ML20245G117

Provides Advance Changes to Be Included in Future FSAR Amend Re Util Responses to TMI Items II.E.3.1, Emergency Power for Pressurizer Heaters & II.E.4.2, Containment Isolation Dependability

ML20245G117
Person / Time
Site:	Comanche Peak
Issue date:	08/07/1989
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TASK-2.E.3.1, TASK-2.E.4.2, TASK-TM TXX-89464, NUDOCS 8908150213
Download: ML20245G117 (23)

Text

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Log # TXX-89464 File # 10010

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" # **C'"'** #'b' 1UELECTRiC l

' William J. Cahill. Jr.

Exnutive Vice President .

U..S. Nuclear Regulatory Commission Attn:. Document Control Desk

~ Washington, D. C. 20555

SUBJECT:

COMAK AE! PEAK STEAM ELECTRIC STATION (CPSES)  !

.DOCKE1.N05. 50-445 AND 50-446 j'

' ADVANCE'FSAR SUPMITTAL' EMERGENCY POWER SUPPLY FOR PRESSURIZER HEATERS &

CONTAINMENT. ISOLATION ACTUATION SIGNAL SETPOINT ,

Gentlemen: l This'1etter provides an advance copy of changes to be included in a future FSAR amendment dealing with the CPSES responses to TMI Item II.E.3.1 -

Emergency Power for. Pressurizer Heaters and Item II.E.4.2 - Containment Isoletion Dependability.

The TMI Item II.E.3.1 discussion of the installed pressurizer heater group j '

configurations has been corrected to reflect the final CPSES as-built design.

Second,. based on updated Westinghouse' analysis, CPSES commitments regarding the use of pressurizer heaters during natural circulation conditions are

. modified. Last, the discussion is rewritten for clarity. j The response to THI Item II.E.4.2 is updated to reflect the correct '

containment isolation actuation signal setpoint for containment pressure,

. consistent with current Westinghouse documentation.

In order to facilitate NRC staff review of these changes, the enclosure is 3 organized as follows:

1. Draft revised FSAR pages, with changed portions indicated by a bar  ;

in the margin, as they are to appear in a future amendment (additional pages immediately preceeding and/or following the revised pages are provided if needed to understand the change).

- 2. A line-by-line description / justification of each item revised.

3. A copy of related SER/SSER sections.

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400 North Olive Street LB 81 Dallas, Texas 75201 i i

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. 4 TXX-89464 August 7, 1989

- Page 2 of 2 1

4. An index page containing the title of " bullets" which consolidates and categorizes similar individual changes by subject and related SER section.

5. A discussion of each " bullet" which includes:

- The line-by-line description / justification for e ach item related to the " bullet" which has been screened is a group 1 or 2 item or.a group 3 or 4 item which. impacts tte existing SER/SSER's. (The discussion of these groups is contained in TV Electric letter TXX-88467 dated June 1, 1988).

- The bold / overstrike' version of the revised FSAR pages referenced by the description / justification for ea:h item identified above. The bold /cverstrike version facilitates review of the revisions by highlighting each addition of new text in bold type font and overstriking with a slash (/) the portion of the text that is deleted.

If you have any questions regarding this submittal please contact Joe Harnden at (214) 812-8226.

Sincerely,

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William J. Cahill, Jr.

WJH/vid Enclosure c Mr. R. D. Martin, Region IV Resident Inspectors =CPSES (3) i i

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T 4 Enclosure to TXX-89464-

, August 7. 1989 Advance FSAR Change Regarding the Emergency-Power Supply .

for Pressurizer l' eaters and Containment Isolation -

Actuation Signal Setpoint Item 1- Draft Revised FSAR Pages pg. 2 thru 8 Item.2- Description / Justification pg. 9 thru 10 Item 3 Related SER/SSER Pages pg. 11 thru 17

' Item 4 Index'Page'Containing the pg. 18 h

Title of " Bullets" Item 5 Description / Justification for pg. 19 Screened.FSAR Changes .

Markup'of. Existing FSAR Pages '

pg. 20 thru 21 Pg. 1 of 21 i..

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b .

Enclosure to TXX-89464'

~ . ' Au, gust 7, ' 1989 -  ;

~Pg. 2 ofL21 CPSES/FSAR l

E ' RESP 0t!SE TO NRC ACTIOR~EAN r e l NUREC-0578 Position 2 i i-l h The auxiliary feedwater flow. instrument channels shall be powered from the emergency buses. consistent with satisfying the emergency power diversity requirements of the auxiliary feedwater system set forth in Auxiliary Systems Branch Technical Position 10-l' of Standa'rd Review Plan, Section 10.4.9.

