ML17174A466
| ML17174A466 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, Zion  |
| Issue date: | 02/29/1980 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| TASK-03-11, TASK-3-11, TASK-RR NUDOCS 8003270346 | |
| Download: ML17174A466 (2) | |
Text
-e Commonwealth E n
One First National Plaza, icago. Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 Mr. James G. Keppler, Director Directorate of Inspection and Enforcement - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 February 29, 1980
Subject:
Dresden Station Units 2 and 3 Quad Cities Station Units 1 and 2 Zion Station Units l and 2 February 22, 1980 Telephone Conversation Concerning IE Bulletin 79-02
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NRC Docket Nos. 50-237/249, 50-254/265, and 50-295/304
Dear Mr. Keppler:
On Friday, February 22, 1980, a telephone conversation was held between Commonwealth Edison Company (CECo.). in Chicago, NRC headquarters in Bethesda, and NRC Region III in Glen Ellyn, IL.
Those representing CECo. were Messrs. J. S.
Abel, G. J. Pliml, and D. B. Wozniak of Station Nuclear Engineering, R. F. Janecek of Nuclear Licensing, and Messrs. T.
G. Langlais and T. A. McKenna of Sargent & Lundy.
Representing NRC headquarters was Mr. H. Wong and representing NRC Region III was Mr. G. Gallagher.
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This conversation was requested by members of the NRC staff for purposes of discussing a CECo. letter dated February 19, 1980.
In reference to item 2 of our letter, CECo. has ~
recalculated the factors of safety on shell-type expansio~-
anchors on safety related piping systems, as requested by the c
- NRC, at Dresden, Quad Cities, and Zion Stations.
Increased i
concrete strengths resulting from concrete mix overdesign, and
/
concrete aging, and the utilization of curvilinear shear-tension interaction curves, were taken into account for the recalculation of safety factors.
Results of this analysis indicate 15 expansion anchored hanger assemblies have factors f
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9:ommonwealth Edison Mr. James G. Keppler, Director February 29, 1980 Page 2 of safety between 4 and 5.
All rema1n1ng assemblies on safety related piping systems assemblies at Dresden, Quad Cities, and Zion have been found, by analysis, to have factors of safety of 5 or above.
The 15 assemblies are currently being reviewed by CECo. and S&L to determine the feasibility of upgrading these assemblies to a factor of safety of 5.
However, as stated in our February 19, 1980 letter, CECo. maintains that a factor of safety of 4 is still acceptable for shell-type expansion anchors, and will demonstrate this through our dynamic test program.
In reference to item 3, CECo. *maintains that a factor of safety of 2 is a correct design basis for concrete expansion anchors for safety related pipe systems under SSE loads.
However, it should be noted that a review of the design basis for Dresden, Quad Cities, and Zion have indicated that a minimum factor of safety of 4 was used for safety related pipe systems under SSE loading conditions.
In reference to item 4, CECo. is load testing bolts from each safety related pipe system at Dresden, Quad Cities and Zion Stations.
Although the number of bolts load tested will not be such a quantity to meet the 95-5 criteria on a system basis, it will be met on a station basis.
Base plates on safety related pipe systems will continue to be inspected for oversized/flame-cut holes, and corrective measures will be taken where required to repair this condition.
Please address any questions you may have concerning this matter to this office.
cc:
Director, Division of Reactor Operations Inspection 2107A Very truly yours,
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LJ 1,.t(;71/LL-(
D. L. Peoples Director*of Nuclear Licensing