ML19343C344
| ML19343C344 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 06/09/1973 |
| From: | Hartley F CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-73-04, AO-73-4, CYH-2397, NUDOCS 8103100444 | |
| Download: ML19343C344 (2) | |
Text
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HADDAM NECK PLANT f,,
YANKEE AT O MIC POWEP COMPANY I
8 RR cl. BOX 127E. EAST HAMPTON, CONN. o6424 tp g135 gj June 9,1973 g Ygp M[r}) ~
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4 U. S. Atomic Energy Comission y
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Washington, D. C.
20545 ATTENTION: Director, Directorate of Licensing
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REFERENCE:
Provisional License No. DPR-14 Docket No. 50-213 pgay y;te cy, Abnormcl Occurrence 73-4
Dear Sir:
As defined by Technical Specifications for Connecticut Yankee Atomic Power Station, Section 5.3, the following incident involving malfunction of a reactor containment isolation trip valve is reported as Abnormal Occurrence 73-4.
The reactor coolant letdown piping is provided with three parallel automatically operated isolation valves which prevent release of fission products from the reactor containment during accident con-ditions. On 6-2-73, the control room operator attemptr:d to close one of the three letdown isolation trip valves in order to reduce letdown fl ow. The valve would not close upon actuation of the main control board switch. The solenoid valve in the air supply line to the trip valve was replaced and the trip valve operated normally upon actuation of the main control board switch. The removed solenoid valve was disassembled and inspected and no abnomalities were noted. The trip valve was then disassembled to inspect its internals. Boric acid deposits were noted on the packing box gland, packing box flange and the plug stem.
It appears that the frequent cycling of the valve loosens the valve packing resulting in boric acid leakage and deposition on valve components. The valve components were cleaned, the packing adjusted and the valve was successfully tested.
Malfunction of the same valve was reported on October 13, 1972 as Abnormal Occurrence 72-3. At that time the PORC recomended a program of more frequent checks of the operability of this valve until its reliability could be assured. The PORC concluded on December 15, 1972 that the valve had been proven operationally reliable, and the frequency of checks could revert to refueling intervals. The PORC reviewed the incident and concluded that once again more frequent operational checks fl03(dCWc{
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4 U. S. Atomic Energy Commission June 9,~1973-must be made to reassure us of the reliability of the valve.
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addition to increasing the frequency of valve operability checks the valve will be periodically inspected for evidence of packing leakage-and boric acid deposits.
Very truly yours,
, / / 49-s F. t..>rtley Plant Superintendent-RHG/cb cc: Mr. James P. O'Reilly, Director Region 1, Directorate.of Regulatory Operations i
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