ML20137G435

Relief Request BV1-B9.31-2,Rev 0 to Reactor Coolant Sys Branch Connection Welds

ML20137G435
Person / Time
Site:	Beaver Valley
Issue date:	03/12/1997
From:	DUQUESNE LIGHT CO.
To:
Shared Package
ML20137G377	List: ML20137G371 ML20137G408 ML20137G422 ML20137G435 ML20137G444 ML20137G455 ML20137G459 ML20137G465 ML20137G479
References
PROC-970312-02, PROC-970312-2, NUDOCS 9704010395
Download: ML20137G435 (6)

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ITYPP-2 INSERVICE INSPECTION PLAN FOR THE SECOND TEN-YEARINTERVAL AT BEAVER VALLEY POWER STATION UNIT #1 RELIEF REQUEST BVI-B9.31-2, REV. O

SUBJECT:

Reactor Coolant System Branch Connection Welds .

1 Prepared by: ~

'DN Date: ' 30l47 Supenisor, Inspection and Standards Reviewed by: @-- b. .

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1. 1 8Atl Date: 3ltllQ7 Direuvi, Nuclear Analysis and I@on Reviewed by: 3N- 05C - 6 'i7 Date: a/i>h7 OSC Meeting No. l Reviewed by: MS'"9 O. N' I Date: 3/X /f 7 ORC Meeting'No. I Approval by: . 6% n ~

es Date: _7 -/ 2 -$9 DIV. VP, Nu'elear 6perations'/ flant Manager i

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a DUQUESNE LIGHT COMPANY Beaver Valley Power Station Unit No.1 RELIEF REOUEST NO. BV1-B9.31-2. Rev. O COMPONENT Reactor Coolant System (RCS) Branch Connection Welds:

DLW-LOOPI-7-S-04 (6") DLW-LOOP 3-1-S-02 (14")

DLW-LOOPI-7-S-05 (4") DLW-LOOP 3-1-S-04 (6")

DLW-LOOP 2-1-S-03 (6") DLW-LOOP 3-7-S-06 (4")

DLW-LOOP 2-7-S-05 (12")

ASME SECTION XI REOUIREMENT (83S83)

Item No. B9.31 (IWB-2500-1, Category B-J) requires volumetric and surface examinations of the branch pipe connection welds.

BASIS OF RELIEF In accordance with 10CFR50.55a(g)(6)(i), reliefis requested on the basis that compliance with the Code requirement is impractical. Ultrasonic examinations were performed on the RCS branch connection welds listed above. Limitations were identified due to the configuration of the weld joints.

These limitations prevented UT examination of the code defined required examination volume for flaws oriented in the axial direction (with respect to the branch pipe). The limitations also prevented examination of the required volume from both sides of the weld. However, the UT techniques employed were able to examine the required volume (90% or greater) from the branch connection side of the weld in one direction.

The examination techniques employed were developed by the DLC NDE group and required fabrication of three unique calibration standards as well as specialized focused refracted longitudinal transducers to examine the welds. A 55 refracted longitudinal transducer was used for the 4" branch connections. A 60 refracted longitudinal transducer was used for the larger branch connections. These transducers are designed to focus on the inner one third of each of the welds. The attached sketches identify the general weld configuration and the extent of the UT examination coverage.

An informal survey of Westinghouse plants found that there have been no problems with the integrity of this type ofweld configuration.

ALTERNATIVE EXAMINATION The alternative to the examination requirement is to perform the complete surface examination and the ultrasonic examination, using enhanced techniques employing the specialized transducers to the maximum extent possible. These enhanced techniques represent the most current technology available for this examination and result in the maximum coverage allowed by the joint design and materials used in fabrication.

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