ML20151W062

Summary of 880728 Meeting W/Numarc & Utils in Rockville,Md Re Implementation of A-44 Rule.Obtained Staff Feedback on Draft Generic Response to Station Blackout Rule for Plants Not Using Alternate AC Power

ML20151W062
Person / Time
Issue date:	08/15/1988
From:	Serkiz A NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	Kniel K NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
Shared Package
ML20151W065	List: ML20151W062
References
REF-GTECI-A-44, REF-GTECI-EL, TASK-A-44, TASK-OR TAC-40577, NUDOCS 8808230228
Download: ML20151W062 (36)

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,,(pa sto'g f, UNITED STATES y))w( g NUCLEAR REGULATORY COMMISSION 2 ,

j WASHINGTON, D, C. 20555

\.~....j AUG 2 g gggy MEMORANDUM FOR: Karl Kniel, Chief Reactor and Plant Safety Issues Branch Division of Safety Issue Resolution, RES FROM: Aleck W. Serkiz, Senior Task Manager Reactor and Plant Safety Issues Branch Division of Safety Issue Resolution, RES

SUBJECT:

MEETING MINUTES - NUMARC'S IMPLEMENTATION OF THE A-44 RULE Date: July 28, 1988 Location: Room 10 B-11, One White Flint North Building Rockville, Maryland Agenda: See enclosed agenda.

Attendees: See enclosed attendance listing.

Meeting

Purpose:

This meeting was held at the request of NUMARC to obtain staff feedback on the following items:

1. NUMARC's "Draft Generic Response to Station Blackout Rule for Plants Not Using Alterne; AC Power" (Enclosu:e A).

2. NUPARC's "Draft Generic Response to Station Blackout Rule for Plants Using Alternate AC Power" (Enclosure B).

3. NUMARC's "Draft Appendix F: Assessments uf Ec.uipment in Dominant Areas Under Station Blackout Operability Conditions (Revision 1)" (Enclosure C).

4. NUMARC's "Draft Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at 1 Light Water Reactors, Appendix F Topical Report",

July 21, 1988, (Enclosure D).

Meeting Sunwary: NRC and NUMARC staff exchanged initial views regarding the content of Enclosures A, B, C and D. The NRC staff stated that additional time was needed to adequately review these documents and a follow-up meeting was targeted for late August 1988, hhkkkOkdkac enu

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K. Kniel Principal review responsibility rests with NRR/SELB and NRR/SPLB.

Outstanding Actions: Obtain review comments from NRR/SELB and NRR/SPLB prior to the next meeting with NUMARC.

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Aleck W. Serkiz, Senior Task Manager Reactor and Plant Safety Issues Branch Division of Safety Issue Resolution Office of Nuclear Regulatory Research cc: w/ Enclosures T. Speis, RES R. W. Houston, RES W. Minners, RES K. Kniel, RES A. Thadani, NRR F. Gillespie, NRR i W. Schwink, NRR S. Crockett, OGC P. S. Tam, NRR rl"~ POR' ~

4 Central Files l

cc: w/o Enclosures

, Attendees Identified on Attendance Enclosure l

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MEETING AGENDA July 28,1988 NUMARC/NUGSBO MEETING FOLLOW UP A 44 DISCUSSIONS I

10:00- 10:15 AM Opening Remarks 10:15 11:00 Draft Generic Response to A-44 Rule 1

11:00 - 12:00 NUGSBO Review of:

Draft Appendix F (NUMARC 87 00)

Draft Appendix F Topical Report 4

1:00 3:30 PM Discussions related to Draft Appendix F and Appendix F Topical Report 3:30 - 4:00 Identification of Follow up Actions

Participants:

NRC and NUMARC Staff (see Attendance Sheet) ,

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3 MEETING ATTENDEES ,

July 28, 1988 A-44 FOLLOW-UP DISCUSSIONS with NUMARC/NUGSB0 Attendee Affiliation Phone Number Al Serkiz NRC/RES/RPSIB 301/492-3555 Jares E. Knight NRC/NRR/ DEST /SELB 301/492-0803 ilarren Minners NRC/RES/DSIR 301/492-3980 Paul Gill NRC/NRR/ DEST /SELB 301/492-0811 Vittorio Pareto NUMARC/DEVENRUE 617/426-4550 Steve Maloney NUMARC/DEVENRUE 617/426-4550 i Stephen D. Floyd Carolina Power & Light 919/836-6901 W. Joe Harnden TU Electric 214/812-8226 Michael Childers Northeast Utilities 203/665-5949  :

Mike !!cGarry NUMARC/BCP&R 202/371-5733 Alex Marion NUMARC 202/872-1280 Bob Colmar NRC/NRR/PMAS/lLRB 301/492-3076 Faust Rosa NRC/NRR/ DEST /SELB 301/492-0837 l Janak H. Rayal NRC/NRR/ DEST /SPLB 301/492-0857 Paul E. Norian NRC/RES/RPSIB 301/492-3538 l

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E NC L_ O S U R E A y DRAFT GENERIC RESPONSE TO STATION BLACKOUT RULE FOR PLANTS NOT USING ALTERNATE AC POWER the On (date of rule publication in the Federal Register) , amended its regulations in 10 Nuclear Regulatory Commission (NRC)50.63, was added which requires A new section, C.F.R., part 50.

that each light-water-cooled nuclear power plant be able to withstand and recover from a station blackout of a specified duration. It also identifies the factors that must be considered Section 50.63 in specifying the station blackout duration.

for the station blackout duration, the plant be -

requires that, capable of maintaining corefurther cooling and appropriate requires chat eachcontainment licensee integrity. Section 50.63 submit the following information:

1. A proposed station blackout duration;

2. A description of the procedures that will be implemented for station blackout events for the proposed duration; i 3.

A list and schedule for any needed modifications and associated procedures.

The NRC has issued Regulatory Guide 1.155 "Station Blackout" which describes a means acceptable toRegulatory the NRC staff for meeting Guide 1.155 the requirements of 10 C.F.R. 50.63.

states that the NRC staff has determined that NUMARC 87-00 "Guidelines and Technical Bases for NUMARC Initiatives Addressing l Station Blackout At Light Water Reactors" also provides guidance '

acceptable to the NRC staff for meeting these requirements.

Table 1 to Regulatory Guide 1.155 provides a cross-reference between Regulatory Guide 1.155 and NUMARC 87-00 and notes where

l i the Regulatory Guide takes precedence.

(Utility Name) has evaluated the (Unit Name) against the requirements of the Station Blackout rule using NUMARC 87-00.

The results of this evaluation are detailed below.

A. PROPOSED STATION BLACKOUT DURATION NUMARC 87-00 Section 3 was used to determine a proposed station )

If the determined blackout duration of (2 or 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />). (NOTE: l category exceeds 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, modifications and/or procedure changes (

are required to reduce the determined category to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or less l or an alternate AC power source is required to meet the NUMARC initiatives.)

The following plant factors were identified in determining the proposed station blackout duration:

1. AC Power Design Characteristic Group is (P1, P2, P2*,

P3 or P3*) based on:

a. Expected frequency of grid-related LOOPS [3.2, / dl6 /4 (does/does noti exceed once per 20-years f. 3 -3 )

br Estimated frequency of LOOPS due to extremely severe weather places the ylant in ESW Group (1, 2, 3, 4 or 5) ; (f 3. 2.. l Mit e ld j A 3-4)

c. Estimated frequency of LOOPS due to severe weather places the plant in SW Group (1,c2, 3, 4 or 5) ; h 7.2./ AMT/d A3'7) e

d. The offsite pcwer system is in the (Il/2 or I3 Group) ;(g J. 2./ /N' -T /4 A 3-/oj

e. Plant-specific pre-hurricane shutdown requirements and procedures which meet the guidelines of Section 4.2.3 of NUMARC 87-00 have  ;

been implemented.

