ML18153A075
| ML18153A075 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 10/15/1996 |
| From: | Edison G NRC (Affiliation Not Assigned) |
| To: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| TAC-M94330, TAC-M94331, TAC-M94333, TAC-M94334, TAC-M94581, TAC-M94582, NUDOCS 9610170115 | |
| Download: ML18153A075 (5) | |
Text
(
Mr. J.P. 0' Hanlon A
October 15, 1996 Al Senior Vice President..,Nuclear
.a, Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060
SUBJECT:
NORTH ANNA POWER STATION, UNITS 1 & 2, SURRY POWER STATION, UNITS 1 & 2 REQUEST FOR ADDITIONAL INFORMATION REGARDING THE REQUEST FOR EXEMPTION FROM THE REQUIREMENTS OF APPENDIX R TO 10 CFR 50 (TAC NOS. M94333, M94334, M94581, M94582, M94330 AND M94331)
Dear Mr. O'Hanlon:
By letter dated December 15, 1995, you requested an exemption from the requirements of Section III.G.2.f. of Appendix R to 10 CFR Part 50 for Thermo-Lag radiant energy heat shields located inside the containments of North Anna, Units 1 and 2, and Surry, Units 1 and 2.
We have reviewed your submittal and find that additional information is required to continue our evaluation.
Enclosed is our request for this information.
(Original Signed By)
Bart C. Buckley, Sr. Project Manager Project Directorate II-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339 50-280 and 50-281
Enclosure:
As stated cc w/enclosure:
See next page Distribution Docket File PUBLIC PDII-1 RF S. Varga J. Zwolinski OGC ACRS FILENAME - G:
OFFICE PM:
NAME BBu DATE COPY Yes/No Sincerely, (Original Signed By)
Gordon E. Edison, Sr. Project Manager Project Directorate II-1 Division of Reactor Project - I/II Office of Nuclear Reactor Regulation
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e UNITED STATES e
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 15, 1996 Mr. J.P. O'Hanlon Senior Vice President - Nuclear Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060
SUBJECT:
NORTH ANNA POWER STATION, UNITS 1 & 2, SURRY POWER STATION, UNITS 1 & 2 REQUEST FOR ADDITIONAL INFORMATION REGARDING THE REQUEST FOR EXEMPTION FROM THE REQUIREMENTS OF APPENDIX R TO 10 CFR 50 (TAC NOS. M94333, M94334, M94581, M94582, M94330 AND M94331)
Dear Mr. O'Hanlon:
By letter dated December 15, 1995, you requested an exemption from the requirements of Section III.G.2.f. of Appendix R to IO CFR Part 50 for Thermo-Lag radiant energy heat shields located inside the containments of North Anna, Units 1 and 2, and Surry, Units 1 and 2.
We have reviewed your submittal and find that additional information is required to continue our evaluation. Enclosed is our request for this information.
~~£:y~r~~::J Manager Project Directorate 11-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339 50-280 and 50-281
Enclosure:
As stated cc w/enclosure: See next page Sincerely, Gordon E. Edison, Sr. Project Manager Project Directorate II-I Division of Reactor Project - I/II Office of Nuclear Reactor Regulation
Virginia Electric & Power Company cc:
William C. Porter, Jr.
County Administrator, Louisa County P.O. Box 160 Louisa, Virginia 23093 Michael W. Maupin, Esq.
Hunton and Williams Riverfront Plaza, East Tower 951 E. Byrd Street Richmond, Virginia 23219 Dr. W. T. Lough Virginia State Corporation Commission Division of Energy Regulation P.O. Box 1197 Richmond, Virginia 23209 Old Dominion Electric Cooperative 4201 Dominion Boulevard Glen Allen, Virginia 23060 M. L. Bowling, Manager Nuclear Licensing and Operations Support Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, Virginia 23060 Office of the Attorney General Commonwealth of Virginia 900 East Main Street Richmond, Virginia 23219 Senior Resident Inspector North Anna Power Station U.S. Nuclear Regulatory Commission 1024 Haley Drive Mineral, Virginia 23117 Senior Resident Inspector Surry Power Station U.S. Nuclear Regulatory Commission 5850 Hog Island Road Surry, Virginia 23883 Robert B. Strobe, M.D., M.P.H.
State Health Commissioner Office of the Commissioner Virginia Department of Health P.O. Box 2448 Richmond, Virginia 23218 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W. Suite 2900 Atlanta, Georgia 30323 W.R. Matthews, Manager North Anna Power Station P.O. Box 402 Mineral, Virginia 23117 J. P. O'Hanlon Senior Vice President - Nuclear Virginia Electric and Power Co.
Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, Virginia 23060 Mr. David Christian, Manager Surry Power Station Virginia Electric and Power Company 5570 Hog Island Road Surry, Virginia 23883 Chairman Board of Supervisors of Surry County Surry County Courthouse Surry, Virginia 23683 Mr. Al Belisle U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W. Suite 2900 Atlanta, Georgia 30323-0199
e Enclosure VIRGINIA ELECTRIC AND POWER COMPANY REQUEST FOR EXEMPTION FROM SECTION 111.G OF APPENDIX R TO 10 CFR 50 THERMO-LAG RADIANT ENERGY HEAT SHIELDS INSIDE CONTAINMENT REQUEST FOR ADDITIONAL INFORMATION
1.0 INTRODUCTION
In a letter dated December 15, 1995, Virginia Electric and Power Company, the licensee, requested an exemption from the technical radiant energy heat shield requirements to Section III.G.2.f. of Appendix R to 10 CFR 50.
Section III.G.2.f requires that, when separation of cables and equipment and associated circuits of redundant trains by a horizontal distance of 20 feet without intervening combustibles cannot be achieved, inside noninerted containments, these cables and equipment and associated circuits of redundant trains be separated by noncombustible radiant energy heat shields.
In a letter dated November 6, 1986, the staff granted an exemption from the requirements of Section III.G.2.d to the extent that it requires redundant cables and equipment inside a noninerted containment to be separated by 20 feet horizontally with no intervening combustibles.
The staff based its approval of this exemption on the adequacy of the fire stops used on vertical cable trays {intervening combustibles) and noncombustible radiant energy heat shields in the area of the redundant train interactions associated with reactor coolant system {RCS) hot and cold leg temperature, steam generator pressure, excore neutron flux monitoring, RCS pressure and pressurizer level instrumentation.
In order to support the staff's review of the requested exemption, the following additional information is requested:
- a.
The licensee indicated that conduit wrap is provided until a distance of 20 feet of horizontal separation is achieved or until a rated fire barrier is encountered.
Clarify if this conduit wrap is applied to the subject conduits until 20 feet of horizontal separation is achieved between the protected component/conduit and the intervening combustibles.
- b.
The radiant energy heat shield designs used are constructed from 1/2 inch thick Thermo-Lag 330-1 conduit pre-shapes and panels. This material is combustible.
The licensee, in its submittal, stated that this material has a fire resistance rating of 20 minutes or more.
The guidance of Branch Technical Position {BTP) 9.5-1, Section C.7.a.{l)b and of Generic Letter {GL) 86-10, Section 3.7.,
specifies a minimum fire resistance of 30 minutes and infers that a non-combustible material is being used as the radiant energy heat shield. Specifically, GL 86-10 refers to marinite board, a non-combustible material which, when tested as part of a fire barrier assembly, is capable of achieving a 30-minute fire rating.
In addition, the guidance in GL 86-10 specifies that the radiant energy heat shields should be capable of protecting the required component or cabling during a fire from both convective and radiant heat
e e
2 energy.
Explain how a partial radiant energy heat shield, constructed from combustible materials and positioned betwe~n safe shutdown redundancies, is capable of performing its intended function under exposure fire conditions such as that which can be caused by an intervening combustible.
- c.
The radiant energy heat shields used by the licensee inside the containment are presented as having a 2o~minute fire resistive rating.
Provide the analysis performed which demonstrated that your radiant energy heat shields are capable of providing 20 minutes of fire resistance for the protected component.
In addition, provide the analysis which clearly demonstrates that the chemical composition of the Thermo-Lag materials used to construct the installed radiant energy heat shields is equivalent to the chemical composition of the Thermo-Lag materials used to construct the fire barrier test specimens that establish the 20-minute fire rating.
- d.
Provide a description of the automatic fire detection features provided in the areas where the radiant energy heat shields are installed.
- e.
On drawings, identify the physical location of the fire detection devices which are in close proximity of those redundant safe shutdown functions that are being protected by Thermo-Lag radiant energy heat shields.
In addition, from the current level of fire detection intelligence inside the containment, describe how a fire in the area of these safe shutdown systems will be promptly identified and how its exact location will be communicated to the fire brigade. Describe, in a time-line sequence, the control room operators' response to a fire inside the containment, what action they would take prior to alerting the fire brigade, the fire brigade's response, how the brigade would access the containment, locate the area of concern, and what actions would be taken to fight the fire.
- f.
To help mitigate the potential of fire spread along the trays, vertical and horizontal fire stops (Marinite Board and silicone foam) have been installed where the cable trays constitute a potential intervening combustible between redundant instrumentation components and cabling.
The cabling at North Anna is not qualified per the IEEE 383 standard and the licensee has not conducted fire experiments which would validate expected plant-specific fire propagation in representative cable tray configurations. Therefore, the fire propagation characteristics in the various horizontal tray configurations inside the containment are unknown.
In order to substantiate the fire control features of the fire stop design, provide the technical bases and supporting experimental data which demonstrate that the flames of free burning cables in a horizontal cable tray will be adequately interrupted by the fire stops and that the flames will not bypass the fire stops and reach the cables above the fire stop.