JAFP-83-0880, Discusses Recirculation Piping Flaw Indications.Ultrasonic Insps Revealed Indications as Intergranular Stress Corrosion Cracking.Fabrication Defect May Have Initiated Intergranular Stress Corrosion Cracking
| ML20077M907 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 08/24/1983 |
| From: | Corbin McNeil POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20077M911 | List:
|
| References | |
| JAFP-83-0880, JAFP-83-880, NUDOCS 8309120450 | |
| Download: ML20077M907 (2) | |
Text
James A. FitzPatrick CuGar Power Plant P.O. Bon 41 Lycoming, New York 13093 315 342.3840
- > NewVorkPbwer 1sf Authority August 24, 1983 JAFP 83-0880 United States Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention:
Dr. Thomas E. Murley Regional Administrator Gentlemen:
SUBJECT:
JAMES A.
FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333 RECIRCULATION PIPING FLAW INDICATION The ultrasonic inspections for Intergranular Stress Corrosion Cracking (IGSCC) conducted by the Power Authority during the current refueling outage, revealed one indication not attributable to weld / joint geometry.
The indication was approximately 1.9" in length circumferentially and 0.20" in depth.
The ultrasonic test data and plots of this indication were submitted in letter JAFP-83-0769, from Corbin A. McNeill, Jr. to Dr. Thomas E. Murley of I&E Region 1, dated July 22, 1983 (copy attached).
The indication has been evaluated as intergranular stress corrosion cracking (IGSCC).
The baseline radiographs show a slight change in density or an indication, in the same area as that discovered by UT.
This appears to indicate a fabrication defect which may have acted as an initiation site for IGSCC.
Both the original and repair construction radiographs were computer enhanced in an attempt to resolve the nature of this fabrication indication. The letter report describing the results of this enhancement is attached.
A conservative worst case flaw analysis has been performed on this indication to evaluate its impact on the structural margin of this piping.
Also attached is the fracture mechanics analysis of this indication.
This analysis shows that this indication does not reduce the original structural design margin for this piping and would not adversely affect the margin of safety over the next operating cycle.
The evaluation also shows that based on the residual stress pattern of this diameter pipe and on crack growth data from both laboratory and field experience, it will 8309120450 830824 PDR ADOCK 05000333 0
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not reach a critical crack size before the end of plant design life.
Additionally, using a worst case assumption of a small diameter pipe residual stress pattern it would not reach a critical crack size before the end of the next operating cycle.
It should be noted also that this indication meats the acceptance standard for indications in austenitic stainless steel piping that was recently approved as paragraph IWB 3640 and Appendix X to the Winter 1983 Addenda of Section XI of the ASME Code.
Therefore, the original design margin and the correspondingly high level of safety will be maintained during this next operating cycle without a repair or replacement of this joint.
This weld will be re-examined during the next refueling outage and the results, i.e.,
any change in indication length of depth, will be reported and re-evaluated in terms of impact on piping integrity.
Very truly yours, CORBIN A.
MCNEIL RESIDENT MANAGER CAM:DSinan Attachment CC:
Harry B.
Kister Chief RPSIC, DPRP NRC, Region 1 Domenic B.
Vassallo Director of Nuclear Regulations Chief of Operating Reactors Branch #2 United States Nuclear Regulatory Commission Washington, DC 20555 R.
A.
Burns J.
P. Bayne J. Gray T. Dougherty R.
Converse L. Doerflein, NRC Resident Inspector