ML20148D636

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Suppls Re ATWS Mitigating Sys Actuation Circuitry Design,Per 880211 & 0303 Telcons.Final Design Will Not Use RPS Instrument Bus Power as Power Source.Safeguards 125 Ventilation Duct Chase Not Considered for Relay Power
ML20148D636
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 03/15/1988
From: Musolf D
NORTHERN STATES POWER CO.
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8803240104
Download: ML20148D636 (2)


Text

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es Northern States Power Company 414 N collet Matt Minneapohs. Minnesota 55401 Telephone (612) 330-5500 March 15, 1988 10 CFR Part 50 Section 50.62 Director Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISIAND NUCLEAR GENERATING PLANT DOCKET NOS. 50-282 LICENSE NOS. DPR-42 50-306 DPR-60 Additional Information Related to AMSAC Design

Reference:

(a) Letter dated December 1,1987 from D M Musolf, NSP, to Director of NRR, NRC, "Revision to Plant Specific AMSAC Design" The purpose of this letter is to supplement the information we provided in Reference (a) with additional information requested by the NRC Staff during telephone conference calls on February 11, 1988 and March 3, 1988.

1. AMSAC power supply The final Prairie Island AMSAC design will not use RPS instrument bus power (Red, White, Blue, or Yellow inverters) as an AMSAC power source, nor will safeguards 125 VDC be considered for AMSAC actuation relay power.

The AMSAC function will be performed in a separate microprocessor and not combined with the feedwater control logic. This microprocessor will be powered from an inverter which does not supply the RPS.

2. AMSAC Actuation Relays A. Relays will be diverse, by manufacturer or by design, from relays used in the RPS.

B. Relays used as a safety related circuit interface will meet class lE requirements.

C. Relays used as a safety related circuit interface will meet the requirements of Appendix A of the July 7, 1986, NRC Safety Evaluation Report. Item (c) gD 8803240104 880315 hV PDR ADOCK 05000292 p DCD lk

O c-Director of NRR Nodhem States Power Company March 15, 1988 Page 2 of this appendix is understood to mean that the side of the device used in the safety related circuit shall be monitored while the fault is applied to the non safety related circuit side of the device.

D. The data showing qualification of applicable isolation devices to Appendix A (see item C) will be available for a post-installation site audit of the AMSAC installation.

3. Euman Factors Considerations Any changes made to control room indication, controls, or alarms as a result of the AMSAC installation will have the approval of the Prairie Island Control Room Design Review Committee and conform to the stan-dards described in the Detailed Control Room Design Review Report.
4. C20 Setpoint The C20 setpoint will conform to WCAP 10858P-A section 4.12.1, unless future concerns deem it appropriate to make this setpoint variable.

NRC approval would be sought if a variable setpoint is used.

5. Schedule We will make every effort to meet our commitment dates for installation of AMSAC. AMSAC implementation in Unit 1 is scheduled prior to startup for Cycle 14 (about November, 1989). AMSAC implementation in Unit 2 is scheduled prior to startup for cycle 13 (about March 1989). However, the elimination of instrument busses as a potential power source will result in a change in the Prairie Irland design as described in item (1) above. This may require additional time for AMSAC implementation.

We will inform the NRC Staff of any schedule changes which may become necessary.

Q3 %.

Dsvid Musolf Manager Nuclear Support Ser ices c: Resident T- - tor, NRC Regional ....utstrator, Region III, NRC G Charnoff