ML19327A609
| ML19327A609 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/03/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8008060469 | |
| Download: ML19327A609 (1) | |
Text
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UNITED STATES 8
NUCLEAR REEULATORY ?OMMISSION s
,E REGION 11
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o, 101 MARIETTA ST., N.W.. Sul!W 3100 ATLANTA, GEORGIA So3o3
%.....o In Reply Refer To:
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50-259 50-260 50-296, j
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Tennessee Valley Authority ATTN:
H. G. Parris Manager of Power 500A Chestnut Street Tower II Chattanooga, TN 37401 Gentlemen:
The enclosed IE Bulletin No. 80-17 is forwarded for action.
Prepare to perform the scram tests contained in the Bulletin; however, the 20-day time clock for completing will begin upon notification by telephone from the IE Regional Office.
The testing shall be performed as directed unless shutdown would severely impact the power reliability in your area as shown by appropriate and timely documentation to the Director of the Office of Inspection and Enforcement.
A written response to the Bulletin is required.
If you desire additional informa-tion regarding this matter, please contact this office.
Sincerely, MJ es 0
1 Director i
Enclosure-IE Bulletin No. 80-17 1
cc w/ enc 1:
H. L. Abercrombie, Plant Superintendent R. E. Rogers, Project Engineer H. N. Culver, Chief, Nuclear Safety Review Staff 8360N7 800
I i
i' FSINS No.: 6820 i
Accession No.:
8005050076 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMEh"I JULY 3, 1980 IE BULLETIN NO. 80-17 FAILURE OF 76 0F 185 CONTROL RODS TO FULLY INSERT DURING A dCRAM AT A BWR Description of Circumstacces:
On June 28, 1980, 76 of the 185 control rods failed to fully insert during a routine shutdown at TVA's Browns Ferry Unit No. 3 located at Athens, Alabama. The reactor was manually scrammed from about 30 percent power in accordance with routine shutdown procedures. The shutdown was initiated to repair the feedwater system. The 76 control rods that failed to fully
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insert were all on the east side of the core.
Following scram discharge volume (SDV) high level bypass and a short drain period of the SDV, a second manual scram was initiated and all partially inserted rods were observed to drive inward, but 59 remained partially withdrawn. A third manual scram was made, again following high level in the SDV and bypassing for another short drain of the SDV, with the result that 47 rods.' remained partially withdrawn. Following a longer drain j
of the SDV, an automatic scram occurred that was initiated by a scram discharge volume tank high water level signal when the scram reset switch was placed in " Normal"; with this scram all remaining rods fully inserted. The total j
time elapse from the initial scram to the time that all rods were inserted i
wa:: approximately 15 minutes.
Core coolant flow, temperature and pressure 4
remained normal for plant conditions. The unit is now shutdown and additional testing indicates that a possible cause of the malfunction was the retention of a significant amount of water in the east bank scram discharge i
volume.
In view of these interim findings and pending results of continued investigatioa, the following actions are to be taken.
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Actions To Be Taken By Licensees:
All General Electric Boiling Water Reactors with operating licenses which are operating at any power on the date of this Bulletin shall perform the following steps in the time stated. Those that are presently shutdown shall perform the following' steps riar
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Within 3 days from the 2d DUPLICATE DOCUMENT f
tests to verify that th a t am DischargeVolume(SDV)c}
Entire document previously 3 es are operable and vent sh entered into system under:
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