1 CPSES Response j Of the two safety-grade indicators of auxiliary feedwater flow to each steam generator, one is powered from a Train A vital instrument ESF bus and the other from a Train B vital instrument ESF bus. f

. The pump flow indictors are powered from the vital instrument ESF bus of the same train as the pump. The turbine driven pump flow indication

( is frcm Train A.

II.E.3 DECAY HEAT REMOVAL

'0BJECTIVE:

" Improve the reliability and capability of nuclear power plant systems for removing decay heat and achieving safe shutdown conditions following transients and under postaccident conditions."

. - NUREG 0600, Pg. II.E.3-1 II.E.3.1 Reliability of Power Supplies for Natural Circulation

( II.E-23 JANUARY 30, 1981

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M . Enclosureio:TXX-89464-K " -,Augt!st 7,;1989

+ iPg q 3. o fl1 y y CPSES/FSAR

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RESPONSE TO NRC ACTION ?LAN

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Action' Plan Requirements: -

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Consistent with satisfying the. requirements of' General Design Criteria. .

4 g 10 14,15,17, and 20 of Appendix A to.10 CFR Part 50 for the' event of .  !

I loss of offsite power, the following positions shall be implemented:  !

(1) The pressurizer heater power supply design shall provide the capability to supply, from either the offsite' power source or the emergency power source (when offsite power is not available), a  !

predetermined number ~of pressurizer heaters and associated controls nece'sary s to establish and maintain natural circulation at hot standby conditions. 'The required heaters and their controls shall be connected to the emergency buses in a manner

.i that will provide redundant power supply capability.

^ i (2) Procedures and training shall be established to make the operator q aware of when and how the required pressurizer heaters shall be

. connected to the emergency buses. If required, the procedures.

l shall identify under what conditions selected emergency loads can E

be shed from the emergency power source to provide sufficient l capacity'for the connection of the ' pressurizer heaters.  !

(3) The time required to accomplish the connection of the preselected pressurizer heater to the emergency buses shall be consistent with the timely initiation and maintenance of natural circulation I conditions.

h (4) Pressurizer heater motive and control power interfaces with the emergency buses shall be accomplished through devices that have been qualified in accordance with safety-grade requirements.

- NUREG 0737 I 1

JANUARY 30, 1981 II.E-24 g

1. Enclos~ure to TXX-89464 '

4Augustc7, 1989 CPSES/FSAR ,

Pgd4Lof 21 RESPONSE TO NRC ACTION PLAN l

I CPSES ResDonse Powerlis. supplied'to four pressurizer heater groups from offsite ' DRAFT power, when available, and from the~onsite emergency. diesel generators through ESF buses. Redundancy is provided by supplying two groups of pressurizer heaters from each redundant ESF train. Control power for manual on/off control of each of 'these four heater groups is supplied from the 125 volt DC ESF bus in the same' train as the main power supply.

. Procedures are established to control Reactor Coolant System pressure DRAFT

' and temperature. Per Westinghouse analysis, pressurizer. heaters are not required during natural circulation cooldown to Hot Shutdown or Cold Shutdown.

Training will be established to ensure that the operator reenergizes. DRAFT the pressurizer heaters via the control room handswitch(s) as required to maintain saturation margin during ne.tural circulation at Hot Standby conditions when component availability may not allow the plant to be brought directly to Hot Shutdown. No loads rceed to be shed from the' emergency power source to provide sufficient capacity for the connection of the pressurizer heaters.

The electrical interface between each of the'four pressurizer heater DRAFT groups and its associated ESF bus of concern is through a circuit breaker which trips on an 'S' signal and is qualified in accordance with safety-grade requirements. The manual controls for these breakers are qualified in accordance with safety-grade requirements.

II.E-25 Draft Version

! Enclosure to TXX-89464-

. August-7, 1989-

" Pg '. - 5 o f 21 CPSES/FSAR RESPONSE TO NRC ACTMrPLAN -

II.E.4.1 Dedicated Penetration y .

s Action Plan Requirements:

Plants using external recombiners or purge systems for postaccident combustible gas control of the containnunt atmusphere should provide containment penetration systems for external recombiner or purge systems that are dedicated to that service only, that meet the redundancy and single. failure requirements of General Design Criteria 54 and 56 of Appendix A to 10 CFR 50, and that are sized to satisfy the flow requirements of the recombiner or purge system.

The procedures for the use of combustible gas control systems following an accident that results in a ' degraded core and release of radioactivity to the containment must be reviewed and revised, if necessary.

- NUREG 0737 QSESResponse CPSES has redundant safety-grade hydrogen recombiners located inside each containment for post accident hydrogen control. These recombiners are controlled from outside the containment.

II.E.4.2 Isolation Dependability Action Ma_n Requirements:

" Provide containment isolation on diverse signals in conformance with Section 6.2.4 of the Standard Review Flan, review isolation provisions for non-essential systems and revise as necessary, and modify containment isolation designs as necessary to eliminate the potential fer inadvertent reopening upon reset of the isalation signal."

