ML19312C130

Forwards Addl Info Re Seismic Design of Emergency Power Path Through 230 Kv Switchyard,In Response to NRC 760630 Request

ML19312C130
Person / Time
Site:	Oconee
Issue date:	10/07/1976
From:	Parker W DUKE POWER CO.
To:	Rusche B Office of Nuclear Reactor Regulation
References
NUDOCS 7912060680
Download: ML19312C130 (11)

Text

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DUKE POWER COMPANY Powen BUILDING 422 SorTn Cuencu STarrT, CnAHLOTTE, N. C. 2e242 wn.ua-o naaxca..m.

October 7, 1976 v.c t Pa t O D t w Y TC E**0NE:A*ES 704 S t r a ma Peoowevion 373-43S3 em i }.i D Office of Nuclear Reactor Regulation

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n..? s Mr. Benard C. Rusche, Director Ot

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Attention:

Mr. A. Schwencer 3yr-

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Dear Sir:

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Your letter dated June 30, 1976 enclosed Amendments Nos. 27, 27 and 24 for Oconee Facility Operating Licenses DPR-38, -47, and -55 respectively. The accompanying supporting safety evaluation by the staff stated that the Licensee had advised that the emergency power path through the 230 kV switch-yard had been seismically designed to withstand the 0.15g earthquake referenced to in the Oconee FSAR for Class I structures.

Information identifying the details of the seismic design of this path were requested in sufficient time for staff review prior to the restart of Oconee 3 following the Fall, 1976 refueling outage.

The Oconee Nuclear Station Emergency Power System was designed before seismic design criteria for the overhead transmission path was required.

It was our belief, however, that this system had been designed to the same criteria as other Class I structures.

Since your request for supporting information was received three months ago, a review of existing documentation has been con-ducted to determine its acceptability to demonstrate the qualification of the path.

Considerable effort has been expended in additional analyses and tests which have been considered necessary. Although these analyses are being com-pleted as expeditiously as possible the complexity, diversity and vintage of the equipment comprising this path, and the short period of time which has transpired, has precluded completion of these tasks.

Attached is a summary of the seismic qualifications of the path.

Dates for completion of those analyses remaining and for the design of certain modifications necessary to assure the seismic integrity of the path are also provided.

Supplemental reports will be submitted detailing the schedule for implementation of modifi-cations as soon as their design effort is completed.

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r Mr Benard C. Rurche r

Pcg2 2 October 7, 1976 In view of the extremely low probability of a seismic event at the Oconee Nuclear Station and the relatively short period of time which will be necessary for the completion of additional analyses and modifications, it is considered that the health and safety of the public will not be affected by the continued operation of the Oconee Nuclear Station.

Very truly yours, h

/

r William O. Parker, Jr.

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KE0 WEE OVERHEAD EMERGENCY POWER PATH SEISMIC QUALIFICATION AND ANALYSIS REQUEST FOR ADDITIONAL INFORMATION The Keowee overhead emergency power path provices a highly reliable source of power to the Engineered Safeguards Systems of the Oconee Nuclear Station.

The Keowee overhead emergency power path consists of a transmission line f rom the Keowee main stepup transformer to the Oconee 230kV switchyard; one 230kV switchyard bus system including power circuit breakers, disconnect switches, and associated controls; and overhead lines from the Oconee 230kV switchyard to the Oconee startup transformers.

The Keowee overhead emergency power path interfaces with the Keowee main stepup transformer; 230kV switchyard power circuit breakers (numbe rs 8, 12, 15, 17, 21, 24, 26, 28, and 33); and the Oconee startup transformers (CT1, CT2, and CT3). This overhead emergency power path interfaces have the same seismic qualifications as the systems or equipment of the path itself.

The structures associated with the Keowee emergency overhead power path are Class 2 structures as defined by the Oconee Nucl ear Station FSAR, Appendix 5A, Section 5A.I.2 and the PSAR Appendix 5A, Section 1.2.

Class 2 structures are designed in accordance with the structural design bases stated in the Oconee Nuclear Station FSAR, Section SA.3 for normal operation and accident and seismic conditions. The seismic criteria used in the design of Class 2 structures is the same as the criteria specified for Class I structures in the Oconee Nuclear Station FSAR, Section SA.2.

2 The structures and equipment comprising the Keowee overhead energency power path are listed in Tables I and IL respectively.

The Keowee Overhead Emergency Power Path is shown in bold lines on Figure I.

