ML20247J705

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Summary of 890501 Meeting w/C-E Owners Group in Rockville,Md Re Diverse Emergency Feedwater Actuation Sys,Per 10CFR50.62 Requirements.List of Meeting Attendees & Viewgraphs Encl. Record Copy
ML20247J705
Person / Time
Site: Arkansas Nuclear, Waterford, San Onofre, 05000000
Issue date: 05/19/1989
From: Huan Li
Office of Nuclear Reactor Regulation
To: Newberry S
Office of Nuclear Reactor Regulation
References
NUDOCS 8906010109
Download: ML20247J705 (35)


Text

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/ o UNITED STATES 6  !" '

% NUCLEAR REGULATORY COMMISSION

.( ,$. WASHINGTON, D. C. 20555

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MAY J g Lagg item 0RANDUM FOR: Scott Newberry, Chief Instrumentation & Control Systems Branch Division of Engineering & Systems Technology THRU: Jerry L. Mauck, Section Chief Instrumentation & Control Systems Branch Division of Engineering & Systems Technology FROM: Hulbert C. Li Instrumentation & Control Systems Branch Division of Engineering & Systems Technology

SUBJECT:

SUMMARY

OF MEETING WITH CE0G ON DIVERSE EMERGENCY FEEDWATER ACTUATION SYSTEM DESIGN IN ACCORDANCE WITH 10CFR50.62 REQUIREMENTS At the request of the CE Owners Group (ANO-2, Waterford 3, San Onofre 2&3), a meeting was held on May 1, 1989 in Rockville, Maryland. The purpose of the meeting was to discuss a conceptual design of the diverse emergency feedwater actuation system in accordance with 10CFR50.62 requirements. The CE0G's presentation outline is shown in Attachment 1. A list of attendees is shown in Attachment 2.

The CEOG submitted a report CEN-384 " Design for a Diverse Emergency Feedwater Actuation System " dated April 1989 on the Docket Nos. 50-361, 50-362, 50-368 and 50-382. This report was submitted in response to the NRC's previous denial on exemption requests with respect to 10CFR50.62 diversity requirements. The report describes a Non-Class 1E Diverse Emergency Feedwater Actuation System (DEFAS) that addresses the conformance to the requirements of 10CFR50.62.

A key design basis of the DEFAS is that the DEFAS would be required only upon failureoftheexistingPlantProtectionSystem(PPS)demandsforEmergency Feedwater and the initiation of the Diverse Scram system (DSS). The DEFAS would not interfere with accident mitigation function by the PPS.

The staff acknowledges the need for the PPS to override the DEFAS, however, the staff is questioning the timing of Emergency Feedwater under an ATWS event due to this adoitional DSS interlock in the DEFAS system. The staff needs further investigation on this subject.

The conceptual design will be applicable to ANO-2 and Sin Onofre 2 and 3.

The Waterford plant DEFAS, which is diverse from the PPS, will employ a 2-out-of-2 logic Class 1E subsystem added in the existing EFAS cabinets.

The DEFAS logic will also incorporate a steam generator (SG) high level S

gowoioD n %p

b Scott Newberry i input to protect the SG and the turbine from damage. The staff finds that the Waterford conceptual design is a valid ,npproach. However, the information in' Appendix B of the CEN-384 report is not sufficient to make a final e determination. .The Waterford licensee has agreed to provide more detailed -

information on their design in the near future.

'A key concern that was presented by CE0G was'their continual belief that the implementation of DEFAS could have a negative impact on plant safety. This was discussed at length but the concern was not resolved. The staff indicated that we would not accept any system design that would negatively impact safety  ;

however the staff did not share the CEOG belief that DEFAS would have a negative <

safety impact. This will be the subject of continuing discussions in the near future.

A*J[ed

/

Cb Hulbert C. Li Instrumentation & Control Systems Branch Division of Engineering & Systems Technology

Enclosures:

As stated cc w/ enclosures:

A. Thadani W. Hodges J. Calvo-G. Knighton D. Lynch V. Thomas D. Hickman C. Poslusny D. Wigginton T. Chan A.Nolan(INEL) I i DISTRIBUTION: i l :ContralEFiles2 l l SICB RF PDR l LPDR l SNewberry l JMauck HLi SICB: DEST SICB: DESTf gg ,

HLi /ft fjy JMauck I Sh f/89 5////89 E________----___--__--___--- . _ - - - - - - - . - _ - - - - - - - - - - -J

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C-E OWNERS GROUP (ANO-2, WATERFORD 3, SAN ONOFRE 2&3)

MEETING WITH THE NRC STAFF ON DIVERSE EMERGENCY FEEDWATER ACTUATION SYSTEM (DEFAS)

