ML20094E027
| ML20094E027 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/24/1984 |
| From: | Jens W DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 130, EF2-69660, NUDOCS 8408090071 | |
| Download: ML20094E027 (2) | |
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' Neear Operations Ferms-2 6400 North Dme H@way Newrort, Megan 48166 0 0) m-460 July 24, 1984 EF2-69660 Mr. James G.
Keppler Regional Administrator Region III U.
S.
Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
Reference:
Fermi 2 NRC Docket No. 50-341
Subject:
Final Report of 10CFR50.55(e) Item 130 "As-Built Deviation for the Main Steam Pipe Deflection Clearance" On June 26, 1984, Detroit Edison's Mr.
L.
P.
- Bregni, Engineer-Licensing, telephoned Mr.
P.
Pelke of NRC Region III, to report a potential deff lency concerning insuffi-cient clearance between main steam lines and the containment wall.
Description of Deficiency As part of the inside containment pipe break reevaluation it was discovered that three of the four main steam line "as-built" clearances were insufficient to allow for the predicted pipe deflection during a postulated main steam line break at the reactor nozzle.
The available clearance between the pipe elbow surfaces and the primary containment shell was less than the predicted pipe deflection during the postulated pipe break.
Analysis of Safety Implications The installed main steam line pipe whip restraints would not prevent main steam line impingement of the containment wall during the postulated main steam line break. Main steam line impingement onto the containment wall during a postulated main steam line break may affect containment integrity during this type of loss of coolant accident.
8408090071 840724 PDR ADOCK 05000341 S
PDR yy
I b
%c Mr. James G.
Keppler July 24, 1984
-EF2-69660 Page 2 Corrective Action Detroit Edison is currently' implementing a design modification to the pipe whip restraints which will alleviate concerns about main steam line impingement on the containment wall. This modification will reduce tAe gap-between each main steam line and its pipe whip restraint.
By reducing this. gap, main steam line deflection is reduced to within the available clearance with the containment wall.
The purpose of the pipe break reevaluation was to reconcile the "as-built" plant with the previous pipe-break analysis.
This is Detroit Edison's final report on this item.
If you have questions concerning this matter, please contact Mr. Lewis P.
Bregni, (313) 586-5083.
Sincerely, cc:
Mr.
P. M.
Byron Mr.
R. C.
DeYoung Mr.
R. C.
Knop i
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