ML18153C907

Ro:On 920106,discovered That Portion of Wall Separating Cable Vault & Auxiliary Bldg Was of 4-inch Block Const Instead of Being Designated as Separate Fire Areas.Fire Watches Established Per Station Operating Procedures

ML18153C907
Person / Time
Site:	Surry
Issue date:	02/24/1992
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
92-089, 92-89, NUDOCS 9203020240
Download: ML18153C907 (5)

Text

e VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA. 23261 February 24, 1992 U.S. Nuclear Regulatory Commission Serial No.: 92-089 Region II SPS/RCB-CGL R7 101 Marietta Street, N.W. Docket Nos: 50-280 Suite 2900 50-281 Atlanta, GA, 30323 License Nos: DPR-32 DPR-37 Gentlemen:

. VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 10CFR50 APPENDIX ,R FIRE BARRIERS During recent cable installation activities, an Appendix R discrepancy was discovered with regard to the thickness and fire *rating of a four-inch block wall between the auxiliary building and the Unit 1 cable vault. The same condition was found in Unit 2.

While investigating these discrepancies, an additional discrepancy was discovered in a twelve-inch auxiliary building wall. These as-built configurations are not consistent with the considerations used in establishing compliance with 10CFRSO Appendix R.

As *an interim measure, compensatory measures have been put in place and corrective measures are being planned to restore the fire_ ratings of these walls to the ratings specified in the Surry Appendix R Report.

A more detailed discussion is provided in the attachment. We will *inform you of the status of our corrective actions by April 30, 1992. Should you have any questions, please contact us.

Very truly yours,

~~J W. L. Stewart Senior Vice President - Nuclear Attachment - Inadequate Fire Rating of Auxiliary Building Block Walls cc: U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Mr. M.W. Branch Senior Resident Inspector Surry P~wer Station q203020240 920224 PDR ADDCK 05000280 s PDR

e e INADEQUATE ,FIRE RATING OF- AUXILIARY BUILDING BLOCK WALLS .

On January 6, 1992, while installing cables *between the Unit 1 cable vault and the auxiliary building,. construction personnel discovered that a portion of the wall separating the two areas was of four-inch block wall construction. The same condition was found to exist between the Unit 2 cable vault and the auxiliary building.- The Unit 1 cable vault, the auxiliary building, and the Unit 2 cable vault are designated as separate fire areas (Fire Areas 1, 17, and 2, respectively - see Sketch 1).

During resolution of 1OQFRSO Appendix R issues, Virginia Electric and Power Company had requested certain exemptions from Appendix R requirements .. Included were requests for exemptions from the specific requirements for a three-hour fire barrier for the walls described above. In our exemption request, the two walls of concern were described as eight-inch thick masonry, conservatively rated as two-hour fire barriers. In the NRC Safety Evaluation Report (SER) dated February 25, 1988, it was concluded that the eight-inch thick masonry wall, combined with the installed fire detection and suppression features, provided adequate justification for non-three-hour rated features. Consistent with the Generic Letter 86-1 O interpretation of Appendix R that non-fire-rated features in fire area boundaries may be evaluated by a fire hazards .

analysis, the NRC SER concluded that no exemptions were required. Uncorrected, the discrepant conditions would adversely impact the basis for this SER conclusion.

As a result of this discovery, a review of Class. 1 block walls was conducted to determine if a similar discrepant condition existed at other fire areas which utilize such walls as barriers. This review disclosed one other discrepancy in the block wall in the auxiliary building. This *discrepancy involved a wall of twelve-inch thickness, which

• had been breached for the .installation of a portable air conditioning* unit (see Sketch 2).

We have evaluated the discrepancies and have concluded that continued operation is acceptable based on a number of mitigating factors which are enumerated below. A Justification for Continued Operation (JCO) has been prepared and approved by the Station Nuclear Safety and Op~rating Committee (SNSOC).

• Each of the fire areas contains fire detection equipment which annunciates in the main control room. *

• The cable vaults contain fire suppression equipment which would actuate automatically in the event of a fire. *

• Transient combustible loading is maintained at a low level.

Also, upon discovery of the discrepant conditions, appropriate compensatory measures (i.e., the utilization of fire watches) were established in accordance with station operating procedures.

e Corrective actions to eliminate the problems with the fire barriers described above are*

under evaluation. Walkdowns of the remaining fire walls to confirm their compliance with the Appendix R Report are in progress. Compensatory measures will remain in place until permanent corrective actions have been completed. We will inform you of the. status of these .corrective actions by April 30, 1992.

I* -

.AUXILIARY BUILDING FIRE AREA 17 UNIT 1 UNIT2 CNTMT CNTMT I AREAS OF CONCERN 15 16 1 2 Sketch 1 (not to scale)

e AUXILIARY BLDG APPROXIMATE LOCATION OF BREACH (NOT TO SCALE)

HALLWAY SERVICE BLDG (CLEAN CHANGE AREA)

Sketch 2