DESIGN IN ACCORDANCE WITH 10CFR50.62 l

MONDAY, MAY 1, 1989 I

4

. i TOPICS SECTION TITLE I. OVERVIEW II. EXISTING PPS EFAS DESIGN III. DIVERSE EFAS SYSTEM IV. DEFAS 10CFR50.62 COMPLIANCE V. REQUESTED AREAS OF NRC CONCURRENCE S

6

4 I. OVERVIEW INTENT OF THE MEETING IS TO DISCUSS THE TECHNICAL ISSUES ON THE DESIGN FOR A DIVERSE EMERGENCY FEEDWATER ACTUATION SYSTEM-(DEFAS) TO COMPLY WITH 10CFR50.62 ADDITIONAL DEFAS DESIGN DETAILS ARE PROVIDED IN CEOG DRAFT REPORT (CE-NPSD-384)

GOALS OF THE MEETING INCLUDE PROVIDING THE NRC STAFF WITH' ADDITIONAL INSIGHT INTO THE PROPOSED DEFAS IMPLEMENTATION, COMPLIANCE AND AREAS OF REQUESTED NRC CONCURRENCE b

'4 ..

II. EXISTING PPS EFAS DESIGN

~

PLANT PROTECTION SYSTEM (PPS) CONSISTS OF'

. REACTOR PROTECTIVE SYSTEM (RPS) AND ENGINEERED-SAFETY FEATURES ACTUATION SYSTEM (ESFAS)

THE EMERGENCY FEEDWATER ACTUATION SYSTEM (EFAS)

IS ONE'0F THE ESFAS SYSTEMS AND IS THE BASIS FOR THIS DESIGN EFFORT.

THE EFAS INITIATES EMERGENCY (AUXILIARY)

FEEDWATER TO THE INTACT STEAM GENERATOR (5)

FOLLOWING A LOW INVENTORY FOR WHATEVER REASON

- EFAS INITIATES USING A 2/4 LOGIC WHEN EITHER;

'SETPOINT 4

O_j

0 II. EXISTING PPS EFAS DESIGN (CONT.)

- THE INITIATING SIGNAL INTERFACES WITH THE AUXILIARY RELAY CABINETS (ARC) WHICH IN TURN INTERFACE AND ACTUATE THE VARIOUS EFAS COMPONENTS e

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POTOR CONTICL CENTElt PLDP5 VALVES

Title:

PPS GENERAL BLOCK DIAGRAM

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. o o MOTOR CONTROL CENTER #CTOR CONTROL CENTER TRAIN A TRAIN 8 4 4 I 4 EFAS TRAIN A EFAS TRAIN A EFAS 78ULIN 8 EFAS TRAIN 8 VALVE 5 PtAf5 YALVES PupF

Title:

PPS SYSTEM BLOCK DIAGRAM L

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Title:

PPS EFAS SIGNAL LOGIC DIAGRAM - CHAMEL e

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Title:

ESFAS AUX, RELAY CABINET EXISTING FUNCTIONAL LOGIC DIAGRAM

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III. DIVERSE EFAS SYSTEM A. PURPOSE THE PURPOSE OF THE DIVERSE EMERGENCY FEEDWATER ACTUATION SYSTEM (DEFAS) IS TO PROVIDE EQUIPMENT THAT COMPLIES'WITH THE REQUIREMENTS OF THE ATWS RULE, 10CFR50.62 THE DEFAS PROVIDES'FOR THE ACTUATION OF THE EMERGENCY FEEDWATER DURING AN ANTICIPATED OPERATIONAL OCCURRENCE (A00) REQUIRING EMERGENCY.FEEDWATER COINCIDENT WITH A FAILURE OF THE PLANT PROTECTION SYSTEM (PPS) AND -

INDICATION OF THE DIVERSE SCRAM SYSTEM (DSS) i

III. DIVERSE EFAS SYSTEM B. FUNCTIONAL REQUIREMENTS

- DEFAS MUST INITIATE EMERGENCY FEEDWATER FLOW FOR CONDITIONS INDICATIVE OF AN ATWS WHERE THE EFAS HAS FAILED.

THE DEFAS WILL NOT BE REQUIRED TO PROVIDE ACCIDENT MITIGATION SUCH AS ISOLATION FEED TO A RUPTURED STEAM GENERATOR.

DEFAS WILL SECURE FEEDING THE AFFECTED STEAM GENERATOR (S) UPON REACHING A PREDETERMINED LEVEL SETPOINT (APPROXIMATELY 30 MINUTES AFTER ACTUATION) FOLLOWING WHICH MANUAL OPERATOR INTERVENTION WILL CONTROL SYSTEM.