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JANUARY 30, 1981 II.E-26

. Enclosure to TXX-89464

- August 7. 1989:

Pg._6 of 21

, CPSES/FSAR RESPONSE TO NRC ACTION PLAN

. - NOREG 0578, Pg. 8 ,

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"(1) Containment isolation system designs shall comply with the recommendations of Standard Review Plan Section 6.2.4, (i.e.,

that there be diversity in the parcmeters sensed for the initiationofcontainmentisolation). J

"(2)' All plant personnel shall give carefbl consideration to the definition of essential and nonessential systems, identify each system determined to be nonessential, describe the basis for  !

selection of each essential system, modify their containment isolation designs accordingly, and report the results of the reevaluation to the NRL.

"(3) All nonesse,ntial systems shall be automatically isolated by the containment isolation signal.

"(4) The design of control systems for automatic containment isolation valves shall be such that resetting the isolation signal will not result in the automatic reopening of containment isolation val ves. Reopening of containment isolation valves shall require ,

deliberate operator action.  !

"(5) The containment setooint pressure that initiates containment isolation for nonessential penetrations must be reduced to the minimum compatible with normal operating conditions.

., ,"(6) Containment purge valves that do not satisfy the operability criteria set forth in Branch Technical Position CSB 6-4 or the Staff Interim Position of October 23, 1979 must be sealed closed, as defined in SRP 6.2.4, Item II.3.f during operational conditions 1, 2, 3, and 4. Furthermore, these valves must be verified to be closed at least every 31 days." (A copy of the Staff Interim Position is enclosed as Attachment 1.)

II.E-27 JANUARY 30, 1981

N!g, c c 4 M ' IEnc,losure~to TXX-89464. <

d'7Aug'ust7,'1989

' ' Pg. 7 o f '21 j

CPSES/FSAR

1. RESPONSE TO NRC ACTION. PLAN r (i

"(7) Containment purge and vent isolation valves must close on a high *

' radiation signal.'

- NUREG 0737 CPSES Response

1. There are two phases of containment isolation at CPSES. Phase A isolates all nonessential process lines but does not effe:t safety injection, containment spray, component cooling water supplied to the reactor coolant pumps, or auxiliary feedwater.

Phase B isolates all process lines except safety injectim, cont:ir, ment spray, and auxiliary feedwater.

, Phase A isolation is initiated by high containment pressure, icw steam line pressure, . low pressurizer pressure, or. manual initiation. Phase B. isolation is initiated by high-high containment pressure or manual initiation. (

In addition, containment ventilation isolation is initiated by Phase A isolation, containment spray actuation, or high containment radioactivity.

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JANUARY 30, 1981 II.E-28

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-Enclosure to'TXX-89464-

.! August'9,1989- ..

Pg. . 8 lof 21 .

CPSES/FSAR RESPONSE TO NRC ACTION PLAN This system fully complies with Section II.6 of the SRP 6.2.4.

Compliance with all remaining sections of SRP 6.2.4 is documented in Section 6.2.4.

2. A reevaluation of the classification assigned to each process penetration has been performed and is described in revised Section 6.2.4.3.

3. All nonessential systems use either normally closed manual valves or the valves are automatically isolated on a containment isolation signal. See revised Section 6.2.4.3. .

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4. The CPSES design con. plies with the position. The operator must reset each device individually as desired. See revised Section 7.3.1.1.4.

5. The CPSES containment pressure setpoint (Hi-1) that initiates DRAFT containment isolation for non-essential penetrations is 3.2 psig. This setpoint is the minimum compatible with normal operating conditions and the value used in accident analyses. 20

6. The containment isolation valves for the contair. ment purge 20 system are automatic isolation valves. Furthermore, these valves will be closed during operational modes 1, 2, 3 and 4 (see respense to Question 022.20). These valvss will be verified to be closed at least every 31 days.

7. CPSES complies as described in Section 6.2.4.

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l II.E-29 Draft Version

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'Enbosureto.TXX-89464~ CPSES FSAR

. Augus 1, 1989 l Pg. 9}of 21 DETAILED DESCRIPTION Page l' l FSAR Page <

1(4s.. amen *d) Group Description

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I TMI II.E-25 ~

.3 Corrects the number of pressurizer heater groups l connected to offsite power / emergency diesel generators j and the redundancy of these pressurizer heater groups. 1 Correction: )

The response is corrected to reflect the final CPSES as-built design. Offsite power and ensite emergency .,

diesel generators power four pressurizer heater groups.

two per redundant ESF train. )

, FSAR Change Request. Number: 89-433.1 Related SER Section: II.E.3.1 SER/SSER Impact: Yes .j SER does not reflect.the current configuration of the pressurizer heater groups.

