ML20211N535
| ML20211N535 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 12/12/1986 |
| From: | Williams J TOLEDO EDISON CO. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 1324, NUDOCS 8612180249 | |
| Download: ML20211N535 (2) | |
Text
q TOLEDO Docket No. 50-346 License No. NPF-3 JOE VVILUAMS. JR c-vane w P19) N9 2300 Serial No. 1324 sisi ns sen December 12, 1986 Director of Nuclear Reactor Regulation Attention:
Mr. John F. Stolz PWR Project Directorate No. 6 Division of PWR Licensing-B United States Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Stolz:
This letter is to inform the Commission of Toledo Edison's Inservice Inspection (ISI) program plan with regard to the Reactor Coolant Pump (RCP) casing welds.
The Nuclear Regulatory Commission (NRC), by letter dated May 5, 1982 (Log No. 979), granted Toledo Edison Company (TED) relief from specific require-ments of the ASME Boiler and Pressure Vessel Code Section XI, 1977 Edition through the Summer 1978 Addenda, Table IWB-2500-1, B-L-1 Item B12.10 per-taining to elimination of volumetric examination of the RCP casing welds.
The NRC staff granted relief by stating in their findings that performing a surface examination was adequate to establish the existing structural integrity of RCP casing welds considering the inherent fracture toughness of the material of construction. However, the subject relief required volumetric examination using the EPRI Linear Accelerator (LINAC) if a RCP was disassembled during the ten-year ISI interval. The requested volumetric radiographic examinations (using the LINAC) was considered an experimental technique at the time as stated in the NRC letter to TED.
During 1986, the Davis-Besse RCPs were disassembled to replace the rotating assemblies. Inspections were performed on one RCP using surface examina-tion on the outside surface of the casing welds. On each of the four RCPs, this inspection was supplemented with visual inspection of the inside surfaces of the splitter vanes using a remote television camera.
No rejectable indications were identified in either inspection. A volu-metric examination was not performed during this maintenance work.
It is TED's current understanding that a volumetric examination of one RCP casing veld, as required by ASME Section XI, is required prior to the end of the current ten-year ISI interval. TED is initiating a develop-ment program with the objective of qualifying an acoustic emission technique, such as was used on the ANO-1 RCP flywheel, for inspection of an RCP pump casing without pump disassembly in lieu of performing a
- 1 volumetric examination.
THE TOLEDO EDgiON COMPANY EDtSON PLAZA 300 MADISON AVENUE TOLEDO. OHO 43652
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8612180249 861212 PDR ADOCK 05000346 P
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Dockat N3. 50-346 License No NPF-3 Serial No. 1324 December 12, 1986 Page 2 TED is acquiring a RCP pump casing similar in design and construction to the TED RCP casings. Once qualified, this NDE technique will be filed with the NRC in accordance with 10CFR50.55a. Upon NRC approval, TED plans to utilize the technique for Davis-Besse RCP casing inspections.
TED is planning to meet-with the NRC staff to discuss this acoustic emission inspection technique qualification as soon as the scope and schedule are defined.
As documented in TED letter dated April 29, 1983 (Serial 1-339) and Commission letter dated May 18,1983 (Log 1-791), as recently confirmed by TED letter dated November 26, 1986 (Serial 1-675), the current ISI interval ends at the Spring 1989 Refueling Outage. TED will address RCP volumetric examination with the Commission or comply with the ASME Code requirement by the end of the current 10-year ISI interval.
Very truly yours, l
- DJS:p1f cc: DB-1 NRC Resident Inspector
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