IR 05000336/1979026
| ML19257D003 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/07/1979 |
| From: | Lester Tripp, Walton G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19257C999 | List: |
| References | |
| 50-336-79-26, NUDOCS 8001310197 | |
| Download: ML19257D003 (4) | |
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U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT Region I Report No. 50-336/79-26 Docket No. 50-336 License No. DPR-65 Priority
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Category C
Li::ensee: Northeast Nuclear Energy Comoany P. O. Box 270 Hartford, Connecticut 06101 Facility Name:
Millstone Point 2 Inspection at:
Waterford, Connecticut Inspection conducted: November 3-6, 1979 Inspectors: $ 0, @t 2/ $
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G. A. Walton, Reactor Inspector date' signed date signed date signed
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/h7[79 Approved by: /
4.. E. Trip 6l Chief, Engineering Support
' date signed Section, RC&ES Brcnch Inspection ummary:
Inspection on November 3-6, 1979 (Report No. 50-336/79-26)
Areas Inspected:
Special, announced inspection by one regional based inspector of the re-examination of defects in the feedwater piping. The inspection involved 20 inspector-hours on site by one NRC regional based inspector.
Results:
No items of noncompliance were identified.
1845 101 Region I Form 12 (Rev. April 77)
b OO 1310 l DETAILS 1.
Persons Contacted Principal Licensee Employees E. Farrell, Superintendent, Unit 2 R. Rothgeb, Engineer M. Kapinski, Generation Senior Engineer P. Watson, ISI Coordinator U.S. Nuclear Regulatory Commission T. Shedlosky, Resident Inspector R. Herman, Metallurgist, NRR R. Smith, Consultant, Oak Ridge National Laboratories Westirghouse E. Hughes, Level III Senior Engineer 2.
Nondestructive Examination of Feedwater To Steam Generator Pipe Welds As a result of radiographic examinations performed to comply with I&E Bulletin 79-13, the licenset found crack indications in the base material adjacent to pipe to, safe-end welds AC-G-1 and BC-G-1, and pipe to elbow welds AC-G-2 and BC-G-2.
This examination was performed and defects discovered and reported to the NRC during a plant shutdown that commenced on August 9, 1979. This is further defined in I&E Inspection Report 50-336/79-21.
Based on a " Safety Evaluation Report" by the Office of Nuclear Reactor Regulation (NRR) dated August 25, 1979, the licensee was allowed to operate, provided among other things, that by October 31, 1979, a shutdown was parformed and an ultrasonic examination of the four welds was made using the same methods, techniques, and conditions as were previously used.
In addition to the above, the licensee also re-examined the pipe to safe-end welds using radiography.
The inspector, accompanied by representatives from NRR and an NRC consultant from Oak Ridge National Laboratories, audited these re-examinations conducted on November 3 and 4, 1979.
The following conditions were observed.
The radiographic examinations showed similar defects in the base material as the original radiographs showed.
There were slight variations, however, the inspector attributed this to film densities, and source placement.
No significant changes in the defects were noted.
1845 102
The ultrasonic examinations were only possible on the pipe to safe-end welds because the pipe to nozzle welds were instrumented.
The inspector witnessed the calibration and re-examination of the defects in the pipe to safe-end welds. Two areas were found by the NDE specialist and observed by the inspector which gave different signal responses from the original examinations.
On safe-end to pipe weld BC-G-1, a new reflector was detected at the 46" location which gave amplitude responses of 40 percent. The new indication was located approximately 1/8 inch from a known crack signal.
The second change was found on AC-G-1 which gave an increase of 3 to 4 decibels in amplitude in a portion of the known crack.
All other reflectors gave responses comparable to the original examinations.
No items of noncompliance were identified.
3.
Meetings With NRR and Licensee A meeting was held at Millstone, Unit 2 facility, with representatives from NRR, NRC Consultant, and licensee's representatives on November 5, 1979, to discuss the re-examination finaings.
It was the NRC position that the licensee should repair tne known defects prior to startup. The basis for this is:
a.
The re-examinations did establish some change from the original examin-ations. Although this did not in fact prove that changes were occurring in propagation of cracking, it did not show that additional cracking was not occurring.
b.
The original extension of operation was granted, among other reasons, to allow the licensee ample time to prepare for repairs since the affected welds were semi-encased (2 inch clearance) in concrete and not readily accessible for repairs.
The licensee now has an acceptable method to make repairs from the insine surface of these welds.
The licensee requested a meeting at Bethesda with NRR. This meeting was held on November 6, 1979, and a portion of this meeting was attended by the inspector.
Based on the licensee's presentation and discussion with I&E and NRR technical personnel, NRR informed the licensee that it was prudent to make repairs on all known cracks before commencing operations.
The licensee subsequently informed NRR that repairs would be implemented.
1845 103
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4.
Exit Interview The meetings discussed in Paragraph 3 above were considered the exit interview.
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