ML20134M662

Forwards Status Summary of Efforts to Date & Schedule for Completion of Thermo-Lag Fire Barrier Activities at BVPS Unit 2

ML20134M662
Person / Time
Site:	Beaver Valley
Issue date:	02/14/1997
From:	Jain S DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9702200344
Download: ML20134M662 (3)

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g 8.. v.uy e ., si.imn SNppingport.PA 150U-0004 oEn' vin..w.ni February 14, 1997 p.xl4i$

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l l U. S. Nuclear Regulatory Commission j Attention: Document Control Desk Washington, DC 20555-0001

Subject:

Beaver Valley Power Station, Unit No. 2

Docket No. 50-412, License No. NPF-73 l

Schedule for Completion -

Thermo-Lag 330-1 Fire Barrier Issues i

Our previous submittal of December 27, 1996, identified that a schedule for

completion of the Thermo-Lag fire barrier issues at Beaver Valley Power Station (BVPS) j Unit 2 would be provided by February 14,1997. Based on a telecon with NRC staff on January 14, 1997, a progress summary of our efforts to-date was also requested by the

NRC. Enclosed as Attachment 1 is a status summary of our efforts to date and a schedule for completion of the Thermo-Lag fire barrier activities at BVPS Unit 2.

In summary, we project that the hardware modifications, utilizing additional 1 Thermo-Lag material for upgrading the electrical conduit raceways required for post-fire

. safe shutdown capability, will be completed by August 29, 1997. The engineering I analysis efforts and the ampacity evaluations associated with the Thermo-Lag installations vdll be completed by September 29,1997. If any unforeseen circumstances arise that recessitate a change in this schedule, we will notify you at that time. j

/.s requested in Generic Letter 92-08, confirmation in writing will be provided  !

upeu completion of the actions noted above. In the interim, fire watch patrols will be mauntained for the affected areas until the Thermo-Lag fire barrier issues have been i

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9 resolved. Should you have any questions concerning this matter, please contact Mr. Roy K. Brosi, Manager, Nuclear Safety at (412) 393-5210.

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i Sincerely, Y

j Sushil C. Jain

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Mr. H. J. Miller, NRC Region I Administrator DEllVERING Mr. D. M. Kern, Sr. Resident inspector 0UALITY Mr. D. S. Brinkman, Sr. Project Manager ENERGV a

9702200344 970214 PDR ADOCK 05000412 P PDR

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• /. ATTACHMENT 1 I  !

! Progress Summary of Thermo-Lag 330-1 Fire Barrier Issues at BVPS Unit 2 -

i Thermo-Lag 330-1 fire barrier systems are utilized at BVPS Unit 2 for fire j j protection of safe shutdown circuits on electrical conduit raceways, boxed enclosures  !

) (electricaljunction boxes and pull boxes) and their associated supports. Thermo-Lag is {

not used to protect cable trays at BVPS Unit 2. A different product, 3M Interam fire l l protection system, is used for protection of the cable trays. ,

Based on the results ofindustry testing, the boxed enclosures utilizing Thermo-Lag l

330-1 fire barrier systems were upgraded or justified to meet the required 1-hour fire

resistance capability. These upgrades, utilizing additional Thermo-Lag trowel grade j material and stress skin along the butted seams, were completed during the third quarter

of1996.

, Currently, the smaller size conduit raceways (< 3" in diameter) are being upgraded I due to a change in methodology for compliance with the Thermo-Lag fire barriers issue.

i The upgrades, which utilize an additional layer of Thermo-Lag pre-formed half shells,  !

4 are being perfonned due to recent information from the industry and NRC that the use of l fire modeling would not be an acceptable alternative for resolving the Thermo-Lag fire j barrier issues. Approximately 400 feet of 1 1/2" and 2" diameter conduit raceways are ,

being upgraded to meet the required 1-hour fire resistance capability. This effort is }

} approximately 65% complete at this time, and is expected to be completed by March 31, l j 1997.

4 l j Duquesne Light Company has been actively pursuing a resolution to the Thermo- i j Lag fire barrier issues for BVPS Unit 2. As such, the larger size conduit raceways (3" to j 6" in diameter) encapsulated with Thermo-Lag 330-1 fire barrier systems were in the  :

process of being evaluated by Duquesne Light Company in comparison to industry

j testing which had successfully qualified as c.1-hour fire rated assembly. One of the

parameters previously assumed in the engineering evaluations was the installation i i method of pre-buttering of the joints with trowel grade material vs. post-buttering after

! the assembly is configured. In December of 1996, during the upgrade project for small l size conduits, a 2" diameter conduit was discovered to be void of the trowel grade

material along the seam of the pre-formed half shell installation. Acceptable industry  ;

2 testing on 3" diameter and larger sized conduits has been based on utilizing pre-buttered ,

~j joints. Industry testing of post-butteredjoints on smaller sized conduits (two tests of 2" diameter conduits) had mixed results. The discovery that post-buttering was used on  !

certain installations at BVPS Unit 2 had a direct impact on the acceptability of the  :

engineering analysis efforts that were being developed forjustification of the as-installed '

3" to 6" diameter conduit Thenno-Lag configurations.

i A conservative management decision was made to assume worst case post-buttered j assemblies and proceed to upgrade the remaining (3" to 6" in diameter) conduits j encapsulated with Thermo-Lag 330-1 fire barrier systems which are credited for post-fire Page 1 of 2 4

/' Attachment 1 Progrets Summary of Thermo-Lag 330-1 Fire BarrierIssues at BVPS Unit 2 l

safe shutdown capability. This decision necessitated the need for a scope increase and an extension of the schedule for performing the necessary upgrades for the larger size conduits encapsulated with Thermo-Lag (approximately 900 feet). These upgrades are expected to be completed by August 29,1997. If unforeseen circumstances arise during the course of upgrading the Thermo-Lag installations which necessitate a change in our schedule, we will notify you at that time.

Our objective is to ensure a 1-hour fire rated barrier utilizing Thermo-Lag 330-1 fire barrier systems by bounding our installations at BVPS Unit 2 to a qualified, tested configuration. Minor anomalies or differences with tested configurations will be evaluated and justification provided in supporting engineering analysis. Engineering analysis providing justification of the Thermo-Lag installations at BVPS Unit 2 including l ampacity derating evaluations will be completed by September 29,1997.

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