ML20199B094
| ML20199B094 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/10/1986 |
| From: | Capstick R VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| FVY-86-56, NUDOCS 8606170018 | |
| Download: ML20199B094 (9) | |
Text
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VERMONT YANKEE NUCLEAR POWER CORPORATION RD 5, Box 169, Ferry Road Brattleboro, VT 05301
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_p ENGINEERING OFFICE 1671 WORCESTER ROAD FRAMINGHAM, MASSACHUSETTS 01701 TELEPHONE 617-872-8100 June 10, 1986 FVY 86-56 United States Nuclear Regulatory Commission Washington, DC 20555 Attention:
Office of Nuclear Reactor Regulation Mr. Harold R. Denton, Director
References:
(a) License No. DPR-28 (Docket No. 50-271)
(b) Letter, VYNPC to USNRC, FVY 85-102, dated October 31, 1985
Subject:
Request for Exemption, 10CFR, Part 50, Appendix R, "Special Circumstances and Clarification"
Dear Sir:
By letter, dated October 31, 1985 [ Reference (b)], Vermont Yankee Nuclear Power Corporation requested two exemptions from the provisions of 10CFR, Part 50, Appendix R,Section III.G.I.
We are herein providing additional information in support of these exemption requests as a result of:
- 1) the Commission's December 1985 amendment of 10CFR50.12(a) [50 Federal Register 50764] which clarified the standards to be applied in the consideration of exemptions (i.e., special circumstances); and 2) discussions with your staff held April 2, 1986 wherein additional information in support of our exemptions was requested.
In December 1985, the NRC amended its regulations to clarify the standards that will be applied when it considers the granting of exemptions from the requirements codified in 10CFR, Part 50 [50 Federal Register 50777).
As a result, your staff has informed us that specific information relevant to the "special circunstances" finding required by the revised 10CFR50.12(a) must be submitted in order for the October 31, 1985 exemption requests to be considered.
Section 50.12(a)(2) of the final rule provides that the commission will not consider granting an exemption unless special circumstances are present. One of special circumstances specified in the rule is 50.12(a)(2)(ii) which states, " Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule."
Vermont Yankee believes that the existing fire protection features associated with the two referenced exemption requests accomplish the underlying purpose of the
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Mr. Harold R. Denton June 10, 1986 Page 2 Section III.G.1 to Appendix R states that:
" Fire protection features shall be provided for structures, systems, and components important to safe shutdown. These features shall be capable of limiting fire damage so that:
a.
One train of systems necessary to achieve and maintain hot shutdown conditions from either the Control Room or Emergency Control Station (s) is free of fire damage; and b.
Systems necessary to achieve and maintain cold shutdown from either the Control Room or Emergency Control Station (s) can be repaired within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />."
The objective of this regulation relates to the protection of safe shutdown capability to ensure that at least one means of achieving and maintaining safe shutdown conditions will remain available during and after any postulated fire in the plant (45 Federal Register 76606).
Section III.G.1.a has been interpreted as not allowing for repairs to achieve and maintain hot shutdown. As a result, Vermont Yankee requested an exception from III.G.1.a to allow for the connection of a spare 24 volt battery charger in the event of damage to the normal battery charger caused by a fire in the cable vault room. The procedural controls established involve the connection of a spare 24 volt battery charger to the de system providing power to the ECCS analog trip cabinet and RCIC alternate shutdown panel. This procedure allows the operator flexibility to maintain a hot shutdown condition past 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and until cold shutdown is achieved within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The exemption request established that the purpose of the rule is accomplished because appropriate procedures are in place to ensure the connection of the j
battery charger leads within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of a fire. Without the exemption, an operator would be committed to achieving cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, not the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> that the rule provides, thus unnecessarily constraining operator action. Therefore, Vermont Yankee's established procedural control will achieve an acceptable level of fire protection in the event of a cable vault fire, equivalent to that required by Section III.G.1.a of the rule.
Section III.G.1.a has also been interpreted to include the replacement of fuses as a repair. As a result, Vermont Yankee requested an exemption from III.G.1.a to allow for the replacement of selective fuses in the alternate shutdown system circuitry in the event of a fire. The procedural controls established involve the replacement of blown fuses with readily available fuses at locations that are within a five-minete walk of operator stations.
