ML20203F901
| ML20203F901 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 04/23/1986 |
| From: | Nauman D SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8604280179 | |
| Download: ML20203F901 (4) | |
Text
.
yyna mete a ca comsuny gnggn gum g mis sucw ar cperations SCE&G April 23, 1986 Mr. Harold R. Denton Director, Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C.
20555
SUBJECT:
V. C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Appendix R Reanalysis
Dear Mr. Denton:
On April 2,1986 a meeting was held in Bethesda between South Carolina Electric and Gas Company (SCE&G) and the Staff to clarify details related t' three deviation reciussts submitted in our [[letter::05000395/LER-1985-013, :on 850429,reactor Trip Occurred Due to lo-lo Steam Generator Water Level in Steam Generator B. Caused by Transients in Deaerator Tank Level & Main Feedwater Pump Discharge Pressure|May 29, 1985 letter]] to your office.
and to further discuss our position on natural circulation monitoring as originally detailed in our submitt&1 of November 1, 1985. Attachment I to this letter provides the additional information requested by the staff regarding the deviations to III.G.2 separation in Fire Areas AB-1 and 18-25.
In addition, as a result of SCE&G's continuing Appendix R Reanalysis, an additional deviation relating to III.G.2 separation has been identified in Fire Area 18-25 and is described in detail in Attachment II.
eV truly rs,
% b Wimm
. Na a TJK/HID/ DAN:csw Attachments pc:
- 0. W. Dixon, Jr./T. C. Nichols, Jr.
J. H. Barker E. H. Crews, Jr.
C. L. Ligon (NSRC)
E. C. Roberts R. M. Campbell W. A. Williams, Jr.
K. E. Nodland J. Nelson Grace G. O. Percival Group Managers R. L. Prevatte
- 0. S. Bradhant J. B. Knotts, Jr.
I D. R. Moore H. G. Shealy l
C. A. Price NPCF File 15.1360 8604280179 860423 DR ADOCK 050 5
g 5 l 1
m
ATTACHMENT I Additional Information Regarding Deviation Requests Submitted in our May 29, i
1985 Letter:
Fire Area AB-1 In our [[letter::05000395/LER-1985-013, :on 850429,reactor Trip Occurred Due to lo-lo Steam Generator Water Level in Steam Generator B. Caused by Transients in Deaerator Tank Level & Main Feedwater Pump Discharge Pressure|May 29, 1985 letter]], SCE&G requested a deviation from the requirements in Section III.G.2 of Appendix R for Fire Area AB-1.
The information below is provided to clarify our justification for this deviation:
The "B" train cable in Fire Zone AB-1.8 * (Elev. 397) is separated from redundant "A" train cables and raceways in Fire Zones AB-1.10, 1.18, 1.19
)
(Elev's 412, 436 & 463) by a horizontal distance ranging from 5 to 20 feet.
The floor slab of Elev. 412 provides vertical separation of these redundant cables. All cable tray conduit and pipe penetrations located in the 412 floor are sealed in this area of concern.
Two hatch covers are located in this area for access to the Containment Isolation Valve Chambers.
The hatch covers are constructed of concrete and are installed for the full thickness of the I.12 floor. The closest unsealed openings are two small pipe and conduit penetrations located 30 feet from the "B"
train cable and an open equipment natch located approximately 50 feet from the "B" train cable. A reinforced concrete wall with unprotected openings is located on Elev. 397 and separates the "B" train cable from these unprotected fluor openings. The fire loading in Fire Zone AB-1.8 (Elev. 397) is 12,700 BTU /FT2 and is 29,000 BTU /FT2 in Fire Zone AB-1.10 (Elev. 412). Combustibles within these zones consist of cable insulation which qualifies as IEEE-383.
Intervening combustibles are negligible and consist of isolated cable runs.
In conclusion, it is SCE&G's position based on the relatively large horizontal separation between cables and the unprotected floor openings, the presence of sealed openings within the 20 ft. range, the low fire loading and negligible intervening combustibles and the presence of an automatic detection system, that the level of fire protection is equivalent to the III.G.2 requirements.
- NOTE: Fire Zone AB-1.8 was listed as AB-1.9 in the [[letter::05000395/LER-1985-013, :on 850429,reactor Trip Occurred Due to lo-lo Steam Generator Water Level in Steam Generator B. Caused by Transients in Deaerator Tank Level & Main Feedwater Pump Discharge Pressure|May 29, 1985 letter]] in error.
r Fire Area 18-25 In our [[letter::05000395/LER-1985-013, :on 850429,reactor Trip Occurred Due to lo-lo Steam Generator Water Level in Steam Generator B. Caused by Transients in Deaerator Tank Level & Main Feedwater Pump Discharge Pressure|May 29, 1985 letter]], SCE&G requested a deviation from the requirements in Section III.G.2 of Appendix R for Fire Area 18-25.1 This deviation involved an electrical cable chase located on Elev. 412 and designated as Fire Zone 18-25.10. A further review of this Fire Zone indicates that it can be upgraded to a Fire Area without further modification.
