ML18054A493
| ML18054A493 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 01/19/1989 |
| From: | Frisch R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| TAC-59123, NUDOCS 8901240151 | |
| Download: ML18054A493 (1) | |
Text
L consumers Power l'DWERINli MICHlliAN'S l'RDliRESS General Offices: 1945 West Parnell Road, Jackson,' Ml 49201 * (517) 788-0550 January 19, 1989 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION ON 4TWS MODIFICATION (TAC 59123)
By letters dated April 23, 1986 and June 30, 1987, Consumers Power Company provided proposed design information to meet 10CFR50.62 Anticipated Transients Without Scram (ATWS) rules.
In these previous submittals, we had. proposed to provide 120 VAC for the Diverse Scram System (DSS) ATWS matrix relays from the same four vital AC power source as the existing Reactor Protection System (RPS).
By Nuclear Regulatory Commission letter dated August 5, 1988, Consumers Power Company was informed the design requirement for electrical independence took precedence over power supply reliability.
To accommodate this NRC position, the design for DSS power sources has been changed.
The two left channel ATWS matrix relays are now powered by separate circuit breakers from 120 VAC panel L-59.
The two right channel ATWS matrix relays are now powered by separate circuit breakers from 120 VAC panel L-58.
Both of these panels are located in the cable spreading room.
Panel L-58 is fed from 480 VAC MCC No. 24 and panel L-59 is fed from 480 VAC MCC No. 21.
~hese motor control centers are automatically powered from the emergency diesel generators on loss of offsite power.
This arrangement of power sources provides electrical independence and minimizes the potential for common mode failures.
Senior Licensing Analyst CC Administrator, Region III, NRC NRC Resident Inspector - Palisades
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