ML20238C762

Safety Evaluation Concurring W/Util 870702 & 27 Ltrs & 870818 Telcon Re Elimination or Reduction of Maint Requirements on Certain Fire Seals

ML20238C762
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/02/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20238C754	List: ML20238C752 ML20238C762
References
TAC-54373, NUDOCS 8709100359
Download: ML20238C762 (3)

Text

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1. E' NUCLEAR REGULATORY COMMISSION

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WASHINGTON, D C. 20555

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION CONCERNING REVISED FIRE PENETRATION SEALS AT FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO DOCKET NO. 50-267 l

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1.0 INTRODUCTION AND BACKGROUND

By letter dated July 2,1987 (P-87241), the licensee stated that certain fire barrier penetration seals at Fort St. Vrain had been determined to be unnecessary.

The licensee requested'that the NRC approve a reduction I

in the licensee's commitments to maintain these seals.

The licensee had previously reported a number of defective seals in Licensee Event Report 87-006, dated May 11, 1987 (P-87178).

.In subsequent discussions between the licensee and the staff, the licensee agreed to review and provide more detailed documentation concerning the safety significance of the fire seals in question.

This included j

detailed information on the following l

Seal location, j

Original basis for seal installation, and 1

References to the seals in previous fire protection evaluations.

By letter dated July 27, 1987 (P-87269), the licensee provided the requested supplementary information.

The fire seals in question fall into 4 main groups.

They are:

1.

Reactor and Turbine Building Floors, 2.

Access Control Bay Floors, Walls and CeilinOs, (Except for the "J" wall) 3.

Auxiliary Electric Room Floor, and 4.

Analytical Instrument Room.

i The staff's evaluation of these fire seals and the licensee's~ proposal to j

nodify the requirements for maintenance of the seals follows:

J 8709100359 87 PDR ADOCK O p

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v 2.0 EVALUATION 2.1 Reactor and Turbine Building Floor Seals The licensee has stated that the reactor and turbine building floor seals are not effective as fire barriers since the open space design of these buildings would allow a fire to spread between floors.

Effective horizontal and vertical separation of redundant safe shutdown systems assures adequate fire protection in accordance with Appendix R to 10 CFR 50.

Furthermore, no credit was taken for these seals in previous safety analyses.

The staff has reviewed the argumenti presented by the licensee and agrees with the licensee that floor seals that are completely within either the Reactor or Turbine Building fire areas need not be subject to surveillance requirements.

However, floor seals to any adjacent fire areas, including the Three Room Control Complex, the Diesel Generator Rooms, Auxiliary Boiler Room, Turbine Lube Oil Reservoir and Storage Rooms, and Hydrogert Storage Rooms must be maintained.

2.2 Access Control Bay Floors, Walls, and Ceilings (Expect for "J" wall]

The licensee has stated that the Access Control Bay seals to be abandoned are not vital area seals.

These seals were not j

formally reviewed and approved by the NRC.

The fire barrier i

capability of this structure is in general greater than the calculated fire loading.

The Access Cc c.rol Bay is considered part of the Turbine Building for Appenoix R evaluations.

However,y the staff notes that the Access Control Bay is adjacent to the Reactor Building which is a separate fire area.

The staff was concerned that a fire which originates on either side of the wall which separates these areas could damage systems such that safe plant shutdown could not be achieved and maintained.

However in a telephone conference on August 18, 1987 the licensee j

affirmed that these seals are not relied upon to limit fire spread for the purpose of assuring safe shutdown capability.

The staff has reviewed the balance of the argument presented by the licensee concerning the Access Control Bay seals and agrees that they need not be subject to further surveillance require-j ments.

1 2.3 Auxiliary Electric Equipment Room Floor Seals The Licensee has stated that these floor seals offer presure retention and some degree of fire resistance, but have never been tested to the specific requirements of ASTM, E-119.

The NRC had previously agreed that these stals were adequate for there intended purpose.

The licensee has requested to maintain these seals as " gas tight", but unrated fire seals.

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. l The staff has reviewed the licensee's proposal and agrees that it provides an adequate basis for assuring that the Auxiliary.

Electric Equipment Room Floor seals can be maintained as-orginially intended.

2.4 Analytical Instrument Room a

The licensee has stated that the Analytical Instrument Room, although sealed.for air. tightness, is not considered a separate i

fire area.

This room contains no safety related equipment, and 1

the seals' involved were not previously reviewed or approved by d

the NRC.

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'The staff has reviewed the material presented by the licensee, and concurs that the fire seals for analytical instrument room are not safety related.

Thus, the staff concludes that these seals no longer must be maintained as part of a fire barrier.

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3.0 CONCLUSION

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The staff has reviewed the licensee's proposals to not maintain certain 1

fire barrier penetration ! c als. The staff concludes that this action is J

consistent with other fire protection requirements and is therefore, acceptable.

Principal Contributors:

D. Kubicki:

PSB i

l K. Heitner:

PD-IV Dated: September 2,1987 i

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