IR 05000313/1982008
| ML20054G099 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 05/25/1982 |
| From: | Randy Hall, Hunnicutt D, Roberds M, Tomlinson D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20054G098 | List: |
| References | |
| 50-313-82-08, 50-313-82-8, NUDOCS 8206210095 | |
| Download: ML20054G099 (4) | |
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A_PPENDIX U. S. NUCLEAR REGULATORY COMMISSION
REGION IV
Report:
50-313/82-08 Docket: '50-313 License: DPR-51 Licensee: Arkansas Power and Light Company P. O. Box 551 Little Rock, Arkansas 72203 Facility Name: Arkansas Nuclear One (AN0), Unit 1 Inspection at: AN0 Site, Russellville, Arkansas Inspection conducted: April 12-16, 1982 Inspectors:
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0.' P.' Tomlimion] Reactor Inspector, Engineering Section Date (paragraphs 1, 2, and 3)
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3 0 s-es M. "J. (Toberds, Engineering Technician, Engineering Section Date (paragraph 2)
Reviewed:
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~Tlall, Chief, React'or Project Section C Date Approved:
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l D. M. Hunnicutt, Chief, Engineering Section Fate /
Inspection Summary I_nspection Conducted April 12-16, 1982 (Report 50-313/82-08)
A_reas Inspected:
Special, unannounced inspection of the repair and nondestructive examination of four high pressure injection nozzles. This inspection involved 64 inspector-hours by two NRC inspectors.
Results: Within the areas inspected, no violations or deviations were identified.
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-2-DETAILS 1.
Persons Contacted Principal Licensee Personnel
- J. P. O'Hanlon, Site General Manager
- L. W. Humphrey, Administrative Manager
- R. J. Huggins, SPP Coordinator Babcock < Wilcox (B&W) Personnel T. Scott, Resident Engineer D. Neal, Radiographer L. Adams, Service Engineer W. Johnson, Senior Welding Engineer R. Nelson, Senior QA Engineer J. Barton, Welder NRC Personnel
- W. D. Johnson, Senior Resident Reactor Inspector
- L. J. Callan, Resident Reactor Inspector The NRC inspectors also interviewed other licensee and contractor personnel including members of the engineering and QA/QC staffs.
- Denotes those attending the exit interview.
2.
Repair of HPI Nozzles NRC Report 50-313/82-06 stated the conditions which were noted during the nondestructive examination of four high pressure injection nozzles on the Unit I reactor coolant system piping.
During this inspection, the NRC s
inspectors conducted a second examination of the nozzle radiographs and confirmed the original findings.
Following this review, several B&W per-sonnel were contacted, and discussions were conducted to determine what actions were planned to correct each of the discrepant conditions.
i The NRC inspectors reviewed 19 B&W general procedures deemed to be within I
the scope of these repairs.
These procedures included welders' qualifica-tions, welding, nondestructive examination, material identification, tool control, storage and handling of weld filler metal, and inspection of the completed welds.
In addition, the specific procedures for the repair of each nozzle were reviewed to assure that each was complete, allowed for required inspections, and complied with the general procedures mentioned above. - The NRC inspectors compared drawings of the existing nozzle and safe-end configuration with drawings of the replacement configuration.
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These were then compared to the specific procedures for each nozzle to
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-3-assure that all necessary operations were included and were in the proper sequence. Prior to receipt inspection and acceptance, the replacement hardware for one nozzle was visually inspected in the warehouse area by the NRC. This included a visual comparison of one new thermal sleeve and safe-end with B&W Drawings 1130007 and 1132146 for these parts. The overall configuration, finish, and fit of these parts appeared to be with-in the drawing requirements and tolerances.
The NRC inspectors toured the area being used by welders as a p b:tice area for the welding of mockup parts under conditions simulating tt se to be encountered inside the reactor building.
Each welder to be used for these repairs was required to practice on the mockup and was instructed in the use of the special alignment tooling to be used to monitor and control welding distortion. The qualification records of all nine welders to be used for these repairs were reviewed along with the radiographs of each welded pipe test assembly.
The calibration records for all onsite B&W tools, gages, and meters were reviewed for current dates and traceability to the National Bureau of Standards. The NRC inspectors also reviewed the material certifications for the three lots of weld filler metal to be used.
The chemical composi-tion and test results for each were within the limits established by the individual material specification. The material certification records for the liquid penetrant inspection materials were also checked and found to be within the acceptable limits for sulfur and halogen content.
Pipe to safe-end welded Joint No. 49 on Loop B HPI line was the first to be worked as it seemed to exhibit the most easily corrected condition.
Radiographs of Nozzle "B".contain a dark line in the upstream half of the area where the thermal ~ sleeve was to be hard rolled into the safe-end.
The line indicated that the two-stage hard rolling operation was only half completed when the thermal sleeve was originally installed. The planned fix for this nozzle involved the removal. of Weld No. 49, restoring s
the weld prep areas on both the pipe and safe-end, performing the hard roll operation in the thermal sleeve, and the rewelding of Joint No. 49.
After the weld was saw cut, and during the restoration of the weld prep, an explosion occurred due to an accumulation of free hydrogen apparently in the high pressure injection line. Work was immediately ceased and measures taken to stop the flow of hydrogen and to purge the line with inert argon. Atmospheric samples gathered during the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> continued to show hydrogen in' excess of the 4% explosive concentration.
When no hydrogen was detected in the line, the following operation and the weld preps were completed, and the fit up for rewelding was made.
Some difficulty was encountered when tack welds were made to hold the safe-end to pipe alignment.
Further difficulty was noted during the deposition of the first quarter of the root pass in the open butt joint.
A " sugaring" (oxidizing) condition was noticed on the weld surface by the welder as he worked. He immediately stopped and notified his superviso '
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-4-Because " sugaring" is a weld phenomenon normally associated with a lack of back purge at the weld joint, a check was made of the valve alignment upstream to the purge point of entry.
It was found that a valve that had been reported as open was actually closed, and no argon was present in the line to form a back purge. This was corrected, and the " sugared" weld was removed. When the line purge was established, a second attempt at welding was made. No unusual conditions were noted by the welder, and the welding operation was continued to completion.
The NRC inspectors reviewed the radiographs of the completed weld on the Nozzle "B" safe-end. The joint was radiographed in such a manner that each exposure was used to evaluate only 1 inch of the weld. The NRC
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inspectors noted no rejectable indications in the completed weld.
The work packages and final inspection records for each of the nozzles
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will be reviewed by the NRC during a subsequent inspection.
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No violations or deviations were identified during this inspection.
3.
Exit Interview The NRC inspectors met with the licensee representatives (denoted in para-graph 1) on April 16, 1982, to discuss the scope and findings of the inspection.
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