ML18054A546
| ML18054A546 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 02/16/1989 |
| From: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8902220244 | |
| Download: ML18054A546 (4) | |
Text
consumers Power POWERINli MICHlliAN'S PIUlliRESS General Offices:
1945 West Parnell Road, Jackson, Ml 49201 o (517) 788-1636 February 16, 1989 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
Kenneth W Berry Director Nuclear Lice~ing RESPONSE TO NOTICE OF VIOLATION PRESENTED IN INSPECTION REPORT 88022 NRG Inspection Report 50-255/88-022 dated January 17, 1989 transmitted one notice of violation and requested Consumers Power Company provide a written response.
The requested response ~s as follow~:
Description Of Violation (255/88022-01)
As a result of the inspections conducted on September 15-16, 26-28, November 3-4, December 13, 1988, and January 9-10, 1989, and in accordance with 10CFR Part 2, Appendix C - General Statement of Policy and Procedure for NRC Enforcement Actions (1988), the following violation was identified:
Technical Specification 4.14.5 requires that:
Plugging each end of a defective (steam generator) tube is considered an acceptable repair for all cases in 4.14.4.1 and the CP Quality Assurance Program CPC-2A, paragraph 10.2.2 states that:
Inspections are applied to procurement, maintenance, modification, testing, fuel handling and inservice inspection to verify that items and activities conform to specified requirements.
Contrary to the above, defective tubes were not plugged due to inadequate quality verification of the installation or manufacture of* the plugging template.
CP identified a misplugged tube during the December 1987 outage (reference NRC Inspection Report No 50-255/88004) and, subsequently, discovered another misplugged tube during the August 1988 outage.
These plugs were installed during the 1983 and 1985 outages.
In addition, on December 5, 1988,'
with the reactor at 91 percent power, a steam generator tube leak was identified.
This leak was later established to be the result of a defective plug weld installed during the previous outage.
Failure of the licensee's quality control/non-destructive inspection to identify these deficiencies are examples of inadequate quality verification which resulted in violation of the above referenced Technical Specification requirements.
OC0289-0056-NL02
- c.eol 1/ 0
Nuclear Regulatory Commission Palisades Plant Response to IR 88022 February 16, 1989 This is a Severity Level IV violation.
Reason For Violation 2
Consumers Power recognizes the occurrence of the 1983 and 1985 tube mis-pluggings and the failure of the tube plug weld resulting in the December 1988 Plant shutdown.
A review of past Plant corrective action documents revealed only one other instance of welding inadequacy (identified while steam generator repairs we.re still in progress in 1983).
This instance involved a tube being plugged and tack welded, however, seal welding was not completed.
Investigations in.to the failure to complete the required seal weld was attributed to a failure of the inspector to identify this one anomaly amongst the numerou~
other corrective measures being taken in preparation for steam generator tube removal.
The failure of the welded tube plug installed during the 1988 refueling outage has been attributed to incomplete weld fusion on a portion of the inner diameter of the plug to tube weld zone.
The failure to identify the incomplete weld fusion has been attributed to the extreme difficulty in physically
- viewing this particular weld.
Detection of the weld failure was only possible by direct inspection after this particular tube was identified to be leaking following steam generator pressurization.
The difficulty in identifying the incomplete weld rusion was summarized by the qualified inspector who ideritif ied the problem by stating that had he not known this tube was leaking, he, in all likelihood, would not have found the problem.
It was further noted that a remote inspection would not have identified the problem.
The failures to plug the correct steam generator tubes in 1983 and 1985 have been attributed to improper plugging template manufacturing or incorrect template installation.
Failure to identify the errant tube plugging has been attributed to inadequate quality verification processes through 1985.
- However, since the corrective measures taken during the 1985 eddy current examination and after, no new instances of misplugging have been identified.
The final quality verification process performed by Quality Assurance/Quality Control and/or Non-Destructive Testing personnel is the last step and a common factor in all steam generator tube repair activities.
The current program requires Quality Control verification of template manufactu~ing, tube marking and template installation to assure that appropriate tubes are repaired.
Additionally, non-destructive testing examinations are performed to verify the adequacy of the tube plug welding process.
These activities represent the final verification of the repair process and are intended to identify any and all disciepancies.
Consumers Power believes that the current quality verification process of steam generator tube repairs meets industry standards and was the result of continual development through corrective actions and self-initiated improve-men.t efforts.
While CP does not agree that the examples, noted above, represent OC0289-0056-NL02
Nuclear Regulatory Commission Palisades Plant Response to IR 88022 February 16, 1989 a significant failure of the current quality verification process, CP does recognize that past difficulties occurred and, as a result, are continuing to review our processes.
Corrective Actions Taken And Results Achieved Both misplugged steam generator tubes and tubes which were to be plugged at 3
the time of occurrence in 1983 and 1985 have been verified as properly plugged.
The portion of the weld defect identified as containing incomplete fusion was repaired and verified as acceptable.
No further leakage attributable to this tube was noted during tube sheet inspections conducted in January 1989.
A remote visual scan of the "B" steam generator tube sheet was conducted with no further welding anomalies noted.
A further remote inspection was performed to directly review all tube plugs welded during the 1987 and 1988 outages.
No welding anomalie-s were noted.
To date and as presented by NRC inspectors in IE Inspection Report 88022, no tube mispluggings have been identified. which occurred after 1985.
Actions taken as a result of previously identified mispluggea tubes have included:
a) requiring all tube plugging template sections to be "keyed" off a stay point either directly or by matchup to a "keyed" template, b) a steam generator tube sheet map indicating the status of all tubes is maintained, c) template installation procedures have been strengthened to require verifi-cations after template movements or adjustments and to require direct marking of candidate tubes by eddy current personnel prior to removal of full tube sheet eddy current templates.
Corrective Actions To Be Taken To Avoid Further Non-Compliance To assure that no other anomalies exist from past tube plugging operations, existing video tapes of the tube sheets will be reviewed.
If these tapes do not provide a reliable review, a 100 percent tube sheet verification via video camera will be performed in both "A" and "B" steam generators.
Additionally, an evaluation of existing methods and procedures for the tube plugging identification process will be conducted.
Processes within this evaluation include; plugging template fabrication and/or tube marking methods, template installation methods and final tube sheet verification practices.
This evaluation will resolve the need for additional process verifications by qualified personnel.
To assure integrity of future welds, the steam generator tube plug welding process will be re-evaluated.
Included in this evaluation will be the adequacy of welding procedures and related qualification and testing of involved personnel.
Further, the non-destructive testing process utilized to accept final welds will be reviewed against existing c*orporate and industry acceptance standards, examination methods and factors affecting human perfonnance.
This review will incorporate special circumstances which exist due to physical obstructions within the steam generators.
OC0289-0056-NL02
Nuc~ear Regulatory Commission Palisades.Plant Response to IR 88022 February 16, 1989 Date When Full Compliance Will Be Achieved 4
The t;ube sheet verification will be completed during the next opportunity when the steam generators are opened or during the next refueling outag.e if deemed necessary.
This outage is currently planned to.occur in 1990.
The evaluation of the tube identification process will be completed by June 1, 1989.
Actions regarding the tube plug welding methods and acceptance standards will be completed by June 1, 1989.
Kenneth W Berry Director, Nuclear Licensing CC Administrator, Region III, NRC NRC Resident Inspector - Palisades OC0289-0056-NL02