ML20095G671
| ML20095G671 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna, 05000000 |
| Issue date: | 07/31/1984 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 184, IEB-84-02, IEB-84-2, NUDOCS 8408280150 | |
| Download: ML20095G671 (4) | |
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a VaneswA ELaCTRIC AND Powan COMPANY
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July 31,.1984 1 Weemaan opmanesome
,.Mr..' James P. 0'Reilly; Serial No.
184 Regional Administrator' N0/JHL/ ins
. U. S. Nuclear = Regulatory Commission Docket Nos. 50-280
. Region II' 50-281 Suite 2900 50-338
- 101 Marietta St., N.W.
50-339 Atlants, Georgia ~30323 License Nos.DPR-32 DPR-37 NPF-4 i
' Dear'Mr. O'Reilly l
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNIT NOS. 1 AND 2 SURRY POWER STATION UNIT NOS. 1 AND 2 RESPONSE TO 1.E. BULLETIN No. 84-02 f
I We ' have reviewed I.E.Bulletin 84-02, " Failures of General Electric Type HFA -
.i Malays in.Use in Class 1E Safety Systems", dated March 12, 1984.. As a resuit' f
of this. review,- corrective actions will be taken as described in the attachments.
Based on a ' telephone conversation between Mr. S. ' A. Elrod, NRC
~
and Mr. R. J. Hardwick, Jr., Vepco, an extension to' July 31, 1984 was granted
- by the NMC for the submittal at this information.
I The bulletin requested the following intornation to help the NRC evaluate the cost of the bulletin; staff time to perform requested review: 120 statt hours; staff time to prepara requested documentation: 20 staff hours.
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&, M W. L. Stewart Attachments i
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I' VamoW1A ELhCT30C Awo Powsu Company to James P. O'Reilly
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U. S. Nuclear Regulatory Cossaission AtEn:. Document Control Desk
. Washingtow, D. C., 20555
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~Mr.-D. J. Butka NRC RCsident41nspector
/Surry Power Station ev
. Mr. I1.'W. Branch
'NRC' Resident Inspector North Anna Power Station Mr.. James R. Miller, Chief Operating Reactors Branch No. 3 Division of Licensing NRR U. S. Nuclear Regulatory Connission Washington, D. C. 20555 Mr. Steven.A. Varga, Chief s Operating P.aactors Branch No. 1
- Division of Licensing, NRR U. S. Nuclosr Regulatory Commission Washington, D. C. 20555 s** f
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ATTACHMENT 1 RESPONSE TO IEB 84-02 FAILURES OF CENERAL ELECTRIC TYPE HFA RELAYS IN ifSE IN CLASS 1E SAFETY SYSTEMS NORTH ANNA POWER STATION 1.a(1) All CE type HFA relays used in safety related applications in North Anna Unita 1 and 2 will be replaced.
The normally energized HFA relcys will be replaced as soon as possible depending on parts availability. The replacement relays will be the new " Century Series" HFA relays which are both IE and seismically qualified to the latest IEEE standards.
1.a(2) The Unit I normally de-energized relays are scheduled to be replaced during its next refueling outage.
The Unit 2 normally de-energized relays are scheduled to be replaced during the August, 1984 refueling outage.
The replacement relays will be the new " Century Series" HFA relays which are both IE and seismically qualified to the latest IEEE standards.
1.b (1) No GE type HFA relays are installed in the Reactor Trip System of either North Anna unit.
Therefore, monthly functional tests are not required.
1.b(2) Each North Anna Unit has only two normally energized, safety related liFA relays.
These are direct current (D.C.) relays located in the 4160 Emergency Bus Undervoltage circuitry.
Although the liFA relay failures described in IEB 84-02 involved A.C. HFA relays, North Anna has implemented monthly visual inspections of the four D.C. normally energized relays and plans to continue these inspections until the relays are replaced.
The first inspection was performed in April, 1984 and to date, no deterioration of the coil or spool material has been found.
During the first inspection, one of the relay coil bobbins was found to have a minor crack extending from the center of the bobbin.
The exact cause of the crack is unknown at this time.
Subsequent inspections have indicated that no further coil degradation has occurred.
1.c.
The normally energized safety related HFA relays at North Anna are D.C. excited relays and at this time are not suspected to be subject to the same failure mechanism affecting the A.C.
relays.
- However, these relays are currently being visually inspected on a monthly basis an a precaution.
