ML18139A378
| ML18139A378 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 06/12/1980 |
| From: | Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 421, IEB-80-06, IEB-80-6, NUDOCS 8006300349 | |
| Download: ML18139A378 (10) | |
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June 12,1980 Mr. James P. O'Reilly, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region II Serial No. 421
- 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
IE BULLETIN 80-06 NO/RGS/jmj Docket Nos License Nos.
50..:280 50-281 50-338 50-339 DPR-32 DPR-37 NPF-4 NPF-7 NORTH ANNA POWER STATION UNIT NOS. 1 AND 2 SURRY POWER STATION UNIT NOS. 1 AND 2 This letter is in response to IE Bulletin 80-06:
"Engineered Safety Feature (ESF) Reset Controls".
We have completed our review of the subject bulletin and have determined that certain safety-related equipment does not remain in the emergency mode upon the reset of an ESF actuation signal. Until design modifications can be imple-mented, changes to station procedures have been made to incorporate the re-quirements that the safety-related equipment will remain in its emergency mode following the reset of an ESF signal.
NRC Request
- 1. Review the drawings for all systems serving safety-related functions at the schematic level to determine whether or not upon the reset of an ESF actuation signal, all associated safety-related equipment remains emergency mode.
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Response
I On November 6, 1979, during a review at our North Anna Power Station of syst~' /
.operation subsequent to a unit trip and safety injection actuation, it was discovered that certain safety-related equipment returned to its non-safety mode upon reset of an ESF actuation signal. This condition was reported to the NRC for Unit 1 pursuant to Technical *specification 6.9.1.8.i and for Unit 2 pursuant to 10 CFR 50. 55 (e)
- At that tim.e a review of the drawings for all systems serving safety-related functions was immediately initiated to determine if any other deficiencies existed. This review was performed by our architect ~ngineer and Vepco for North Anna.
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VIRGINIA ELECTRIC AND POWER COMPANY TO e
Mr. James P. O'Reilly 2
When the discrepancies in the ESF control circuits were discovered at North Anna, we instructed our architect-engineer to review the control circuitry of ESF systems at Surry Power Station Units 1 and 2 to determine if similar problems existed at that facility.
The results of our review of North Anna and Surry drawings for all safety-related equipment serving as protective functions indicate that certain equipment will not remain in the emergency mode when the ESF actuation signal is reset.
The affected control circuits are addressed in our response to Item 3 of the Bulletin.
NRC Request
- 2. Verify the actual installed instrumentation and controls at the facility are consistent with the schematics.reviewed in Item 1 above by conducting a test to demonstrate that all equipment remains in its emergency mode upon removal of the actuating signal and/or manual resetti~g of the various isolating or actuation s.ignals.
Provide a schedule for the per-formance of the testing in your response to this Bulletin.
Response
A review was performed by Vepco North Ann~ and Surry site personnel of station procedures used to verify that all safety-related equipment remains in its emergency mode upon the removal of ESF signals.
The results of our.review are as follows:
North Anna Units 1 and 2 Test procedures for both units have been modified to demonstrate that all equipment remain in its emergency mode upon resetting of the actuation signals.
The following tests were modified:
.a.
Safety Injection Functional Test
.b.
Contairnnent Depressurization Actuation Functional Test Verification tests will be performed as a part of required system functional tests during the next unit refueling outage.
The refueling outages for Units 1 and 2 are scheduled for December 1980 and September 1981 respectively
- The following test will be developed to test main steam line isolation
- Main Steam Line Isolation Reset Test This test will also be performed during the refueling shutdown of the applicable unit.
It should be noted that individual control circuit tests have been performed on the modified circuits as listed in Item.3.
These were performed as a part of the implementation of the design change.
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VIRGINIA ELECTRIC AND POWER CoMPA1Y TO Mr. James P. O'Reilly 3
Surry Units 1 artd 2 The following test procedures have been modified for both units to demonstrate that all equipment remains in its emergency mode upon the resetting of the ESF actuation signals:
- a. Safety.Injection Functional Test
- b.
Consequence Limiting Safeguards Functional Test Verification tests will be.performed as a part of required system functional tests during the next Unit 1 refueling outage scheduled for the fall of 1980 and prior to the Unit 2 start-up.
NRC Request
- 3. If any safety-related equipment does not remain in its emergency mode upon reset of an ESF s_ignal at your facility, describe proposed system modifi-cation, design change, or other corrective action planned to resolve the problem.
Response
It has been determined that design modifications should be made to certain safety-related equipment control circuits, as detailed below, to ensure that the equipment remains in its emergency mode upon the reset of an ESF signal.
Component/System
- 1. Inside/Outside Recirc. Spray Pumps
- 2. Control Room Supply and Exhaust AOD NORTH ANNA UNIT NOS. 1 AND 2
- problem CDA Signal energizes a timer after reset time delay timer starts pump.