TM1 II.E-25 2 Updates the CPSES commitment regarding procedures and training for reenergizing the pressurizer heaters at the proper time to initiate natural circulation.

Update:

In accordance with Westinghouse analysis, pressurizer heaters are not required during natural circulation cooldown to Hot Shutdown or Cold Shutdown. However, training will be provided.to ensure that operators reenergize the heaters via the control. room handswitch(s) as required to maintain saturation margin during natural circulation at Hot Standby. I FSAR Change Request Number: 89-433.2 j Related SER Section: II.E.3.1 1 SER/SSER Impact: Yes SER does not reflect Westinghouse analysis i.e. -

heaters need only by energized as required for Hot Standby.

TMI II.E-25 4 Clarifies the statement that no load shedding is required.

Clarification:

No load shedding is required from the emergency power source te provide sufficient capacity for the connection of the pressurizer heaters.

FSAR Change Request Number: 89-433.3 1 l Related SER Section: II.E.3.1 SER/SSER Impact: No ,

THI II.E-25 4 Clarifies that the Class IE pressurizer heater ESF bus circuit breaker trips on a safety injection signal.

Clarification:

The safety-grade circuit breaker which connects the pressurizer heaters to the Class 1E buses provides Class IE to non-Class IE electrical isolation by tripping on the receipt of an 'S' signal.

FSAR Change Request Number: 89-433.4

...._......m.. . . . .... _...._mm . . . . . . . . . -

Enclosure to TXX-89464 August 7.- 1989 CPSES.FSAR Pg.10 of 21' DETAILED DESCRIPTION Page 2 FSAR Page

"(as amended) Group Description Related SER Section: II.E.3.1 SER/SSER Impact: No THI II.E-29 3 Updates CPSES containment pressure setpoint per current' Westinghouse documentation.

Update:

Changes the CPSES containment pressure setpoint (Hi-1),

which initiates containment isolation for non-essential penetrations from 4.0 psig to 3.2 psig, to ensure consistency with the current revision of the Westinghouse Setpoint Methodology.for Protection Systems (WCAP-12123,'Rev. 1).

FSAR Change Request Number: 89-433.5 Related SER Section: II.E.4.2 SER/SSER Impact: Yes SER identifies the previous containment pressure setpoint value of 4.0 psig versus the current value i of 3.2 psig.

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a = Enclosure to TXX-89464; Augu-st 7, 1989 1 iPg. li:of 21 Discussion and Conclusions .

1 PART 1: AFWS A_utomatic Initiation The AFWS automatic initiation. is part of the ESF actuation system and as such -

conforms to the requirements for protection systems in~accordance to IEEE . ,

Therefore, the staff finds

. Standard 279 as noted in Section 7.3.1.6 of this SER.

that the design of this system conforms to the Action Plan guidelines.

PART 2: AFWS Flowrate_ Indication Two safety-grade indicators of auxiliary feedwater flow to each steam generator are provided in the control room. The redundant flow indication is powered from separate ESF instrument buses. The staff finds that the AFWS flow indica-tion satisfies the Action Plan guidelines and is therefere acceptable.  ;

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--e II.E.3.1 Emergency Power Supply for Pressurizer Heaters Position Consistent with satisfying the requirements of GDC 10, 14, 15, 17, and 20 for j loss-of-offsite power, the following positions shall be implemented: ,

I (1) The pressurizer heater power supply design shall provide the capability to supply, from either the offsite power source or the emergency power  !

source (when offsite power is not available), a predetermined number of pressurizer heaters and associated controls necessary to establish and -

maintain natural circulation at hot standby conditions. The required heaters and their controls shall be connected to the emergency buses in a manner that will provide redundant power supply capability.

I (2)' Procedures and training shall be established to make the operator aware '

of when and how the required pressurizer heaters shall be connected to  ;

the emergency buses. If required, the procedures shall identify under what conditions selected emergency loads can be shed from the emergency power source to provide ' sufficient capacity for the connection of the pressurizer heaters.

(3) The time required to accomplish the connection of the preselected pressu-rizer heater to the emergency buses shall be consistent with the timely

• initiation and maintenance of natural circulation conditions.

(4) Pressurizer heater motive and control power interfaces with the emergency ,

1 buses shall be accomplished through devices that have been qualified in l

accordance with safety-grade requirements.

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22-49 A _ _ _ _ _ _ - _ - _ _ _ -

, EnclosureLto TXX-89464 August' 7,1989 Pg. ':12 of' 21 Clarification (1) Redundant heater capacity must be provided, and each redundant heater or group supply.

of heaters should have access to only one Class 1E division power 4

(2) The number of heaters required to have access to each emergency power source is that number required to maintain natural circulation in the hot standby condition.

