ML20083B681

Final Deficiency Rept Re Main Steam & Feedwater Penetration Anchors.Initially Reported on 830426.No Addl Deficiencies Found.Ebasco Procedures Revised

ML20083B681
Person / Time
Site:	Satsop
Issue date:	12/06/1983
From:	Kohler A WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Bishop T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
10CFR-050.55E, 10CFR-50.55E, G3-83-924, GO3-83-924, NUDOCS 8312210247
Download: ML20083B681 (3)

Text

r RECBYED tmc Washington Public Power Supply System Box 1223 Elma, Washington 98541 (206)482@@@C -8 [H 0; ig December 6, 1983 G03-83-924 ggg g g U. S. Nuclear Regulatory Commission, Region V

-Office of Inspection and Enforcement 1450 Maria Lane, Suite 260 Walnut Creek, California 94596-5368 Attention: Mr. T. W. Bishop, Director Division of Resident Reactor Projects and Engineering Programs

Subject:

POTENTIAL 10CFR50.55(e) DEFICIENCY MAIN STEAM AND FEEDWATER PENETRATION ANCHORS (D/N N0. NY-QA-5)

On April 26, 1983 the Supply System notified your office of a potential 10CFR50.55(e) deficiency concerning the subject condition. Based on a subsequent engineering analysis, it has been determined that the defici-ency is significant and reportable per 10CFR50.55(e).

Attached is the Supply System approved final report for the subject deficiency. The report provides a description of the deficiency, analysis of the safety implications and corrective actions planned /taken.

Should you have any questions or require further information, please contact me directly.

A. D. Kohle.c (760)

Program Director, WNP-3 DRC:nj Attachment cc: J. Adams - NESCO D. Smithpeter - BPA Ebasco - Elma R. D. Hill - Puget Sound Power & Light' Company P. Inman - Washington Water Power Company B. D. Withers - Portland General Electric Company E. M. Burton - Pacific Power & Light Company 9312210247 831206 PDR ADOCK 05000508 S PDR j

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. Attachment to: Letter, G03-83-924, dated December 6, 1983 Paga 1 of 2 WASHINGTON NUCLEAR PROJECT NO. 3 (DOCKET NO. 50-508) 10CFR50.55(e) DEFICIENCY FINAL REPORT MAIN STEAM AND FEEDWATER PENETRATION ANCHORS (D/N NO. NY-QA-5)

Description of Deficiency The stress analyses of the Main Steam and Feedwater lines include an anchor point at the outboard end of the containment penetrations. It is assumed, per Ebasco practice, that the anchoring structure provides a gap (between the flued head trunnion and structural element) of 1/16 inch (maximum). However, during investigation of an as-built discrepancy, it was found that 1/4 inch gaps were provided as specified on two Ebasco drawings. Further investigation disclosed that_the Ebasco Civil Group had provided the 1/4 inch gap in order to facilitate installation, but had not obtained approval for this gap magnitude from the Stress Analysis Group.

Analyses were conducted for both seismic and pipe-rupture loading cases to determine if stress criteria was violated with the 1/4 inch gaps incorpor-ated. An engineering " hold" via an approved Design Change Notice (DCN) was placed on the subject structures pending completion of these analyses.

As a result of pipe-rupture analyses of the Main Steam and Feedwater lines, it was found that the BEX region stress criteria (1.8 S ) given in NRCBranchTechnicalPositionMEB3-1isexceededintheMain$teamlineat the branch connection to the atmospheric dump valve line, for a guillotine break inside containment.

. Analyses of the Feedwater lines under seismic pipe rupture and water l hammer loading show compliance within the specified criteria.

In view of the fact that the Main Steam line does not comply with pipe-rupture criteria, the subject deviation is classified as significant.

Safety Analysis i Exceeding the allowable stresses for the Main Steam (MS) lines in the BEX region, is not acceptable. FSAR Subsection 3.6.2.1.4 (a.2) requires stresses in the subject piping to be maintained within the limits speci-fied in NRC Branch Technical Position MEB 3-1. Postulating a Safe Shutdown Earthquake (SSE) concurrently with a Main Steam line break will overstress the piping in the BEX region due to the existing 1/4-inch gap at the anchor point.

1 10CFR50.55(e) DEFICIENCY FINAL REPORT MAIN STEAM AND FEEDWATER PENETRATION ANCHORS

(D/N N0. NY-QA-5)

Page 2 of 2 Safety Analysis (Continued)

Under this accident scenario, the MS pipe is overstressed at a point between the containment penetration and the Main Steam Isolation Valve (MSIV). This overstressed condition may result in:

1. MSIV inoperability.

2. An additional pipe break between the containment penetration and the MSIV.

In order to ensure containment integrity, isolation and shutdown of the reactor, it is required that the Main Steam line stresses in the BEX region be kept within allowables. Therefore, the deficiency, were it to have remained uncorrected, could adversely affect the safety of operations of the plant. Accordingly, the deficiency is reportable per 10CFR50.55(e).

Corrective Action The following actions have been/will be taken to resolve the problem:

1. A Design Change Notification (DCN) was issued to correct the design deficiency. Upon resumption of work after the extended construction delay, shim plates will be installed between the flued head trunnion and structural element. This will then provide a tight fit after thermal expansion associated with operating conditions.

2. A complete engineering review of all pipe rupture restraint designs found no additional deficiencies. Based on this review, it is conclud-ed that the subject problem is an isolated incident.

3. To preclude recurrence of the interface control problem, applicable Ebasco procedures have been revised to strengthen design interface con-trol. These revised procedures have been in effect since February 1983.