ML18005A425

Provides Addl Listed Info Re plant-specific ATWS Mitigation Sys Actuation Circuitry in Response to 880429 Telcon

ML18005A425
Person / Time
Site:	Harris
Issue date:	05/10/1988
From:	Loflin L CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NLS-88-112, NUDOCS 8805190171
Download: ML18005A425 (4)

Text

ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8805190171 DOC.DATE: 88/05/10 NOTARIZED: NO DOCKET FACIL:50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina AUTH. NAME AUTHOR AFFILIATION Carolina Power S Light Co.

'OFLIN,L.I.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Provides addi listed info re plant-specific ATWS mitigation sys actuation circuitry in response to 880429 telcon. 05000400'OTES:Application DISTRIBUTION CODE: AOOID TITLE: OR COPIES RECEIVED:LTR Submittal: General Distribution L ENCL 3 SIZE:

for permit renewal filed. 05000400 ~

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 LA 1 0 PD2-1 PD 5 5 BUCKLEY,B 1 1' A INTERNAL: ACRS 6 ARM/DAF/LFMB 1 0 NRR/DE ST/ADS 7E 1 1 NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/RSB 8E 1 1 NRR/DOEA/TSB 11 1 1 NRR/PMAS/ILRB12 1 1 NUDOCS-ABSTRACT 1 1 OGC 15-B-18 1 0 G FIL 01 1 1 RES/DE/EIB 1 1 EXTERNAL: LPDR 1 .1

'1 NRC PDR NSIC 1 D

A TOTAL NUMBER'OF COPIES REQUIRED: LTTR 28 ENCL 25 I I

I I

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ggQ[l, Carolina Power 8 Light Company Y i0 SN SERIAL: NLS-88-112 United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 SUPPLEMENTAL PLANT-SPECIFIC AMSAC SUBMITTAL References 1) CP&L Letter dated January 11,1988, NLS-87-258 Plant-Specific AMSAC Submittal

2) CP&L Letter dated April 12,1988, NLS-88-084 Supplemental Plant-Specific AMSAC Submittal Gentlemen:

Carolina Power & Light (CP&L) submitted information related to the plant-specific AMSAC implementation at the Shearon Harris Nuclear Power Plant (SHNPP) as required by 10CFR50.62 (references). In conjuction with review of that information, the st:aff requested additional information in an April 29,1988 teleconference. Carolina Power & Light submits the following information in response to the NRC request.

TIMER VALUES The staff requested that, CP&L provide the value to be used for the disarm delay timer (C-20 permissive) and the basis for the setting if it differs from the value specified in the AMSAC Generic Design Package WCAP-10858 revision 1. Carolina Power & Light will use the WCAP specified value of 360 seconds for the disarm delay timer setting in the SHNPP AMSAC system.

The SHNPP AMSAC system will use a setpoint of 25 seconds for the actuate delay timer. This setpoint allows sufficient time to 1) establish auxiliary feedwater flow within the WCAP guidance of 90 seconds after receiving low-low water level signals in 2 out of 3 steam generators, and 2) establish a turbine trip within the WCAP guidance of 30 seconds of receiving 2 out of 3 low-low steam generator water level signals.

5505190171 550510 PDR'DOCK 05000400 I P.. DCD It00l 411 Fayettevilte Street s P. O. Box 1551 s Rateigh. N. C. 27602

Document NLS-88-112 Control Desk

/ Page 2 t

A endix A OUTPUT RELAY INFORMATION The staff requested that CP&L clarify the information provided regarding the maximum credible fault to which the output isolation device (isolation relay) could be subjected. Clarification of CP&L's response to Information Requests B and C in Appendix A of the SER on WCAP 10858, is as follows:

Information Re uest B Data to verify that the maximum credible faults applied during the test were the maximum voltage/current: to which the device could be exposed, and define how the maximum voltage/current was determined.

~Res onse Carolina Power & Light has examined the installed configuration and use of the Struthers-Dunn isolation relays and has determined that the maximum credible fault that these relays may be subjected to is 120 VAC. This is also the maximum potential supplied to the isolation cabinets in which the relays are installed. The Struthers-Dunn isolation relays are designed to operate at 120 VAC.

Information Re uest C Data to verify that the maximum credible fault was applied to the output of the device in the transverse mode (between signal and return) and other faults were considered (i.e., open and short circuits).

~Res ense The maximum credible fault is the design/operating voltage of the relays (coil and contact side) . The 4000 VRHS isolation test between relay coil, contacts, and frame verifies that these relays provide effective isolation at the safety-nonsafety boundary at the maximum credible fault conditions. Due to the design of the isolation device i.e., a relay and not an electronic isolator, open or short circuits on either the safety or nonsafety sides of the isolator would have no effect on the safety-nonsafety boundary isolation. Therefore, CP&L concludes that the isolation relays

4 Document Control Desk I

NLS-88-112 / Page 3 will limit a failure or malfunction to the side of the relay where the failure or malfunction occurs.

Carolina Power & Light expects that this information is responsive to the requests of the staff. Please refer any questions regarding this submittal to Mr. Steven Chaplin at (919) 836-6623.

Yours very truly, Leonar I. L flin Manager Nuclear Licensin Section LIL/SDC cc: Mr. B. C. Buckley Dr. J. Nelson Grace Mr. G. F. Maxwell