(3) The power sources need not necessarily have the capacity to provide power to the heaters concurrent with the loads required for LOCA.

(4) Any change-over of the heaters from normal offsite power to emergency onsite power is to be accomplished manually in the control room.

(5) In establishing procedures to manually reload the pressurizer heaters onto the emergency power sources, careful consideration must be given to (a) which ESF loads may be appropriately shed for a given situation (b) reset of the safety injection actuation signal to permit the operation of the heaters (c) instrumentation and criteria for operator use to prevent overloading a diesel generator (6) The Class 1E interfaces for main power and control power are to be protected by safety grade circuit breakers. (See alto Regulatory Guide 1.75) ,

(7) Being non-Class IE loads, the pressurizer heaters must be automatically shed from the emergency power sources upon the occurrence of a safety injection actuation signal. (See (S.b) above).

Discussion and Conclusions 4

Power is supplied to two of four pressurizer heater groups from offsite power, '

I when available, and from the onsite emergency generators through ESF buses. 1 Redundancy is provided by supplying each group of heaters from a different ESF train. Control power for manual on/off control of each of these two heater j

groups is supplied from the 125-V de ESF bus in the same train as the main t power supply. This is in accordance with position 1 and clarification items 1 I

and 2.

In accordance with position 4 and clarification item 6, the connection of the pressurizer heater elements and controls to the Class 1E buses is through safety- "

l grade circuit breakers, and heaters are automatically tripped off of the emergency buses upon occurrence of a safety injection (SI) signal in accordance with clarification Item 7.

Procedures and training will be established to ensure that the operator reener-gizes the heaters at the proper time to initiate and maintain natural circula-tion. This covers position 2 and clarification Items 3 and 5.

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l 22-50

' Enclosure to TXX.89464

.l August 7, 1989 .

Pg.'11o~f11 The pressurizer heaters which are at the 480-V level are permanently connected to G.9 kV emergency buses through 6.9-kV/480-V transformers. 'This is in accordance with position 3.and clarification-Item 4.

Based.on its review, the staff concludes that the design for providing emergency i . power to the pressurizer heaters at Comanche Peak Units 1 and 2 is consistent with the NRC positions and clarifications in NUREG-0737 and 15'acr.eptable.  :

II.E.4.1 Dedicated Containment Penetrations Posit,i_o_n Plants using external recombinerr, or purge systems for postaccident combustible gas control of the O ntainment atmosphere should provide containment penetration systems for external recombiner or purge systems that are dedicated to that service'only, that meet the redundancy and single-failure requirements of GDC 54 and 56 and that are sized to satisfy the flow requirements of the recombiner or purge system.

The procedures for the use of combustible gas control systems following'an accident that results in a degraded core and release of radioactivity to the containment must be reviewed and revised, if necessary.

Clarification- ,

(1) An acceptable alternative to the dedicated penetration is a combined design that is single-failure proof for containment isolation purposes and singla-failure proof for operation of the recombiner or purge system.

(2) The dedicated penetration or the combined single-failure proof alternative

'l shall be sized so that the flow requirements for the use of the recombiner or purge system are satisfied. The design shall be based on 10 CFR 50.44 requirements.

I l (3) Components furnished to satisfy this requirements shall be safety grade.

i j (4) Licensees that rely on purge systems as the primary means of controlling

> combustible gases following a loss-of-coolant accident should be aware of the positions taken in SECY-80-399, " Proposed Interim Amendments to 10 CFR Part 50 Related to Hydrogen Control and Certain Degraded Core ,

i Considerations." This proposed rule, published in the Federal Register on October 2, 1980, would require plants that do not have recombiners to have the capacity to install external recombiners by January 1,1982. .'

l-l (Installed internal recombiners are an acceptable alternative to the i above.) ,

(5) Containment atmosphere dilution (CAD) systems are considered to be purge systems for the purpose of implementing the requirements of this TMI Task Action item.

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22-51 A . - - . - .--- _ -- - _ -----

Enclosure'to TXX-89464 Augu'st:7, 1989 pg. ,14 o f,21 '

Discussion and Conclusions Because internal recombiners are used at Comanche Peak Units 1 and 2, the requirement for dedicated penetrations for external recombiners is not appli-cable. The. requirement for the installation of dedicated penetrations before issuance of the operating license is, therefore, not applicable.

4 II.E.4.2 Containment Isolation Dependability Position, (1) Containment isolation system designs shall comply with the recommendations of SRP Section 6.2.4; that is, that there be diversity in the parameters  !

sensed for the initiation of containment isolation.

(2) 'All plant personnel shall give careful reconsideration to the definition

), of essential and nonessential systems, identify each system determined to be essential, identify each system determined to be nonessential, describe the basis' for selection of each essential system, modify their containment isolation designs accordingly, and report the results of the reevaluation

, to NRC.

