ML081260162
| ML081260162 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/28/2008 |
| From: | Baxter D Duke Energy Carolinas, Duke Energy Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| EA-03-009 | |
| Download: ML081260162 (6) | |
Text
Duke DAVE BAXTER Vice President PC7 Energy@
Oconee Nuclear Station Duke Energy Corporation ONO VP17800 Rochester Highway Seneca, SC 29672 864-885-4460 864-885-4208 fax dabaxter@dukeenergy. com April 28, 2008 U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Document Control Desk
Subject:
Duke Energy Carolinas, LLC Oconee Nuclear Station, Unit 3, Docket Number 50-287 Inspection Results Required Per First Revised NRC Order (EA-03 -009)
By letter dated February 20, 2004, the NRC issued the First Revised NRC Order (EA 009), "Establishing Interim Inspection Requirements for Reactor Vessel Heads at Pressurized Water Reactors." The Order imposed requirements for pressurized water reactor licensees to inspect reactor pressure vessel heads and related penetration nozzles and to submit a report detailing the inspection results within sixty days after returning the unit to operation.
Duke Energy Carolinas, LLC, performed the required inspections on Oconee Unit 3 during the End-of-Cycle 23 Refueling Outage, but did not submit the report within sixty days after returning the unit to operation. The failure to submit the report has been entered in the corrective action program. The attachment to this letter provides the required reactor pressure vessel head inspection results.
This letter and its attachment do not contain any NRC commitments.
If there are any questions concerning this information, please contact Judy Smith at (864) 885-4309.
Very truly yours, Dave axter, Vice President Oconee Nuclear Site Attachment w( IOen www. du ke-energy, corn
U. S. Nuclear Regulatory Commission April 28, 2008 Page 2 Dave Baxter affirms that he is the person who subscribed his name to the foregoing statement, and that all the matters and facts set forth herein are true and correct to the best of his knowledge.
Dave Baxtef, Vice President Oconee Nuclear Site Subscribed and sworn tc Nofary Public Date ZF 741, -- ý4L My Commission Expires:
Dt2-Date zo/3
, SEAL
U. S. Nuclear Regulatory Commission April 28, 2008 Page 3 cc:
L. N. Olshan, Project Manager Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 0-14 H25 Washington, D. C. 20555 V. M. McCree, Regional Administrator, Acting U. S. Nuclear Regulatory Commission - Region II Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303 Andy Hutto Senior Resident Inspector Oconee Nuclear Station S. E. Jenkins, Manager Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health and Environmental Control 2600 Bull Street Columbia, SC 29201
U. S. Nuclear Regulatory Commission April 28, 2008 Page 4 bcc:
w/attachment B. G. Davenport Carl Fago Rod Emory L. F. Vaughn Jody Shuping R. L. Gill - NRI&A R. D. Hart - CNS K. L. Ashe - MNS NSRB, EC05N ELL, ECO50 ONS Document Management
Attachment Oconee Nuclear Station Unit 3 End-of-Cycle 23 Reactor Pressure Vessel Head (RPVH) Inspection Results Report During the Oconee Unit 3 End-of-Cycle 23 Refueling Outage, Duke performed inspections of the RPVH in accordance with the schedule required by the First Revised NRC Order EA-03-009 dated February 20, 2004. The inspections detected no evidence of pressure boundary leakage, cracking, or wastage.
The susceptibility of the RPVH to Primary Water Stress Corrosion Cracking (PWSCC) related degradation, as represented by a value of Effective Degradation Years (EDY), was calculated.
The calculated value determined that the Oconee Unit 3 RPV head remains in the Replaced Category.
The Bare Metal Visual (BMV) inspection examined 100% of the RPV upper head surface, including 3600 around each RPVH penetration nozzle. The RPVH exhibited no evidence of wastage or pressure boundary leakage.
The inspection was performed through the nine access ports in the service structure support skirt of the reactor vessel head. The general cleanliness condition of the head was such that the source of any leakage was readily identified. The results of the inspection are as follows:
Nozzle 7 Leakage from above the nozzle, down,nozzle, around the annulus, and on down head. Also a leak from above down onto head and continuing between two other nozzles.
Nozzle 14 Accumulation on right side, coming from seam in insulation uphill of nozzle running down onto #30.
Nozzle 19 Dark trail from above, down to nozzle, then on down below nozzle. Appeared to be cutting fluid residue from initial head replacement.
Nozzle 22 Small pile on uphill left side. No trail down nozzle. Accumulation on insulation directly above pile.
Nozzle23 White trail from nozzle 7, around annulus, and on down below nozzle.
Nozzle 30 360 degree residue in annulus area, several trails from uphill side, down to annulus.
Nozzle 31 Thin trail from uphill down to nozzle.
Nozzle 38 Short incomplete trail down left side of nozzle, white residue on uphill side.
Nozzle 39 Powder on uphill side, down around both sides, appears to be from uphill nozzle
- 22.
Attachment Oconee Nuclear Station Unit 3 End-of-Cycle 23 Reactor Pressure Vessel Head (RPVH) Inspection Results Report Nozzle 40 Trail down from above nozzle on head, dripping from seam in insulation, trailing down into annulus and on down below nozzle.
Nozzle 57 (Info only) small rust colored trail (stain) below nozzle, no accumulation of any material.
Nozzle 58 Buildup on uphill side, chunky powder, with small trail. Accumulation on insulation uphill of nozzle.
Nozzle 59 Leak from above nozzle into annulus, then on below nozzle.
Except as stated above, all of the accumulated material was white in color and translucent. The material did not appear to have the same consistency as boron previously seen in head inspecti6ns performed prior to head replacement. No degradation of the head or control rod drive nozzles was noted. The material seen did not have the appearance of primary system leakage from the control rod drive penetrations, and was suspected to be from Component Cooling Water System leakage from the control rod drive stator cooling water piping dripping onto and through the head insulation seams and penetrations.
Samples of the deposits on the Unit 3 head were taken and analyzed by the Duke General Office Metallurgical Lab for chemical constituency, and were determined to be sodium molybdate.
Sodium molybdate is a corrosion inhibitor utilized in the Component Cooling Water System.
The majority of the material was subsequently cleaned off the head, although small amounts remained in the annulus areas of the penetrations, with slight staining on the head surface.