ML20086E244
| ML20086E244 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 02/05/1975 |
| From: | Riley B VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20086E235 | List: |
| References | |
| AO-75-04, AO-75-4, VYV-3644, NUDOCS 8312060437 | |
| Download: ML20086E244 (2) | |
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VEnMONT YANKEM NUCLEAR 1*OWER CORPORATIO'N ScVctJTY CcVCr4 OROVC STRecT RUTi, ann, VI;1tMONT 05701 X 157 VcRrJOrd. VERMOtJT oS354 February 5; 1975 q
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a Director Directorate of Regulatory Operations, Region I ff;h m 6 hg.e-'t United States Atomic Energy Commission F
5 (,\\' ej 631 Park Avenue p ut a King of Prussia, Pennsylvania 19406
REFERENCE:
Operating License DPR-28 Qh Docket No. 50-271 Abnormal Occurrence No. A0-75-04 (24 Hour Report)
Dear Sir:
As defined by Technical Specifications for the Vermont Yankee Nucicar Power Station, bection o. /, we are repon.ing the following Abnormal Occurrence as A0-75-04 and confirming our telephone conversation with your office.
At approximately 1035 on February 4,1975, Chenistry and Health Physicc personnel attccpted to determine the cause of a very gradual flow reduction in the Air Ejector Off-gas Monitoring system, which resulted in a corresponding decrease in activity level as indicated by the radiation monitors in the Control Room. The cause of the flow restriction was traced to a 3-way solenoid valve which was removed and replaced with a temporary Tygon bypass line. At approximately 1215, with the bypass line in place, flow inacdiately returned to normal.
During this period of 1 3/4 hours, the reduced flow rendered both channels of the associated Off-gas System Isolation instrumentation incapable of scusing the trip 1cvel settings of 0.3 Ci/sec. and 1.5 Ci/sec. as required by Technical Specifications Table 3.2.4.
The 3-way valve was cleaned, repaired and replaced by 1530.
0312060437 750214 PDR ADOCK 05000271 s
PDR 1484 J
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VERMONT YANKLu NuCLCAR POvVER CORPOD ATION e
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.s Directorate of Ecgulatory operations February 5, 1975 Page 2 Because of the brief time periods during which the reduced and interrupted flow caused both channels of the trip system to be l
unavailabic, and since the plant was utilizing the Augmented Off-gas System with its associated discharge monitors throughout the incident, the action required by Note 2 of Table 3.2.4 was deemed to be unnecessary.
The plant was operating at 99.7% power at the tinci l
l Very trul yours,
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