(3) All nonessential systems shall be automatically isolated by the containment i isolation signal.

(4) The design of control systems for automatic containment isolation valves shall be such that resetting the isolation signal will not result in the automatic reopening of containment isolation valves. Reepening of contain-ment isolation valves shall require deliberate operater action.

(5) The containment setpoint pressure that initiates containment isoletion ,

for nonessential penetrations must be reduced to the minimum compatible with normal operating conditions. 1 (6) Containment purge valves that do not satisfy the operability criteria set for the in Branch Technical Position CSB 6-4 or the Staff Interim Position ,

of October 23, 1979 must be sealed closed, as defined in SRP Section 6.2.4, i Item II.3f during operational conditions 1, 2, 3, and 4. Furthermore, <

these valves must be verified to be closed at least every 31 days.

(7) Containment purge and vent isolation valves must close on a high radiation signal.

4 Clarification L (1) The reference to SRP Section 6.2.4 in position 1 is only to the diversity requirements set forth in that document.

(2) For postaccident situations, each nonessential penetration (except instru-  !

ment lines) is required to have two isolation barriers in series that meet  ;

the requirements of GDC 54, 55, 56, and 57, as clarified by SRP Section 6.2.4.

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22-52

Enclosure to TXX-89464

. August 7,1989-Pg.15' of 21

' isolation must be performed automatically (no credit can be given for oper-ator action). Manual valves must be sealed closed, as defined by SRP Each automatic isolation Section 6.2.4, to qualify as an isolation barrier.

valve in a nonessential penetration must receive the diverse isolation signals.

(3) Revision 2 to Regulatory Guide 1.141 will contain guidance on the classifi-cation of essential versus nonessential systems. Requirements for operating plants to review their list of essential and nonessential systems will be issued in conjunction with this guide including an appropriate time schedule for completion.

(4) Administrative provisions to close all isolation valves manually before resetting the isolation signals is not an acceptable method of meeting position 4.

Reopen-(5) Ganged reopening of containment isolation valves.is not acceptable.

ing of isolation vaines must be performed on a valve-by-valve basis, or on a line-by-line basis, provided that electrical independence and other I single-failure criteria containue to be satisfied.

(6) The containment pressure history during normal operation should be used as a basis for arriving at an appropriate minimum pressure setpoint for initiating containment isolation. The pressure setpoint selected should i i

be far enough above the maximum observed (or expected) pressure inside containment during normal operation so that inadvertent containment isola.- i i

tion does not occur during normal operation from instrument drift or fluc-tuations due to the accuracy of the pressure sensor. A margin of 1 psi i above the maximum expected containment pressure should be adequate to account for instrument error. Any proposed values greater than 1 psi will require detailed justification. Applicants for an Operating License and l licensees of plants that have operated less than 1 yr should use pressure history data from similar plants that have operated more than 1 yr, if possible, to arrive at a minimum containment setpoint pressure.

l- Sealed-closed purge isolation valves shall be under administrative con-(7) trol to ensure that they cannot be inadvertently opened. Administrative l

control includes mechanical devices to seal or lock the valve closed, or ,

to prevent power from being supplied to the valve oprator. Checking the l

valve position light in the control room is an adequate method for verifying I every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> that the purge valves are closed.

. Discussion ano1 Conclusions The containment isolation system is designed to automatically isolate the containment atmosphere from the outside environment under accident conditions.

Double barrier protection, in the forn of closed systems and isolation valves, is provided to ensure that no single failure will result in the loss of contain-ment integrity.

The licensee has categorized all systems penetrating containment as being either essential or nonessential. Essential systems were selected on the basis of their postaccident safety function, or potential usefulness following an accident.

All nonessential systems are closeu by a containment isolation signal. The operator will have the option of manually resetting the actuation signal and 22-53 A .____-

Encloture to TXX-89464

" Augu'st 7,1989

'Pg. ; 16 o f '21 i

.4 taking deliberate action to open the isolation valves of certain nonessential systems if post-LOCA conditions warrant their use.

The staff review of the containment isolation system includes verification that there is diversity of parameters sensed for the initiation of containment isola-tion, as called for by SRP Section 6.2.4. For Comanche Peak, the containment isolation actuation signal (CIAS) includes diversity in the parameters sensed for initiation as recommended by SRP Section 6.2.4. CIAS takes place on high containment pressure and all safety injection signals. Therefore, the staff

,. concludes that the requirement to sense diverse parameters for containment isolation actuation has been met.

All containment isolation valves (CIVs) in nonessential systems that are designed to close upon receipt of an automatic isolation signal meet the Lessons-Learned 3 position on diversity.