These inspections have been included in the atation's Preventative Maintenanca program. The Unit 1 relays will be functionally tested prior to the end of the current Unit I refueling outage as part of a Technical Specification required Periodic Test to verify ESF/Undervoltage performance.
Each of the two relnys por unit provides n starting signal to its rsspective Emergency Diesel Generator on an undervoltage signal.
A f ailure of either relay to de-energize would result in a failure of its respective EDG to auto-start if an undervoltage condition existed, lloweve r,
the affected EDG would not be rendered inoperable.
The EDG would still automatically start on ESF actuation and could be started manually.
In addition the redundant EDG would not be affected.
These reasons provide a basis for continued operation of both North Anna Units until the normally energized relays are replaced.
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- Not applicable.
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'Not applicable..
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'All North Anna defined safety _related HFA relays will-lbe replaced'with
- c j,the new ~ " Century? Series": HFA relays, as ' described,in the ' response - to 1
- - t ' item i 1.a.
- Upon, installation ofn these ; relays, any spare - parts - for
'these' relays,will.~have to..be. IE qualified.; - At the;present time, North
- Anna.does not stock replacement 1 parts-for HFA relays.
However, it is'
' planned - to stock.Espare.and. replacement parts for the. Century series -
HFA relays'. The Quality!Coiitrol_ Department: at the station is required
-( to.' ' rec'eipt. inspect. replacement - parts ' to ;, the.' requirements of t the e
' procurementj ~' document.
This. will -ensure. that :only. qualified purchased: for - use fin ? he' Century Series HFA '
replacement r parts are t
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' relays rint safety
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systems.
Therefore, appropriate related administrative--controls exist.to ensure that the older coils are not
- used as; replacement parts.
__ 10ther ftypes. of safe'ty ;.related relays '. utilized at North Anna were
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investigated. to determine if. any generic concerns could exist.
This investigation concluded that no generic concerns exist at the present:
~ ime'with regard to those: relays.
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ATTACHMENT 2 RESPONSE TO IEB 84-02 FAILURES OF GENERAL ELECTRIC TYPE HFA RELAYS IN USE IN CLASS 1E SAFETY SYSTEMS SURRY POWER STATION 1.a (1).All GE type HFA relays used in' safety related applications in Surry.
Units.1 and 2 will be replaced. The normally. energized HFA relays are on, order and will be. replaced as soon as.possible depending on parts availability.. The replacement relays will be the new " Century Series" HFA relays which are both IE'and seismically qualified to the latest IEEE standards.
1.a(2) The normally de-energized relays are on order and will be replaced
.upon receipt _ during the first outage of sufficient duration.
The replacement relays will be the new " Century Series" HFA relays which are both IE and seismically qualified to the latest IEEE standards.
1.b (1) No GE type HFA relays are installed in the Reactor Trip System of either~ Surry unit.
Therefore, monthly functional tests are not required.
1.b(2) Each Surry Unit has only two normally energized, safety;related HFA relays.
These are direct current (D.C.) relays located in the 4160 Emergency Bus Undervoltage circuitry. Although the HFA relay failures
' described in IEB 84-02 involved A.C. HFA relays, Surry will implement monthly visual inspections of the four D.C. normally energized relays and plans to continue these inspections until'the relays are replaced.
1.c The normally energized safety related HFA relays at Surry are D.C excited relays andrat this time are not suspected to be subject to, s same failure mechanism affecting the A.C..
relays.
However, all
, Safety-Related HFA Relays. were visually ' inspected and the 10 pound.
tensile - test was '. performed on relays without Tefzel spools.
In addition, all HFA relays were electrically tested satisfactorily during recent-refueling outages.
Each of the two - relays per unit provides a starting signal to its respective Emergency Diesel Generator on an undervoltage signal.
A failure of either relay to 1de-energize wculd result in a failure of its respective EDG to
' auto-start if~ an undervoltage condition-existed.
- However, the
.affected EDG would still be available as it could be started manually.
In addition the redundant EDG would not be affected and the auto-start signals from ESF's would still be available.
These reasons provide a.
. basis for continued operation of both Surry ' Units until the normally energized relays are replaced.
- 1. d -
Replacement relays will' be replaced upon receipt during the first outage of sufficient duration.
2.:
Not applicable.
'3.
Not applicable.
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- ATTACHMENT 2
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All Surry defined ~ safety related HFA relays will be replaced with the; new " Century Series" HFA relays as described in the response to item
.1.a.
Appropriate administrative controls. will - be. implemented. to
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- assure that older :and. problematic HFA relay coils ' are not used as replacement.part's in safety-related app 11 cations.
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