IR 05000334/1978029
| ML19338E726 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 06/02/1980 |
| From: | Robert Carlson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Dunn C DUQUESNE LIGHT CO. |
| References | |
| NUDOCS 8010060056 | |
| Download: ML19338E726 (2) | |
Text
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JiHi 0 2 0B0 Docket No. 50-334 Duquesne Light Company ATTN:
Mr. C. N. Dunn Vice President Operations Division 435 Sixth Avenue Pittsburgh, Pennsylvania 15219 Gentlemen:
,
Subject:
Inspection 50-334/78-29 This refers to unresolved item 334/78-29-02.
Steam generator weld 1-1, 2-1, 3-1 and pressurizer weld 7 were ultrasonically examined during a 1978 outage to satisfy the inservice in::pection requirements of the ASME Code,Section XI, 1974 Edition including the Summer 1975 Addenda, 10 CFR 50.55a(g) and the facility technical specifications at the Beaver Valley Power Station, Unit 1.
An unresolved item concerning the above examinations was identified in IE Inspec-tion No. 78-29 by the NRC inspector (see unresolved item 334/78-29-02) as follows:
The base material adjacent to the above welds is SA 508 Class 2 (forged material) on one side and SA 216 Grade WCC (cast material) on the other side.
The calibration blocks used to calibrate the instruments were SA 508 Class 2.
The applicable Code,Section XI, paragraph I-3121 requires that:
"When
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it is not possible to fabricate the block from material taken from the component, the block may be fabricated from a material of a specification included in the applicable examination volumes of the component.
It is
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required that acoustic velocity and attenuation of such a block be demon-strated to fall within the range of straight beam longitudinal wave velo-city and attenuation found in the unclad component."
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l The blocks used for the weld examinations were not fabricated from material taken from the component, were of a different material specifi-cation than one side of the weld (i.e., SA 508 forging vs SA 216 casting),
and acoustic velocity and attenuation has not been demonstrated.
It is known that a material's acoustic properties are influenced by its product form composition and heat treatment.
Consequently, the reference Distance AmplitudeCurve(DAC)andthecorrespondingdefectsizebasedonresponsesignal 801000005(o
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Duquesne Light Company
amplitudes can vary significantly when the calibration block is not representa-tive of the weldment being examinea.
This can result in nonconservatism in defect detection and size measurement.
For this reason, and because no material was available from the components, Amendment 22 to the Beaver Valley Unit 1 license was written with the provision that a calibration block be fabricated of the same specification, product form andheattreatmentasthematerialsbeingjoined.
This would satisfy the intent of the Code that the calibration block and the material being examined should be accustically similar.
As of April 17, 1980, a calibration block, as described above, has not been fabri-cated; therefore, a demonstration that the block used is acoustically similar to the material that was examined is desirable.
It is our conclusion that, unless better evidence is provided of the effective-ness of the ultrasonic examination done as a part of the inservice inspection program, that program cannot be considered to be adequate for the steam genera-tor and pressurizer welds identified herein.
Please review this concern and inform us of your position and intentions.
Should.you decide to accomplish a demonstration of acoustic similarity of the calibration blocks and the materials joined, please contact our office (L. Tripp, 215-337-5282) in advance so that we may witness the performance of that demonstration.
If this is not accomplished, the Duquesne Light pcsition should address the safety of continued operation prior to plant restart from the current outage.
Your cooperation with us is appreciated.
Sincere'iy, p56 N=
Robert T. Carlson, Chief Reactor Construction & Engineering i
Support Branch cc:
F. Bissert, Technical Assistant Nuclear R. Washabau J. Werling,gh, QA ManagerStation Superintendent G. Moore, General Superir.tendent, Power Stations Department J. J. Carey, Director of Nuclear Operations R. Martin, Nuclear Engineer J. Sieber, Superintendent of Licensing anc' v. pliance, BVPS
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