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The Comanche Peak design precludes automatic reopening of containment isolation

- valves upon reset of the isolation signal. .,

--+ The containment isolation actuation signal setpoint for containment pressure

, is 4.0 psig and is considered by the applicant to be the minimum level compatible with normal operation. The channel accuracy assumed in the safety analysis is 11.2 psi (*1.8% of pressure indication at full scale). With a 1.0 psi margin,

)

the normal operating containment pressure can be as high as 1.8 psig. This pressure setpoint is consistent with setpoint pressures at other facilities

! with similar containment designs and is, therefore, acceptable.

The staff has reviewed the information presented by the applicant concerning the containment purge / vent systems. Its evaluation of this matter is discussed below.

The containment 48-in. purge supply and exhaust valves will be sealed closed by administrative control, which will require checking valve position lights in the control room once every 31 days. This requirement will be included in the Technical Specifications. Furthermore, as a result of the staff study of valve leakage due to seal deterioration, periodic leakage integrity tests of the isolation valves in the containment purge supply and exhaust lines will be

required. This requirement, together with the testing frequency, will be included in the Technical Specifications.

The 18-in. containment pressure relief system is designed to maintain the containment pressure within a prescribed range during normal plant operation.

However, the usage of the system will be limited to 90 hr/yr during plant oper-ating modes 1 through 4. The staff has reviewed the system against the guidelines of BTP CSB 6-4 and finds it acceptable. Checking of isolation valve position lights and a provision on isolation valve testing frequency will be included i

in the Technical Specifications.

i In addition to the phase A containment isolation signal which closes all the l nonessential systems, the containment isolation valves for the purge / pressure relief systems will receive an automatic closure signal on high radiation.

I 22-54

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MET- ; 3 - - -

TEnclosure t'o;TXX-89464

, J Au' gust 7,1989?

e  !.Pg. "17 ofL.21 The' large. (48ain.) containment' purge valves will be sealed closed during oper-ating modes 1 through.4, and therefore do not require an' operability' review.

['

The' isolation. valves of the 18-in. pressure relief system will be open.during normal plant. operating modes. The applicant has stated the pressure relief

. system valves are qualified to'close against 50 psi, which'is the containment

. design pressure. . In addition the applicant has confirmed the closure time is

'l Lless.than.5 sec. The applicant's program to meet this requirement is found acceptable; however, a confirmatory audit on'the operability program.will be X performed prior to fuel load.

-II.F.1' Additional' Accident Monitoring Instrumentation n' Introduction -

I' . . .

Item II.F.1 of NUREG-0660 contains the following subparts:

} (1)' noble gas affluent radiological monitor i

L (2) provisions for' continuous sampling of plant effluents for postaccident l releases of radioactive. iodines and particulate and onsite laboratory

(

capabilities (this requirement was inadvertently omitted from NUREG-0660; see Attachment 2 that follows for position)

(3) containment high-range radiation monitor

..' (4) containment. pressure monitor (5) containment water level monitor (6)' containment hydrogen concentration monitor NUREG-0578 provided the basic' requirements associated with' items 1 through 3 above. NRC staff letters issued to all operating nuclear power plants dated i September 13, 1979 and October 30, 1979 provided clarification of staff require-ments associated with Items 1 through 6 above. Attachments 1 through 6 present the staff position on these matters.

The requirements associated with the recommendations of this section should be  !

considered as advanced implementation of certain requirements to be included j in Revision 2 to Regulatory Guide 1.97, " Instrumentation to Follow the Course of an Accident," which was issued for comment in November, 1980. .

It is important that the displays and controls added to the control room as a result of this requirement not increase the potential for operator error. A y human factors analysis has been performed (see Section II.D.2) taking into

, consideration:-

I (1) the use of this information by an operator during both normal and abnormal 1 plant conditions

! (2) integration into emergency procedures

. 22-55 dh _

Enclosure to TXX-89464

• August 7,1989 pg. l'8 o f. 2 1-SECTION 22 - THI-2/ REQUIREMENTS II.E.3.1 Emeraency Power Sunolv for Pressurizer Heaters

1. The FSAR has been corrected to reflect the final C95ES as-built design and updated to reflect current Westinghouse analysis.

II.E.4.2 Containment Isolation Dependability

1. The FSAR has been updated to reflect the correct containment isolation actuation signal setpoint for containment pressure. consistent i with Westinghouse documentation. , j 1

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'Enclosurs to TXX-89464 CPSES FSAR lf August;7,1989 - DETAILED DESCRIPTION Page'1

.pg.J19 of.24

• FSAR Page-(as amended) Atgut Description THI II.E-25 3

~

Corrects the number of pressurizer heater groups connected to offsiteLpower/ emergency diesel generators and the redundancy of these pressurizer heater groups. i Correction:

The response is corrected to reflect the final CPSES as-built design. . Offsite power and onsite emergency diesel generators' power four pressurizer heater groups, two per redundant ESF train.

