ML19296B630

Final Deficiency Rept (Significant Deficiency 79-04) Re Radiographic Examination of Flued Head penetration-to-sleeve Welds.Weld Defects (Slag,Lack of Fusion & Porosity) Exceeded Acceptance Stds.Welds Will Be Removed & Repaired

ML19296B630
Person / Time
Site:	Beaver Valley
Issue date:	01/03/1980
From:	STONE & WEBSTER, INC.
To:
Shared Package
ML19296B613	List: ML19296B617 ML19296B630
References
NUDOCS 8002210153
Download: ML19296B630 (3)

Text

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FINAL REPORT ON REACTOR CONTAINMENT LINER FLUED HEAD TO SLEEVE WELDS

_A_T BEAVER VALLEY POWER STATION - UNIT NO. 2 Copyright 1979 STONE & WEBSTER ENGINEERING CORPORATION BOSTON, MASSACHUSETTS 8002210 15 3

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BEAVER VALLEY POWER STATION - UNIT NO. 2 FINAL REPORT ON REACTOR CONTAINMENT FLUED HEAD TO SLEEVE WELDS SIGNIFICANT DEFICIENCY 79-04 1.0

SUMMARY

A radiographic examination (RT) of the flued head forging to sleeve welds for process piping penetrations required -

by ASME III, 1971 edition through and including 1972 winter addenda, was not performed by the liner contractor. A Nbnconformance and Disposition Report was written to document the deficiency. The resultant RT revealed wold defects (namely slag, lack of fusion and porosity, primarily at the root of the backing ring weld joint) that exceeded ASME III Appendix X acceptance standards.

2.0 IMMEDIATE ACTION TAKEN Since the weld defects could have adversely affected the safety of operation of the nuclear power plant and repre-sented a significant deficiency in construction which will require extensive repair, this problem was considered a reportable deficiency per 10CFRt0.55 (e) .

The U.S. Nuclear Regulatory Commission (NRC) was notified orally of the situation on December 7, 1979.

3.0 ' DESCRIPTION OF THE DEFICIENCY The requirement for volumetric examination by RT of the flued

' head to sleeve weld was overlooked by the liner contractor-and, in subsequent revi~ews, by other parties. Further review of nondestructive examination (NDE) records for this weld joint revealed that proper NDE, as invoked by the requirements

,of the procurement specification, was not performed. This oversight was documented by a Nonconformance and Disposition Report.

RT examination of the welds revealed subsurface weld defects that exceeded the acceptance standards of ASME III Appendix X.

Therefore, repairs were necessary to return the welds to the specified configuration.

The removal, repair, and re-examination of weld' defects can be accomplished using standard procedures and techniques.

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4.0 ANALYSIS OF SAFETY IMPLICATIONS Had the weld defects remained undetected and unrepaired, the potential would exist for the weld to fail to perform.

its intended function over th.e design life of the power station. This failure would violate design code (ASME_III)

• and SAR licensing commitments and could provide the potential for adversely affecting the safety of operation of the nuclear power plant through an increase in containment leakage rate.

5.0 CORRECTIVE ACTION TO REMEDY THE DEFICIENCY All weld defects found to exceed the acceptance standards '

of ASME III Appendix X will be removed and repaired in accordance with the techniques of ASME III Class MC for repairs.

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