ML17305A253

Responds to Request for Addl Info Re 10CFR50.62 (ATWS Rule). Westinghouse Relays (Isolation Devices) to Be Utilized Will Comply W/Environ & Seismic Qualification Design Basis for Licensing

ML17305A253
Person / Time
Site:	Palo Verde
Issue date:	09/29/1989
From:	Conway W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
161-02405-WFC-A, 161-2405-WFC-A, NUDOCS 8910030339
Download: ML17305A253 (18)

Text

AC CELE RATED STRIBU'n ON DEMON RATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

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05000528 05000529 05000530 NOTES: Standardized plant.

Standardized plant.

ACCESSION NBR:8910030339 DOC.DATE: 89/09/29 NOTARIZED: NO DOCKET FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH.NAME AUTHOR AFFILIATION CONWAY,W.F.

Arizona Public Service Co.

(formerly 'Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Responds to request for addi info re 10CFR50.62 (ATWS Rule).

DISTRIBUTION CODE:

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TITLE: OR/Licensing Submittal:

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PHOENIX, ARIZONA85072-3999 WILLIAMF. CONWAY EXECUTIVEVICEPRESIDENT NUCLEAR 161-02405-WFC/ACR/KLMC September 29, 1989 Docket Nos.

STN 50-528/529/530 Document Control Desk U.

S. Nuclear Regulatory Commission Mail Station Pl-37 Washington, D.

C.

20555

References:

1) 2)

Letter from T. L. Chan, NRC, to D. B. Karner, APS, dated April 5, 1989.

Subject:

Request for Additional Information - 10 CFR 50.62 (ATWS Rule)

Letter to the NRC from D. B. Karner,

APS, dated April 27, 1989.

Subject:

Schedule for

Response

to Request for Additional Information-10 CFR 50.62 (ATWS Rule)

Dear Sirs:

Subj ect:

Palo Verde Nuclear Generating Station Units 1, 2 and 3

Response

to Request for Additional Information-10 CFR 50.62 (ATWS Rule)

File: 89-056-026 As requested by Reference 1),

Arizona Public Service Company (APS) is providing a response to the request for additional information.

APS's response to Item 2 of Reference

1) is provided in the attachment to this letter.

If you should have any questions concerning this matter please contact Mr. A. C. Rogers of my staff, at (602) 371-4041.

Sincerely, WFC/ACR/KLMC/jle Attachment cc:

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B. Martin T. L. Chan M. J.

Davis T. J. Polich (all with Attachment) 85'10030335'90929 PDR ADOCK 0500052S P

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ATTACHMENT APS Response to Request for Additional Information -

DSS Modification NRC Position Based on the staff's review of CE letters. dated February 27, and September 18,

1987, the following list, of questions was generated.

Please provide the response to these questions.

network that opens the MG Set output load contactors.

APS Res onse Diagram A (attached) reflects the Diverse Scram System (DSS) modification and the selective logic that will open the Motor-Generator (M-G) Set output load contactors.

grade portion of the circuits and show the location of the isolators

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APS Res onse The control grade portion of the ATWS DSS modification is depicted on Diagram A (attached).

their source of power.

APS Res onse Figure 1 ('attached),

has been modified to contain the requested information on the power supplies and sources.

Item 2

d Contrary to the statement in CEN-362, the diverse reactor trip and diverse turbine trip have not been resolved.

Provide the details showing how these two trip systems are in conformance with the ATWS Rule implementation guidance.

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APS Res onse The existing PVNGS

design, as described in the

UFSAR, incorporates several safety grade systems designed to protect the plant and'mitigate the consequences of the ATWS event in addition to various design basis events.

These include the following features:

Reactor Protective System (RPS)

- Initiates a reactor trip to protect the RCS pressure boundary in the event of high pressurizer pressure, or low.steam generator level'(conditions indicative.of an ATWS).

The syst: em consists of sensors, bi'stables, bistable relays, matrix relays, initiation,rel'ays, and actuation devices.

Core Protection Calculators (CPCs)

- Provide inputs,to the Reactor Protective System (RPS) by actuating the appropriate RPS bistable relays when cold leg temperature.or pressurizer pressure exceed the allowable range '(conditions indicative of an ATWS).

Engineered Safety Features Actuation System (ESFAS)

Generates an Auxiliary Feedwater Actuation Signal (AFAS), in the event of low steam. generator level.

The system utilizes the outputs from RPS sensors to actuate the AFAS specific bistables, bistable relays, matrix relays, initiation relays, and actuation devi;ces.

Supplementary Protection. System (SPS)

- This diverse reactor trip system augments the RPS by utilizing an independent

-and diverse trip logic (relative to the RPS) for initiation of a reactor trip.