The applicable criteria used in the design, fabrication, and installation of the structures and supports associated with the overhead emergency power path are found in the Oconee Nuclear Station FSAR, Section 5A;2. The applicable I

criteria for equipment associated with this power path are specified in the individual equipment specifications.

The seismic inputs and applicable loads and load combinations used in i

.i) the testing and/or analysis of the structures and supports in the overhead emergency power path are covered in the Oconee Nuclear Station FSAR, Section 5A.2. - For the seismic inputs used in the testing and/or anal' sis of equipment y

in the subject power path, refer to Table II.

Stress analyses using static loading conditions were used in the design and analysis of the structures and supports in the overhead emergency power path. These stress analyses used the maximum acceleration response value (i.e., the peak value of the response spectra curve corresponding to the appropriate' damping factor) to calculate the static loads. The basis for this type analysis is.given in the Oconee Nuclear Station FSAR, Section 2.6, and the PSAR, Supplement 1, Section 8.4.3 (c). The design calculations for the above structures and supports are in the Duke Power Company Design Engineering Department files. The design and analysis methods, the design parameters, and the design limits used are shown in the calculations.

For information regarding the equipment seismic qualification methods, refer to a

Table II.

3 The structures and supports for the overhead emergency power path are typical structural steel framing. The materials used and the design of the framing require no special fabrication or construction techniques other than accepted Industry standards. There were no formal qu?llty control procedures in effect for the procurement of material or the fabrication of Class 2 structures or supports.

For equipment in the subject power path, any special materials or fabrication techn: ques required are stated in the individual equipment _ speci fication. There were no formal quality control

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procedures in effect for the procurement of. equipment used in this power path. The equipment manufacturers were required to submit a statement Indicating conformance with the equipnent specification.

Duke Power Company.

engineers also reviewed the manufacturers' designs, inspected eguj ment p

r, during various steps of manufacturing,,,and witnessed manufacturers' tests on the major equipment in the emergency power path.

Testing and inservice surveillance requirements are not applicable to the structures and supports of the overhead emergency power path. The equipment associated with this path is functionally tested monthly during the Emergency Power System Test,(refer to the Oconee Nuclear Station Technical Specifications, Section 4.6).

Additionally, all applicable equipment undergoes routine preventive maintenance in accordance with procedures established by Duk'e Power Company.

The Ocor 230kV switchyard strain structures are designed for allowable unit stresses in accordance with AISC Specifications (1963) with provisions for allowable stress increase of one-third for load combinations with 115 HPH wind. All strain structures are also designed for wind and

4 ice loads on conductors and shield wires in accordance with the National Electric Safety Code, Fourth Edition, for heavy loading (0.5 inches of radial ice and eight pounds wind at O'F).

The 230kV switchyard bus system (i.e., bus, bus supports, disconnect switches, lighting, arresters, etc.)

are designed for 95 MPH winds.

(Refer to the Oconee Nuclear Station FSAR, Section 5A.5).

Flood and tornado effects are not appl.icable to Class 2 structures.

Flood studies (refer to the Oconee Nuclear Station FSAR, Section 2.4.3)

I show that Lake Keowee and Lake Jocassee are designed to contain and control floods such as to po*e no risk to the Oconee Nuclear Station site.

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TABLE 1 Sheet I of 2 KE0 VEE-0CONEE OVERHEAD ENERGEllCY POWER PATH STRUCTURES QUAllFICATIO!I SUMiiARY STRUCTURE 0UALIFIED HETil0D DASIS FOR 0,UAliFICAT10N 1.

Keewe's Main Stepup Trans former Base See flote 1 Analys is 0.159 Ground ibtion 2.

Oconee Startup Transformer Bases See flote 2 Analysis 0.15q Ground Motion 3

Keowee 230KV Line Pulloff Structure Yes Analysis 0.15g Ground Motion 4.

230KV Transmission Line and Towers from See flote 3 Analysis 0.150 Ground Hotion j

Keowee to Oconee 5.

Oconee 230KV Strain Structures Yes Analysis 0.159 Ground Motion 6.

Oconee 230KV Swyd. Bus Support Structure Yes Analysis 0.15g Ground Hotion 7.

Oconee 230KV Swyd. Wave Trap Support Yes Analysis 0.159 Ground Motion S t ructu re 8.