(P2* and P3* units only.)

2. The emergency AC 7ower configuration group is (A, B, C or D) based on: ([7 2,2j/. 3 -/3) ,

L/Mr2d,

a. There are (insert number) emergency AC power suppliespotcredite$asaltSrnataACpower source s . ( f 3,2 . 2. / $7~M, 8 3-/5~ )

b. (Insert number) emergency AC power supplies are l

necessary to operate safe shutdown equipment following a losts of offsite power.(f 3,2. 2. /A%7 2d de 3~/J"

3. The target EDG reliability is (0.95 or 0.975) . [f J.2.j7 S,2.h IF A TARGET RELIABILITY OF 0.975 IS SELECTED USE CNE OF THE FOLLOWING JUSTIFICATIONS:

A target EDG reliability of 0.975 was selected based on I (insert one of the following). l

a. Having a nuclear unit average EDG reliability for )

I the last 20 demands 0.90 and the EAC Group classified as Group (A, 3, C or D) ;

b. Having a nuclear unit average EDG reliability for the last 50 demands 0.94 and the EAC Group classified as Group (A, B, C or D) ; l I c. H5ving a nuclear unit average EDG reliability for

! the last 100 dCmands 0.95 and the EAC Group

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classified as Group (A, B, C or D).

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ME B. PROCEDURE DESCRIPTION 4 Plant procedures have been reviewed and modified, if necessary, to meet the guidelines in NUMARC 87-00 Section 4 in the following areas:

1. AC power restoration per NUMARC 87-00 Section 4.2.2;  ;

2. Severe weather per NUMARC 87-00 Section 4.2.3.

Plant procedures have been reviewed and changes necessary to meet NUMARC 87-00 will be implemented in the following areas:

1. Station Blackout response per NUMARC 87-00 Section-4.2.1;

2. Procedure changes required after assessing coping capability per NUMARC 87-00 Section 7.

C. PIANT MODIFICATIONS AND PROPQSED SCHEDULE The ability of (insert unit name) to cope with a station blackout for (insert duration in hours) vss assessed using NUMARC 87-00 Section 7 with the following results:

1. Condensate Inventory for Decay Heat Removal SELECT ONE OF THE FOLLOWING PARAGRAPHS:

It has been determined from Section 7.2.1 of NUMARC 87-00 that (insert number) gallons of water are required for decay heat removal for the proposed station blackout duration. The minimum permissible condensate storage tank level per technical specifications providen (insert number) gallons of water, which exceeds the required quantity for ccping with a (two- or four-) hour station blackout; or It has been determined from Section 7.2.1 of NUMARC 87-00 that (insert number) gallons of water are  !

required for decay heat removal for the proposed station blackout duration. The minimum permissible )

condensate storage tank level per technical I specifications provides (insert number) gallons of l vater. The following additional water sources have '

been identified as being necessary to provide the total required amount of condensate for decay heat removal for (two or four) hours: (LIST SOURCES AND NUMBER OF GALLONS PROVIDED BY EACH SOURCE). SELECT ONE.OF THE l FOLLOWING SENTENCES AND INSERT HERE:

$b 1 .

a. No plant modifications or procedure changes are needed to utilize these water sourcost or

b. The following plant modifications are necessary to utilize these water sources: (LIST).

2. Class 1E Battery Capacity SELECT ONE OF THE FOLLOWING PARAGRAPHS:

QMTo % L 1 A battery capacity calculation has been performedAto verify that the Class 1E battery has sufficient capacity to mest station blackout loads for the proposed station blackout duration; or A battery capacity calculation verifies that the Class lE battery has sufficient capacity to meet station blackout loads for the proposed station blackout duration assuming stripping of loads not needed to cope with a station blackout. These loads are identified in plant procedures; or The class 1E battery was determined to be inadequate to meet station blackout loads for the proposed station blackout duration. The following modifications are necessary to provide the additional capacity to meet the proposed station blackout durations: (LIST).

3. ComoressedAir((~/,2,3)

SELECT ONE OF THE FOLLOWING PARAGRAPHS:

No air-operated valves are relied upon to cope with a station blackout for the proposed duration; or

. Air-operated valves relied upon to cope with a station l blackout for the proposed duration can either be l cperated manually or have sufficient backup sourcen  :

independent of the preferred and blacked out unit's class 1E power supply. Valves requiring manual operation or that need backup sources for operation are identifjed in plant procedures; or The following modifications are necessary to ensure that air-operated valves required for decay heat  !

removal during a station blackout of the proposed 1 duration have sufficient backup sources for operation or can be manually operated: (LIST).

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4. EffectsofLossofVentilation(f7,1.Y FOR PWR's The calculated steady state ambient air temperature for the steam driven AFW pump room (the dominant area of concern for a PWR) during a station blackout induced loss of ventilation is (insert temperature).

FOR BWR's The steady state ambient air temperature has been calculated for the following dominant areas of concern:

AREA TEMPERATURE HPCI/HPCS Room (insert value)

RCIC Room (insert value)

Main Steam Tunnel (insert value)

ALL PLANTS - SELECT ONE OF THE FOLLOWING PARAGRAPHS:

Reasonable assurance of the operability of station blackout response equipment in the above area (s) has been assessed using Appendix F to NUMARC 87-00. No modifications or associated procedures are required to provide reasonable assurance for equipment operability; or Reasonable assuranco of the operability of station blackout response equipment in the above areas (s) has been assessed using Appendix F to NUMARC 87-00. The

following modifications and associated procedure t

changes are required to provide reasonable assurance for equipment operability' (us7)

5. ggntainment Isolation (f 7, Z ,

SELECT ONE OF THE FOLLOWING PARAGRAPHS:

The plant list of containment isolation valves has been l reviewed to verify that valves which must be capable of being closed or that must be operated (cycled) under station blackout conditions can be positioned (with indication) independent of the preferred and blacked-out unit's Class 1E power supplies. No plant modifications and associated procedure changes were determined to be required; or The plant list of containment isolation valves has been

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reviewed to verify that valves which must be capable of 3

being closed i- that must be operated (cycled) under

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)hbbf station blackout conditions can be positioned (with indication) independent of the preferred and blacked-out unit's class 1E power supplies. The following modifications and associated procedure changes are required to ensure that appropriate containment integrity can be provided under station blackout conditions: (LIST). ,

The modifications and associated procedure changes identified above will be completed (insert time) after the notification provided by the Director, Office of Nuclear Reactor Regulation in accordance with 10 C.F.R. 50. 63 (c) (3) .

Very truly yours, Company Official 4

cc: NUMARC f

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ENCtosURE B DM

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DRAFT GENERIC RESPONSE TO STATION BLACKOUT RULE FOR PLANTS USING ALTERNATE AC POWER On (date of rule publication in the-Federal Register), the Nuclear Regulatory Commission (NRC) amended its regulations in 10 C.F.R. Parc 50. A new section, 50.63, was added which requires  :

that each light-water-cooled nuclear power plant be able to  !

withstand and recover from a station blackout of a specified duration. It also identifies the factors that must be considered in specifying the station blackout duration. Section 50.63 requires that, for the station blackout duration, the plant be capable of maintaining core cooling and appropriate containment integrity. Section 50.63 further requires that each licensee submit the following information:

1. A proposed station blackout duration;

2. A description of the procedures that will be implemented for station blackout events for the proposed duration;

3. A list and schedule for any needed modifications and associated procedures.

The NRC has issued Regulatory Guide 1.155 "Station Blackout" which describes a means acceptable to the NRC staff for meeting the requirements of 10 C.F.R. 50.63. Regulatory Guide 1.155 states that the NRC staff has determined that NUMARC 47-00 "Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout At Light Water Reactors" also provides guidance acceptable to the NRC staff for meeting these requirements.