The SPS provides a simple, reliable, and diverse mechanism to increase

.the reliability of a reactor trip when the pressurizer pressure exceeds a predetermined value.,

The existing.

SPS is a four channel safety grade system which is independent and diverse from the

CPCs, RPS (up to the final actuation device),

and the AFAS.

The final actuation devices for the SPS safety grade reactor trip are the reactor trip breakers whi.'ch are also actuated by an RPS trip signal.

To provide full compliance with the ATWS rule, APS will modify, by the 'DSS modification, the existing SPS to reflect the addition of control grade circuitry to allow the 'SPS to trip the CEDM M-G Set output load contactors.

'This trip, with appropri'ate isolation, will be diverse and independent from the RPS actuation of the reactor trip breakers.

The isolation devices will maintain the current.reliability of the,SPS as a safety grade.system.

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The SPS, with the DSS,Modification, provides a turbine trip initiation that is diverse and independent from the reactor'rip system.

The SPS causes a reactor trip by interrupting power to the Control Element Assembly common power bus.

Upon interruption of this power, undervoltage relays attached to the bus de-energize, causing actuation of the turbine trip circuitry.

The turbine trip is initiated from both the existing RPS and through the diverse modified SPS.

.APS Res onse This information, as requested, is provided in Attachment l.

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Attachment 1

Isolation 'Devi'ce Request for Additional Information NRC Position Each light-water-cooled nuclear reactor shall be provi'ded with a system for the prevention and/or mitigation of the effects from Anticipated Transient Without Scram (ATWS),

events.

The Commissi'on-approved requirements for the prevention/mitigation of ATWS events are defined in the Code of Federal Regulations (CFR) Section 10 paragraph 50.62.

The staff has determined that the isolation devices used within ATWS prevention/mitigation systems (to provide isolation between class lE and non-class lE circuits or between redundant class lE circuits) will'e reviewed on a plant-specific

'basis.

The following additional informati'on is required to continue and complete the plant-spec'ific isolator review:

Isolation Devices

,Please provide the following:

(a)

For the type of device, used to accomplish electrical isolation, describe the specific testing performed.to demonstrate that the device is acceptabl'e for 'its application(s).

Thi:s description should include elementary diagrams, when necessary, to indicate the test configuration and should describe how the maximum credible faults were applied to the devices.

(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.

(c)

Data to verify that the maximum credible fault was applied to the non-Class 1E side of the device in the transverse mode (between signal and return) and'hat other faults were considered (i.e.,

open and short circuits).

(d)

Define the pass/fail acceptance criteria for each type of device.

APS Response Westinghouse

relays, Catalog ¹AR440A, are to be utilized as the isolation device for the DSS Modification.

This type of relay has been qualified and utilized as isolation devices. in existing design applications at PVNGS.

The Westinghouse

¹AR440A relay is an industrial type device.

The relay

contacts, which have a.high current rating, are utilized in a low energy contol circuit application;

hence, the maximum credible fault issue is considered'o be incredible for this application.

No additional testing or analysis will be performed based on the design application of the

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relays.

The coil of the relay is wired in the Class 1E circuitry of the existing Supplementary Protection System (SPS) and the contacts, which are considered non-lE, supply, open signals to the M-G set output load contactor control circuitry.

(e)

A commitment that the isolation devices comply with the environmental qualifications (10 CFR 50.49) and seismic qualifications that were the basis for plant licensing.

APS Res onse The Westinghouse relays (isolation devices) to be utilized willcomply with the environmental and seismic qualification design basis for PVNGS licensing.

(f)

A description of the measures taken to protect the safety systems from electrical interference (i.e., Electrostatic

Coupling, EMI, Common Mode and Crosstalk) that may be generated by the ATWS circuits.

APS Res onse The isolation relays have been qualified and utilized as isolation devices in existing similar design applications at PVNGS.

The relay design application is in accordance with IEEE Standard 384 and has proven itself by past operation as no electrical interference (Electrostatic

Coupling, EMI, Common Mode and Crosstalk) has been experienced by these design applications.

(g)

Information to verify that the Class lE isolator is powered from a Class lE'source.

APS Res onse The isolation relays (Class 1E coil, non-lE contacts) for the M-G Set contactors actuation is powered from the same Class 1E source as its respective Supplementary Protection Logic Assembly panel.

These panels are powered from the four Class 1E 120 VAC Vital Instrument buses (channels)

E-PNA-D25, E-PNB-D26, E-PNC-D27 and E-PND-D28.

