ML20056B990
| ML20056B990 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 03/08/1974 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 9105060231 | |
| Download: ML20056B990 (1) | |
Text
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Rekulatory File Cy.
NSF NORTHERN STATES POWER COMPANY MI N N E A POLI S. M IN N E S OTA 58401 March 8, 1974 p
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Mr. J F O' Leary M
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Nf Office of Regulation M
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Washington, DC 20545
Dear Mr. O' Leary:
W i
}DNTICELID NUCLEAR GENERATING PIANT Docket No. 50-263 License No. DPR-22 Supplement No. I to" January 23, 1974 Report Entitled
" Permanent Plant Changes to Accommodate Equilibrium t
Core Scram Reactivity Characteristics" l
on January 23, 1974, we submitted a report entitled " Permanent Plant j
Changes to Accommodate Equilibrium Core Scram Reactivity Characteristics."
l In subsequent discussions on the subject, you requested that we identify the measures taken to interface the Prompt Relief Trip System (PRT) without degrading existing safety systems. The PRT interfaces with the Reactor Protection System (RPS) and the Automatic Pressure Relief System (APR).
The PRT does not degrade the capability of either of these systems.
The PRT receives isolated relay contact outputs from the RPS. The inputs to PRT channel A (division 1) are from RPS channels A (division IA) and B (division IB). A single failure in PRT channel A will not disable both RPS channels A and B.
The relay contacts will prevent reflection into the remainder of each RPS channel.
The PRT has outputs to the relief valves through the APR syste:n in several cases.
The PRT outputs are electrically paralleled with the APR outputs. A short circuit of the PRT output will open a relief valve but will not affect the APR. A hot short of the wrong polarity on a PRT output will blow the fuses in the APR for one relief valve. The outputs from the PRT are of the same grade and configuration as the APR outputs.
Yours truly, gO.
gQ ; psf L 0 Mayer, PE h] $
Director of Nuclear Support Services 3
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Minnesota Pollution Control Agency bw g W' 2113 Attn. E A Pryzina rr 9105060231 740308 C
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