DEFAS WILL UTILIZE LOGIC AND REDUNDANCY TO ACHIEVE A 2-0UT-0F-2 INITIATION, AS A MINIMUM.

- DEFAS WILL UTILIZE STEAM GENERATOR LEVEL AS THE PARAMETER INDICATIVE OF THE NEED FOR EFAS ACTUATION.

III. DIV RSE EFAS SYSTEM B. FUNCTIONAL REQUIREMENTS (CONT.)

DEFAS WILL INTERFACE TO THE ACTUATED CGMPONENTS~

VIA THE EXISTING AUXILIARY RELAY CABINET (ARC)

RELAYS.

-- DEFAS WILL BE BLOCKED BY THE EFAS TO PREVENT CONTROL / SAFETY INTERACTIONS AND TO DISABLE DEFAS WHEN THE EFAS SYSTEM ACTUATES.

DEFAS WILL BE BLOCKED BY THE MSIS SIGNAL TO PREVENT CONTROL / SAFETY INTERACTIONS AND TO .

DISABLE THE DEFAS WHEN CONDITIONS FOR MSIS EXISTS.

4

- DEFAS WILL BE ENABLED BY AN ENABLE SIGNAL, INDICATING DSS ACTUATION, FROM THE DIVERSE l SCRAM SYSTEM (DSS).

- DEFAS WILL INCLUDE TESTING CAPABILITIES THAT ALLOW TESTING TO OCCUR AT POWER.

F ...

III. DIVERSE EFAS SYSTEM B. FUNCTIONAL REQUIREMENTS- (CONT.)

DEFAS WILL INCLUDE FEATURES THAT PROVIDE ANNUNCIATOR, PLANT COMPUTER AND OPERATOR INTERFACE TO ALLOW FOR SYSTEM STATUS AND OPERABILITY REQUIREMENTS.

DEFAS SETPOINTS WILL BE LOWER THAT THE PPS SETF0INTS S0 THAT A RACE CONDITION BETWEEN THE PPS AND DEFAS MAY BE PREVENTED.

. 1 e

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--- - _ _ . - . _ _ - - _ _ . - - ____. _____________________________________1

4 III.DIVIRSEEFASSYSTEM-C. SYSTEM INTERFACES SENSORS

  • EXISTING NARROW RANGE SENSORS
  • FIBER-OPTIC ISOLATGRS
  • EXISTING POWER IN PROCESS CABINETS TO -

POWER FIBER-OPTIC ISOLATORS DEFAS HARDWARE

  • CONTROL GRADE EQUIPMENT l
  • TWO (2) PLC's RECEIVE IDENTICAL SIGNALS
  • UNINTERRUPTABLE POWER SUPPLY
  • TEST PANEL

- III. DIVERSE EFAS SYSTEM C. . SYSTEM INTERFACES (CONT.)

- DEFAS HARDWARE (CONT.)

  • FIBER-OPTIC COMMUNICATION WITH AUXILIARY RELAY CABINET DISTRIBUTED I/O SYSTEM DEFAS LOGIC
  • 2/4 LOGIC
  • PLC #1 TRIPS ARC TRIP LEG 1 - 3
  • PLC #2 TRIPS ARC TRIP LEG 2 - 4
  • TESTING AT POWER CAPABILITIES
  • EACH PLC GENERATES TWO OUTPUTS:

DEFAS 1 AND DEFAS 2

  • TRANSMISSION OF DEFAS 1 AND DEFAS 2 OVER SERIAL FIBER-OPTIC LINKS TO ARC 4

9

- - - - _ . _ _ _ _ _ _- _ _ _ _ _ _ - - _ _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ - _ - _ _ _ - - - - _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _

III. DIVERSE EFAS SYSTEM C. SYSTEM INTERFACES (CONT.)

- AUXILIARY RELAY CABINET

  • DEFAS RELAYS CONTROL CYCLING RELAY TRIP LEGS i
  • INDICATOR PANEL FOR TESTING AND RELAY INDICATION
  • BYPASS CAPABILITY
  • TESTING CAPABILITY l
  • BLOCKING LOGIC TO DISABLE DEFAS WHEN PPS FUNCTIONING NORMALLY S

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Title:

DEFAS/PPS GENERAL BLOCK DIAGRAM

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DEFAS CONCEPTUAL LOGIC DIAGRAM FOR SG-1 l

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Title:

l ESFAS AUX RELAY CABINET SIMPLIFIED FUNCTIONAL DIAGRAM

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DIVERSE EMERGENCY FEEDWATER ACTUATION SYSTEM I I I I I I I I I I I I I I I I DEFAS 1 l 2 TEST DEFAS 2 4 5 6 TEST e

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Title TYPICAL DEFAS INDICATOR FOR AUX RELAY CABINET