The procedure allows the operator to replace any blown fuses on the RCIC and RHR control circuits (43 minutes and three hours, respectively, are available to perform this task). The exemption request established that the purpose of the rule is accomplished as a result of adequate procedural controls and time availability for fuse replacement. Therefore, Vermont Yankee's established procedural control will achieve an acceptable level of fire protection in the event of a fire, equivalent to that required by Section III.G.1.a of the rule.
F-Mr. Harold R. Denton June 10, 1986 Page 3 Additionally, another of the special circumstances identified in the final rule, Section 50.12(a)(2)(iii), is applicable to these exemption requests and states, " Compliance would result in undue hardship or other costs that are significantly in excess of those contemplated when the regulation was adopted or that are significantly in excess of those incurred by others similarly situated." Implementing the additional modifications to provide redundant instrumentation power (24 Volt battery charger) and redundant electrical protection (parallel fuses) would require the expenditure of engineering and construction resources, as well as the associated capital costs, representing an unwarranted burden on Vermont Yankee's resources. The costs to be incurred include the following:
o Engineering of additional power and control circuits and the analysis and design of associated equipment supports.
o Significant additions and routing of power and control cables, associated conduits, and supports; and Increased congestion in numerous plant locations complicating plant o
modifications and operation.
Based on the above, Vermont Yankee has determined that "special circumstances" exist for the requested exemptions in that epplication of the regulation in these particular circumstances is not necessary to achieve the underlying purposes of Section III.G.1 of Appendix R to 10CFR50.
In addition to the supporting technical documentation provided in the October 31, 1985 exemption request submittal, further information demonstrating the technical basis for our position is provided in Enclosures 1 and 2 to this letter which directly respond to the staff's April 2, 1986 requests.
We trust that the information provided is acceptable; however, should you r
have any questions or require additional information, please contact this office.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION
[
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l R. W. Capstick Licensing Engineer RWC/jlc Enclosures (2) a
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ENCLO3URE 1 The instructions for energizing the Standby 24 volt de ECCS Battery Charger are detailed in the Alternate Shutdown Procedure. As outlined on the attached instruction sheet, this procedure is not required to be completed until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following loss of the "B" battery charger.
The procedure involves actions on the 252' and 303' elevations (within a five minute walk of each other) of the Reactor Building. On the 252' olevation at MCC 9D. the supply breaker to the 24 volt battery charger is opened. On the 303' elevation, at Distribution Panel BS II, the circuit breaker from the battery charger feed is opened prior to unbolting the supply cable. This circuit breaker prevents damage to the battery in the event of charger or cable failure. The cable from the spare charger is then connected (bolted) prior to closing the breaker. Finally, the supply breaker at MCC 9D is closed.
This procedure ensures that power to the ECCS' cabinets and to RCIC Alternate Shutdown Panel CP-82-1 will be available. Without the power for level instrumentation available at Panel CP-82-l'j the RCIC System can still be operated. Pressure and flow indication is available from a rack adjacent to CP-82-1.
In addition, the operator would be in communication with operators at other areas of the plant, thereby obtaining-information required to maximize operation of the system.
And, in the abeence of any information, the operator would run the system in a conservative fully opened state.
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r APPENDIX M Instructions for Energizing the Standby 24 VDC ECCS Battery Charger r
Purpose / Discussion:
This procedure provides detailed instructions for the use of the Standby 24 V ECCS Battery Charger as a replacement for "B" 24 V Battery Charger. The standby battery charger is mounted on a column near the East wall of Elevation 303' of the Reactor Building. The "B" charger is located on the East wall of the East Switchgear Room.
In the event of loss of the "B" 24 V battery charger due to a fire, the 24 V batteries will last for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
If the 24 V battery charger is not available within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the following procedure should be followed to connect the standby battery charger to the 24 V distribution panel B SII.
Procedure:
1.
Obtain permission from the Shift Supervisor to perform the wiring change.
Authorized by/ Date 2.
At 480 volt MCC-90.gompartment IM,copen the,24 V., battery. charger supply breaker.
Performed by Verified by 3.
At 24 V battery distribution panel BSII on Elevation 303', open the 80 amp DC circuit breaker from the battery charger feed (connected to C1873]SII).
Performed by Verified by 4.
