ML17187A326
| ML17187A326 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/23/1996 |
| From: | Stang J NRC (Affiliation Not Assigned) |
| To: | Farrar D COMMONWEALTH EDISON CO. |
| Shared Package | |
| ML17187A327 | List: |
| References | |
| TAC-M93590, NUDOCS 9602280278 | |
| Download: ML17187A326 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION Mr. D. L. Farrar WASHINGTON, D.C. 20555--0001 February 23, 1996 Manager, Nuclear Regulatory Services Commonwealth Edison Company Executive Towers West III 1400 Opus Place, Suite 500 Downers Grove, IL 60515 S:o - Z 37
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNIT 2 - EVALUATION OF CORE SPRAY PIPING INDICATIONS (TAC NO. M93590)
Dear Mr. Farrar:
By letter dated September 12, 1995, Commonwealth Edison Company (ComEd) submitted an evaluation of three indications in the core spray internal p1p1ng components identified through in-vessel inspection activities performed during the current refueling outage at Dresden, Unit 2. Additional information was provided.by your letter dated September 25, 1995.
Based on your evaluation, you concluded that the structural integrity of the core spray internal piping will maintain adequate structural integrity for the next operating eye le without the need to repair the indications.
The inspection of the subject piping was preformed in accordance with the requested actions of NRC IE Bulletin 80-13, "Cracking in Core Spray Spargers,"
dated May 12, 1980. This Bulletin requires all licensees of operating boiling water reactors to perform a visual inspection of the core spray sparger and the segment of piping between the inlet nozzle and the vessel shroud every refueling outage. Ultrasonic examinations were used to size the length of the flaw indications.
During the visual inspection, crack like indications were visually observed at three components of the core spray downcomer piping.
The three flawed components are a lower sparger inlet elbow and an upper and lower sparger inlet thermal sleeve collars. The length of these indications as measured by ultrasonic examinations varied from 2 inches to 5.5 inches.
The indications were reported to be very tight and showed characteristics of jagging and branching, which are typical of intergranular stress corrosion cracking.
The staff's Safety Evaluation (SE) concerning the subject flaw indications is enclosed. Based on the SE, the staff concludes that the structural integrity of the subject flawed core spray components will be maintained during the next fuel cycle on the basis that the final flaw sizes at the end of the next fuel cycle will not exceed the American Society of Mechanical Engineers (ASME)
Boiler and Pressure Vessel Code (Code) allowable values. Therefore, Dresden, Unit 2, can be operated safely for the next fuel cycle without repairing the subject flawed core spray piping components.
Continued plant operation beyond
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the next fuel cycle should be supported by the results of re-inspection and reevaluation of the subject flaw indications.
In addition, to ensure safe plant operation in the long-term, please provide an evaluation to address the plant capabilities in the detection of loose parts during power operation and the program for removing loose parts from the reactor vessel. This evaluation should be provided ftor staff review prior to restart of the unit from the next scheduled refueling outage.
This completes the fiRC staff review of the subject evaluation and closes TAC No. M93590.
If you :have any questions regarding this issue, please contact me at (301) 415-1345.
Docket No. 50-237
Enclosure:
Safety Evaluation cc w/encl: see next page Sincerely,
~~~.
Senior Project Manager Project Directorate III-2 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation
I D. L. Farrar Commonwealth Edison Company cc:
Michael I. Miller, Esquire Sidley and Austin One First National Plaza Chicago, Illinois 60603 Site Vice President Dresden Nuclear Power Station 6500 North Dresden Road Morris, Illinois 60450-9765 Station Manager Dresden Nuclear Power Station 6500 North Dresden Road Morris, Illinois 60450-9765 U.S. Nuclear Regulatory Commission Resident Inspectors Office Dresden Station 6500 North Dresden Road Morris, Illinois 60450-9766 Regional Administrator U.S. NRC, Region III 801 Warrenville Road Lisle, Illinois 60532-4351 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Chairman Grundy County Board Administration Building 1320 Union Street Morris, Illinois 60450 Document Control Desk-Licensing Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Dresden Nuclear Power Station Unit Nos. 2 and 3