ML20096F433
| ML20096F433 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 08/20/1984 |
| From: | Jens W DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 115, EF2-69694, NUDOCS 8409070443 | |
| Download: ML20096F433 (3) | |
Text
8m3 Wayne M. Jens y
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%ce Presd+nt fiacter Owatens yQ rem 2 Edison =co wnn c.co se a<
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^eeuet 20 1984 EF2-69694 i
Mr. James G.
Keppler Regional Administrator Region III U.
S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
Reference:
(1) Fermi 2 NRC Docket No. 50-341 (2) Letter, D.
A. Wells to J.
G.
- Keppler, l
February 25, 1984, OA-84-325
Subject:
Final Report of 10CFR50.55(e) Item 115 "Possible Impingement of Essential Piping During Pipe Break" This is Detroit Edison's final report of Item ll5,"Possible Impingement of Essential Piping during Pipe Break".
Item 115 was originally reported as a potential deficiency on January 24, 1984, and subsequently documented in Reference (2).
Description of Deficiency During design reviews, Detroit Edison determined that in this case, although the Fermi 2 plant design basis included appropriate protection for the dynamic effects associated with the postulated rupture of piping inside containment, field design groups had not been supplied with definitive descriptions of the pipe sweep, jet impingement zones, and system protection criteria.
The potential existed that field run, small bore piping, instrument lines, and electri-cal conduit required for safe shutdown were constructed in areas where they could have been subjected to damage from pipe sweep and/or jet impingement from postulated pipe breaks.
8409070443 s40epo PDR ADDCK 05000341
-AUG 27 lSb4 PDR
.ISc27>[o
t Mr. James G.
Keppler August 20, 1984 EF2-69694 Page 2 Analysis of Safety Implications If the potential dynamic effects of high energy pipe breaks are not adequately evaluated, safety related system opera-tion cannot be assured under these conditions.
The post installation evaluation indicated that the safe shutdown capability of the plant had not been impaired.
Corrective Action Detroit Edison Engineering performed an evaluation to assure that the safe shutdown functions had not been impaired.
This evaluation included:
o A review and evaluation of as-built configurations and actual component locations.
o A conservative definition of the pipe sweep and jet impingement zone for the postulated break locations.
o Comprehensive field and design drawing survey to identify all mechanical, instrument and electrical components located inside the defined sweep and jet zones.
o Confirmation of the safe shutdown capability of the plant considering the systems, components and instruments affected by pipe sweep and/or jet impingement, and con-current assumptions of loss of offsite power and single active component failures.
This evaluation determined that no modifications wer'e required to meet safe shutdowa requirements.
To prevent recurrence, specification No. 3071-536 was issued.
This defines multi-discipline design requirements to ensure that designs properly consider the effects of pipe rupture.
The specification includes a definitive descrip-tion of pipe sweep and jet impingement zones.
The specifi-cation also identifies the system components an1 instruments which contribute to safe shutdown for postulated pipe break events.
The methods outlined in the specification apply to any future design work inside primary containment.
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-Mr. James-G..Keppler
' August' 20;-1984; EF2-69694
' Page 3
^
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. Dyron Mr.
R. C.
DeYoung y
Mr..R. C.
Knop-P
.