ML19262C638
| ML19262C638 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck, Millstone File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 01/09/1980 |
| From: | Counsil W NORTHEAST UTILITIES |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-28, NUDOCS 8002150188 | |
| Download: ML19262C638 (3) | |
Text
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January 9,1980 Docket Nos. 50-213 50-245 50-336 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Reference:
(1)
B. H. Grier letter to W. G. Counsil dated December 7,1979, transmitting I&E Bulletin No. 79-28.
Gentlemen:
Haddam Neck Plant Millstone Nuclear Power Station, Unit Nos.1 and 2 I&E Bulletin No. 79-28 In Reference (1), the NRC Staff informed both Connecticut Yankee Atomic Power Company (CYAPCO) and Northeast Nuclear Energy Company (NNECO) that certain stem-mounted limit switches (SMLS) manufactured by NAMCO Controls contain defective top cover gaskets which could deteriorate during normal operation causing the SMLS's to fail.
The Staf f has requested CYAPCO and NNECO to determine if NAMCO Model EA-180 switches are installed or planned for installation in any safety-related equipment including valve position circuitry related to containment isolation valves.
If these switches are identified, CYAPCO and NNECO are requested to determine if the SMLS's were manufactured with the defective gasket by examining the date code stamped on the switch housing.
If the date code falls between 02-79 through 08-79, CYAPCO and NNECO are requested to replace the top gasket of the switch in accordance with the manufacturer's recommendations.
CYAPCO and NNECO hereby provide the following information for the Haddam Neck Plant and Millstone Unit Nos.1 and 2, respectively:
Haddam Neck Plant CYAPCO has determined that the SMLS's described in Ref erence (1) are not installed nor planned for installation on any safety-related system at the Haddam Neck Plant.
O 8 0 0 215 0 /E8'
Millstone Unit No.1 NNECO has determined that the SMLS's described in Ref erence (1) are not installed nor planned for installation on any safety-related system at Millstone Unit No. 1.
Millsto?.e Unit No. 2 NNECO has determined that twenty four (24) SMLS's of the type described in Ref erence (1) are installed at Millstone Unit No. 2.
All of these switches have date codes falling between 02-79 through 08-79.
A listing of the valves and the number of switches installed on the valve is included as Table 1.
The deficiency associated with the subject SMLS's is such that operability is unaffected by the normal operating environment.
Neither will the deficiency preclude the valves from achieving their safe position upon receipt of an accident signal.
Should the SMLS's fail in a post-LOCA environment, adequate alternate methods of post-LOCA valve operation and determination of valve position indication exist.
In recognition of the desirability to maintain design valve operation and position indication post-LOCA, NNECO plans to replace the gaskets in the affected switches during the 1980 refueling outage.
NNECO has examined the subj ect switches in spare parts at Millstone Nuclear Power Station.
The affected switches have been QA red-tagged and will be repaired prior to inctallation.
We trust this information satisfactorily dispositions the Ref erence (1) concerns.
Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTHEAST NUCLEAR ENERGY COMPANY
_!Ih??-
s W.'G.
Counsil Vice President Attachment
S e
O TABLE 1 DEFECTIVE NAMCO LIMIT SWITCHES -
INSTALLED AT MILLSTONE UNIT NO. 2 VALVE NO. SWITCHES INSTALLED 2-CH-515 2
2-CH-516 2
2-CH-517 2
2-CH-518 2
2-CH-519 2
2-SI-614 1
2-SI-624 1
2-SI-634 1
2-SI-644 1
2-SI-618 2
2-SI-628 2
2-S1-638 2
2-S 1-64 8 2
2-AC-5 2
2-AC-6 2