ML20094Q194
| ML20094Q194 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 08/03/1984 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8408200100 | |
| Download: ML20094Q194 (4) | |
Text
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- s Duxn Powsn GOMPANY P.O. ISOX 33180 CitAMIXFrTE, N.C. 28242 HALH. TUCKER
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August 3, 1984 (m) am-4mi Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: McGuire Nuclear Station Docket Nos. 50-369, 50-370
Dear Mr. Denton:
As a result of an ongoing review of the Fire Protection Program at McGuire, several apparent deviations from Appendix R criteria have been identified.
. The deviations as well as technical justifications are provided in the attached.
This information is provided to the NRC for information.
If there are any questions on this submittal, please adivse.
Very truly yours, l
c.t.d b y
Hal B. Tucker RLG/rbs Attachment cc:
Mr. J. P. O'Reilly, Regional Administrator Mr. Ralph Birkel U. S. Nuclear Regulatory Commission NRC Project Manager Suite 2900' 101 Marietta Street, NW Mr. W. T. Orders Atlanta, Georgia 30323 Senior Resident Inspector McGuire Nuclear Station t
84C3200100 840803 PDR ADOCK 05000369 PDR F
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the Annulus would be detected in the incipient stages and suppressed by fire brigade response or automatic sprinklers in the Annulus.
Considering the above, a fire which originates on one side of the Reactor Building wall will not generate sufficient heat to propagate a fire across the wall. Therefore, additional fire resistance of Reactor Building mechanical penetrations is not considered necessary.
c) HVAC duct penetrations in Reactor Building walls do not have fire rated dampers. A description is as follows:
l The Containment Purge System (described in FSAR Section 9.4.5) has four penetrations per unit, located near Column HH-52 (Unit 2 at HH-60) between Elevations 776 and 787. Two penetrations are 24 inches by 64 inches.
Penetration sleeves are 3/16 inch stainless steel plate designed to withstand thermal and seismic loading.
These penetrations l
are flashed with 1/4 inch stainless steel angles similar to a fire damper sleeve arrangement. A motor operated damper is provided in each duct consisting of 10 gauge steel housing and 16 gauge stect baldes, considerably heavier than 18 gauge housing and 22 gauge blades for a typical fire damper. The remaining two penetrations of the containment purge system consist of 10 inch diameter schedule 20 stainless steel i
pipe also designed to withstand thermal and seismic loading. A motor operated butterfly damper is provided in each duct consisting of 11 gauage steel frame and 10 gauge steel blade. All dampers are normally closed and fail closed.
if fire dampeis were included in the design of this system, an inadvertent damper closure could result in a positive or negative containment pressure that exceeds the values set forth for normal plant operation.
The Annulus Ventilation System (described in FSAR Section 6.2.3) has four penetrations per unit in Reactor Building wall near the Contain-ment Purge System penetrations.
Two penetrations are 28 inches by 16 Inches. Penetration, sleeves are 3/16 inch stainless steel plate designed for thermal and seismic loading. These penetrations are flashed with 1/4 inch stainless steel angles similar to a fire damper sleeve arrangement. The remaining two penetrations of the Annulus Ventilation System consist of 16 inch diameter schedule 20 stainless steel pipe also designed for thermal and seismic loading. The Annulus Ventilation System is an engineered safety feature system.
The system functions.to achieve a negative annulus pressure with respect to the atrosphere following a LOCA.
If fire dampers were included in the design of this system, the potential for inadvertent damper closure would decrease the system rellability. Additionally, the duct is seal-ed to maintain secondary containment Integrity so that dampers could not be reopened in the event of inadvertent closure.
d) Access into the Peactor Buildings from the Auxiliary Building is pro-vided by portals located at two elevations. The fire boundary walls of each Reactor Building has been revised to include the walls enclos-Ing the personnel access portals.
These revisions were necessary due to the degree of difficulty expected in sealing the Reactor Building shleid walls where the portals penetrate.
The walls and ceilings of the enclosure on Elavation 778+0 are con-l structed of 3/16 inch steel plating on both sides of eight inch steel 2
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columns or beams.
The space between the steel plating is filled with Dow Corning 3-6548 Silicone RTV foam. The walls of the enclosures on Elevation 733+0 are constructed as previously described with one exception. The wall containing the entrance door into the Personnel Access Portal is constructed of 3/16 inch steel plating on both sides of three inch steel columns. The space between the steel plating is filled with Dow Corning 3-6548 Silicone RTV foam. All walls on the 733+0 elevation extend to the concrete floor slab above.
Although fire tests' of these assemblies have.not been conducted, as constructed, these walls form a substantial fire barrier.
Administra-tive control of combustible loading provides further. assurance of bar-rier integrity.
3 Fire Boundary Doors With Security Hardware At walls which are both fire and security boundaries, doors are constructed identical to those which are UL listed for three-hour fire resistence with labels attached.
This security hardware was not subjected to fire tests and the door units are mortised to accept security hardware, therefore, UL labels are not attached. Considering there are nc combustible materials adjacent to either side of these doors, doors are constructed identical to UL labeled doors installation of security hardware does not represent potential for fire propagation across the boundary.
4.
Cork Expansion Joints in areas where the Auxiliary Building abutts the Reactor and Diesel Genera-tor Buildings, the structures are spaced approximately three inches apart so that during a Design Basis Seismic Event the buildings would move independently rather than act as a rigid frame structure, in constructing the walls, floors and roof of the Auxiliary Building, compressed cork was installed in the three inch gap as' filler material at all interfaces with the Reactor Buildings.
Electrical penetration rooms for redundant trains of cables required for hot shutdown are located in the Auxiliary Building on Elevations 733+0 and l
-750+0.
These cables are required by 10CFR50, Appendix R to be separated by full. three-hour fi re rated barriers. Walls, floors and ceilings of the l
Aux!llary Building are twelve inches to twenty-four inches of reinforced concrete with electrical and mechanical penetrations sealed to maintain l
three-hour fire rating.
An investigation has identified that the arrangement as described above i
does not comply.with Appendix R in that the cork configuration has not been tested and approved for three-hour fire resistance. The compressed cork l
has been removed from the floor, ceiling and wall of the Electrical Pene-tration on Elevation 750+0 where they abutt the Reactor Building and an approved three-hour fire rated material is installed in the voids as stated In correspondence'of September 28, 1983 from H. B. Tucker to J. P. O'Reilly of NRC Region 11.
The gap between the Auxiliary Building and the Diesel Generator Building at the 750+0 elevation has also been filled with an approved three-hour fire rated material.
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Cork remains in place at Elevation 733. Automatic sprinkler systems and fire' detection systems are provided in motor driven Auxiliary Feedwater Pump Rooms-below seismic expansion joints and will preclude the potential for fire spread between Elevations 716 and 733 e
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