ML20058K914
| ML20058K914 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 03/15/1972 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20058K918 | List: |
| References | |
| NUDOCS 9104260276 | |
| Download: ML20058K914 (1) | |
Text
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NORTHERN STATES POWER COMPANY fh nneapolis, f/innesota 55401 March 15, 1972 p.
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Dr. Peter A. florris Division of Reactor Licensing "g, a 3
United States Atomic Energy Commission y
Washington, D C 20545 8a 8*.au y
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Dear Dr. ido r r i s:
f.OffilCELLO fl) CLEAR GENERAT l!S PLAT (I Docket No. 50-263 License No. DPR-22 Malfunction of RCIC High Steam flew Isolation Saitch A cc,ndition has occurred recently at the f/onticello Nuclear Generating Plant which we interpret to be reportable in accordar.ce wi th Section 6.6.C.1 of ihe Techni cal Speci fi cat ions.
T be Region II! Compli ance of fi ce has been noti fied of this event.
Sunmarv of Occu rrence On Varch 1,1972, while performinE a regularly scheduled surrillance test, the trip setting of one of the two RCIC Hich Steam Flow Isolaticn switches was found to be ~48,600 #/Hr, 3,600 #/Hr 'above the requi red t rip setting of 45,00') #/Hr.
The instrument was visually inspected and the cause of the failure was fr und to be excessive f ree covecent ( v 1/16") of a link connection tha! allowed interference in the refer movecent enen above 95% of scale.
The corrective action taken on the date of the occurrence consisted of reducing the f ree novecent of the link assembly to an acceptable value, and recoving excess retal f rom the novement connection. T he inst rucent was recalibrated and functionally tested.
All similar safety system instru-cents which have potential for such a malfunction will be inspected for excessive f r ee mo vecent o f the l i nkage.
A Significant Operating Event report has been written for this occurrence and will be made available to the Pegion 111 Compliance I nspector fo r review during his next visit.
Yours very truly,
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L. O. Mayer 7
g~ gy )g7g y I. i Director of Nuclear Support Services
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