ML19351E584
| ML19351E584 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 12/02/1980 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8012100482 | |
| Download: ML19351E584 (2) | |
Text
i Commonwrith Edison One First Nabonal P!aza. Chicago. libnois
' 4 cress Recly to: Post Cifice Box 767
.CNcagG. !Itinois 60690 C'
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'w Decemcer 2, 1960 1
Mr. James G. Keppler, Director Directorate of Inspection and Enforcement - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137
Subject:
Syron Stat 1.on Units 1 and 2 Braidwood Station Units 1 and 2 Motor Operated Valve Failure to Close NRC Docket Nos. 50-454, 50-455, 50-456 and 50-457
Dear Mr. Keppler:
On November 6, 1980 Commonwealth Edison Company notified Mr. Conklin of your of fice that certain motor operated valves at Byron and Braidwooo appear to have a deficiency reportable pursuant to 10 CFR 50.55(e).
This letter fulfills the thirty day reporting requirement of 50.55(e) regarding that item.
Descriotion of tne Deficiency During peroperational test ng at comestic station and a foreign station proolems were encountered when testing the Westinghouse Electro-Mechanical Division manufactured three inch gate valves, Mode-1 3GM88, 1500 lb. class.
The tested valves failed to completely close under precaerational test conditions (i.e.,
approximately 2700 psi as flow approaches zero) which are less severe than the eculpment specification design conditions (i.e.,
2750 psi as flow approaches zero).
The valves stroked to significantly rastrict flow, but the full stroke was not accomplisned to trip the " closed" position indication contacts in the motor operator or to seat the valve disc within the valve booy.
Westinghouse has advised us that valves similar to those that failed the test have been supplied for use at the Byron and Braidwood stations.
There are two such valves in each of the four units that are installed in " active
- applications (i.e., mechanical operation is required to accomplish a safety function).
The valves are contalment isolation valves on the charging line, CV 8105 and CV 8106.
30/7 1
5
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8012100
.Mr. James G. Keppler, Director December 2, 1980 Page 2 Analysis of Safety Imolications The charging line isolation valves are supposed to close automatically to divert high head safety injection flow to the four cold leg injection points.
Failure at these valves to close would result in high head injection flow distribution that has not been ccvered by the FSAR analyses.
It appears, however, that the functional requirement pressure / flow condition under which these isolation valves must close.7.ey be significantly less than the preoperational test and equipment specification conditions unoer which the tested valves failed to close.
Consequently, it is possible that complete closure ref the subject valvde may be accarolished under actual operating conditons even though ccmolete-closure was not accomplished under preoperational test conoiticns.
Corrective Action Westinghouse is developing a generic solction to this proolem.
We will monitor their efforts and incorporate their recommendations as they apply to Byron ano Braidwood.
If physical modifications are required, they will be tested prior to fuel load.
Please address any questions that you have regarding this matter to my office.
e t
Very truly yours, TM Mor
- 7. R.Tramm Nuclear Licensing Administrator Pressurized Water Reactors
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cc:
Director of Inspection and Enforcement 8569A-M-