Table 1 to Regulatory Guide 1.155 provides a cross-reference between Regulatory Guide 1.155 and NUMARC 87-00 and notes where

the Regulatory Guide takes precedence.

(Utility Name) has evaluated the (Unit Name) against the requirements of the Station Blackout rule using NUMARC 87-00.

The results of this evaluation are detailed below.

A. FROPOSED STATION BLACKOUT DURATION An Alternate AC (AAC) power source will be utilizad at (Unit Name) which meets the criteria specified in Appendix B to NUMARC 87-00. ADD THE FOLLOWING SENTENCE IF THE AAC SOURCES IS A CLASS lE EAC SOURCE: The AAC source is an EAC power source which meets the assumptions in Section 2.3.1 of NUMARC 87-00.

USE ONE OF THE FOLLOWING PARAGRAPHS:  !

The AAC source is available within one hour of the onset of the station blackout event and has sufficient capacity to operate systems necessary for coping with a static 1 blackout for the time f

t required to bring and maintain the plant in safe shutdown. '

Therefore, the proposed station blackout duration is one hour; or The AAC source is available within 10 minutes of the onset of the station blackout event and has sufficient capacity to operate systems necessary for coping with a station blackout for the time required to bring and maintain the plant in' safe shutdown. l Therefore, the proposed station blackout duration is zero hours.  !

BRIEFLY DESCRIBE THE AAC SOURCE AND ITS CONFIGURATION REFERENCING A FIGURE IN APPENDIX C TO NUMARC 87-00 IF POSSIBLE.

i B. PROCEDURE DESCRIPTION i

Plant precedures have been reviewed and modified, if necessary, to meet the guidelines in NUMARC 87-00 Section 4 in the following

.,)eas:

1. AC power restoration per NUMARC 87-00 Section 4.2.2; i 2. Severe weather per NUMARC 87-00 Section 4.2.3.

Plant procedures have been reviewed and changes necessary to meet NUMARC 87-00 will be implemented in the following areas:

1. Station Blackout response per NUMARC 87-00 Sec! ion 4.2.1; J a

2. Procedure changes required after assessing coping

capability per NUMARC 87-00 Section 7.

C. PLANT MODIFICATIONS AND PROPOSED SCHEDULE i

BRIEFLY DESCRIBE ANY MODIFICATIONS AND ASSOCIATED PROCEDURE CHANGES REQUIRED TO UTILIZE THE AAC POWER SOURCE.

COMPLETE THE FOLLOWING SECTIONS FOR BOTH THE ONE-HOUR AND 10 i MINUTE AAC OPTION.

The AAC source powers the loads necessary to cope with a station 4 blackout in accordance with NUMARC 87 +)O Section 7 for the  :

J required coping duration determined in NUMARC 87-00 Section 3.2.5.

1. Condensate Inventor _L '_De_ cay Heat Removal

SELECT ONE OF THE FOLLOWING PARAGRAPHS

It has been determined from Section 7.2.1 of NUMARC 87-00 that (insert number) gallons of water are required for decay heat removal for (insert required coping duration category from NUMARC 87-00 Section 3.2.5)

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hours. The minimum permissible condensate storage tank level per technical specifications provides (insert number) gallons of water, which exceeds the required quantity for coping with a (insert required coping duration category from NUMARC 87-00 Section 3.2.5) -hour station blackout; or It has been determined from Section 7.2.1 of NUMARC 87-00 that (insert number) gallons of water are required for decay heat removal for (insert required coping duration category from NUMARC 87-00 Section 3.2.5) hours. The minimum permissible. condensate storage tank level per technical specifications provides (insert number) gallons of water. The following additional water sources have been identified as being necessary to provide the total required amount of condensate for

, decay heat removal for (insert required coping duration

! category from NUMARC 87-00 Section 3.2.5) hours: (LIST SOURCES AND NUMBER OF GALLONS PROVIDED BY EACH SOURCE).

SELECT ONE OF THE FOLLOWING SENTENCES AND INSERT HERE:

a. No plant modifications or procedure changes are needed to utilize these water sources; or

, b. The following plant modifications are necessary to

utilize these water sources

(LIST).

COMPLETE THE FOLLOWING ADDITIONAL SECTIONS IF THE AAC SOURCE IS AVAILABLE WITHIN ONE HOUR OF THE ONS T OF STATION BLACKOUT:

2. Class 1E Battery CaDacity { }?, g, 3)

SELECT ONE OF THE FOLLOWING PARAGRAPHS:

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A battery capacity calculation has been performed to verify that the Class lE battery has sufficient capacity to met station blackout loads for one hour; A battery capacity calculation verifies that the Class lE battery has sufficient capacity to meet station  ;

blackout loads for one hour assuming stripping of loads '

not needed to cope with a station blackout. These loads are identified in plant procedures; or The Class lE battery was determined to be inadequate to meet station blackout loads for one hour. The following l modifications are necessary to provide a one-hour i capacity: (LIST).

3. Comoressed Air 7, 2.

SELECT ONE OF THE FOLLOWING PARAGRAPHS IF THE COMPRESSOR IS POWERED FORM THE AAC SOURCE. OTHERWISE USE THE I

)

COMPRESSED AIR SECTION FROM THE GENERAL RESPONSE'FOR  ;

PLANTS NOT USING AAC POWER:

No air-operated valves are relied upon to cope with a '

station blackout for one hour; Air-operated valves relied upon to cope with a station blackout for one hour can either be operated manually or have sufficient backup sources indopendent of the ,

preferred and blacked out unit's Class lE power supply.

Valves requiring manual operation or that need backup sources for operation are identified in plant procedures; or The following modifications are necessary to ensure that air-operated valvec required for decay heat removal during a station blackout of a one-hour duration have sufficient backup sources for operation or can be manually operated: (LIST).

4. Effects of Loss of Ventilation p FOR PWR's The calculated steady state ambient air temperature for the steam driven AFW pump room (the dominant area of concern for a PWR) during a station blackout induced loss of ventilation is (insert temperature).

FOR BWR's ,

The steady s+. ate ambient air temprrature has been calculated ',or the following dominant areas of concern:

AREA TEMPERATURE HPCI/HPCS Room (insert value)

RCIC Room (insert value)

Main Steam Tunnel (insert value)

ALL PLANTS: SELECT ONE OF THE FOLLOWING PARAGRAPHS:

Reasonable assurance of the operability of station blackout response equipment in the above area (s) has

, been assessed using Appendix F to NUMARC 87-00. No modifications or associated procedures are required to provide reasonable assurance for equipment operability; 9

or 4

Reasonable assurance of the operability of station blackout response equipment in the above areas (s) has

, been assessed using Appendix F to NUMARC 87-00. The

following modifications and associated procedure c::anges are required to provide reasonable assurance for equipment operability.

5. Containment Isolation 7, 2. <f SELECT ONE OF THE FOLLOWING PARAGRAPHS:

The plant list of containment isolation valves has been reviewed to verify that valves which must be capable of ,

being closed or that must be operated (cycled) under station blackout conditions can be positioned (with indication) independent of the preferred and blacked-out unit's Class 1E power supplies. No plant modifications ,

and associated procedure changes were determined to be '

required; or The plant list of containment isolation valves has been reviewed to verify that valves which must be capable of being closed or that must be operated (cycled) under station blackout conditions can be positioned (with indication) independent of the preferred and blacked-out unit's Class 1E power supplies. The following modifications and associated procedure changes are required to ensure that appropriate containment integrity can be provided under station blackout conditions: (LIST).

