ML17252A245
| ML17252A245 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 11/04/1976 |
| From: | Stephenson B Commonwealth Edison Co |
| To: | Keepler J NRC/RGN-III |
| References | |
| BBS Ltr. #76-776 | |
| Download: ML17252A245 (3) | |
Text
,/
e o:if*e-gu-,*f""'a_to_ry_;;,
-4, 1976 Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations - Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 I
i Enclosed please find Reportable Occurrence report number 50-249/1976-25.
This report is being submitted to your office in accordance with the Dresden Nuclear Power Station Technical Specifications, Section 6.6.B.
... ~'fYl~*
, BBS :jo Enclosure h.
B. Stephenson.
tation Superintendent Dresden N~clear Power Station cc:
Director of Inspection & Enforcement Director.of Management Information & Program Control File/NRC
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LICENSEE NAME
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LOSS OR DAMAGE TO FACILITY TYPE DESCRIPTION
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EVENT DESCRIPTION (Continued) the Tech Spec limit.
A few days later, these check valves were pressurized with water to 500 PSIG in an attempt to more closely approximate accident con-ditions.
Subseq~ent retesting of valves 3~220-58B and -62B yielded leakage rates of 15.9 and 29.7 SCFH respectively.
Since the leakage through valve 3-220-58B was reduced to a value below Tech Spec limits, no further action was necessary.
Valve 220-62B.was disassembled and inspected.
Redundant valves were available and operable during unit operation.
This is a repetitive occurrence*.
(50..:..249/1976-25)
CAUSE DESCRIPTION (Continued) these clear.ances and resulted in much lower leakage rates.
Disassembly of valve -62B revealed abnormality was dirt in the valve* seat.
assembly and seai ring.were replaced as reassem"ly, valve 220-62B was retested, obtained.
no defective components; the only The valve was cleaned, and the d.isc a precautionary measure *. Following and a leak rate of. 1.03 SCFH was Because of the high incidence of initial LLRT failures on the* feedwater check vaJ_ves, the station has reevaluated the present method. of testing these.**
vaives ~ **A new method has* been developed which more closely represents the
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a let.te~ will be submitted delineating.the station's 'prop_os~l.
Bo1h valves are *18-inch tilting disc check valves manufa'ctured by the Cra.ne Company..