- - - - - - - -________--__________________________L

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III.DIVkRSEEFASSYSTEM D. . WATERFORD 3 PLANT SPECIFIC EFAS DESIGN 1

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IV. DEFAS'10CFR50.62 COMPLIANCE THE DEFAS HAS BEEN DESIGNED IN ACCORDANCE'WITH THE GUIDELINES SET FORTH IN 10CFR50.62

' GUIDELINE COMPLIANCE INCLUDES; A. SAFETY CLASSIFICATION

  • DEFAS IS A NON-SAFETY RELATED CONTROL GRADE SYSTEM THAT INTERFACES WITH'OTHER SAFETY RELATED SYSTEMS THROUGH QUALIFIED ISOLATORS B. REDUNDANCY
  • DEFAS IS NOT REQUIRED TO CONTAIN REDUNDANCY -

C. SEPARATION FROM EXISTING REACTOR TRIP SYSTEM  ;

  • DEFAS IS ISOLATED THROUGH QUALIFIED ISOLATORS AND IS ELECTRICALLY AND PHYSICALLY SEPARATED FROM THE EXISTING REACTOR TRIP SYSTEM D. ENVIRONMENTAL QUALIFICATION
  • DEFAS IS ENVIRONMENTALLY QUALIFIED FOR A00 CONDITIONS 9

i

  • +.

IV. DEFAS IOCFR50.62 COMPLIANCE (CONT.)

E. SEISMIC QUALIFICATION

  • DEFAS IS NOT REQUIRED TO BE SEISMICALLY QUALIFIED F. QUALITY ASSURANCE
  • DEFAS WILL BE DESIGNED AND MANUFACTURED

^

CONSISTENT WITH SUITABLE QUALITY ASSURANCE PROCEDURES G. SAFETY RELATED POWER SUPPLY

  • DEFAS LOGIC IS POWERED BY BATTERY BACKED NON-SAFETY RELATED POWER SUPPLIES -

H. TESTABILITY AT POWER

  • DEFAS DESIGN SUPPORTS TESTING AT POWER I. DIVERSITY FROM EXISTING REACTOR TRIP SYSTEM
  • DEFAS IS DIVERSE FROM THE EXISTING REACTOR TRIP SYSTEM CONSISTENT WITH THE IOCFR50.62 GUIDANCE i

i 4

IV. ' DEFAS 10CFR50.62 COMPLIANCE (CONT.)

J. ELECTRICAL INDEPENDENCE

  • DEFAS IS ELECTRICALLY INDEPENDENT FROM THE EXISTING REACTOR TRIP SYSTEM I. INADVERTENT ACTUATION
  • DEFAS IS DESIGNED TO MINIMIZED INADVERTENT ACTUATIONS W

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4 V. REQUESTEDAREASOFNRCCONCURRENCE SEVERAL SAFETY RELATED IMPLICATIONS HAVE BEEN IDENTIFIED DURING THE DESIGN OF THE DEFAS THAT NEED TO BE ADDRESSED BASED ON THE PRESENT STATE OF DESIGN THE FOLLOWING IMPLICATIONS HAVE BEEN DEVELOPED; CONTROL SYSTEM INTERACTIONS FUNCTIONAL DUPLICATION ISOLATION OF RUPTURED STEAM GENERATOR OPERATOR ACTION

-/ POWER SOURCES n;;-

INADVERTENT ACTUATION -

SEPARATION FROM EXISTING SYSTEM

-/ TECHNICAL SPECIFICATIONS l THESE AND POSSIBILITY OTHER AREAS OF THE DEFAS DESIGN i

WILL REQUIRE NRC FLEXIBILITY IN THE REVIEW PROCESS PRIOR TO THE INSTALLATION OF A DEFAS I

i j

l IS01.ATION OF A RUPTURED STEAM GENERATOR ,

DEFAS HAS NO ISOLATION LOGIC STEAMLINE BREAK INSIDE CONTAINMENT INADVERTENT ACTUATION JUST PRIOR TO STEAMLINE BREAK DURING A STEAM GENERATOR TUBE RUPTURE BEST ESTIMATE ANALYSIS CEPAC COMPUTER CODE USED ON PC STEAMLINE BREAK INSIDE CONTAINMENT WITH AND WITHOUT DEFAS ACTUATION SGTR WITH DEFAS MISOPERATION

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STEAMLINE BREAK RESULTS MORE RAPID C00LDOWN OF PRIMARY 0 MODERATOR FEEDBACK 0 DNB CONCERNS 0 RETURN TO POWER 0 INCREASE IN CONTAIMENT PRESSURE ESTIMATED APPROXIMATELY 2 PSI 4

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