ML20127K595

Ro:On 731002,one of Sixteen HPCI Steam Line High Area Temp Switches Tripped Due to Defective Switch.Switch Replaced W/ New Calibrated Switch

ML20127K595
Person / Time
Site:	Monticello
Issue date:	10/12/1973
From:	Mayer L NORTHERN STATES POWER CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9211200444
Download: ML20127K595 (1)

Text

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NORTHERN STATES POWER COMPANY Minneapolis, Funnesota 55401 o O October 12, 1973 69

/ /b o it- 007 !A" f Mr. J. F. O' Leary, Director Z q' 25 I e 7MJA [9 i

Dir2ctorate of Licensing 2 Office of Regulation c, .

United States Atomic Energy Commission 4 .o N

Washington, D. C. 20545 ObsY

Dear Mr. O' Leary:

FONTICELLO NUCLEAR GENERATING PIM Docket No. 50-263 License No. DPR-22 IIPCI Steam Line High Area Temperature Switch hhlfunction i

l A condition occurred at the Monticello Nuclear Generating Plant which we are reporting to your office in accordance with Section 6.7.B.1, Abnormal Occurrence Reports, of Appendix A, Technical Specifications, of Provisional Operating License DPR-22.

On October 2,1973, while performing a quarterly surveillance test, one of sixteen HPCI Steam Line High Area Temperature switches was found to trip at 208'F. Section 3.2.1, of the Technical Specifications requires the HIEI Steam Line High Area Temperature switches to be set at <200*F. Erratic per-formance was demonstrated in subsequent retesting of the temperature switch.

The switch was therefore considered defective and will be discarded. It has been replaced with a new calibrated switch.

l This occurrence did not affect safe operation since redundant switches at the l

same location were tested and found to trip at the desired trip setting. No I previous erratic perfonnance of these or similar switches has been observed.

The temperature switch malfunction is believed to be a randam component failure, and as such, no further action is planned.

Yours very truly, M 10; f#

L. O. Mayer, PE Director of Nuclear Support Services # h IN/kik 4 94[5 g1 C b

cc: J G Keppler G Charnoff G

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Minnesota Pollution Control Agency x Attn: Ken Dzugan r.

4/ 4, 9P11200444 731012 7pg PDR ADOCK 05000263 S PDR

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