If the CDA signal is reset before timer starts the pump, the pump will not start which is its non-safe mode.
An S. I. signal closes all AOD's when S. I. is reset the A;OD's reopen.
- solution Add an auxiliary relay in parallel with timer and seal-in CDA contact such that if CDA is reset prior to timer starting pump, timer will remain energized, the operator must place control switch in "stop" or "Pull-to-Lock" Position to then defeat pump starting.
Wire a*seal-in contact such that when S.I. is reset the S.I. output relay remains energized.
Manual reset switch from bottled air system used Des_ign Change Implementation
- schedule Design Change implementation completed.
Design Change implementation completed.
to return system to normal.
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VIRGINIA ELECTRIC AND POWER COMPANY TO Mr. James P. O'Reilly 4
- 5. Containment Recirc *.
Cooling fans
- 6. Service Water valves to containment Recirc *. Air Coolers
- 7. Service Water Radiation Monitoring Sample Pumps CDA s_ignal de-energizes SOV to*
admit air to charcoal filter.
Resetting CDA signal re-energizes SOV diverting air flow around..
charcoal.filter.
Added an auxiliary relay to seal-in CDA signal such that operator must also place AOD selector swi.tch* in "Open" position to reposition AOD's after resetting CDA.
Des_ign Change implementation completed.
CDA signal de-*
energizes SOV to admit air to charcoal filter.
Resetting CDA signal re-energizes SOV diverting air flow around charcoal filter.
Added an auxiliary relay.. Design Change to seal-in CDA s_ignal. such implementation that operator must also completed.
place AOD selector switch in "Open" position tore-position AOD after re-setting CDA.
CDA signal trips the Containment Recirc. Cooling Fans, resetting the CDA signal restarts fan *.
. Removed auto start contact Des_ign Change on control switch from implementation control circuit. This completed.
forces operator to*
manually restart the fans if required.
CDA signal operates A letter to the NRC from None required
- associated SW.
Vepco dated Dec *. 14, 1979 valves.
Should discussing CDA/SI.reset Service Water mode modifications at North selector switch be *Anna 1 committed to using in Service Water administrative procedures position, resett~ng to adequately control these CDA will auto-devices.
matically shift valves to nonsafety mode.
CDA s_ignal.
energizes timer after reset
- Des_ign Change is to be implemented at time delay timer
.starts pump.
If
.CDA signal is reset before timer starts pump, pump **
will not start which is the nonsafe mode
- Utilize existing spare relay in MCC circuit to seal-in CDA signal such that resetting CDA will not defeat pump.starting.
.the next refueling outage.
The operator must also place pump selector switch
.in the "Stopf' position to defeat.starting.
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VIHGINIA ELECTRIC AND POWER COMPANY TO Mr. James P. O'Reilly Component/System
- 8. Main Condenser Air Ej ec te>r to containment
- 9. Control Rod Drive Cooling Fans
- 10. Turbine Driven Auxiliary Feedpump
- 11. Main.Steam Line Trip Valves SOV's Problem Normally closed contaimnent isolation valves between condenser and contaimnent open on high radioactivity level in condenser and close on Solution Install an additional relay & selector switch to achieve the two operator actions required when resetting a safety signal.
containment isolation Phase A (CI~A)
Problem arises when operator resets Contaimnent Isolation Phase A (CI-¢A) signal and containment isolation valves re-open.
CDA signal stops Control Rod Drive Cooling Fans.
Resetting CDA signal starts fans returning them to non-safety mode.
A SI signal starts pump.
Resetting SI signal.stops the pump, returning it to the non-safetymode.
Two delibrate -~
operator.actions should be required to return pump to nonemergency *.. mode.
With a main.steam line isolation signal, the trip valves will*. close.*
When CDA is reset~.
the trip valve
- will attempt to open which is the nonsafety mode.
Provide seal-in CDA output relay in relay.
cabinet and add reset switch such that operator must reset CDA signal and reset seal-in CDA output relays via
.. reset switch.
Add relay to seal-in SI contact since resetting SI will not.stop pump.
Pump selector switch must also be placed in "stop" position to stop pump
- Modify controlcircuit*
for SOV' s such*- that *it
- will be necessary to press an open switch
- to break a seal-in of the sov to open' the trip valve.*
5 Design Change Implementation Schedule Design Change to be implemented at the next refueling outage.
Design Change is to be implemented at the next refueling outage for Unit 1.
Design Change completed for Unit 2.
Design Change is to be implemented at the next refueling outage for Unit 1.
- Design Change completed for Unit 2.
Des_ign Change is to be implemented at the next refueling outage.
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VIRGINIA ELECTRIC AND POWER COMPANY TO Mr. James P. O'Reilly Component/
System
- 1.
Inside/Outside Rec ir. Spray Pumps
- 2.
Control Room Supply and Exhaust MOV's
- 3.
Iodine Filter Bank AOD's
- 4.
