ML20030B162
| ML20030B162 | |
| Person / Time | |
|---|---|
| Site: | Shoreham File:Long Island Lighting Company icon.png |
| Issue date: | 07/24/1981 |
| From: | Pollock M LONG ISLAND LIGHTING CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, SNRC-606, NUDOCS 8108060172 | |
| Download: ML20030B162 (2) | |
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LONG ISLAND LIGHTING COMPANY
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LONG ISLAND LIGilTING COMPANY SilOREIIAM NUCLEAR POWER STATION - UNIT 1
/p Docket No. 50-372 y
Dear Mr. Grier:
On June 26, 1981, in accordance with 10CPR50.55(e), we reported verbally to Region 1, a deficiency with resistance temperature detector (RTD) connector heads supplied by Rosemount Incorporated.
This letter serves as our 30-day written report of this deficiency.
Description of Deficiency The instruments experiencing the failures are Rosemount's RTD connector heads identifiable by Model number 89-86-4.
The RTD attached to the connector head is not at fault in any way.
The connector heads involved are for dual element RTD's.
The assembly consists of a cast iron head (Crouse-IIinds), with two (2) ring-shaped ceramic terminal bases cemented (epoxy 6203) to the bottom surface.
Each of the two terminal bases has four (4) kidney shaped brass terminal plates secured to *he base with one (1) mounting screw each.
Each terminal plato has two screws for electrical connections and one tapped hold for mounting.
The mounting screw head is recessed into th( underside of the base, and is not acces-sible after the base is cemented to the head.
The failure occurs due to the loosening of these mounting screws, a condition found in the field by Construction and in shelved spares by Project.
The geometry of the assembly is such that the mounting screw can back out completely, causing detachment of the terminal plate from the base.
This would allow the free terminal 8108060172 810724 f*
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Grier Page Two July 24, 1981 to make contact with aliy other terminal in the head, including the head itself (ground).
Should this occur, an erroneous signal would be introduced into the affected control loop which would in turn cause loss of system function.
There is no known way of preventing this screw from loosening on existing equipment.
The deficient RTD connector heads are utilized in six (6) safety-related systems.
The installed number is twenty-four (24) and two (2) are stored as spares.
Tne systems affected are listed below with the quantity of subject connector heads in parentheses.
- Nuclear Boiler System (4)
- Reactor Remote Shutdown System (1)
- Service Water System (4)
- Reactor Building Standby Ventilation System (11)
- ~3ntrol Room Air Conditioning System (2)
- Miscellaneous HVAC System (2)
Therefore, based on the above, this condition constitutes a significant deficiency in component construction which requires repair of a safety-related componert.
Had this condition gone uncorrected, it could have adversely affected the operational safety of this plant.
Corrective Action Corrective action in our case will entail replacement of all twenty-six (26) connector head assemblies.
The replacement connector heads are being purchased trom Rosemount under part numbers 89-138-01, 02.
We anticipate completion of the replacement process by January 1, 1982.
Very truly yours, M.
S. Pollock BWC/mh cc: Mr. Victor Stello, Director NRC Office of Inspection and Enforcement Div. of Reactor Operations Inspection Washi.ngton, D.C.
20555 Mr.
J.
Higgins, NRC Site Trailer
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