HL-1825, Application for Amend to License DPR-57,revising Tech Specs to Delete Tables on Undervoltage Relays to Reflect 1983 Implementation of Design Change Request 82-34,to Resolve Deficiency Noted in 1991 Electrical Distribution Sys Insp

Application for Amend to License DPR-57,revising Tech Specs to Delete Tables on Undervoltage Relays to Reflect 1983 Implementation of Design Change Request 82-34,to Resolve Deficiency Noted in 1991 Electrical Distribution Sys Insp

ML20086D174
Person / Time
Site:	Hatch
Issue date:	11/18/1991
From:	Beckham J GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20086D177	List: HL-1825, Application for Amend to License DPR-57,revising Tech Specs to Delete Tables on Undervoltage Relays to Reflect 1983 Implementation of Design Change Request 82-34,to Resolve Deficiency Noted in 1991 Electrical Distribution Sys Insp ML20086D179
References
HL-1825, NUDOCS 9111260001
Download: ML20086D174 (7)

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1 u,unm u. Geo(gia Power v ce ewet- n.ae, ti 1Rh DOmCI HL-1825 002152 Novemoer 18, 1991 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 PLANT HATCH - UNIT 1 NRC DOCKET 50-321 OPERATING LICENSE DPR-57 RE0 VEST TO REVISE (ECHNICAL SPECIFICATIONS TO DELETE TABLES ON UNDERVOLTAGE RELAYS Gentlemen:

In accordance with the provisions of 10 CFR 50.90, as required by 10 CFR 50.59(c)(1), Georgia Power Company (GPC) hereby proposes changes to the Plant Hatch Unit 1 Technical Specifications (TS), Appendix A to Operating License DPR-57.

The proposed amendment incorporates changes to the Plant Hatch Unit 1 TS to reflect as-built plant conditions and to resolve NRC deficiency 91-202-03 identified during the 1991 Electrical Distribution System Functional Inspection at Plant Hatch. The portions of the TS requiring revision address the undervoltage and degraded voltage relays, and are being revised to reflect the 1983 implementation of Design Change Request 82-34.

Enclosure 1 provides detailed descriptions of the proposed TS changes and circumstances necessitating the change request. Enclosure 2 details the bases for our determination the proposed TS changes do not involve significant hazards considerations. Enclosure 3 provides page change instructins for incorporating the proposed changes. Following Enclosure 3 are the pn: posed '3 pages, along with their markups.

To allcw time for procedure revisions and orderly incorporation into copies of the TS, GPC requests the proposed amendment, once approved by the NRC, be issued with an ef fective date no later than 60 days from the date of issuance of the amendment.

In accordance with the requirements of 10 CFR 50.91, the designated State official will be sent a copy of this letter and all applicable enclosures.

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Georgitt Powerkh U.S. Nuclear Regulatory Commission November ib, 1991 Page Two Mr. J. T. Beckham, Jr. states he is Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Company, and to the best of his knowledge and belief, the facts set forth in this letter are true.

GEORGIA POWER COMPANY BY:[J.T.Beckham,Jr(/~

Sworn to and subscribed before me this i8 day of 'Ilnut&o 1991.

kha Notary

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Enclosure:

cc: Georaia Power Comnany Mr. H. L. Sumner, General Manager - Nuclear Plant NORMS U.S. Nuclear Requlatory Commission. Washinaton. D.C.

Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Reaulatory Commission. Reaion 11 Mr. S. D. Ebneter, Regional Administrator Mr. L. D. Wert, Senior Resident inspector - Hatch Stale of Georcia Mr. J. D. Tanner, Commissioner - Department of Natural Resources vm::s

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ENCLOSURE 1 PLANT HATCH - UNIT 1 NRC DOCKET 50-321 OPERATING LICENSE DPR-57 RLquEST TO REVISE TECHNICAL SPECIFICATIONS JO DELETE UNDERVOLTAGE RELAY TABLES

. Basis for Chance Re2HRit The proposed change will revise the Unit 1 Technical Specifications to reflect as-built conditions of the plant. Specifically, it is proposed to revise Unit 1 Technical Specifications Tables 3.2-12, 3.2-13, 4.2-12, and 4.2-13, along with Section 4.9.A.7.b.2. These portions of the Technical Specifications deal with 4160V undervoltage relays and are being revised to reflect the 1983 implementation of a design change performed under Design Change Request (DCR) 82-34. The proposed change will resolve NRC deficiency 91-202-03 identified during the Summer 1991 Electrical Distribution System Functional Inspection (EDSFI) at Plant Hatch.