The modifications and associated procedure changes identified above will be completed (insert time) after the notification provided by the Director, Office of Nuclear Reactor Regulation in accordance with 10 C. F.R. 50. 63 (c) (3) .

Very truly yours, Company Official cc: NUMARC ENCL OSURE C GUIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVES NUMARC 37 00 DRAFT hly 18,1988 APPENDIX F: ASSESS 5 TENTS OF EQUIPS 1ENT OPERABILITY IN DOMINANT AREAS UNDER STATION BLACKOUT CONDITIONS (REVISION 1)

F.1 Introduction This appendix outlines a methodology for providing reasonable assurance of the operability of equipment used to cope with a station blackout in the dominant areas of concern.

Station blackout is not a design basis accident and, therefore, is not subject to the requirements of 10 CFR 150.49 and the rigorous certification process for equipment operability. However, since station blackout copeng equipment needs to operate in order to achieve safe shutdown, reasonable assurance should be provided that no thermally induced failures will result due to loss of forced ventilation. Station blackout environments in the dominant areas of concem outside containment are expected to experience increases in air temperature. The resulting temperatures are expected to range from slight to moderate in most cases not exceeding 150' F.

Most equipment is expected to operate in these station blackout environments with no loss of function for the short duration (i.e., four hours). The basis for this general conclusion can be traced to previous studies and analyses performed, as well as plant operating experience. The approaches discussed in this appendix provide acceptable bases for reaching this conclusion on a plant specific basis. In particular, the approaches justify. removing classes of equipment (i.e., relt s. switches) from further consideration and focusing attention on those components of concem.

i The approaches may be used individaaily or in combir:ation in reaching a conclusion that an acceptable basis exists for equipment operability in a station blackout emironment.

1 Six approaches may be used to establish equipment operability in a station blackout:

(1) 1!quipment pmiously evaluated; (2) Equipment design capability; i

(3) Materials; (4) Equipment inside instrumentation and control cabinets; (5) Genene studies and experience:or, (6) Plant. specific experience and tests.  !

Each of these approaches is described in detail in this appendix; a general statement of a method guidance, specific l

proceduets, and exarnples are provided.

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GUIDELINES ASD TECHNICAL BASES FOR NUMARC INITIATIVES NUM ARC 8?c.00 DRAFT jg July 18,1988 In the development of approaches. it became clear that station blackout response equiprnent fell into several generic categories. It also became clear that reasonable assurance of operability for these categories could be established within certain temperature ranges. A topical report has been prepared and is being made a part of Appendix F to address this situation. The Topical Report provides a technical evaluation of these categories establishing a temperature for which reasonable assurance of operability can be generically established in a station blackout l environment.

Due to the variety of equipment types in each category, the temperatures established are necessarily conservative. It I is recognized that equipment specific analysis may establish reasonable assurance of operability for higher temperatures. The Nuclear Utility Group on Station Blackout (NUGSBO) has compiled an equipment operability database (EODB) containing information which may be helpful for supporting such evaluations.

Users may refer to and use the Topical Report and the EODB database as fo!!ows:

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4 (1) Determine the bulk room temperature for the dominant areas of concern in accordance with Section 7 of NUMARC 87 00; i

1 C) Identify the station blackout response equipment located in these areas; ,

, t (3) Determine the duration these components must remain operable under loss of ventilation j conditions (i.e., up to one hour for plants using alternate AC. up to two hours for plants in the j P! A classificat.on identified in Section 3 of NUMARC 87 00, otherwise up to four hours);

(1) Determine whether station blackout response equipment falls within any of the equipment categories whose operability is evaluated in the Appendix F Topical Report. if so, determine ,

whether the assessed temperature and duration for the category envelopes the temperature of the dominant area of concem where equipment is located for the duration the equipment is necessary; if 4

not.

i l 1 i (5) Establish reasonable assurance by following any of the approaches discussed in this appendix. The

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. NUGSBO equipment operability database (EODB) may contain informat on to help support the i

evalut. tion.  !

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GUIDELINES ANI) TI'CilNICAL DASES FOR NUMARC INITIATIVES NUMARC 87 00 DRAFT July 18.1988 F.1.1 Assumptions and Definitions The approaches described in this appendix are designed to establish reasonable assurance of operability of equipment and components in dominant areas of concern for station blackout environments. These methods are equally applicable to establishing the operability of individual components or of entire equipment categories. Table F.1 shows the results of evaluations supporting the operability of entire equipment categories provided in the Appendix F Topical Report.

Table F.1: Operability Conditions By Category Station Blackout Appendix F Equipment Operability Temperature Duration Approaches Used

('F) (hrs)

MECHANICAL EQUIPMENT Pumps 180 4 F.4 F.6 Turbines w/ MechanicalGovemors 180 4 F.4,F.6 DC Motors, Fans, and Blowers 180 4 F.4,F.6 Valves 200 4 F.4,F.6 Motor Operated Valve Actuators Limitorque 200 4 F.2,F.3,F.6 Rotork 180 4 F.2.F.3,F.6 Other 180 4 F.4. F.6 ELECTRICAL AND ELECTRONIC EQUIPMENT Cables 185 4 F.2,F.3,E.6 Switches and Relays 185 4 F.2,F.4,F.6 Sensors and Electronic Transmitters 180 4 F.3,F.6 Electronic Turbine Governors 160 4 F.4, F.6 Assurnetions I l

The following assumptions are consistent with establishing reasonable assurance of operability for equipment in station blackout environments:

i I (1) Documentation standards for equipment operability are not to be as rigorous as are typically required to meet l l

the design basis requirements of 10 CFR 150.49. For example, there is no need to address the effects of l

aging or synergisms. In addition, engineering judgement may be exercised to peimit the acceptance of installed configurations that diverge from test conditions. Thh is consistent with the scope and intent of 10 CFR 150.63. These assumptions are reasonab!c due to the low temperatures (and correspondingly slower i

reaction rates), and short durations (and correspondingly short reaction times) expected during a station blackout. Documentation records establishing operability need not address more than:(a) the equipment l l

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GUIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVES NUMARC 37 00

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DRAFT Jdy 18,1988 name and model number, (b) the dominant area of concem. (c) the station blackout temperature (TDAC), (d) the station blackout operability temperature (Topp), and (c) the Appendix F method used or the Topica! ,

Report category.

(2) In accordance with Section 2.7.1 of NUMARC 87 00, only station blackout response equipment located in dominant areas of concem which have not been previously evaluated as a harsh environment need be assessed for operability.

(3) Determinatien of similarity does not need to consider the effects of aging, fatigue life, or synergisms.

Defbitiom The terms defined below were specifically developed for these guidelines and are consistent with the definitions used throughout NUMARC 87 00.

DOMINANT AREAS OF CONCERN (DAC) - The representative analysis provided in this section addresses a limited set of plant areas deerr.ed to be potentially susceptible to heat.up upon loss of ventilation, such as would occur in a station blackout. 7hese areas are defined by three factors: (1) their containing equipment normally required 2 to function early in a station blackout to remove decay heat (i.e., equipment whose failure within the first hour of a station blackout would disable the auxiliary feed. water or boiler makeup systems), (2) the presence of significant heat  ;

generation terms (after AC power is lost) relative to their free volume (i.e. process steam or DC electrical power supplies in small rooms or encloses), and (3) the absence of heat removal capability in a station blackout without  ;

operator stion. These areas are have been determined to be:

l (1) Steam Driven AFW Pump Room (PWRs only);

(2) HPCl/HPCS Room (BWRs only);

(3) RCIC Room (BWRs only); and.

