ML20067D457

Interim Deficiency Rept DER-82-61 Re Reactor Coolant Pumps diffusor-ring Cap Screws Which May Fail & Damage Pump.Cap Screw Matl Heat Treatment Will Be Changed So That Matl Will Not Be Susceptible to Cracking

ML20067D457
Person / Time
Site:	Palo Verde
Issue date:	11/22/1982
From:	Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Sternberg D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
10CFR-050.55E, 10CFR-50.55E, ANPP-22368-GHD, DER-82-61, NUDOCS 8212130267
Download: ML20067D457 (3)

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!i Arizona Public Service Company 2

Po. BOX 21666. PHOENIX. ARIZONA 85036 Spy O[C,

November 22, 1982 ANPP-22368-GIID/BSK lllln op i

OfQg,2 U. S. Nuclear Regulatory Commission Region V

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2 Creekside Oaks Office Park 1450 !! aria Iane - Suite 210 Walnut Creek, California Attention:

Mr. D. M. Sternberg, Chief Reactor Projects Branch 1

Subject:

Interim Report - DER 82-61 A 50.55(e) Potential Reportable Deficiency Relating to Reactor Coolant Pump Diffusor-Ring Cap Screws !!ay Fail And Damage Puop.

File: 82-019-026 D.4.33.2

Reference:

Telephone Conversation'between J. Eckhardt and G. Duckworth on October 21, 1982 l

Dear Sir:

The NRC was notified of a potential reportable deficiency in the referenced telephone conversation. At that time, it was estimated that a determination of reportability would be made within thirty (30) days.

Due to the extensive investigation and evaluation required, an Interim Report is attached. It is now expected that this information will be-i finalized by February 24, 1983, at which time a complete report will be submitted.

Very truly yours, l

.E CLLC W U-E. E. Van Brunt, Jr.

APS Vice President Nuclear Projects Management ANPP Project Director EEVBJr/ Gild:db i

Enclosure cc: See Attached Page 2 8212130267 821122 PDR ADDCK 05000528 6

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U. S. Nuclear Regulatory Commission November 22, 1982 Attention:

Mr. D. M. Sternberg, Chief ANPP-22368-GIID/BSK Page 2 cc: Richard DeYoung, Director Office of Inspection and Enforcetent U. S. Nuclear Regulatory Commission Washington, D. C. 20555 T. G. Woods, Jr.

J. A. Roedel D. B. Fasnacht G. C. Andognini A. C. Rogers B. S. Kaplan W. E. Ide J. Vorees J. A. Brand A. C. Gehr W. J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher R. M. Grant D. R. llawkinson L. E. Vorderbrueggen G. A. Florelli J. R. Bynum Lynne Bernabel, Esq.

liarmon & Weiss 1725 "I" Street, NW Washington, D. C. 20006 R. L. Greenfield Assistant Attorney General Bataan Memorial Building Santa Fe, New Mexico 87503

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INTERIM REPORT - DER 82-61 POTENTIAL REPORTABLE DEFICIENCY l

l ARIZONA PUBLIC SERVICE COMPANY (APS) l PVNGS UNITS 1, 2 & 3 I.

POTENTIAL PROBLEM Diffusor retaining cap screws of the System 80 Reactor Coolant Pumps supplied by Comubustion Engineering (CE) as part of the NSSS have recently failed in the CE-KSB test loop. These cap screws support the diffusor-suction ring assembly of an idle pump. With the pump running, hydraulic forces unload the sixteen (16) cap screws in question. Two (2) cap screws secure each retaining ring segment, and locking devices retain the cap acrews. The screws that have failed to date have failed either under the head or at the first thread. The heat treatment condition of the material of these screws causes the material to be susceptible to hydrogen embrittlement / stress corrosion cracking.

If both cap screws per segment ring failed, a loose ring segment / cap screw element would exist. While this element is trapped above the impeller, it would be free to move around above the impeller, and r

some damage might occur. Should all or some of the diffusor retaining cap screws fail, CE would not anticipate any increase in risk to the health and safety of the public. Rather, CE considers this problem as a risk to the continued operational capability of the reactor coolant pump (s).

II.

APPROACll TO AND STATUS OF PROPOSED RESOLUTION CE is continuing its evaluation of the problem and some potential solutions. The results of this effort will be presented in the t

j final report.

The cap screw material heat treatment is to be changed to a condition such that the material is not susceptible to hydrogen embrittlement / stress corrosion cracking. Some other minor changes will be included in the change-out to alleviate the load these screws see.

III. PROJECTED COMPLETION OF CORRECTIVE ACTION AND SUBHITTAL OF THE FINAL REPORT Evaluation of this condition and submittal of the Final Report is forecast to be completed by February 24, 1983 4

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