1CAN089302, Informs That Commitment Contained in Ltr Dtd 911220,revised to Reflect Deferral of Permanent Repair & Evaluation of Pressurizer Upper Level Instrumentation Nozzle to Satisfactory Nondestructive Exams Results
| ML20046C597 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/05/1993 |
| From: | James Fisicaro ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1CAN089302, 1CAN89302, NUDOCS 9308110203 | |
| Download: ML20046C597 (2) | |
Text
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-g Entergy operatbns,Inc.
wae a sw mo Operations eam=
m wma mou August 5,1993 ICAN089302 U. S. Nuclear Regulatory Commission l
Document Control Desk Mail Station Pl-137 Washington, DC 20555
Subject:
Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. DPR-51 Deferral of Pressurizer Nozzle Permanent Repair Gentlemen:
Entergy Operations' letter ICAN129104, dated December 20, 1991, described actions ANO has taken regarding repair and evaluation of the Arkansas Nuclear One Unit 1 (ANO-1) pressurizer upper level instrumentation nozzle. The engineering report attached to that letter stated that the replacement nozzle and new weld meet ASME Code requirements.
It also recommended deferral of a permanent repair beyond 1R11 (September-October 1993) if either inspections could be performed on the carbon steel vessel or corrosion data was obtained which verified that carbon steel degradation of the pressurizer vessel is not a safety concern. Since there has been no significant corrosion, the code requirements continue to be maintained.
The NRC Safety Evaluation transmitted in your letter dated May 13.1992, (OCNA059201) concurred with the ANO position contingent upon ANO's development and use of an i
acceptable method for detecting corrosion of the carbon steel vessel. The December 20, 1991 report stated that a nondestructive examination (NDE) method was being developed to determine if the carbon steel base metal has corroded due to contact with boric acid.
This ultrasonic inspection technique was developed and demonstrated on a mock-up of the pressurizer vessel wall, prior to use during 1R10 (February-May 1992). The technique surveys 1/2" above and below the transition region between the alloy 600 nozzle sections using two focused wedge angle transducers. This method was used during 1R10 and the inspection results verified that the boric acid corrosion of the carbon steel was less than the detectable limit of 5 mils ?nd that deferral for additional fuel cycles isjustified.
Based on the successful use of this NDE method, the inspection procedure was formalized and incorporated into the ANO Inservice Inspection Program (ISI) and inspections will be performed during 1Rll and 1R12. If the inspections continue to show no or minimal i
corrosion, the inspection frequency will be reevaluated and deferral of the permanent repair will be continued until it is found necessary or prudent to repair the nozzle.
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1CAN089302 Page 2 Therefore, the commitment contained in our letter ICAN129104, is revised to reflect
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deferral of the permanent repair subject to satisfactory nondestmetive examination results.
This action is consistent with the NRC staffs safety evaluation dated May 13,1992.
Should you have any questions regarding this submittal, please contact me.
Very truly yours, l
~ ' Ce-
.w I
ames J. Fisicaro Director, Licensing JJF/jrh i
cc:
Mr. James L. Milhoan Regional Administrator l
U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 3
Arlington, TX 76011-8064 h1C Senior Resident Inspector Arkansas ~ Nuclear One - ANO-1 & 2 Number 1, Nuclear Plant Road Russellsille, AR 72801 Mr. Roby B. Bevan, Jr.
NRR Project Manager Region IV/ANO-1 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-H-3 One White Flint North 11555 Rocksille Pike Rockville, MD 20852 Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO-2 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-H-3 One White Flint North 11555 Rocksille Pike Rockville, MD 20852 i
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