ML17296B322

Final Deficiency Rept Re Excessive Shear Stresses in Facility Concrete Slabs Supporting Safety Injection Tanks 1B,2A & 2B,initially Reported 800828.Re-evaluation Showed Stresses Below Design Criteria Allowable Values

ML17296B322
Person / Time
Site:	Palo Verde
Issue date:	03/30/1981
From:	Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Spencer G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
10CFR-050.55E, 10CFR-50.55E, ANPP-17667-BSK, NUDOCS 8104070529
Download: ML17296B322 (8)

Text

ACCESSION NBR: 8104070529 DOC, DATE! '1/03/30 NOTARIZED! NO DOCKET

.FACIL::STN 50 528 Palo Verde Nuclear Stations Unit ii Ar)zone Publi 05000528 STN 50 529 Palo Verde Nuclear Stations Unit 2i Ar izona Publi 05000529 AUTH, NAME, Au THOR AFFILIATION.

VAN BRUNTiK".E. Arizona Public, Service Co,,

RECIP ~ NAME RECIPIENT AFFIL~IATION.

SPENCERPGBS ~ Region Sr San Francisco'-Reactor Construction L Engineer SUBJECT!" Fina'l deficiency rept reI excess)ve shear stresses"$ n facility concrete slabs supporting safety inJection tanks 1B<,2A tt 28<initially reported 800828.Reevaluation showed stresses below design criteria allowable values, DISTRIBUTION CODE'I B019S COPIES'ECEITED:LTR ', ENCL L SIZE.:

Construction DeficienCy Reports (10CFR50<55E) 'ITLE.'g NOTES!Standard)zed P)ant.i cy',C. Grimes 05000528 Standardized Plant,i cy!C Grimes 05000529 RECIPIENT , RKCIPIENT ID CODE/NAtlE! LTTR ENCL ID CODE/NAME LTTR ENCL ACTION>> A/D LICENSNG 04 1 1 MIRAGLIArF>>. 05 1 1 LEE"eJ 06 1 KERRIGANg J ~ 07 1 1

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~0 ARIZONA NUCLEAR POWER PROJECT Post Office Box 216 hoenix. Arizona 85036 March 30, 1981 ANPP-17667-BSK/JAR e

U. S. Nuclear Regulatory Commission e(g/yp~

Region V Walnut Creek Plaza Suite 202 1981 E 1990 North California Boulevard Walnut Creek, California 94596 Attention: Mr. G. S. Spencer, Chief Reactor Construction and Engineering Support'ranch,

Subject:

iFinal Report A 50.55(e) Reportable Condition Relating to Excessive Shear Stresses in Units 1 and 2'Concrete Slabs Supporting the Safety Injection Tanks 1B, 2A and 2B File: 81-019-026; D.4.33.2

Reference:

(1) Telephone Conversation between R. Dodds and B. S. Kaplan on August 28, 1980 (DER-80-24)

(2) Interim Report, ANPP-16430-BSK/JAR, dated September 26, 1980 (3) Letter ANPP-16891-BSK/JAR, dated December 12, 1980 (4) Letter ANPP-17358-BSK/JAR, dated February 24, 1981

Dear Sir:

Attached, is our final written report of the reportable deficiency under 10CFR50.55(e) referenced above.

During the final checking of the concrete slabs supporting the Safety Inject'ion Tanks with'-;the certified loads, -it was discovered that the shear stresses in the concrete slabs supporting the Safety In"ection Tanks 1B, 2A and 2B exceed Design Criteria allowable stress values due to the high seismic forces.

Reevaluation of the seismic loads by Combustion Engineering and Bechtel using the actual spring stiffnesses of the current structural steel framing revealed all stresses are now below allowable limits. It has been demon-strated that over-stressing will not occur under. seismic conditions.

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U. S. Nuclear Regulatory Commission Attention: Mr. G. S. Spencer, Chief ANPP-17667-BSK/JAR March, 30,, 1981 Page 2 Therefore, it is concluded that this would not have constituted a significant safety condition.

Very truly yours E. E. Van Brunt, Jr.

APS Vice President Nuclear Projects ANPP Project Director EEVBJr/BSK:sRc Attachment cc: '-.Victor. Stello, Jr., Director/

Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 A. C. Gehr Snell & Wilmer R. L. Robb D. B. Pasnacht W. E. Ide A. C. Rogers J. M. Allen J. A. Brand W; H. Wilson W; G. Bingham W. J. Stubblefield R. L. Patterson R. W. Welcher D. R. Hawkinson

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FINAL REPORT REPORTABLE DEFICIENCY 50.55(e)

ARIZONA PUBLIC SERVICE COMPANY (APS)

PVNGS UNITS /!1 AND //2 I., Descri tion of Deficienc During final checking and verification of the Containment Building calculations for the Elevation 100'-0" concrete slabs, it was discovered that the shear stresses in the concrete slabs supporting Safety Injection Tanks 1B, 2A and 2B c..ceed thc De 'gn Criteria allowable values due to high seismic forces.

The apparent over-stress in the concrete at the slab to wall junction existed in conjunction with the use of overly conservative design loads and generic response spectra, along with. preliminary boundary conditions (upper lateral support spring stiffness).

To resolve the condition, Combustion Engineering has reevaluated the seismic loads on the 'Safety Injection Tank Supports using the actual spring stiffnesses of the current structural steel framing at Elevation 140'-0" and project response spectra curves. As expected, these loads are considerably lower than those used previously. Bechtel has reevaluated the concrete slabs at Elevation 100'-0" using the revised loads. All stresses are now below allowable limits. No revision to the original design drawing is required.

I'I, 'Anal sis of Safet Im lication If this condition had remained undetected, it would not constitute a safety significant condition since it has been demonstrated that over-stressing will not occur under seismic conditions.

III, Corrective Action The Bechtel calculation (13-.CC-.ZC-205) is being updated to be consistent with the actual data as submitted by Combustion Engineering.

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