IR 05000309/1985022
| ML20198B883 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 11/30/1985 |
| From: | Gray E, Wiggins J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20198B873 | List: |
| References | |
| 50-309-85-22, NUDOCS 8511070340 | |
| Download: ML20198B883 (5) | |
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t U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
50-309/85-22 Docket No.
50-309 License No.
DPR-36 Licensee: Maine Yankee Atomic Power Company 83 Edison Drive Augusta, Maine 04336 Facility Name: Maine Yankee Nuclear Power Station Inspection At: Wiscasset, Maine Inspection Conducted: September 16-19, 1985 Inspector:
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E. H. Gray, Lead Reactor Engineer date Approved by:
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J.p.Wiggins,fbfef date Mat 4 rials and Fr& esses Section Inspection Summary:
Inspection on September 16-19, 1985 Areas Inspected:
Routine unannounced inspection of welding activities, con-denser replacement, diesel generator brush support details, stellite surfacing of main steam valve seat (MS-M-10), eddy current examination of steam generator tubing and review of procedural controls on QA evaluation of contractors. The inspection involved 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> on site and four hours of followup in the Region office.
Results: No violations were identified.
8511070340 851104 PDR ADOCK 05000309 G
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Persons Contacted Maine Yankee Atomic Power Company (MY APC)
- R. Crosby, QA Section Head
- J. Garrity, Plant Manager-C. Eames, Engineer, Eddy Current Coordinator H. Gilpatrick, Engineer, Condenser Replacement
- F.- Gleason, Plant Engineering Supervisor A. Jordan, QC Supervisor
- L. Lawson, QA Engineer S. McAllister, Engineer, Valve Surfacing P. Plante, Metallurgical Engineer
- C. Shaw, Engineer, PED
- Indicates presence at exit meeting on September 19, 1985.
2.
Followup on Previous Inspection Findings (Closed) Unresolved Item (309/83-03-02). This unresolved item questioned the procedural control on the QA activity of reviewing contractor submittals such as procedures and performance qualifications prior to and during outages.
The QA Administrative Procedures 0-02-1, 0-06-2 and 0-07-2 as revised since 1983 were reviewed.
Portions of these procedures
- material equipment and service requisitioning; procedure review, approval, distribution and adherence; and control of special processes, describe QA activities that result in contractor submittal review.
In areas covered in this 85-22 inspection, QA was noted to have been involved in review of welding, NDE procedures, welding performance qualification and NDE personnel qualifications.
The inspector concluded that procedures now include sections that prescribe QA review of contractor submittals in the area of special processes.
This item is closed.
3.
Valve Seat Surfacing Previously, the seat area of the main steam valve, MS-M-10, located in.the Steam Valve House, was partially resurfaced on the valve body with Stellite #21. This area was scheduled for removal of the. Stellite #21 and replacement with Stellite #6, the original seat surfacing material. The repair was conducted under work order DR/R0-4340-85 in accordance with the applicable sections of the ANSI B31.1 Code and ASME Section IX.
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The inspector observed the area requiring repair and reviewed the welding procedure, WPS-27 Rev. 1; the documentation of steps to make the repair-including preheat, post-weld heat treatment (PWHT), control of welding materials; and welder qualification _
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Subsequent to this inspection, during PWHT the valve surfacing was water quenched by failure of a hydro test boundary. This quenching caused ex-tensive hardsurfacing cracks. The surfacing was removed and replaced with carbon steel weld deposit.
The licensee's evaluation of the temporary use of carbon steel as the valve seating material for this normally open valve was done under D.R.00 Number 85-4635. This evaluation established that deformation of the seat during rapid valve accuation would not interfere with valve performance.
Hardsurfacing of the seat is delayed until the next refueling outage.
The inspector reviewed FSAR section G.1 and 10.2 regarding the design functions of this valve. According to the FSAR, the main steam non-return valve is used to isolate the steam generator, to minimize the reactor coolant system cooldown rate after a steam line break.