DCR 82-34 modified the undervol tage relay logic which was originally designed to cause a trip of the Loss of Offsite Power (LOSP) lockout relay if voltage was lost on the IC Startup Transformer (SUT). This transformer is the alternate offsite power supply to the Unit 1 emergency 4160V busses.

The LOSP relay initiates closure of the emergency diesel generator output breaker to the bus. The original design required a loss of voltage on both the emergency 4160V bus and the alternate power supply (SUT 10) before the LOSP relay would trip, s.llowing the diesel generator output breaker to close and supply the emergency bus. The original design is reflected in Technical Specifications Tables 3.2-13 and 4.2-13, and Section 4.9. A.7.b.2 which refum :o " loss of voltage" relays monitoring voltage on SVT IC and

, providing a permissive for the diesel generator output breaker to close.

l The current design, which was implemented in 1983, removed from the LOSP lockout relay circuits the contacts from the auxiliary relays controlled by the SUT IC undervoltage relays. Per this design, the circuit requires only a loss of voltage signal from the energency bus to trip the LOSP lockout relays and allow the diesel generator output breaker to close. The Technical Specifications do not reflect tb present design. Georgia Power Company first informed the NRC of .e decision to implement the modification in a letter dated January i 1982.

Tables 3.2-13 and 4.2-13 list surveillance requirements for the SUT 10 undervoltage relays. The tables state that these relays " initiate energization of onsite power sources." As noted in the previous paragraphs, these relays no longer input to the LOSP lockout relay circuitry. Therefore, we are proposing that these tables be deleted.

Under the existing design, the SVT 10 undervoltage relays are not involved in starting the diesel generators, tripping the LOSP lockout relay, or l closing the diesel output breaker. The relays which d_o perform thase 002152 El-1 l

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ENCLOSURE ' (Continued)

RE0 VEST TO REVISE TECHNICAL SPECIFICATIONS TO DELETE UNDERVOLTAGE RELAY TABLEji Basis for Chanae Reauest functions are the 4kV emergency bus undervoltage relays; their surveillance requirements are given in tables 3.2-12 and 4.2-12. It is acceptable to delete tables 3.2-13 and 4.2-13, because the SUI 10 relays covered by these tables do not perform the functions described in the tables.

Although the SVT IC undervoltage relays no longer perform the functions given in tables 3.2-13 and 4.2-13, they still input to the diesel test circuitry and the legic for closure of the 4kV energency bus alternate supply breaker. These functions are already adequately covered by Technical Specifications requirements listed in Section 4.9.A.7.b.1.

Accordingly, no changes are being proposed to these specifications.

Unit 1 Technical Specification 4.9.A.7.b.2 would also be changed. The reference to "startup transformer IC" would be deleted for the reasons given in the preceding paragraph. The SUT IC undervoltage relays no longer

" initiate energization of the emergency busses by the diesel generators when voltage is lost on the ... startup transformer IC." This function is performed by the emergency 4160V bus undervoltage relays which will continue to be tested by this specification.

It is also proposed to change Unit 1 Technical Specifications Tables 3.2-12 and 4.2-12. This change would consist of revising the table titles to agree with the titles of the corresponding Unit 2 Technical Specifications tables (tables 3.3.8-1 and 4.3.8-1) and to reflect more accurately the functions of the 4160V emergency bus undervoltage relays. The present function of these relays is not altered by this change.

Finally, in support of the above described proposed changes, it is proposed to change the table on page 3.2-1 of the Unit 1 Technical Specifications, and ti c Bases section for Unit 1 Technical Specifications tables 3.2-12 and 3.2-1 , and Section 4.9.A.7.b.2. Changes are made also to page ii of the Table of Contents.

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ENCLOSURE 2 PLANT HATCH - UNIT 1 NRC DOCKET 50-321 OPERATING LICENSE DPR-57 RE0 VEST TO REVISE TECHNICAL SPECIFICATIONS TO DELETE UNDERVOL1 AGE RELAY TABLES 10 CFR 50.92 Evaluatioc.

The Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazards consideration-exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed -

amendment would not: (1) involve a significant increase in the probability

, or consequences of an accident previously evaluated, (2) create the l

possibility of a new or different kind of accident from any accident previously evaluated, or (3) involve a significant reduction in a margin of safety.

Georgia- Power Company has reviewed this proposed license amendment request and determined that its adoption would not involve a significant hazards consideration. The bases for this determination is given below.

E_ asis for-Proposed No Sionificant Hazirds Consideration Determination:

This change does not involve a significant hazards consideration for the l

following reasons:

1. The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.

These changes are being made to reflect the actual as-built plant conditions for the 4160V emergency busses and the IC Startup Transformer (SUT) undervoltage relays. The previous design required a loss of voltage signal on both the SUT 1C and the 4160V emergency bus to trip the Loss of Offsite Power (LOSP) relay and allow the diesel generator output breaker to close and supply the emergency bus. Per l

this design, two relays were used to sense undervoltage on the IC trarsformer. Operating experience has shown that having the diesel tie

logic dependent on these non-Class IE relays was not reliable. In March 1981, during a simulated loss of offsite power event, all three diesels failed to tie to their emergency busses due to a fatiure of these two relays. In a letter dated January 26, 1982, Georgia Power Company -notified the NRC of the intent to remove these relays and modify the LOSP circuitry. -In the Safety Evaluation Report (SER) for Technical Specifications Amendments 88 and 27, dated May 6, 1982, the NRC implied that the modifications described in GPC's January 26 letter were acceptable. The existing design, which has been in place since 002152 E2-1

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ENCLOSURE 2 (CONTINUED)

BE0 VEST TO REVISE TECHNICAL SPECIFICATIONS TO DELETE UNDERVOLTAGE RELAY TABLES 10 CFR 50.92 Evaluation that undervoltage exist on the emergency bus before the diesel generator output breaker closes. This occurs after a time delay to allow the alternate supply breaker to close. The relays that presently control the LOSP circuitry meet IEEE Standard 279-1971. The proposed changes to the Technical Specifications are being made only to reflect present design. No physical changes are being made to the plant as a result of this proposed amendment. Also, no chan;es are being made to the function, operation, or testing of Lny of the undervoltage relays.

The undervoltage relays for both the SUT and the emergency 4160V bus only sense an undervoltage condition. These changes, therefore, do not increase the probability of occurrence of an LOSP event. The consequences of the LOSP event me also not increased since no operability requirements, functional requirements, or surveillance requirements are being changed. Also, the existing relays that sense undervoltage conditions on the emergency busses and trip the LOSP circuitry meet IEEE Standard 279-1971. The existing relays are more reliable than the original relays, which did not meet IEEE 279-1971.

These changes are necessary to update the Technical Specifications to reflect accurately and completely the previously proposed, and implemented, changes. These administrative changes do not result in any physical changes o the plant. All equipment affected by this change will be operated and tested as before.

2. The proposed amendment does not create the possibility of a new or different kind of accident froni any previously evaluated.

The change does not result in any new or different modes of operation, because the changes are being proposed to update the specifications to reflect the present plant design. The function of the relays will continue to be as described in Design Change Request 82-34 and GPC to NRC correspondence dated January 26, 1982. Also, as noted previously, all surveillances and testing presently performed on the relays will continue to be performed.

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ENCLOSURE 2 (CON 11NUED)

REQRFST TO kEVISLlLCENICAL SELClflCAT10111

10. DELETE UNDERVOLTAGE RELAY TABLES 10 CFR 5.qa2 Evaluation

3. The proposed amendment does not involve a significant reduction in the margin of safety.

These proposed changes only update the specifications to accurately reflect the rela) functions. The undervoltage relays monitoring emergency br, voltage and inputting to the LOSP circuitry meet IEEE Standard 279-1971.

All surveillance and testing requirement

• wh;t . assure the operability of these undervoltage relays remain the same. The margin of safety to the LOSP event is, therefore, not reduced.

1 59?mJlr1 Georgia Power Company has concluded the change does not significantly increase the probability or consequences of an accident previously evaluated, create the possib'.lity of a new or different kind of accident than previously evaluated, or significantly reduce the margin of safety.

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