag envelopes protecting power circuits.
The data obtained by this effort showed that ampacity derating is an issue that applies only to cable raceways containing energized power cables and is not a concern for instrument and control circuits or power circuits which were only intermittently operated.
GPUN found that internal envelope temperatures measured in the field for THI-1 configurations would not result in long term cable degradation.
Based on those test results, GPUN determined the effects of the actual ampacity derating values were acceptable.
Therefore, GPUN will take no action for the existing Thermo-Lag barrier configurations based on those results.
2.
For the barriers you have determined fall within the scope of the NEI program, describe what additional testing or evaluation you will need to perform to derive valid ampacity derating factors.
Response
Additional evaluation of the effect of upgrades to existing thermal barriers containing power cables would be performed to verify that there were no significant changes in the temperature conditions within the barriers resulting from the upgrade.
If significant changes are noted, further evaluations will be performed.
C311-94-2307 Page 5 of 8 3.
For the barrier configurations that you have determined will not be bounded by the NEI test program, describe your plan for evaluating whether or not the ampacity derating tests relied upon for the ampacity derating factors used for those electrical components protected by Thermo-Lag 330-1 (for protecting the safe shutdown capability from fire or to achieve physical independence of electrical systems) are correct and applicable to the plant design.
Describe all corrective actions needed and submit the schedule for completing such actions.
Response
Based on the response to IV.B.1, the ampacity concerns for untested configurations will be considered to be acceptable. No further action is necessary regarding non-upgraded Thermo-Lag barriers.
The content of a corrective action plan for identified ampacity deficiencies will be dependent on identifying the need to upgrade a specific fire barrier and the identification of the ampacity derating factor deficiency resulting from the upgrade.
Corrective actions and the scheduling thereof will be addressed by a future submittal once the need for upgrades is identified.
4.
In the event that the NEI fire barrier tests indicate the need to upgrade existing in-plant barriers or to replace existing Thermo-Lag barriers with another fire barrier system, describe the alternative actions you will take (and the schedule for -
performing those actions) to confirm that the ampacity derating factors were derived by valid tests and are applicable to the modified plant design.
Response
As previously noted, GPUN has determined the validity of the ampacity derating factors for as-built configurations.
They may be applied conservatively to configurations containing continuously energized power circuits requiring upgrade.
Such efforts would be Ilmited to upgrades using TSI material since there has been no determination made on the adequacy of the fire endurance performance of other fire barrier manufacturers' products. For the reasons expressed above, no attempt is being made to plan or schedule alternative actions at this time.
The subject will be addressed by a future submittal if the need is identified.
C311-94-2307 Page 6 of 8 V.
Alternatives B.
Required Information:
Describe the specific alternatives available to you for achieving compliance with NRC fire protection requirements in plant areas thatcontain Thermo-Lag fire barriers.
Examples of possible alternatives to Thermo-Lag based upgrades include the following:
1.
Upgrade existing in-plant barriers using other materials.
2.
Replace Thermo-Lag barriers with other fire barrier materials or systems.
3.
Reroute cables or relocate other protected components.
4.
Qualify 3-hour barriers as 1-hour barriers and install detection and suppression systems to satisfy NRC fire protection requirements.
Response
Since the last response, the NRC has confirmed that the ASTM E-119 test would remain the source standard for fire barrier acceptance criteria. As such the alternatives available to achieve compliance with the fire protection requirements still include one or more of the alternatives described above and the possibility for inclusion of an additional alternative.
Exemption requests using baseline (non-up-graded) test results which
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demonstrate adequate protection for the installed hazard will be pursued by GPUN.
Alternatively or in conjunction, fire modeling or probabilistic safety analysis (PSA) will be used to support the justification for the exemption.
Fire endurance evaluations are in progress for fire areas with 1-hour barriers installed. Based on actual fire loading and fire modeling results, GPUN intends to submit an exemption from 1-hour fire barriers where necessary.
3-hour barriers will be requalified as 1-hour barriers.
GPUN plans to install detectior systems as necessary to satisfy the requirements of Appendix R and will also request exemptions (with supporting justification) from the requirement for automatic suppression in areas where 3-hour barriers are requalified as 1-hour barriers.
Originally, 3-hour barriers were installed in locations where automatic suppression is considered undesirable, i.e. in electrical equipment rooms.
Gaseous suppression systems are impractical due to the unavailability of Halon and the personnel safety hazards associated with Carbon Dioxide. Hence, the basis for our plans in the aforementioned locations will consider appropriate levels of fixed fire protection features with the actual hazard.
C311-94-2307 Page 7 of 8 VI.
Schedules B.
Required Information:
Submit an integrated schedule that addresses the overall corrective action schedule for the plant. At a minimum, the schedule should address the following aspects for the plant:
1.
implementation and completion of corrective actions and fire barrier upgrades for fire barrier configurations within the scope of the NEI program, 2.
implementation and completion of plant-specific analyses, testing, or alternative actions for fire barriers outside the scope of the NEI program.
Response
GPUN has initiated and scheduled additional activities to address the inability of Thermo-Lag to provide t'oe required level of fire protection.
Thse activities include:
1.
Complete walkdown to identify the element details of the plant installed configurations and t. circuit schedule review (the balance of the walkdowns will be completed no later than 11R Refueling Outage: Fall 1995.
As previously identified, the delay in completing this task is based on industrial safety and ALARA considerations).
2.
Complete plant specific database for use in evaluating and assigning ratings to bounding configurations.
3.
Evaluate alternatives for unacceptable configurations: identify potential resolutions: activities involving plant modifications such as Thermo-Lag upgrades, replacement of Thermo-Lag with other materials, rerouting cables or relocating protective components, or installation of suppresston and/or detection or a combination including a request for exemption.
4.
GPUN has completed the Appendix R safe shutdown evaluation and determined that no reduction in fire barrier applications was possible.
Complete resolution of unacceptable configurations involving Appendix R fire modeling and/or exemption requests
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where appropriate and the activities identified in items 2 and 3 are scheduled for completion by the end of 1996.
Implementation will be in accordance with the Long Range Planning Program Integrated Schedule with completion pursuant to License DPR-50, Condition 2.c.(9).
e o
C311-94-2307 Page 8 of 8 i
5.
Evaluate the effect of upgrades on the ampacity derating factor.
i Planning and scheduling corrective actions on the ampacity issue will be addressed by a future submittal once the need is identified and the scope of ampacity derating factor deficiencies ls determined.
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