ML17187B127
| ML17187B127 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/24/1997 |
| From: | Stang J NRC (Affiliation Not Assigned) |
| To: | Johnson I COMMONWEALTH EDISON CO. |
| References | |
| TAC-M95296, TAC-M97463, NUDOCS 9710020132 | |
| Download: ML17187B127 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555--0001 Ms. Irene Johnson, Acting Manager Nuclear Regulatory Services
.Commonwealth Edison Company Executive Towers West III 1400 Opus Place, Suite 500 Downers Grove, IL 60515 September 24, 1997
SUBJECT:
VERIFICATION OF ADEQUATE WALL THICKNESS FOR MARK I TORUS SHELLS -
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 (TAC NOS *. M95296 AND M97463)
Dear Ms. Johnson:
The NRC staff is interested in obtaining information from several licensees relating to the minimum code wall thickness of the torus structure in containments with the Mark I torus structure. Torus wall thinning may have occurred as a result of corrosion of the steel shell in areas that have defective or missing coatings. Information on the results of inspection of the Mark I torus structure in the vicinity of the torus to ring girder support welds, at the air water interface, and in submerged areas is requested.
The wall thickness at those locations may be below the code* allowable wall thickness. While UT thickness measurements would usually be made from. the outside of the torus, it is important to visually i~spect the condition of the coatings on the inside of the torus. The staff is requesting that ComEd verify the torus wall thickness at Dresden, Units 2 and 3, meets the minimum wall thickness requirements. This can be accomplished by review of recent prior inspection results or by inspection of the torus structure.
The staff is requesting a report containing the minimum wall thicknesses in
~
these locations, the method/criteria for these thickne~ses~ the-actual l
thicknesses in these locations, the condition of the coatings on the inside of
- the torus, and the date of these measurements/observ~tions. If degradation has been' found, the licensee should provide an assessment of the condition and ~fiJ) long-term integrity of the torus. 'The NRC staff requests that any available information be provided within 60 days of the date of receipt of this letter.
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I. Johnson 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 Ro*ad
. 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 l400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Dresden Nuclear Power Station Unit Nos. 2 and 3
If the information is not available and an inspection is required, the staff expects the data would be taken at the next outage of sufficient duration and followed up with a report within 60 days. If there are any questions, please call me at (301) 415-1345.
Docket Nos. 50-237, 50-249 cc:
see next page Distribution:
Docket -File PUBLIC PDIII.;.2 r/f E. Adensam, EGAl R. Capra C. Moore J. Stang OGC, 015818 ACRS, T2E26 W.
Krop~, RIII C. ttJ:LL\\:12..
Sincerely, John F. Stang, Senior Project Manager Project Directorate III-2 Division of Reactor Projects - III/IV Office of Nuclear Reactor Regulation DOCUMENT NAME: G*\\CMNTJR\\DRESDEN\\TORUS.DR 0 E0 = Copy with enclosures 0 N* = No copy OFFICE EMCB D:PDIII-2 NAME ESULLIVAN RCAPRA,_____
DATE 1
09120/97 09/V( /97 OFFICIAL RECORD COPY~