ML19347E227
| ML19347E227 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/13/1981 |
| From: | Dunn C DUQUESNE LIGHT CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-11, TAC-42858, NUDOCS 8104240294 | |
| Download: ML19347E227 (6) | |
Text
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912) 458.cooo 435 Sesm Avenue 727"^
March 13, 1981 United States Nuclear Regulatory Commission Office of Inspection and Enforcement U
Attn:
Boyce H. Grier, Regional Director
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Region I 631 Park Avenue 4
h 7-U[ p King of Prussia, Pennsylvania 19406 6~ APR 'o 2 /S81 V
Reference:
Beaver Valley Power Station, Unit No. 1 g
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Docket No. 50-334, License No. DPR-66 IE Bulletin 80-11 6
x7 Gentlemen:
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Attached is a copy of our safety evaluation for the postulated wall failures as discussed in our previous response dated February 23, 1981 to IE Bulletin 80-11.
As stated in that response, based on this safety eval-uation report for the postulated wall failures and a review of potentially affected systems, it was determined that there was no safety related equip-ment as required by the plant Technical Specifications that would be rendered inoperable upon failure of the identified walls.
This final report supplements our previous submittals dated October 31, 1980, February 2, 1981 and February 23, 1981 to provide the information required by Bulletin 80-11.
If you have any questions concerning this response, please contact my office.
Very truly yours, I
hew C. N. Dunn l
Vice President, Operations l
Attachment l
l cc:
D. A. Beckman, Resident Inspector l
U.S. Nuclear Regulatory Commission Beaver Valley Power Station l
Shippingport, PA 15077 U.S. Nuclear Regulatory Commission c/o Document Management Branch Washington, DC 20555 l
U.S. Nuclear Regulatory Commission l
Office of Inspection and Enforcement Division of Reactor Inspections Operation Washington, DC 20555 8104240294 l
s/
L FINAL RESPONSE TO IE BULLETIN 80-11 BEAVER VALLEY POWER STATION - UNIT NO. 1 March 12, 1981 This report is provided as a Final Response to IE Bulletin 80-11 " Masonry Wall Design." The following is intended to supplement that information provided in the " Supplemental Response to IE Bulletin 80-11," dated January 30, 1981, and the " Report for 180 Day Response to IE Bulletin 80-11," dated November 4,1980.
SAFETY EVALUATIONS OF AFFECTED SYSTEMS AND EQUIPMENT The following is a summary of the evaluation performed for the safety-related equipment and systems that could be affected by the possible failure of overstressed walls.
Auxiliarv Building Walls AB-4-2, AB-4-3, AB-4-4, A3-4-12 and AB-4-13 represent the shielding enclosure for the main filter banks.
Electrical Assessment:
Walls AB-4-2, AB-4-4 and AB-4-13 have no electrical safety-related equipment on or in proximity of the walls. Wall AB-4-3 has safety-related conduit, but the conduit contains neutral cables. Wall AB-4-12 has safety-related cables to redundant heaters for the Boric Acid Tank B.
Heater operability would not be a serious problem since the building heating is adequate to maintain the 4% boric acid in Tank B from solidifying.
Mechanical Assessment:
The following safety-related equipment is subtended by the post-ulated wall failure:
a.
Main filter banks VS-FL-4-9 and associated dampers and ducting.
Gaseous, waste ducting to the cooling tower.
o.
c.
Line 1-CV-17-153B-Q3 (Part of the aerated vent / containment vacuum systems).
A safety analysis review of the above items indicates that the failure modes of the designated walls will not result in the loss of required safety function normally provided by items a, b or c.
The basis of this assessment is delineated below:
The filter banks and associated ducting and dampers were designated as safety-related due to their inclusion in the Leak Collection System.
No credit has been taken for this system in the calculation of the site boundary dose rate.
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This system, however, also provides a ventilation flow path, under emergency conditions, for the charging pump cubicles:
Inspection of drawing 11700-RB-8J-6 indicates that the ventilation path through filters VS-FL-4, 5 and 6 would be unaffected by the postulated wall failure except by debris impact on the parallel flow path through filter VS-FL-7, 8 and 9.
Based upon the high pressure seismic con-struction of the ductwork, and the inherent shielding provided by the included columns placenent and intermediate shielding slab between the filters, the structural integrity of the flow path can be justified.
It is expected that damage, if any, to the filter banks would be minimal (i.e., denting of casing and/or ductwork) and filter banks would remain operable.
The damper leadages of VS-D-4-10AlB could be damaged by the wall failure but this failure mode would not prejudice the integrity of the exhaust flow path.
Additional ducting is supported from the above-referenced walls.
In the unlikely event that the charging pump cubicle exhaust flow were partially occluded due to the postulated wall failure during this emergency mode of operation, the operation staff could divert flow through dampers VS-D-4 /A/B, by passing the filters B/C.
Both of these items, designated as Q system components, are not required for safe shutdown or to mitigate the consequences of an accident.
Proposed Modification i
Change the Boundary Conditions of the walls by stiffening the wall columns.
Wall AB-4-5:
shielding enclosure for the main filter banks.
Electrical Assessment:
Wall AB-4-5 has safety-related conduit, but conduit contains neutral cables.
Mechanical Assessment:
No mechanical safety-related equipment on or in proximity to the wall.
Proposed Modification:
Change the Boundary Condition by stiffening the wall colu=n.
Walls AB-4-14. AB-4-15:
elevator / stairwell walls.