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DIAGRAMA Channel A Initiation Relay Leach Model ¹9207-805 Channel B Initiation Relay Leach Model ¹9207-805

~ Control Grade Channel A holation Rchy Wcstintthouse Model NAR440A Channel B hobtiott Relay Wcstintthouse Model NAR440A C

H A

B N

N E

L D

T R

C B

S I

C N

A D

L Open Contactor Panel ¹1 Channel C Initiation Relay Leach Model ¹9207-805 Channel D Initiation Relay Leach Model ¹9207-805 ChannclC Isolation Rchy Westinghouse Model NAR440A Channel D holation Rchy Westinghouse Model NAR440A Control Grade C

H A

B N

N E

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B S

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L Open Contactor Panel ¹2 SPLA Panels SPLA Isolation Panels M-G Set Control Panels 1 8c 2 ATWS DSS MODIFICATION

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FIGURE I: DIVERSIIYOF THE EXISTINGAUXILIARYFEEDWA'IERACIUATIONCIRCUIIRYFOR PALO VERDE NUCLEARGI2KRATINGSTATIONUNITS I, 2, &3 (ModiT!cd to include power supplies snd power sources)

~S~OQ h<KhX!QK j3EVICFQ PZR Presaue Rosemont Ca-paeitancc Sens-ing Element (Hyperio N HY-7210-1)

<120 VAC 1E Vital inst pwrs Simmonds Pre-cision Compara-tor Model N 104-13-D 104191 (Hyperion N HY-7210.1)

<120 VAC IE Vital Inst Pwr.

Leach Relay hfo.

dcl N9207405 (Hyperion N HY-7210-1)

<120 VAC 18 Vital InstPcs CEDhI M<3Sct Output Load Coatsctors (aoac)

<120 VAC, non.lEs SPS ACIUATION CIRCUITRY CPC - PRZ Press Barton Bourdon Tube Core Inkt Temp RdF RTD w/Foxboro Whcatstonc Bridge (Simmonds Prec Yiion N3118050411)

<120 VAClE Vital Inst Pwr>

Gould (SEL)

Voltage Compar.

atof (Simmonds Pre elsion N3118-05001)

<120 VAC 18 Vital Inst Pwrs E.MTransistor Driver@cod Re-lays Model Assy 33335 (Lambda NLRS 57-1242793)

<120 VAC18 Vital Inst Pwas E.MTransistor Driver-Rccd Re-lays Model Assy 3333$

(Lambda NLNS-4-1242794)

<120 VAC 18 Vital Inst Pwrs P&B Model KAIIDGEkc-tro-Mochanical Relay (Laabda NLNS-4-1242794)

<120 VAC1E Vital Inst Pwrs Wcsdagho use Model DS206 &

GBModel AK22S (none)

<12S VDC(IE)s REACI'OR TRIP SYSTEM ACTUATION CIRCUIIRY PRZ Pressure Banon Bourdon Tube/Bellows (Foxboro N2AI.

12V)

<120 VAC lE Vital Imt Pwe>

E.M Bistabk Comp arator hiodcl Assy 33441 (Lambda NLRS-57-1242793)

<120 VAC 18 Vital InstPwro E.MTraasistor Dnvcrdiced Re-lays Model Assy 3333$

(Lanbda NLRS-57-1242793)

<120 VAC 18 Vital Inst Pwrs 8-MTransistor Ddvcr-Rccd Re-lays Model Assy 3333$

(Lanbda NLNS-4-1242794)

<120 VAC 18 Vital Inst Pwin (Vendor &P/N) - Power Supply

<)-Power Soumc, Iurur 18 Channels A,B, C &D SG Level Birton Mechanical Bel.

iowa/Straia Gage (Foxboro N2AI-12V)

<120 VAC18 Vital Inst Pwca E MBhtablc Corap are tot hiodcl Assy 33441 (Lambda NLRS-S7-1242793)

<120 VAC18 Vital Inst Pwu E-MTransistor Drivcr-Rocd Re-lays hfodel Assy 33335 (Lanbda NLRS 57-1242793)

<120 VAC18 Vital Iast Pvne.

F MTransistor Driver-Reed Re-lays Model Assy 3333$

(Lambda NLNS-4-1242794)

<120 VAC 18 Vital Inst Pwtn P&B Model KR3-DH12Elcc-tio-Mechanical Relay (Lambda NLNS-4-1~4)

<120 VAC 18 Vied inst Pcs P&8 Rotary Re-lays MDR 7032, 7033 &7034 and MDR-138-1 (Lambda NLRS-584843054)

<120 VAC 18 Vital Inst Pwrs AUXILIARY FEEDWATER SYSTEM ACIUATION CIRCUIIRY

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