ML20003H537
| ML20003H537 | |
| Person / Time | |
|---|---|
| Site: | Fermi, 05000452, 05000453  |
| Issue date: | 04/27/1981 |
| From: | Wells D DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, EF2-49-966, NUDOCS 8105060287 | |
| Download: ML20003H537 (2) | |
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April 27, 1981
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EF2-49,966 Mr. James G. Keppler, Director Region III U.S. Nuclear Regulatory Ccmnission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Interim Report of 10CFR50.55(e) Item on Traversing In-Core Probe System (#36).
Dear Mr. Keppler:
The final report on the Traversing In-Core Probe System problem cannot be subnitted to you by April 27, 1981, as scheduled. This additional interim report is to provide you with the current status of the evaluation of this problem.
This item was originally reported to Mr. R. Knop of NRC-Region III by Detroit Edison's Mr. H.A. Walker, Supervisor-Construction Quality Assurance, on December 29, 1980.
At that tine, Engineering investigation indicated that the traversing in-core probe instrument tube is deficient. This determination was rade by Project Design and Field Engineering while reviewing the thermal mcvements associated with the primary containment liner during a loss of coolant accident (LOCA).
Descriotion of Deficiency The instrument tube (3/8 O.D. stainless steel) connecting the isolation valve and the primary containment penetration was designed without due consideration l
for the thenral movement during a IOCA. This tube provides part of the primary containment boundary during containment isolation. Analysis of the thermal movements associated with the primary containment liner and penetration during
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a IOCA indicates that this tube is over stressed and may rupture, thus breaching primary contairnent.
Action Taken The cmpoter analysis performed on the instrument tubing design to determine the stress level is based on a non-linear system. Engineering judgement indicates that the instrument tube will be subjected to bending, but may not rupture. Therefore, the follow-up action is to deterrine, by test, if indeed the tube does rupture. The Detroit Edison Engineering Research Departrent did l
mock-up the existing design, and performed tests based on the thermal novement gel 5 B'10506 0 037 6Io
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Mr. Jares G. Keppler April 27, 1981 Page Tao EF2-49,966 associated with a IOCA. 'Ihe test results will '.e dmmnted and then reviewd by Engineering to deter:nine whether or not the original design is acceptable.
Another report en this item, either interim or final, is scheduled to be sent to you en or before August 25, 1981. If you have questions concerning this matter, please contact Mr. H.A. Walker, Supervisor-Corstruction Quality Assurance.
Very truly yours, f
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Donald A. Wells, Panager Quality Assurance D*/Hm/cp
/ r. Victor Stello Jr., Director M
cc:
Office of Inspection and Enforcement Division of Reactor Inspection P.ps U.S. Nuclear Regulatory Ccruission Washington, D.C. 20555 Mr. Bruce Little, Resident Inspector U.S. Nuclear Regulatory Ccrcission Resident Inspectors Office 6450 North Dixie Highway Newport, Michigan 48166 l
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