Tb cable chase is constructed of reinforced concrete satisfying the requiremer *, s for a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier. All penetrations are sealed to provide i fire resistance rating equal to that of the barrier. SCE&G requests that this deviation request be withdrawn since full compliance with Appendix R,Section III.G.2.a will be provided.
ATTACHMENT II Tit le: Fire Area 18-25, Deviation to III.G.2 Separation Requirements Area
Description:
j Fire Area 18-25 is the general floor area of the Intermediate Building on elevation 412' and 436' and the east and west penetration access areas.
This area is comprised of nine separate fire zones. Walls surrounding this area are of reinforced concrete and satisfy the requirements for three hour rated barriers where they separate this area from other fire areas.
Floors and ceilings are also of reinforced concrete but do not satisfy the requirements for a three hour rated barrier due to unprotected or protected steel supports i
with a one hour fire resistance rating. Floor / ceiling openings between elevation 412' and 436' are unsealed in order to provide venting in case of a high energy line rupture. A more detailed description of this fire area is contained in Section 4.4 of the Fire Protection Evaluation Report.
Affected Safe Shutdown Capability:
Redundant' trains for the Service Water Booster Pumps are located in this area.
Fire Area Analysis:
Fire Area 13-25 contains redundant trains for the Service Water Booster Pumps. Train "A" equipment and cables are located in Fire Zones 18-25.1.
(elevation 412) and 18-25.6 (elevation 436). Train "B" equipment and cables are located in Fire Zone 18-25.1.
Separation equivalent to III.G.2 requirements is provided on Elev. 412 (Fire Zone 1B-25.1). The "A" train power cables are wrapped with 3 layers of Kaowool which provides an equivalent I hour rated barrier and the "A" train pump is separated from redundant "B" train cables above by an "M" board fire barrier as discussed in our letters of September 20, 1985 and December 30, 1985. However, the "A" train power cables in Fire Zone 18-25.6 are unprotected. The floor / ceiling between Fire Zones 18-25.1 and 18-25.6 is constructed of reinforced concrete which would satisfy the requirements for a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier if not for unprotected floor / ceiling openings. Automatic detection and suppression systems are provided in Fire Zone 18-25.1.
Fire Zone IB-25.6 contains automatic detection only.
Deviation:
l Fire Area 18-25 does not comply with the requirements in Section III.G.2 of Appendix R to 10CFR50, in that cable of one redundant train is not enclosed in a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire barrier throughout the Fire Area.
i I
l PAGE 1 0F 2
.O I
Justification for the Deviation The train "A" power cables in Fire Zone 18-25.6 are separated from the redundant train "B" cables and equipment in Fire Zones 18-25.1 on the elevation below by a reinforced concrete floor / ceiling which would satisfy the requirements for a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier if not for unprotected openings. The openings in the 436 floor slab consist of conduit and pipe penetrations, a personnel access hatch and an open equipment hatch. The conduit penetrations are located against the north wall of the 480V Switchgear Room. Since these penetrations include the "A" train cables of concern and are located almost directly above the redundant "B" train cables, SCE&G proposes to seal these penetrations in order to prevent fire propagation through these openings. The pipe penetrations are located to the north of the train "A" conduits by approximately 20 feet. These openings are of a size and location which would not present a significant pathway for propagation to the train "A" cables.
The personnel access hatch cover is constructed of steel and is located approximately 10 feet from the "A" train t.onduit. Although it is not a rated fire assembly, it is of substantial construction and will prevent fire propagation.
The equipment hatch is located against the east wall of the Switchgear Rocm and is 15 feet from the
'A" train conduits. The "A" train conduits are shielded from direct fire exposure from the hatch by the northeast corner of the Switchgear Room.
The fire loading in Fire Zones 18-25.1 and 18-25.6 are 43,000 BTU /Ft2 and 20,600 ETU/Ft2, respectively.
In addition to this passiva protection, active fire protection is provided by an automatic fire detection and suppression system located in Fire Zone IB-25.1.
Automatic detection and manual hose stations are provided in Fire Zone 18-25.6.
The pre-fire plan for Fire Zone 18-25.1 will irdicate the manning of these hose stations to prevent propagation to 18-25.6.
The<e systems provide a reasonable assurance that a fire would be detected and controlled in its initial stage before significant damage or propagation occurred.
In conclusion, it is SCE&G's position that the existing and proposed fire protection features, both active and passive in nature for Fire Area IB-25, provide a high level of assurance that at least one train of safe shutdown equipment will remain free of fire damage. These fire protection features provide a level of fire protection equivalent to that of III.G.2.
Further modification required to meet III.G.2 would not enhance fire protection safety.
i l
{
PAGE 2 0F 2 l
---