(4) Main Steam Tunnel (BWRs only). ,

i It should be noted that any site specific plant area found meeting the three factors above should also be considered to be a dominant area of concem.

l STATION BLACKOUT EQUIPMENT equipment located in dominant areas of concern which are used to bring the I plant to safe shutdown during station blackout conditions.

STATION BI.ACKOUT TEMPERATURE (TDAc) . the average steady state bulk air temperature in a dominant area of concem dunng a four hour station blackout.

F4

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GUIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVES NUMARC 87 00

. DRAFT July 18,1988 STATION BLACKOUT OPERABILITY TEMPERATURE (Topp) the temperature for which reasonable assurance of operability has been established for a specific component or for an equipment category. This temperature is established for a variety of equipment categories in the Appendix F Topical Report, and may be established for individual equipment using the approaches described herein.

SIMILAR EQUIPMENT equipment whose characteristics are such that:

(1) ine limiting sub components have cortparable or less limiting thermal properties; and.

(2) the limiting materials have comparable or less limiting thermal properties.

In the content of station blackout. limiting sub components or limiting materials are those sub<omponents or materials which are most susceptible to significant degradation at e!cvated temperatures. The application of this principle is illustrated in Example 3 of Section F.2A.

i

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1 i

F-5 l

GtJIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVES NUM ARC 37c00 DRAFT July is,1988 F.2 Equipment Previously Evaluated Q{.

F.2.1 General Statement of Method Equipment that is similar to equipment already qualified under 10 CFR 150.49 need not be further evaluated if the station blackout temperatures do not exceed qualification temperatures.

F.2.2 Guldance Existing tests and analyses of specific equipment may be used to establish operability in a station blackout.

Reasonable assurance of operability is met if the equipment or reasonably similar equipment has been previously qualified to a temperature and duration enveloping TDAC and the required coping duration category.

F.2.3 Procedure Apply the following steps for station blackout response equipment located in dominant areas of concern experiencing a totalloss of forced ventilation.

(1) Determine T DAC for the area containing the equipment in accordance with Section 7.2.4.

(2) (a) Determine the time period that the equipment must remain operable for the appropriate station blackout coping method; or.

~

(b) Assume the equipment must remain operabic for the entire duration of the station blackout (i.e.,

one, two or four hours).

(3) Locate a test or analysis that provides reasonable assurance of operability for the identified equipment (or similar equipment) for the temperature specified in Step I and the duration specified in Step 2. A paniallist of equipment qualified under 10 CFR 150.49 for a number of participating utilities is available in the NUGSBO Equipment Operability Database.

(4) Reasonable assurance of operability is established if the specific equipment or similar equipment has been previously evaluated for conditions enveloping the temperature determined in Step 1 and the duration determmed in Step 2.

F.2.4 Examples

] The following examples illustrate the establishment of reasonable assurance of operability on the basis of previous d

qualification.

Fs

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GUIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVES NUMARC 37 00 hly 18,1988  :

. DRAFT Ennmde 1:

l A Ilmit switch is identified as being needed for station blackout response. The switch is located in a dominant ama of concem with r>TDAC - 145' F and is required to function for one hour. This switch was evaluated under another utility's equipment qualification program and qualified for a temperature of 180' F for two hours. Reasonable assurance of operability is therefore estabilshed.

ErsmMe2-A Ilmit switch required for station blackout is located in a dominant area of concem with a TDAC - 150' F. The switch needs to function for one hour under station blackout conditions. The switch was evaluated for a temperature f of 180' F for two hours under the plant's equipment qualification program. Reasonable assurance of operability is t

therefore established.

I EtsmMe 3 l

A motor required for station blackout response is located in a dominant area of concem with a D T AC - 150' F. The NUGSBO equipment operability database shows that a potentially similar motor has been evaluated under another utility's equipment qualification program for continuous operation below 170'F. A review of the Appendix F Topical Report reveals that (a) the most limiting sub components for rnotors are their bearings and windings, and (b) the most limiting materials used in motors are the winding insulation and the bearing lubricant. After contacting the other utility, it is verified that:

(1) Both motors use joumal bearings.

(2) Both tubricants used are rated for continuous operation above 170' F.

(3) The winding insulation for both motors are rated for continuous operation above 170' F.

These motors may therefore be considered similar for the purposes of determining operability la a station bla.kout. ,

I Reasonable assurance of operability is, therefore, established.

l l

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F.7

GUIDELINES AND TECilNICAL BASES FOR NUMARC INITIATIVES SUM ARC 87 00 DRAFT My is,1988 F.3 Equipinent Design - Capab:alty 3

r F.3.1 General Statement of Method i Equipment vendors generally provide a design temperature. associated with the continuous operation of their equipment. A margin may exist above design temperature which varies according to equipment class (e.g., smaller ,

margins for electronic equipment relative to electro-mechanical devices) and the expected operating conditions (e.g.,

temperature levels, time at these clavated temperatures, duty cycle, etc.). Reasonable assurance of equipment operability is provided if it is shown that the design temperature plus the expected margin for the equipment or component class oors not exceed the bulk air temperature expected in a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> station blxkout.

t l

F.3.2 Guidance Vendors specify design temperatures associated with continuous operation of their equipment. In general, the equipment may still operate for the !!mited duration of a station blackout at even higher temperatures. His additional capability represents the equipment's thermal margin in a station blaczout. Bis margin may be established on the 4

basis of estimating thermally induced failure rates, by locating vendor documentation, by performing tests and experiments, or as derived from experience. Using the thermal margin approach, reasonable assurance of equipment

. operability is established if the equipment's rated temperature for continuous operation plus its thermal margin envelopes station blackout con (tions. ,

Verdor documentation certifying equipment operability at temperatures in excess of the tated temperature for  !

contmuous operation may be used to establish thermal margins. These documents include, but are not limited to: i a k 4

(1) Published catalog data:

(2) Correspondence (including letters, memoranda, and technical advisories);

(3) Technical manuals; and.

(4) Engineering, design, or vendor test data.

l l

} i In addition to vendor documentation, test data and documented operational occurrences may also be used to establish <

\

] thermal margins Operational occurrences, for example, may have created conditions that exceed the design of the  !

equipment without adversely affecting operability.

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)

Also, the mean time between failures for some station blackout components may be suf!>lently long to entMJ reasonable assurance of operability to be established at elevated temperatures for short durations, $1 mil:r!y, d operabtlity is established for higher temperatures for shorter durations than needed for coping, the thermal effects on equipment reliability may demonstrate operability at lower temperatures for the longer duration needed for ecping with a station blackout. Exarnples 4 and 5 illust ate the application of this methodology, F-8 i

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GUIDELINES AND TECllNICAL BASES F1R NUMARC INITIATIVES NUM ARC 87 00 DRAFT J:ly 18,1988 F.3.3 Procedure '

Apply the following steps for station blackout response equipment located in dominant areas of concern experiencing a totalloss of forced ventilation.

(1) Determine TDAC or f the area containing the equipment in accordance with Section 7.2A, (2) (a) Determine de time period that the equipment mut' remain operable for the appropriate station blackout coping method; or, (b) Assume the equipment must remain operable for the entire duration of the station blackout (i.e.,

one, two, or four hours).

(3) (a) Establithine Reasonsbfe Assurance m the Bseis of Avaitsbie Therms! Marcin (i) Determine the design temperature of the equipment.