Safeguards Area Exhaust Fan Filter SOV's SURRY UNITS NOS. 1 AND 2 Problem Resetting CLS signal before
.time delay will defeat starting of pumps.
Control Room Ventilation Valves are MOV's not AOD's as on North Anna Units.
Resetting CLS signal will divert air flow around charcoal filter.
Resetting CLS signal will divert air flow around charcoal filter.
Solution The capability of re-setting the CLS signal prior to the completion of the time delay may be desirable, but could only occur if the containment-were subatmospheric which would not represent a safety hazard.
No problem exists with present circuits.
- Auxiliary Building Ventilation System is being extensively modified.
Problem will be mitigated by administra-tive control in the interim.
Auxiliary Building Ventilation System is being extensively modified.
Problem will be mitigated 'by administrative control in the interim *
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6 Design Change Implementation Schedule None Required None Required Modified circuits are to be installed in the fall of 1980.
Modified circuits are to be installed in the fall of 1980.
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e VIHOINIA ELECTRIC AND POWER COMPANY TO Mr. James P. O'Reilly 7
Component/
System
- 5.
Containment Recirc.
Cooling Fans
- 6.
Service Water Valves to Containment Recirc. Air Coolers
- 7.
Service Water Radiation Monitoring Sample Pumps
- 8.
Main Condenser Air Ejector to Containment
- 9.
Control Rod Drive Cooling Fans Problem Containment Recirc. Fans trip on CLS, no auto start.
. No mode selector switch is used.
The control circuits operate properly.
No change in mode when the CLS signal is reset.
CLS Signal starts Rad.
Monitoring Pumps with no time delay in circuit.
The CLS contact is sealed in by a starter contact, therefore resetting CLS signal causes no problem.
TV-SV-102 will reopen when CLS (both trains) is reset with a high radiation signal from condenser.
These circuits contain no CLS inputs, only manual on-off selector switches.
Solution No problem exists with present circuits.
No problem exists with presen~
circuits.
No problem exists with-present circuits.
Design Change Implementation Schedule None required None required None required A containment isolation None required valve has been installed between the containment and TV-SV-102 which does not receive an air ejector high radiation signal.
This TV-SV-102 is no longer considered to be a containment isola-tion valve.
No problem None required exists with present circuits.
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VIRGINIA ELECTRIC AND POWER ColNY TO e
Mr. James P. O'Reilly Component/
System Problem Solution
- 10.
Turbine Driven Auxiliary Feedpump An MOV and a PCV are used to supply the motive force to the Aux.
Feedpump (turbine driven).
SI or CLS contacts are not used for pump start initiation.
No pr-0blem exists with present circuits.
- 11. Main Steam Line Trip Valve SOV's NRC Request With CLS signal initiated, the trip valves will close.
When CLS is reset, the trip valves should not attempt to open as the Train A control circuit is designed with a seal-in function.
Should control power be lost to the Train A circuit, resetting the CLS signal will attempt to open the trip valves which is the nonsafe mode.
Modify control circuit for SOV's such that it will be necessary to reset the seal-in feature of the SOV to open the trip valve.
Interim administra-tive procedures are being utilized until the Design Change can be implemented.
8 Design Change Implementation Schedule None required Design Change to be imple-mented at the next refueling outage.
- 4.
Report in writing within 90 days, the results of your review and include a list of all devices which *respond as discussed in item 3 above, actions taken or planned to assure adequate equipment control, and a schedule for implementation of corrective action.
This information is requested under the provisions of 10 CFR 50.54 (f). Accordingly, you are requested to provide, within the time period specified above, written statements of the above information, signed under oath or affirmation.
Reports shall be submitted to the Director of the appropriate NRC Regional Office and a copy shall be forwarded to the NRC Office of Inspection and Enforcement Division of Reactor Operations Inspection, Washington, D. C.
20555.
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e VIROINIA ELECTRIC AND POWER COMPA?IY TO Mr. Jame_s P. O'Reilly
Response
The actions taken or planned to assure adequate equipment control and a sche-dule for implementation of corrective action have-been delineated in our response to Item 3 of the subject Bulletin.
cc:
Mr. Victor Stello, Director NRC Office of Inspection and Enforcement Division-of Reactor Operations Enforcement Washington, D. C.
20555 Very truly yours,
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B. R~l::a --
Manager - Nuclear Operations and Maintenance 9
COMMONWEALTH OF VIRGINIA CITY OF RICHMOND
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Before me, a Notary Public, in and for the City and Commonwealth aforesaid, today personally appeared B. R. Sylvia, who being duly sworn, made oath and said (1) that he is Manager-Nuclear Operations and Maintenance of the Virginia Electric and Power Company, (2) that he is duly authorized to execute and file the foregoing statements in behalf of that Company, and (3) that the state-ments are true to the best of his knowledge and belief.
Given under my hand and notarial seal this.*2 -th day of Jene My Commission expires
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