Remove cable C1873]SII from the 80 amp circuit breaker.
Performed by Verified by 5.
Connect cable C1873B coiled and taped inside the 24 V distribution panel BSII to the 80 amp circuit breaker.
Performed by Verifled by 6.
Close the 80 amp circuit breaker.
Performed by Verified by 7.
At MCC-90 close the standby battery circuit breaker at compartment IC.
Performed by Verifieo by Page 1 of 1
m ENCLOSURE 2 Components which may require control power fuse replacement are detailed in Vermont Yankee's existing Alternate Shutdown Operating Procedure. As shown on the attached sheet from that procedure, the location of control fuses and fuse size (amperage) is provided for each component.
The RCIC System components, which must be operable within 43 minutes of reactor scram, are controlled from Panel CP-82-1 located in the RCIC Room on the 213' elevation of the Reactor Building. This control panel is within a five-minute walk of the Control Room. Space fuses for the 125 volt de control circuits of these components are sealed and labeled, and located along with necessary tools in a metal enclosure adjacent to Panel CP-82-1.
An additional set of spare fuses will be located in a locked metal enclosure (accessible to operators only) also within the immediate vicinity of Panel CP-82-1.
The location of the in-line control fuses (two per component) for Components RCIC-18, -20, -21, -27 39
-41, -131, -132, -1, -vacuum pump and condensate pump is within MCC DC-2B, situated directly across (within ten feet) from CP-82-1.
The in-line fuse pair for RCIC-15 is located in MCC 89B on the 252' level of the Reactor Building (within five-minute walk from CP-82-1).
The in-line fuse pair for RCIC-16 is located in a local starter, also on the 252' level of the Reactor Building (within five-minute walk from CP-82-1).
As stated in the instructions for MCC control power fuse replacement, the MCC control switch is placed in the OFF position prior to opening the compartment door; however, as a precaution, a mechanical interlock prevents opening the compartment cover unless the MCC control switch is in the OFF position.
An operator would follow this procedure for all RCIC System fuse replacements except at the local starter for RCIC-16.
Inside the screw-on cover of this starter, a stamped nameplate will be installed directing that the breaker be opened prior to replacing the fuses.
The RHR System components, which must be operable within three hours, are controlled from Panel CP-82-2 located on the 280' level of the Reactor Building. Spares for the 120 volt ac control circuits of these components are located, with the spare RCIC System fuses, in the metal enclosure adjacent to CP-82-1 in the RCIC Room (within five-minute walk from CP-82-2).
An additional set of spare fuses will be located in the new locked metal enclosure within the immediate vicinity of Panel CP-82-1.
The location of the in-line control fuses for Components RHR-13A, -15A, -34A,
-39A, -65A, -89A, and RRU-5 and -7 is within MCC 9B which is situated adjacent (within ten feet) to CP-82-2.
The location of the in-line fuse for RHR-18 is within MCC 8B, which also is situated on the 280' level of the Reactor Building (within five-minute walk from CP-82-2).
The location of the in-line fuses for RHR-25A,_-27A, RV-43, and SW-20 is within MCC 89A and MCC 9D, which are situated on the 252' level of the Reactor Building (within five-minute l
walk from CP-82-2).
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ENCLOSURE 2 (continued)
To ensure the availability of the RHR System, a diesel generator as well as 4,160 and 480 volt buses must be operable. Therefore, fuse replacement may be necessary in the Diesel Generator Room and the Switchgear Room; however, this would be accomplished by an operator already assigned to these areas.
In the Diesel Generator Room, fuses for the 120 volt ac control circuits may have to be replaced for Fuel Oil Transfer Pump P92-1A and Diesel Generator Room Exhaust Fan TEF-2.
The in-line control fuses for these components are within MCC 9C in the Diesel Generator Room. The spare fuses for these components are located within a relay cabinet also in the Diesel Generator Room.
In addition, two sets of 15 Amp, and one set of 30 Amp fuses for the 125 volt de control circuits may require replacement in the Diesel Generator local control panel. These spare fuses are also located within the relay cabinet. An additional set of spare fuses will be located in a locked, metal enclosure (accessible to operators only) in the immediate vicinity of the relay cabinet.