(U) Determine the available thermal margin based on vendor documentation, test reports, plant experience, or vendor correspondence for the specific equipment. The NUGSBO Equipment Operability Database contains a listing of equipment types sorted by vendor to a110w utilities to locate other sites using equipment supplied by the same vendor, (Ul) Reasonable assurance of operability is established if the design temperature plus the available thermal margin exceeds TDACfor the period determmed in Step 2.

OR (b) Establishine Rerensbie Assurance by Estimsnee Fsilure Rates (i) Determine the expected mean time between failures under normal operating conditions for the equipment. ,

(U) Calculate the thermal effects on equipment failure rate for conditions determined in Step 1 and Step 2 (sce Examples .t and 5 in Section F.3,4),

(ui) Reasonable usurance of operability is established if the mean time Setween failures determined in Step (b)(ii) is greater than the duration specified in Step 2.

F.3.4 Examples The following examples illustrate the establishment of reasonable assurance of operability on the basis of equipment design capability. ,

F9

GUIDELINES AND TECilNICAL BASES FOR NUSIARC INITIATIVES NUM ARC 87c00

+

DRAFT July 18,1988 Etsmele li An electronic transmitter required for ccping with a station blackout is located in a do tinant area of concern with a Tore of 170'F. De rnanufacturer's catalog states that the maximum continuous Operating temperature for the electronic transmitter is 180' F. Based on the catalog data the transmitter is considead operab!c for the assumed station blackout event.

Etsme!e 2:

A motor operated valve actuator has a maximum continuous operating temperature of 140' F. Correspondence from the manufacturer indicates that they roudnely supply standard units for continuous operating temperatures up to 170* F with recommendations for increased grease surveillance and periodic maintenance. Based on this information, the utility concludes that the actuator is operable for a four hour duration at 170'F with additional special maintenance and surveillance actions.

Etsmele 3:

A motor has published NEMA standard rating based on a 40' C (IO4'F) ambient temperature. The utility calculates a TDAc of 150' F. Using the guidance provided in NEM A standard MG 1, the utility determines that the motor is rated for continuous operation at the higher tem; trature based on an operational load less than the rated full load !. Based on this analysis the motor is considered operable for an assumed four hour duration.

Etsmele 0 he thermal effects on the failure rate of some components can be estimated by utiliaing engineering methods such the 10' C rule, his rule states that a 10' C increase in the winding temperature of a motor decreases the mean time between failures of the motor by a factor of 2. This rule is represented by the following equatiort:

3 ((TDAC Tl yl0) where:

ti represents the mean time between failures for a mctor operating continuously at a temperature Ti ,

I t2 represents the mean time between fallares for a motor operating at a higher temperature TDAc.

ToAc represents the bulk air temp.rature in the dominar.t area of concern, and ,

Ti represents the temperature for which the motor is rated for continuous operation.

1 I lt is assumed that the insulaton tec:perature is based on ambient tempraturs ele -u rua te A the cotar load.1 further assa'r.cs that the heat nse is propomonal to tactual horsepower $ / (rtS "I E sc Trdt ca 'Jc1. .s' )

nse for as operauomalload less than t*.e meters rated fullload. l F 10 l

1

GUIDELINES AND TECPNICAL BASES FOR NUMARC INITIATIVES NUM ARC 87 00

. DRAFT hly 18,1988 If, for eaample, the mean time between failures for a motor operating in a 40' C (104' F) room is 500 houn, the ,

10 degive rule can be used in estimate the mean time between failures for when the motor is operating in a 60* C i

(140' F) room.

-((60* C 40' Cy10 'b t2.125 hours0.00145 days <br />0.0347 hours <br />2.066799e-4 weeks <br />4.75625e-5 months <br /> Since t2is still cor.siderably longer than the four hours for which the motor is needed to perform its stauon blackout I

function, russonable assurance of operability is established.

l l I FusmMe t-A pressure switch qualified for outside containment pipe creak conditions of 100' C (212' F) for 30 minutes is required to operate in a dominant area of concern with a TDAc of 71.11' C (160' F) for four hours. This switch may be demonstrated opersble for the blackout event by determining the thermal degradation equivalency.

Thermal degradation equivalency is demonstrated using the following form of the Antonius equation:

g, k

• In (tg 1/ Tt .1/ ToAc .

where:

ti represents the mean time between failures for a motor operating at a temperature T t,  !

t2 represents the mean time between failures for a motor operating at a temperature TDAc,  !

Tore represents the bulk air temperature in the dominant area of concem in Kelvins (K),

Ti represents the temperature for which the motor is rated for continuous oper1 tion in Kelvins (K), ,

i Eo represents the activation energy for the component necessary to achieve equivalency and k Boltzman's constant - 8.63 x 10-8 eV / K l In this forrn, the activation energy (E,) necessary to achieve equivalency is determined based on the two temperatures (T) and time (t) values. In this example the resulting value for E, to achieve equivalency is 0,797 eV, l

l A review of EPRl NP 1$$8, Review of Equipment A ting and Theory. and Technology, Appendix C, reveals that activation energies for ma:eriaJt typically used in pressure switches exhibit activation energies above 0.85 eV. Since this value is A'gAer than 0.797 eV, reasonable assurance cf operability is established.

F ll 1

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- GUIDELINES AND TECilNICAL B ASES FOR NUM ARC INITIATIVES NUSIARC 87 00 DRAFT Jcly is,1988 Thermal equivalency could n!so have been established using the 10' C rule, w hich is illustrated in Example 4.

l E umNe 6-  ;

4 The motor starters for selected coping equipment are located in a dominant area of concern. The stated maximum temperature for the starters is 104' F. Operability is required fer a four hour duration at a Tore of 140' F. The l

utility reviews plant specific and industry generic data on failure rates for motor starters. The thermal effects on the failure rate can be conservatively approximated with the Arrhenius equation: l 1

A - exp [Ea (1/T.1/Toykl i where: I

! A = Stress Acceleration Factor (decreaseinieliability) l Ea - Activation energy (eV)(a unique comtant for each specific chemical reaction or failure mechanism)

) k - Boltzman's constant - 8.63 X 10-se yfg l 4  :

T - Ambient temperature in degrees Kelvin (K) [

To - Reference temperature (K)(used for normalization to the given temperature) (

By selecting a conservative activation energy it is possible to establish an upper bound for the decrease in the reliability of the component. From the utility's review of failure rates for motor starters, it is determined that 0.9 eV corresponds to a conservatively high activation energy. That is, when this activation energy is used in the Arrhenius equation to predict increases in failure rates due to operation at higher temperatures, the equation consistently predicts

] {

q higher failure rates than those determined in the utility's analysis. By entering this figure into the Arrhenius

{

] equation, a temperature increase from 40' C (IN' F) to 60' C (140' F) will result in a decrease in reliability by a j j factor of 18. Thus, if the mean time between failures (MTBF) for a component is only one year (8760 hours0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br />) w hen l j operating at IN' F, then at 140' F the htTBF will be reduced to 486 hours0.00563 days <br />0.135 hours <br />8.035714e-4 weeks <br />1.84923e-4 months <br />. Since this number is still considerably  !

) higher than four hours,it can be concluded that motor starters designed for continuous operation at 104' F can be expected to operate at 140' F for the full four hour duration of a station blackout.

l 1 l Since operability of a typical safety related motor starter is verified by monthly surveillance testing, the total j J

probability of a motor starter failure for the blackout duration should not exceed the failure probability for a 30 day period during normal operation. Consequently, the Stress Acceleration Fxtor must be less than or equal to ISO (i.e i

180 24 hrs I day a 30 days I 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />). The use of a bounding activation energy results in a calculated Stress j Acceleration Factor less than 30.1 Consequently, operability is demonstrated for the four hour duration.

