ML20010E727
| ML20010E727 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 08/25/1981 |
| From: | Graves R CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| RO-50-213-81-02, RO-50-213-81-2, NUDOCS 8109080204 | |
| Download: ML20010E727 (2) | |
Text
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(C CONNECTICUT YANKEE ATOMIC POWER COMPANY HADDAM NECK PLANT RR 31 BOX 127E. EAST HAMPTON, CONN. 06424 August 25, 1981 U. S. Nuclear Regulatory Commission Region 1 Office of T7spection and Enforcement 631 Park Avenue King of Prussia, Pennsylvania 19406 Attn: Mr. Boyce Grier, Director Refercnce: Facility Operating License No. DPR-61 Docket No. 50-213 ETS-hT/50-213/81-02
Dear Mr. Grier:
On August 16, 1981, during startup of the boron dilution system, an unplanned radioactive gas release occurred at the Connecticut Yankee site. The release exceeded the instantaneous rate for gaseous dis-charges as specified in Envircnmental Technical Specifications, Section 2.4.3.1. A prompt report was made to your office on A. gust 16, 1981. A written report containing a detailed description as required by Environmental Technical Specifications, Section 5.6.2.a(1) is attached. cp i I#6,f Y ' D s. .s h,oA*O'g%A5Q'h Very truly yours, N&'L-xea Richard H. Graves f r Station Superintendent y/ j .-i \\ RHG:RZT/jhb y-{- At* chment cc: Dir., Office of Nuclear Reactor Regulation, Washington, D. C (17) USNRC c/o Document Management Brancb, Washington, D. C. (1) 8109080204 810825 PDR ADOCK 05000213 S PDR
ATTACIDfENT EVENT DESCRIPTION AND DOSE ASSESSMENT On August 16,1981, at 2015 an unplanned release of gaseous activity caused the technical specification limit for instantaneous releasa rate for noble gases to be exceeded, 5.89 x 103 uci/sec versus the limit of 4.70 x 103 uci/sec. Whole body dose at site bouadary from this release was 0.00037 millirem. Release calculation was bcsed on the higher _ reading of two staci. monitoring instruments. EVENT CAUSE Start.1 vent valves WG-V-423 and WG-V-427 were left open, presumably during an i'.,estigation to identify and isolate a previous problem in the waste gas complessor. When the boron dilution system was started, the vent line with its two open valves provided an unplanned release path to the stack. CORRECTIVE ACTION The Shif t Supervisor immediately directed shutdown of the boron dilution operation, causing the stack monitor reading to fall off to background i level. Following the investigation by operating personnel, the open vent i valves were shut. All operators were reinstructed with the description j and cause of this event. Af ter an evaluation, the valve lineup procedure was modified to lock shut WG-V-423 and 427 as their normal operating position. 4 4 i i i 1 1 I i l -. -}}