ML20202A955
| ML20202A955 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/03/1997 |
| From: | Legrand R DUQUESNE LIGHT CO. |
| To: | |
| Shared Package | |
| ML20202A937 | List: |
| References | |
| NUDOCS 9712030026 | |
| Download: ML20202A955 (14) | |
Text
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ITYPP 2 INSERVICE INSPECTION PLAN FOR THE SECOND TEN YEARINTERVAL AT BEAVER VALLEY POWER STATION UNIT #1 RELTEF REQUEST BVI RV WELDS, REY.1
SUBJECT:
Reactor Vessel Circumfenstial Welds (RC R 1 C 1 and RC R 1 C 4)
EDE Date:
8-t5-97 Prepared by:
Supervisor, Nuclear Programs 9/78!97 Roiewed by.
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Date:
Director, Design BasiEngineering i 2- 'I7 Rniewed by:
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ANilf Reviewed by:
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Date: N ' S-9 7 4
Div. VP, Nuclear Operations / Plant Manager 9712030026 971124 PDR ADOCK 05000334 O
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DUQUESNE LIGHT COMPANY f
Besvar Valley Power Station Unit No,1
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RFI TFF REQUEST NO. BVI R%Wpt nS. Rev.1 COMPONENT Reactor Vessel Circumferential Welds (RC-R 1-C-1 and RC R 1-C-8)
DRAWING NO.
. 8700-ISI-E-1 A _
A*iME SECTION XI REOUIREMENT (83S831
- i item Noi,. Bl.l l and Bl.30 (IWB 2500-1, Category B.A) require volumetric examination of essentially 100% of the weld length each to year interval.
i BASIS OF RELIEF In accordance with 10CFR50.55a(g)(6)(i), reliefis requested on the basis that compliance with the Code requirement is impractical. The flange to upper circumferential shell weld (RC R-1-C-1) examination is limited due to component geometry. The lower head to shell wold (RC-R-1 C-8) examination is limited due to interference by the four radial support keyways.
The flange to upper circumferential shell weld (RC bl-C-1) was examined using an automated technique i
during the IRll refueling outage. Additionally, a manual UT examination was performed on weld RC R-1-C-1 from the flange face su6ce in September 1989 (1st period of the current interval) in accordance with Note 5 of Examination Category B-A. The first pe'iod examination from the flange face surface covered 62% of the weld circumference and used 5 different beam angles (16' out,12' out, 6' out, O', and i
6' in, as permitted by ASME V, Article 4, T441.4.2) to cover the required volume. There were no
. limitations for this examination.
The automated examination of the Range to shell weld (RC R 1-C-1) was limited to 54% of the required 4
- volume due to the inside and outs!de diameter taper of the flange (see sketch on next page for general configuration). Scan angles of 0*,45',60', and 70' were used. The movement of the transducer was limited on the inside surface above the mark noted due to the curvature of the flange taper (detailed proprietary vendor supplied drawings are available on site). Considering both examinations (i.e., from tlw
- fhnge face and from the inside surface of the vessel wall) approximately 82.5% of tb total required volume was examined during the current interval.
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Page 2 cf 2 Relief Request No. DV1.RV-WELDS. Rev.1 The automated examination of the lower head to shell weld (C-8) was limited to 85% of the required volume. The four radial support keyways, equally spaced around the circumference, are located adjacent to the weld and preclude the examination of C-8 at these areas.
Since the examination limitations are due to the geometry of the component or interference by adjacent components, redesign of the reactor vessel would be necessary to completely accomplish the required examinations. It is impractical to redesign the reactor vessel for this purpose. A majority of the required volume was covered in both cases.
AI,TERNATIVE EXAMINATION The altemative to the examination requirement is to perform the exnninations to the maximum extent possible. These examinations are supplemented by the visual examination performed on the interior of the vessel. The four support lugs and the flange to shell weld are included in this examination. Therefore, the UT examinations coupled with the visual examination of the support lugs and the surrounding areas and the visual examination of the interior surface of t'/ Sange to shell weld provide an adequate measure of assurance of the integrity of these welds.
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