I When perfomung such ansipit,it should be noted that larger acuvation energy values result in larger Stress Accelerauon l Factors. If one conservauvely assumes that relay components have values bounded by eV = 2.0, then the Stress

! Acceleration Factor for ambient temperature increases from 104' F to 130' F is approximately 26.

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GUIDELINES AND TECliNICAL BASES FOR NUMARC INITIATIVES NUMARC 87 00 DRAFT Jrly 18.1988 F.4 Materials -'

l F.4.1 General Statement of Method [

The primary consideration for equipment operability in a station blackout is the potential for thermally induced failure. Most materials used in plant equipment and components are not subject to physical or chemical changes in ,

the range of temperamres expected to result in a station blackout. Materials or combinations of materials that are susceptible to significant changes in these ranges will be identified and itsed to screen components that are potentially sensitive to station 1;lackout conditions.

Reasonable assurance for equipment operability is provided if it is shown that the station blackout coping equipment j does not contain materials that are susceptible to significant physical or chemical changes in a station blaciout

! environment.

F.4.2 Guidance Due to the relatively low temperaturcs expected to be encountered during a station blackout, the vast majority of 1 materials used in nuclear grade equipment and components are not expected to impair operation. Non. metallic i materials (i,c. insulators and lubricants) are generally recognized rs being most susceptible to potential thermal degradation in the temperature ranges expected to be encountered in the dominant areas of concern. Reasonable assurance of operability is provided if the specific component does not contain materials known to be susceptib!c to significant thermal changes w hen exposed to ToAc for the limited duration of a station blackou't. -

A reference tabic showing the maximum continuous service temperature for representative insulators and lubricants j which may be found in station blackout equipment is provided in the Appendix F Topical Report.

l 1

F.4.3 Procedure

\

] Apply the following steps for station blackout response equipment located in dominant areas of concem experiencing a totalloss of forced ventilation.

(1) Determine the TDAc for the area containing the equipment in accordace with Section 7.2.4.

(2) (a) Prepare a list of temperature sensitive materials for the station blackout equipment. (When the exact material types are not known but the material class is, the most thermally sensitive material j type in the class should be used.) I I

(b) Determine whether the materials listed in step 2(a) are operaung within their maximum continuous  !

service temperature. A reference list of temperstare sensitive materials commonly used in station blackout equipment is reovided in the Appendix F Topical Report.

F 13 l 1

GUIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVES NUMARC 87 06 DRAFT g Jdy 18,1998 (c) Reasonable assurance of opea .a .* thed if the materials identified have a muimum continuous service temperatur ..  ! . m ,. . Note: If the continuous service temperature for some of the most temperature sensitige materials falls below TDAC. it may still be possible to  ;

estabilsh operability for the limited duration of a stadon blackout. Section F.3 of this appendix Introduces methods for establishing the operability of equipment for short durations above their rated temperature for continuous operation. ,

F.4.4 Exampies ne following examples illustrate the establishment of reasonable assurance of operability on the basis of materials analysis.

(

Etsmete H An air operated diaphragm valve actuator is required for three hours in a dominant area of concern with a Tore of 140' F. A review of the components identified polystyrene as the only temperature sensidve material. A review of the Topical Report identifies a muimum condnuous service temperature of 151' F which is greater than ToAc.

Based on this materials review the actuator is considered operable for the three hour duration.

Enmete $ i 4

A manufacturer's generic qualification report demonstrates qualification of a nuclear grade solenoid operated valve (SOV) for in containment conditions. A similar valve that has riot been tested by the manufacturer is considered as i

station blackout response equipment and is located in a dominant area of concern. De manufacturer indicates that the only significant difference between the SOVs is the use of Buna N instead of EPT as the valve elastomer. A l

review of the Topical Report reveals that the muimum continuous operability temperatures for Buna N and EPT are f

240' F and 300' F respectively. The utility determines that reasonable assurance of operability is established since the valve is only required to function for two hours in a dominant area of concern with a TDAC of 145' F.

1 Enmete h . -

A pressure switch is rated for continuous operation at 125' F. De manufacturer believes the switch will function at higher temperatures but will not formally state this opinion. De utility reviews the switch design and determines that the thermally limiting sub-components are the intemal snap acting switch and the Viton pressure retaining j diaphragm and seals. De snap-acting switch is rated by its manufacturer for a 90' C (194* F) muimum continuous service temperature, General material information indicates that the Viton pressure retaining diaphragm and seals are

, acceptable for temperatures in excess of a 350' F muimum continuous service temperature. Based on this data the utility can conclude that the pressure switch is operable for the four hour duration of a station blackout at a Tore of  ;

160' F, w l

GUIDELINES AND TECllNICAL BASES FOR NUMARC INITIATIVES NUM ARC 87 00 9

DRAFT hly 18,1988 t

F.5 Equipment inside Instrumentation and Control Cabinets lY. . ..

F.5.1 General Statement of Method Components located inside instrumentadon and control cabinets are normally exposed to the heat generated by electrical power supplies. Most cabinets are not equipped with forced ventilation, relying. instead, on natural

- convection through louvers in the cabinet. Guidelines direct operators to open doors for cabinets containing energized

equipment relied upon to cope with a station blackout within 30 minutes in order to provide more extensive air ,

mixing with the general area. This action is expected to reduce the potential for building up higher air tempecatures in the immediate vicinity of electrical and electronic equipment and components.

l Reasonable assurance for equipment operability is provided if it is shown that the station blackout coping equipment and components inside instrumentation and control cabinets with open doors tvill not be exposed to a thermal environment that exceeds normal operating conditions with the doors closed.

F . 5.1, Guidance Equipment located inside instrumentation and control cabinets normally operate at steady state temperatures which ,

are frequently higher than the expected room temperatures in dominant areas of concern during a station blackout. If I

cabinet doors are opened to improve ventilation within the first 30 minutes of a station blackout, these components are not expected to experience temperature environments which would be substantially different from their normal -

operating conditions. In fact. due to the site of the cabinet doors it is reasonable to assume th'at the cabinet internal temperatures do not exceed the ambient temperature of the room once the doors are opened. On this basis, reascnsble assurance of equipment operability in a station blackout is established if it can be shown by analysis or measurement that such cabinets with open doors will not expose the components inside to a thermal environment that exceeds normal operating condinons with the doors closed.

Reliance on this method requires station blackout response procedures which direct operators to open cabinet doors in

! dominant areas of concem (please see Section 4.2.l(10)) within the first 30 minutes of a station blackout event.

i i

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, F.5.3 Procedure l Apply the followiag steps for station blackout response equipment located in dominant areas of concern experiencing a totalloss of forced ventilation.

(1) Determine TDAc fer the area containing the equipment in acccrdance with Section 7.2.4.

F 15 l

4

GUIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVE 5 NUMARC 87 00 DRAFT i J:ly .18, 1988 p,t. .

(2) Determine the maximum design temperature for the equipment or measure the normal bulk air operating .

temperature inside the cab! net (whichever is higher). One measurement at a location near the top of the cabinet is sufficient for the purpose of establishing operability during a station blackout.

(3) Reasonable assurance cf operability is established if:

(a) The temperature determined in Step 2 is higher than the temperature determined in Step It and.

