ML19345G159
| ML19345G159 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 06/24/1974 |
| From: | Hartley F CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | |
| References | |
| AO-50-213-74-10, NUDOCS 8103090055 | |
| Download: ML19345G159 (2) | |
Text
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Report Number:
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Report Date:
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Pccurrence Date:
6-14-74 NM W
Facility:
Haddam Neck Plant Identification of Occurrence:
Unsatisfactory Test of #2 Main Steam Isolation Valve Conditions Prior to Occurrence:
Steady State Power; conducting routine weekly main steam isolation valve movement test.
Description of Occurrence:
In accordance with Section 4.9 of the CY Technical Specifications, the main steam isolation valves are tested each week for movement of the valve disc through a distance of approximately one and one-half inches. Upon, actuation of the test switch for the #2 main steam isolation valve, no valve movement was noted. The other three main steam isolation valves were successfully tested.
Designation of Apparent Cause of Occurrence:
Dried out valve packing.
An,alysis __of Occurrence:
The malfunction of the #2 main steam isolation valve did not present a significant hazard to the safety of the public.
Even if a steam line rupture occurred coincident with the malfunction of the main steam isolation valve, analyses have demonstrated that neither DNB nor fuel damage will occur as a result of any of the steam line rupture incidents.
Corrective Action:
The packing gland was adjusted followed by a successful valve movement test. The test was repeated the 19th and the valve responded nomally.
Failure Data:
Early in the plants lifetime an incompatability was discovered between the packing material and the valve stems of the main steam isolation valves, resulting in corrosion of the valve stem and subsequent binding of the stem. Design changes were made by selecting a different packing material and installing an on-line test stroking device. Test stroking has been conducted regularly and a review of the test results indicates only three cases in nearly nine hundred valve strckes that revealed U N. J M
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i ABNORMAL OCCURREllCE REPORT - Haddam Neck Plant 213/74-10 abnomalities. The three problems were corrected by adjusting the valve packing gland followed by nomal operation of the valve. The valve in question is a 24" Main Steam Trip Valve manufactured by Schutte and Koerting Company.
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