The valve is nor-mally open during plant operations. Based on this review the inspector concluded that, although the carbon steel surfacing would be more suscep-tible to wear-related erosion than the Stellite surface, leakage caused by steam erosion of the valve seat would not appear to detrimentally impact the ability of the valve to fulfill its design objective.
No violations were identified.
4.
Outage Welding Activities The inspector observed completed welds and welding in progress on safety related piping and nonsafety related piping and supports. Observations were made and documentation including weld procedures, welder identifica-tion, welder qualifications, and quality control inspections was reviewed for the following:
Auxiliary Steam Line Modification-(Valve House and Turbine Hall)
DR/R0 84-37-2-1 Job #85-28-1-1 (Vent Lines)
Condenser Supports Condenser Piping The condenser welding was to the Heat Exchange Institute Standard, Eighth Edition, while pipe welding was to the ANSI Code with welder qualification to the ASME Code Section IX.
The inspector noted the conditions of fitup of components for welding and the appearance and sizes of completed welds.
Records of welder qualifica-tions were found to be available and current for the weld processes in use. Quality control inspections of welding were observed to be in progress and properly documented.
No violations were identified.
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5.
Steam Generator Eddy Current Tube Examinations The Maine Yankee Steam Generator (SG) Eddy Current (EC) tube examination requirements are shown in part 4.10 of the Plant Technical Specifications (Tech Specs) Amendment 84. The inspector observed EC examination in prog-ress including EC tube probing, data recording, data evaluation and co-ordination of the EC examination process.
The EC findings in SG#2 resulted in an increase in EC sample size as re-quired by Tech Specs from 514 tubes to 3598 tubes, in accordance with the requirements for Category C2 indications. A total of 4960 tubes (out of 5703) from SG#2 were actually examined which was significantly above the Technical Specification requirement. The purpose for the increased sample size above the Tech Spec requirements was to evaluate the size and dis-tribution of indications; particularly, pitting near the tube sheet and a previously unreported type of indication in the return bend horizontal run of tubes between rows 60 and 90. A total of six tubes from SG#2 were found to have this new type of indication. The indications were deter-mined to be greater than 40% throughwall. These six tubes were plugged.
Approximately 1800 tubes from SG#1 and 2000 tubes from SG#3 were also ex-amined primarily between rows 60 to 90 to determine the extent of indi-cations in the horizontal return bend area and to provide a baseline for comparison during future EC examinations. Two additional defective tubes
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were identified and plugged.
The inspector determined that the SG#1 and SG#3 tube examinations represented an examination scope above the Tech Spec requirement and provided added assurance of tube integrity.
The inspector reviewed the Tech Spec requirement for EC examination of S.G. tubes, NRC Regulatory Guide 1.83 Rev 1 of July 1975, Combustion En-gineering (CE) procedure MY ISI-077 Rev 01, and Westinghouse procedure MRS 2.4.2 Gen-28 Rev 0 as applicable to the eddy current testing.
The data evaluation procedure consisting of full data analysis by two sep-arate teams followed by comparison of results and review of differences was noted to be in progress.
No violations were identified.
6.
Diesel Generator Rotor Brush Support The brush support detail on the A-diesel generator was examined as followup to the failure (August 1985) of the support mounting hexagonal nut at Mill-stone Unit #3. The Maine Yankee diesel generators are Model A-20-C2, Serial Numbers 70F1-1043 and 70G1-1064 manufactured by the Electromotive Division of GM and are rated at 3575KVA. The support arm mounting dis-tance to the first and second brushes are 2" and 3 " respectively. The inspector concluded that the support arm mounting component design is different from the failed type at Millstone and does not appear to be subject to Millstone type fatigue failur,
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'No violations were identified.
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7.
Exit Meeting
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The. inspector met with licensee representatives, listed in paragraph 1,.
at the conclusion of-the inspection to summarize the scope and findings of the. inspection. At no time during this inspection was written material provided to the licensee by the inspector.
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