ML20148C810

Forwards Table Summarizing Design Basis Info for Plant Sgs, Pertinent to Eggcrate Supports

ML20148C810
Person / Time
Site:	San Onofre
Issue date:	05/26/1997
From:	Rainsberry J SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9705290105
Download: ML20148C810 (4)

Text

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WEDISON !iOtu_ , ,

, An EDISON INTL RNATIOMI'* Company l i May 26, 1997

! U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555 ,

Gentlemen:

Subj ect: Docket No. 50-362 l Steam Generator Tube Eggerate Supports l San Onofre Nuclear Generating Station Unit 3 1 l.

! As requested by the NRC Project Manager for San Onofre Units 2 and 3, enclosed is a table which summarizes design basis information for the San Onofre steam generators which is pertinent to the eggcrate supports. This information is currently being reviewed by Southern California Edison in connection with our evaluation of the areas of degradation observed in the San Onofre Unit 3 eggrate supports.

If you have any questions or would like additional information, please contact i me.

l Sincerely, od l

Enclosure l

l cc: E. W. Merschoff, P.egional Administrator, NRC Region IV K. E. Perkins, Jr., Director, Walnut Creek Field Office, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 2 & 3 M. B. Fields, NRC Project Manager, San Onofre Units 2 and 3 J

9705290105 970526

PDR ADOCK 05000361 i i P PDR 4, k OJ ;

[ San Onofre Nudear Generating Station

.a 1 nient CA 9267441128 .

714 368-7420 i

. I San Onofre Unit 3 Steam Generator Eggerate - Design Basis Analysis Summary l Design Basis Analysis of Record Acceptance Criteria Analysis of Record Quantitative Results Normal Operating Conditions Single Tube Analysis ASME Section 111, Class I (1971 Edition with Addenda through Summer 1971):

a) Primary local membrane a) 12 ksi j plus bending <l.5 S = ['

35 ksi b) Primary plus secondary b) 17.3 ksi l Si range <3S = 69.9 ksi i c) Fatigue usage factor c) U = 0 [

U<1.0 l i

Loss of Coolant Accident (LOCA) Single Tube Analysis ASME Section 111, Class 1 Limiting tube row 147, l with Safe Shutdown Earthquake (1971 Edition with Addenda w/64% thickness reduction:  ;

(SSE) through Summer 1971):

f,(0.7 S, ) = 80.6 ksi 69.9 ksi(I) i Main Steam Line Break (MSLB) Single Tube Analysis ASME Section 111, Class 1 i with SSE (1971 Edition with Addenda  ;

through Summer 1971):

l f,(0.7 S, ) = 80.6 ksi Limiting tube row 25:

21.9 ksi(1) t ts -

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San Onofre " nit 3 Steam Generator Eggerate - Design Basis Analysis Summary I

Design Basis Analysis of Record Acceptance Criteria Analysis of Record Quantitative Results Normal O,)eration - Flow induced Single Tube Analysis a) Free stream velocity (V) < a) V/V, <=0.45 j Vibration critical velocity (V,) e a) Cross flow b) Midspan displacement b) Displacement <=

b) Parallel flow (0.0625" 0.0022" i c) RCP impeller d) RCP pressure pulse due to RCP c) Pump freq.< % tube natural c) fn = 49.2 cps i impeller vane interaction freq. or > 1.5 tube natural freq:

fn#< 12.7 cps or fn >40 cps d) Alternating stress due to d) Alternating stress = ,

pressure pulse good for 0.958 ksi (limiting tube infinite number of cycles row 25; U=0)

(U=0)  ;

MSLB Flow Induced Vibration Single Tube Analysis Free stream velocity (V) <= V/V, <= 0.47 Loads critical velocity (V,)

In b.

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San Onofre Unit 3 Steam Generator Eggerate - Additional Design Considerations 1 Design Consideration Analysis of Record Acceptance Criteria Analysis of Record '

Quantitative Results P

h1ain Steam Line Break (h1SLil) Eggerate Evaluation N1aintain tube integrity Tube integrity maintained with Safe Shutdown Earthquake (2) (2)

(SSE)  !

Loss of Coolant Accident (LOCA) Eggerate Evaluation hiaintain tube integrity Tube integrity maintained with Safe Shutdawn Eanhquake (Whole Bundle) (4) (4)

(SSE) (3) i t

Notes: (1) Stress value shown varies from the value shown in the UFSAR and represents the latest analysis of record.

(2) N1anufacturer met this criteria by limiting stresses in the eggcrate lattice bars to 1.05 S = 44.1 ksi. Calculated stressed 10.7 ksi.

(3) Design basis analyses performed to support Operating License issuance evaluated only single tube response to design basis events; this design analysis is not part of the original design basis.

(4) There is no specific design basis acceptance criteria associated with this consideration. An analysis was performed to assess alternative  ;

methods to control secondary chemistry, and included a uniform corrosion allowance for all lattice bars. Analysis demonstrated that the ,

eggcrates, and therefore the tubes, retained integrity with no credit taken for some of the lattice bars.

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