(b) Procedures requiring opening of cabinet panels and doors within 30 minutes of the loss of vutilation avent t.reimplemented, i F.5.4 Example The following example illustrates the establishrnent of reasonable assurance of operability on the basis of equipment located inside instrumentation and control cabinets. ,

Eth&t*

A cabinet containing heat generating station blackout instrumentation is located in a dominant area with a TDAC of 140* F. The normal steady state bulk air temperature inside the cabinet. Tcabinet, is determined to be 150' F. Plant procedures are implemented to open the doors to this cabinet within one half hour of loss of venclation. Reasonable assurance of operability is established since TDAC < Tcabinet.

2

] F 16 1

GUIDEl.!NES AND TECHNICAL BASES FOR NUhtARC INITIATIVES NUht ARC - 37 60 DRAFT July 18,1988 c

F.6 Generic Studies and Experience < l 0 k.

F.6.1 General Statement of Method De current state of knowledge conceming equipment operability in elevated thermal environments provides a substantial basis for concluding that plant equipment can properly function in thermal environments above design  ;

conditions. Two recent studies support the conclusion that plant equipment can operate under loss of fcreed ventilation for periods !coger than four hours: ,

(1) Letter Report on Equipment Operability During Station Blackout Events. M. J., lacobus.

V. F. Nicolette , and A. C. Payne. Sandia National Laboratories, (1986); and. ,

- C) Efects of Ambient Temperature on Electronic Components in Safety Relatedlastrumentation and Control Systems, M. Chiramal. AEOD/C604, United States Nuclear Regulatory Commission. (1986).

< ne Jacobus report found that certain classes of equipment will not be affected when exposed to temperatures above 150' F for eight houn or longer. The Chiramal report concluded that an actual loss of ventilati?n event did not I

adversely affect the performance of equipment needed for safe shutdon.

i Dese studies can be used to suppott conclusions of equiprnent operability undet elevated temperature conditions  !

estimated for the station blackout coping duration.

If the site. specific application is not covered by the above data base or other generic studies. then other sources of data, such as Ucensee Event Reports (LERs) cr the Nuclear Plant Reliability Data System (NPRDS), can be used to  ;

j support conclusions of equipment operability under elevated temperature conditions estimated for the station blackout coping duration.

)

i F.6.2 Guidance 1

l A variety of studies and reports contain information on the operability of equipment above design conditions. De information contained in these reports can be used to establish reasonable assurance of operability. Examples of these include:  ;

(1) Ucensee Event Reports:

C) Nuclear Plant Reliability Data Systems (NPRDS);

0) NUREGs-

, (.8) ANSI. ASME. ASTM or ANS standards:

1 i

F 17 ,

GUIDELINES AND TECllNICAL DASES FOR NUM ARC INITIATIVES NUMARC 87 00 DRAFT Jtly 18,1988

($) Scientific literature: and.

(6) Vendorinfcrmation.

F.6.3 Procedure Apply the following steps for station blackout response equipment Iccated in dominant ueas of concern experiencing a totalloss of forced ventiluion.

(1) Determine TDAc for the vea containing the equipment in accordance with Section 7.2.4.

(2) (a) Determine the time priod that the equipment must remain operable for the appropriate stati,on blackout coping method:ct, (b) Assume the equipment must remain operable for the entire duration of the station blackout (i.e.,

one, two, or fous hours).

(3) Determine whether any generic analyses, tests, or reporu exist that address the operability of equipment exposed to the conditions which envelope Steps I and 2. A bibliography of reports w hich may be helpful to establish reasonable assurance of operability sorted by equipment ca.egory is provided in the NUGSBO Equipment Operability Database.

(4) Reasonable assurance of operability is provided if the temperature specifled in Step 1 and the duration specified in Step 2 are envekved by the conditions for the equipment as determined from generic studies and experiments.

F.6.4 Examples The following examples illustrate the estab!!shment of reasonable assurance of operrbility on the basis of generic studies and experience.

Eumele);

A solenoid valve is located in a dominant area of concem where TDAC - 150' F. Vendor documentation is available supperung operability at 1:0* F. A generic report, however, is available documenting events'in which similar solenoid valves operated without failure at !$1' F fcr time perio1s longer than four hours. Reasonable assurance of operability is therefore established.

Eume!e h The espected TDAc for an operaung BWR is calcula:ed for all dorrunant areas of concern. These values are compared to those calculated or measured for an actualloss of venulation esent at a similar BWR. If the Tore values at this, F 18

JIDELINES AND TECHNICAI, BASES FOR StJMARC INITIATIVF.S Ninf ARC 87 00 DRAFT July 18,1988 .

second plant envelope those calculated for the first, then operability is established for similar equipment. Information describing the evert and equipment performance should be obtained from the facility experiencing the event.

Examole 1-A utidtv deternunes that a piece of equipment is required in a TDAc of 140* F for four hours. Similar equipment installed in another plant area functioned appropriately when subjected to loca' temperature excursions which exceeded the TDAc value for four hours. Reasonable assurance of operability is based on this plant specific informarion.

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GUIDELINES AND TECHNICAL BASES FOR NU51 ARC INITIATIVES NU5f ARC 87 00 DRAFT -July 18,1988 F.7 Plaat Specific Experience and Tests F.7.1 General Statement of Method Some plants have actually experienced the effects of loss of ventilation or have studied the issue for specific applications. For such cases, reasonable assurance for equipment operability is provided if no failures of equipment needed to et ith a station blackout resulted from exposing the equipment to temperatures expected from a four hour statiot. ..ackout during tests or operational events.

F.7.2 Guidance This method allows the use of plant specific experience to establish operability. A loss of ventilation event, for example may be used as a basis to establish oper-ioility. Reasonable assurance of operability for the duration of the event is established if the loss of ventilation does not impact the operability of station blackout components.

Alternatively, utilities may demonstrati, operability in a station blackout environment by testing.

F.7.3 Procedure Apply the following steps for station blackout response equipment located in dominant areas of concern experiencing a totalloss of forced ventilation.

(1) Determine TDAc for the area containing the equipment in accordance with Section 7.2.4.

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(2) - ' (a) Determine the time period that the~cquipment must' remain operable f6r'the appropriate station ~~ ~~ ~

blackout coping method; or, (b) Assume the equipment must remain operab!c for the entire duration of the station blackout (i.e.,

one two. or four hours).

(3) Reasonable assurance of operability is established if any plant specific analyses, tests. cr experience subjected the equipment, without failure, to conditions enveloping those determined in Steps 1 and 2.

F.7.4 Examples The following examples illustrate the establishment of reasonable assurance of operability on the basis of plant specific experience and tests.

Exam + 1:

Dunng an extended loss of off site power event a BWR achieved safe shutdown without restoring normal Reactor Building ventilation for ten hours. Ventilation through the Standby Gas Treatment System was available but provided insignificant cooling to the building areas. The RCIC system successfully operated throughout the event:

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GUIDELINES AND TECHNICAL BASES FOR NUMARC INITIATIVES NUM ARC 87o00

, .. DRAFT July 18,1988 the HPCI sytem was secured after the first hour of operation. After res, oration of off site power, all systems and equipment fu ctioned normally and the unit was returne ,ower. No subsequent failures of the equipment due to exposure to elevated temperatures during the loss of ventilauon were identified. No replacements with new designs had been made or were necessary for equipment required for coping with a station blackout in these dominant areas of concern. As a result of this operating experience, reasonabic assurance is established that equipment in this BWR will perform during the four hout temperature environments anticipated during station blacLaut events.

Enmele 2' Station blackout equipment located in the auxiliary feed water (AFW) pump room is required to operate for one hour in order to cope with a station blackout event. The components in this room were shown to operate under station blackout conditions for two hours as part of post TMI NRC requirements. Reasonable as. - -

of operability is, therefore, established for all equipment located in the AFW pump room of this PWR.

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