Electrical Assessment:
Wall AB-4-15 has no electrical safety-related equipment located on or in the proximity of the wall.
Wall AB-4-14 has safety-related conduit, but the conduit contains neutral cables.
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Mechanical Assessment:
A postulated failure of these walls could damage the supply tubing to RM-VS107 (elevated release monitor). Altbaugh the radiation monitor RK-VS107 was specified seismic, the E3AR does not require the monitor (including the Sampling line) to be seismic.
In addition, NUREG-737, which specifies post-accident monitoring requirments for BV1, does not require this monitor to be seismic.
Therefore, there is no need at this time to relocate this sample line to assure safe shutdown or to mitigate the consequences of an accident.
Proposed Modification:
Change the Boundary Conditions by stiffening the wall columns.
Fuel Building Wall FB-1-1:
fuel building wall located at elevation 735'-6".
Electrical Assessment:
No electrical safety-related equipment on or in proximity to the wall.
Mechanical Assessment:
No mechanical safety-related equipment on or in proximity to the wall.
Proposed Modification:
Remove the induced wall loads.
Wall FB-1-2:
fuel building wall located at elevation 735'-6".
Electrical Assessment:
No electrical safety-related equipment on or in proximity to the wall.
Mechanical Assessment:
A postulated failure of these walls would not have any detrimental l
effect on systems required for safe shutdown or to mitigate the consequences of an accident.
The postulated failure of systems in the proximity to the wall could, however, have an adverse effect on safety-related lines used for fuel pool cooling.
If the cooling were lost due to a postulated wall failure, fuel pool cooling would be provided by pool boiling augmented by a safety makeup water supply.
Prooosed Modification:
i Remove the induced wall loads.
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Service Building Wall SB-3-1:
control room wall located at elevation 735'-6".
1 Electrical Assessment:
No electrical safety-related equipment located on or in proximity to the wall.
4i-Mechanical Assessment:
The postulated failure of wall SB-3-1 could impart minor damage to the ventilation system.
The only item that would be damaged by a wall failure is the supply duct (14" x 48").
This duct: penetrates the wall in the top course and is supported from the ceiling.
There-fore, any damage impa' ted to this duct due to a postulated wall r
failure would have negligible effect on the performance of the -
1 system.
An exhaust duct that runs parallel,to the wall and near' l
the top course could be crushed but would have negligible impact on air distribution and would not prejudice the operability of the j,
control room ventilation system.
Proposed Modification:
Change the Boundary Conditions by making the wall a propped canti-lever and modify the wall at the door opening.
Wall SB-3-6, SB-3-9, SB-3-12: control room walls' located at elevation 735'-6".
Electrical Assessment:
The following cat as are located on or within proximity to these 3
4
- walls, i
i INMPARX035 INMPBWX035 INMPARX036 INMPBWX036 INMPCBX033 INMPDYX030 INMPCBX034 INMPDYX031 l
These cables provide the reactor power range inputs to develop i
the train A and'B 2/4 logic for the P-9 permissive.
The P-9 permissive is interlocked with the turbine trip to initiate a i
reactor trip when the power range is in excess of 50 percent.
i The loss of these cables would result in the loss of both trains A and B trip permissives which are required.
If P-9 permissive is lost, the reactor'will trip on a turbine trip which is a fail l
' safe condition.
In addition, the following cables are located in P.he proximity of these walls:
IHVCAOC 506 IHVCBPC 505 These cables initiate trains A and B control room ventilation chlorine isolation signal and actuation of the control room i
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g.
L bottled air supply.
This system is not required for hot shutdown.
It could, however, be postulated that loss of these cables could result in the control supply fans being tripped and the air supply dampers closed without the bottled air supply being energized.
This air supply could be manually initiated, if needed, by the control room operator.
There is also a self-contained air system-3 in the control room for emergency situations.
Mechanical Assessment:
A postulated failure of these walls could cause damage to the ventilation supply duct feeding the west computer room, reducing flow in the portion of the supply system by as much as 50 percent.
This failure would not hinder any safety-related function that would be required for instituting safe shutdown or accident mitigation.
Prooosed Modification:
Remove the induced wall loads.
Wall SB-2-1:
cable spreading area firewall.
Electrical Assessment:
A preliminary review of cable trays lIX105R, 1TX305B and conduit 1CY305B which are attached to block wall SB-2-1 indicates that several cables are required for initiation of safe shutdown.
The following cables were retiewed:
lLMSARXO61 and ILMSCBX001 which provide containment pressure inputs from PT-LM100A and C, lQSSCRX002-and lQSSABX001 which provide refueling water storage tank level inputs from LT-QS100C and A, and IRCPNRX001 and IRCPNBX001 which j
provide pressurizer pressure inputs from PT-RC455 and 457.
It can be postulated that the loss of these cables will result in the loss of their required actuation function.
The BVPS Onsite Safety Committee visually examined the wall area in question to aid in their determination of whether the postulated wall failure woule render the cables unable to perform their required function.
It was judged that any collapse of the block wall would j
result in no degradation of system perfor=ance for the following l
reasons:
(1) each cable tray has a sheet metal cover which would protect the cables and (2) the close proximity of numerous other cable trays would minimize any damage that might occur to the trays.
Mechanical Assessment:
No mechanical safety-r;1ated equipment on or in proximity to the wall.
l Prooosed Modification:
Remove supports for the cables, trays and conduit from the wall. l I
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