ML19329E393
| ML19329E393 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 05/31/1978 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8006120711 | |
| Download: ML19329E393 (1) | |
Text
'
L M MTle.AL PILLS
.c-MAY 31198 Docket No. 50-329 Docket No. 50-330 Consumers Power Conpany ATTN:
Mr. Stephen H. Howell Vice President 1945 West Parnall Road Jackson, MI 49201 Gentlemen:
The enclosed IE Circular No. 78-06, is forwarded to you for irfor-mation. No written response is required. Should you have any questions related to your understanding of this matter, please contact this offica.
Sincerely, James C. Kepplar Director
Enclosures:
1.
IE Circular No. 78-06 2.
List of IE Circulars Issued in 1978 cc w/enels:
THIS DOCUMENT CONTAINS
/ Central Files P00R QUALITY PAGES
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Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commission Dr. Wayne E. North Myron M. Cherry, Chicago h
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5/30/78 o^rr,
NRC Form 318A (R2ZE) (5-76) NRCM 02040
.U. S. GOVERNMENT PRINTJNG OFFICE: 1978-253-818 8006 12'O 7/7 p
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P-U.S. NUCLEAK REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III May 31, 1978 IE Circular No. 78-06 POTENTIAL COMMON MODE FLOODING OF ECCS EQUIPMENT ROOMS AT BWR FACILITIES Georgia Power Company (GPC), by letter dated March 22, 1978, reported that during a review of the design of the ECCS corner room equipment drain systems at the Hatch facilities, the equipment drain lines for Hatch 1 were found piped into the top of an open 6-inch pipe (standpipe) in each corner room. These corner room standpipes are interconnected by a 6-inch pipe to a common sump in one corner room. This sump has redundant pumps which are powered from different amergency buses. The equipment drain system does not have any isolation valves within any of the piping between corner rooms. Therefore, in the event of a pipe break of sufficient size to flood sump pumps, the other ECCS corner rooms would be subject to flooding via the equipment drain piping.
Since one of the reasons for installing the ECCS equipment in separate, water-tight rooms was to eliminate the potential for common flooding, GPC is "hard piping" all of the equipment drain lines into the side of the corner room standpipe and capping the standpipe. This limits the size of the potential flooding backflow to the small size (approxi-mately 1/2") piping of the equipment leakoff drain line.
The above described design for Hatch I and 2 was part of the A-E balance-of-plant design provided by Bechtel.
All holders of reactor operating licenses should assure that similar pathways, which could lead to ecmmon flooding of redundant equipment, do not exist in their facilities. It is recommended that the following items be considersd in your review of this matter:
1.
The specific design and installation for floor and equipment drains should be reviewed to verify that a flood in any one room or loca-f tion would not result in flooding redundant equipment in other ECCS p3 0gl equipment rooms or in areas at a lower elevation.
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2-May 31, 1978 II Circular No. 78-06 1
2.
If your installation depends on isolation valves and limit switches to prevent cunmon flooding, your surveillance program should be reviewed to verify adequate maintenance of protection. Your Technical Specifications should be reviewed to assure that necessary surveillance of isolation valves, level switches, or sump pumps are included as appropriate.
3.
Your administrativt controls should also be reviewed to assure that separation criteria is maintained and water tight doors and/or hatches are closed as appropriate.
This circular is also issued to holders of construction permits for information or use as appropriate to the status of plant construction.
No written response to this circular is required. If you require additional information regarding this matter, contact the Director of the appropriate NRC Regional Office.
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IE Circular No. 78-06 May 31, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Subject Data Issued To No.
of Issue 78-01 Loss of Well Logging 4/3/78 All Holders of Source Well Leigging Source Licenses 78-0; Proper Lubricating 011 4/20/78 All Holders of for Terry Turbines Reactor OLs or cps 78-03 Packaging Greater Than 5/12/78 All Holders of Type A Quantities of Reactor OLs, cps, Few Specific Activity Fuel Cycle, Radioactive Material Priority I Material for Transport and Waste Disposal Licenses 78-04 Installation Error That 5/15/78 All Holders of Could Prevent Closing of Reactor OLs or Fire Doors cps 78-05 Inadvertent Safety Injection 5/23/78 All Holders of During Cooldown Reacter OLs or cps 9
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