Finally, in the Switchgear Room, a pair of 15 Amp and a pair of 35 Amp fuses for the 125 volt de control circuits may require replacement for 4,160 Volt Bus 4 and 480 Volt Bus 9 Switchgear. The in-line fuses are within the switchgear compartments and the affected components include "A" RHR pump, "A"
RHRSW pump, "A" station cervice water pump, the diesel generator control breakce, and Station Service Transformer T-9.
The spare fuses, along with necessary equipment, are located in a metal enclosure behind (within ten feet)
Bus 4 Switchgear. An additional set of spare fuses will be located in a locked, metal enclosure in the vicinity of the switchgear.
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APPENDIX N l
r Instructions for Control Power Fuse Replacement Purpose / Discussion:
This procedure provides detailed instructions for replacement of control power fuses for the alternate shutdown equipment.
Although the Alternate Shutdown Transfer Switches will isolate the Alternate Shutdown Control Circuits, a few control circuit fuses may blow due to fire damage before the transfer switches have been operated.
In order to insure the affected circuits can be made operable, replacement fuses are provided for the Alternate Shutdown Control Circuits. Spare fuses for equipment located in the Reactor Building are located in the SRV Local Operation junction box in the RCIC Room adjacent to Control Panel CP-82-1.
The fuses for equipment located in the A Diesel Generator Room are located in the A Diesel Generator local control panel. The fuses for the 4KV breakers are located in the com-partment for the Bus 4125 VDC control power transfer switch.
Procedure:
1.
For MCC control power fuse replacement, proceed as follows:
a.
Determine the compartment location for the affected equipment and.
the fuse size from Fig' re'N-1.
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u b.
Position the MCC control switch' for the affected equipment to the OFF position.
c.
Open the compartment door and replace the control power fuse, d.
Close the compartment door and position the MCC control switch to the ON position.
2.
For 4 KV SWOR control power fuse replacement, proceed -as follows:
a.
Open the compartment door for the affected equipment and remove the fuse holder for the affected control circuit.
The fuse holders are labled to identify the close and trip circuit fuses.
b.
Replace the fuses in the fuse holder.
Install 15 amp fuses for the close circuits and 35 amp fuses for the trip circuits.
c.
Place the fuse holder back into the compartment.
Insure the ON is located in the upper left corner when installing the fuse holder, d.
Close the compartment door and check the breaker position indi-cating lights to verify restoration of breaker control power.
3.
For replacement of the A Diesel Generator control panel fuses, replace the two 15 amp fuses mounted in the back of the local control panel.
4.
For replacement of the RCIC speed controller control power fuses, replace the two 1 amp fuses mounted in CP-82-1.
Page 1 of 2
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APPENDIX N e
Figure N-1 Component Location Fuse Size RCIC-18 MCC DC-28 Comp IK 3A RCIC-20 MCC DC-28 Comp 2E 3A RCIC-21 MCC DC-28 Comp 2K 3A RCIC-27 MCC DC-28 Comp 3E 1A RCIC-30 MCC DC-28 Comp 3K 3A RCIC-39 MCC DC-28 Comp 4E 1A RCIC-41 MCC DC-28 Comp 4K 1A RCIC-131 MCC DC-28 Comp SE 1A RCIC-132 MCC DC-28 Comp 5K 1A RCIC-1 MCC DC-28 Comp IE 3A RCIC-15 MCC 898 2A RCIC-16 Local Starter 3A RCIC Vacuum Pump MCC DC-28 Comp 6E 1A RCIC Condensate Pump MCC DC-28 Comp 6K 3A RHR-13A MCC 98 Comp 4C 1A RHR-15A MCC 98 Comp SC 1A RHR-34A MCC 98 Comp 3C 1A
.RHR-39A NCC 98 Comp'5J-
'1A RHR-65A MCC 98 Como 3J 1A RHR-89A MCC 98 Comp 2F 1A RHR-25A MCC 89A Comp 3A 2A RV-43 MCC 89A Comp 48 2A RHR-27A MCC 89A Comp 28 3A RHR-18 MCC 88 Comp 7F 1A SW-20 MCC 9D Comp 2C 1A RRU-5 MCC 98 Camp 68 1A RRU-7 MCC 98 Comp 6D 1A P92-1A MCC 9C Comp 1B 1A TEF-2 MCC 9C Comp 1F 1A Page 2 of 2
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