FSAR Change Request Number: 89-433.1 Related SER Section: II.E.3.1 SER/SSER Impac* !as SER does not reflect the current configuration of the pressurizer heater grcups.

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THI II.E-25 2 Updates the CPSES commitment _regarding procedures and training for reenergizing the pressurizer heaters at the proper time to initiate natural circulation.

Update:

In accordance with Westinghouse analysis, pressurizer heaters are not required during natural circulation cooldown to Hot Shutdown or Cold Shutdown. However, training will be provided to ensure that operators reenergize the heaters via the control room handswitch(s) as required to maintain saturation margin during natural circulation at Hot Standby.

FSAR Change Request Number: 89-433.2

{ Related SER Section: II.E.3.1 SER/SSER Impact: Yes SER does not reflect Westinghouse analysis, i.e.

heaters need only by energized as required for Hot Standby.

THI II.E-29 3 Updates CPSES containment pressure setpoint per current Westinghouse documentation.

Update:

Changes the CPSES containment pressure setpoint (Hi-1).

which initiates containment isolation for non-essential penetrations from 4.0 psig to 3.2 psig. to ensure ~

~ consistency with the current revision of the Westinghouse Setpoint Methodology for Protection Systems (WCAP-12123, Rev. 1).

FSAR Change Request Number: 89 433.5 Related SER Section: II.E.4.2 SER/SSER Impact: Yes SER identifies the previous containment pressure g setpoint value of 4.0 psig versus the~ current value of 3.2 psig.

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Enclosure to TXX-89464 CPSES/FSAR {

9 RESPONSE TO NRC ACTION PLAN l

CPSES Resoonse  !

Power is supplied to fdd df four pressurizer heater groups from offsite power, when available, and from the onsite emergency diesel generators through ESF buses. Redundancy is provided by supplying tuo dddM groups of pressurizer heaters from each redundant i diffd/ddf ESF train. Control power for manual on/off control of each of these fear fdd heater groups is supplied from the 125 volt DC ESF bus in the same train as the main power supply. -i Procedures are established to control Reactor Coolant System pressure and temperature. Per Westinghouse analysis, pressurizer heaters are not required during natural circulation cooldown to Not Shutdown or Cold Shutdeun.

Training will be established to ensure that the operator reenergizes the pressurizer heaters via the centrol room handswitch(s) as rtvired to maintain saturation margin during natural circulation at Not Standby conditions when component availability say not allow the plant to be brought directly to Not Shutdeun. Ne leads need to be shed from the emergency power source to provide sufficient capacity for the connection of the pressurizer heaters.

Ptddddd/dd ddd f/dididd dill 5d difd57fdNdd fd dddd/d fMdf fMd did/dfdt /ddddfdifdd fMd Nddfd/d it fNd (/dpdf find fd idiffdtd ddd difdtdid ddfdtd7 df/ddidifddi Nd 7ddd WNdddfdd id (ddditddf i

WdiffddNdddd id didIddffdd fMd fidd Nf WMidM fMd Mddfd/d ddf Ed fiddifddl The electrical interface between each of the four fdd pressurizer heater groups and its associated ESF bus of concern is through a circuit breaker which trips on an 'S' signal and is qualified in accordance with safety-grade requirements. The menual controls for these breakers are qualified in accordance with safety-grade requirements.

!!.E-25 BOL oVEA57fJkE VGrSION

• ~

Enclosure to TXX-89464 1 August . 7,1989 Pg.,'21of2'1' CPSES/FSAR RESPONSE TO NRC ACTION PLAN This system fully complies with Section II.6 of the SRP 6.2.4.

Compliance with all remaining sections of SRP 6.2.4 is documented in Section 6.2.4.

1

2. A reevaluation of the classification assigned to each process j penetration has been performed and is described in revised i Section 6.2.4.3.

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3. All nonessential systems use either normally closed manual '

valves or the valves are automatically isolated on a containment isolation signal. See revised Section 6.2.4.3. i

4. The CP5ES design complies with the position. The operator must reset each device individually as desired. See revised Section 7.3.1.1.4.

5. The CPSES containment pressure setpoint (Hi-1) that initiates 20 containment isolation for non-essential penetrations is 3.2 4 22 psig. This setpoint is the minimum compatible with normal f operating conditions and the value used in accident analyses. 20

6. The containment isolation velves for the containment purge 20 system are automatic isolation valves. Furthermore, these valves will be closed during operational modes 1, 2, 3 and 4 (see response to Question 022.20). These valves will be

! verified to be closed at least every 31 days.

7. CPSES complies as described in Section 6.2.4.

l II.E-29 GOLD [ovrAsTg*E VC#.Siod

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