Oconee 230KV Swyd. Lightr.ing Arrestor Yes Analysis 0.159 Ground Hotion Support S tructure 9

Oconee 230KV Swyd. Coupling Capaci tor See flote 4 Analysis 0.159 Ground Motion Potential Devices (CCPD) Support Structure

10. Oconee 230KV Swyd. Disconnect Switch See flote 5 Analysis 0.15g Ground Motion Support Structure 3

11. Oconee 230KV Swyd. PCB Support Structure 5~ee flote 6 Analysis 0.15g Ground Hotion

12. Oconee 230KV Swyd. Relay House See.flot,e 7 Analysis 0.159 Ground Hotion

13. Oconee 230KV Swyd. Relay House ~ Equipment See flo6e 7 Analysis 0.159 Ground Motion Anchoring th. 230hV Lines from Oconee 230KV Switchyard Yes Analysis 0.15g Ground Mo tion to S artup Trans formers

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15. Oconee cwee house 230KV Line and Shield Yes Analysis 0.150 Ground Motion Wire Pulloff Structures 4

TABLE I Shast 2 of 2 Note I:

Additional base restraints are to be added.

Estimated scheduled completion for design of these modifications is December 1, 1976.

Note 2:

Additional base restraints to be added as results of analysis and design.

Design modification completion is scheduled fy November 1, 1976.

Note 3:

Analyses scheduled for completion November 1, 1976.

Note 4:

Those CCPD structures'with bases located in fill-soil are qualified. Analysis is being conducted on those CCPD structures with bases located in original soII. Tests are scheduled to be completed by December 15. 1977 I

Note 5:

Same as Note 4 except applicable to Disconnect Switch Support Structures.

Note 6:

Analysis scheduled for completion December 1, 1976.

Note 7:

The relay house structure is qualified. Modificat ions are to be made to cable trenches, concrete block walis, and the anchorage of some equipment. The completion of the design for these moficiations is scheduled for February 1, 1977.

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1 TABLE 11 Sheet 1 of 2 KEOUEE-0CONEE OVERHEAD EMERGENCY POUER PATH EO.UlPHENT SEISMIC 0.UAllFICATION

SUMMARY

BASIS OF EQUlPHENT TYPE ID EllTI FICATION QUALIFIED PETl!OD QUAllFICATION-1.

Keowee Nain Stepup Trans former Tran s fo rme r 'No.

I Yes Manufac ture r 0.369 Test / Analysis Yes Manufacturer 0.36g 2.'

Oconee Startup.Trans formers CTI, CT2, CT3 '

Test / Analysis 3

230KV Disconnect Swi tches Yes Manufacturer 0.34g Test / Analysis

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Oconee 230KV Swyd. Bus Conductor See Note 1 Analysis 0.369 Sys tem 5.

230KV Power Circuit Breakers (PCB's)

PCB Nos. 8, 9, 12, See Note 2 Test / Analysis 0.369 15, 17, 18, 21, 24, 26, 27, 28, 30, 33 6.

230KV Swyd, Coupling Capacitor Yes Manufacturer 0.369 Poten tial Devices Tes t/Analys is 7

230KV Swyd. Lightning Arrestors Yes Manufacturer 0 36g Tes t/Analys is

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230KV Swyd. DC Distribution Centers, Nos. SY-DC1, SY-DC2 Yes Test 0.369 9

230KV Swyd. DC Pane 1 boards.

Nos. DYA, DYB, DYC, DYD, Yes Manufacturer 0.36r DYE, DYF, DYG, DYH Test

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230KV Swyd. Con trol Power Nos. SY-1, SY-2' Yes Manufacturer 0.36g Test Batteries g

5 11.

230KV Swyd. Battery Chargers Nos. SY-1, SY-2, SY-S Yes Manu facturer 0.36g Test 12.

230KV Swyd. Relay House Light.ing Yes Analysis.

0.36g System s

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TABLE 11 shoot 2 of 2 BASIS OF EQUIPMENT TYPE IDENTIFICATION QUALI FIED METHOD QUALIFICATION 13.

230KV Swyd. Relay Panels &

Note 3 Test / Analysis 0.36g Eq ui pment -

14 230 KV Swyd. Relay House Roof See Note 4 Analysis 0.36g Drain Pipe 15.

230KV Swyd. Relay House HVAC Duct See Note 4 Anal ysis 0.36g 16.

230KV Swyd. Relay House Air Handling See Note 4 Analysis 0.36g Unit r T Note 1:

^nalysis' incomplete.

Scheduled to be completed by November 1, 1976.

Nste.2:

Analysis incomplete.

Scheduled to be completed by March I, 1977.

Note 3:

Analysis incomplete.

Scheduled to be completed by November I, 1976.

Note 4:

Hinor field modifications are to be made. ' Schedule for modification design coi.ipletion is November I, 1976.

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