ML20058K803
| ML20058K803 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 09/17/1973 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 9102140421 | |
| Download: ML20058K803 (1) | |
Text
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D C.f MSP NORTHERN STATES POWER COMPANY M IN N E A PO LI S, MIN N E SOT A 55401
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.f September 17, 1973
/p Oj ED.,
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wfs Mr. J F O' Leary, Director s..
Directorate of Licensing
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Office of Regulation y,'
U S Atomic Energy Commission
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Washington, D C 20545 N'
Dear Mr. O' Leary:
MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Further Vacuum Breaker Modifications The purpose of this letter is to advise you that NSP plans to install, at Monticello, circuitry providing control room annunciation of torus-to-drywell vacuum breaker operation.
The planned installation will utilize existing closed position limit switch viring and detection capability.
Relays in parallel with each indicator lamp at the local panel will be arranged to energize a single control room annunciator.
Similarly, relays shall be provided for the ten control room indicators to actuate a second control room annunciator.
This will provide two alarm circuits, each with separate position detector switches, and so arranged that loss of power will result in annunciation (redundant and fail-safe to loss-of-power). Operator re-sponse to the annunciation system will follow the same pattern as proposed in regard to light indications.
Until the proposed alarm system is installed and operational, NSP will con-duct a vacuum breaker leakage test on a monthly basis.
This test shall be conducted in accordance with our " Proposed Changes to the Technical Specifi-cations" dated July 10, 1973, and would verify that leakage is less than that shown on Figure 3.7.1 of that document.
Yours very truly, IQ
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4 L 0 Mayer, FL G
g; gun SEP 21 1973 $,d Director of Nuclear Support Services Enc
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Attn. K Dzugan 7()72 9102140421 730917 CF ADDCK 05000263 CF
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