ML20148D603

Summary of 781019 Meeting in Phoenix,Az Re Safety Review, Containment & Power Sys & Structural Engineering of Proposed Facility.Agenda Encl

ML20148D603
Person / Time
Site:	Palo Verde
Issue date:	10/24/1978
From:	Stright R Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 7811020426
Download: ML20148D603 (36)

Text

.. . - . . . . .

t

x. ,

de UNITED STATES j -' '-

-3" *a - NUCLEAR REGULATORY COMMisslON

1. 'I WASHINGTON, D. C. 20555

. 3. ../ $

v.

/ OCT 2 41978 Docket Nos. STN Ss and STN Sr 33 APPLICANT: Arizona Public Service Company FACILITY: Palo Verde Nuclear Generating Station, Units 4 and 5

SUMMARY

OF MEETING HELD ON OCTOBER 19, 1978 REGARDING THE SAFETY REVIEW 0F PALO VERDE, UNITS 4 AND 5 A meeting was held between NRR staff members and representatives of the Arizona Public Service Company and th:ir consultants in Phoenix, Arizona on October 19, 1978 to discuss the safety review of Palo Verde 4 & 5. - The public was invited to attend the meeting, but less than five members of the public were present. The meeting agenda and list of attendees are . ,

attached as Enclosures 1 and 2.

Summary of Meeting Enclosure 3 to this summary is a compilation of the questions and applicant responses discussed during the meeting. In addition to the responses documented in the Enclosure, the following points were made:

1. Concerning Containment Systems question number 2, the applicant agreed (a) to confirm that the nodalization study was based on the peak pressure loads and (b) to provide the acceptance criteria for the nodal array used.

The staff will inform the applicant if more detailed information is j required to complete confirmatory analyses.

2. Concerning Power Systems question numbers 3 and 4, the staff agreed to discuss these matters .further at a future meeting.

l Questions from the public concerned the adequacy of ECCS and the Palo Verde cooling water supply.

, qq g w w+-i e + ,e ~g w,-, ,w= ,ew. - e -w--- ----- *- . r- e --

me----~ ** wm w - * * ' - - - < * - ' * -

2- OCT 2 41978 Conclusions The staff will evaluate the infortnation provided by the applicant and will determine if more information is required in order to draw the conclusions necessary for a safety evaluation report. For those question responses that provided substantive information, the applicant will incorporate the infor-mation into a future PSAR amendment.

Ro ert L. Stright, Project Manager Light Water Reactors Branch No. 3 Division of Project Management

Enclosures:

1. Meeting Agenda

2. List of Attendees

3. Questions and Responses cc w/ enclosures:

See next page

Mr. E. E. Van Brunt, Jr.

Vice President-Construction Projects Arizona Public Service Company P. O. Box 21666 Phoenix, Arizona 85036 cc: Arthur C. Gehr, Esq.

Snell & Wilmer 3100 Valley Center Phoenix, Arizona 85073 Charles S. Pierson, Assistant Attorney General.

200 State Capitol 1700 West Washington Phoenix, Arizona 85007 Donald G. Gilbert, Executive Director Arizona Atomic Energy Commission 2929 Indian School Road Phoenix, Arizona 85017 George Campbell, Chairman Maricopa County Board of Supervisors 111 South Third Avenue Phoenix, Arizona 85003 t

_ . , , ..y_.e . _ - -- . . .m, -

ENCLOSURE 1 NUCLEAR REGULATORY COMMISSION - ARIZONA PUBLIC. SERVICE COMPANY MEETING - OCT03ER 19,'1978 - PHOENIX, ARIZONA

1. Introductory Remarks - Roger Boyd II. NRC Staff - APS Technical Meeting - Robert Stright A. Introduction of Participants B. Presentation by APS C. Technical Subjects

-1. Containment Systems -

Stuart Brown (a) Asymetric Loads in Subcompartments (b) Main Steam Line Break Analysis

2. Power Systems - Om Chopra (a) Containment Electrical Penetrations (b) Abnormal Grid Voltage Conditions (c) Use of Load Sequencer (d) Switchyard Layout (e) Startup Transformers

3. Structural Engineering - Sai Chan (a) Soil-Structure Interaction (b) Seismic Instrumentation (c) Clarification of Base Plant Changes

4. Materials Engineering -

Dave Sellers (a) Regulatory Guide 1.99 III. Questions _From Public IV. ' Closing Remarks - Roger Boyd j

I i

ENCLOSURE 2 LIST OF ATTENDEES NRC ,

R. Boyd ,

R. Stright S. Brown O. Chopra S. Chan C. Sellers R. Stevens J. Wermiel C. Long G. Georgiev Arizona Public Service Company E. E. Van Brunt, Jr.

J. Allen D. Karner M. Hodge J. Berrow W. Quinn D. Keith - Bechtel J. Goldberg - Combustion Engineering

ENCLOSURE 3 j ' VERDE NUCLEAR GENERATING STATION UNITS 4 AND 5

. DOCKET NOS. STN 50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION Containment Systems Question 1 In the qualification review item number E.28, an analysis of the containment response to an assumed steam line break inside the containment, assuming the failure of the broken loop main steam isolation valve to close, was requested. In response (Amendment 17) you stated that this analysis was performed with conservative assumptions and the result was an incremental increase of pressure (2.8 psi). However, for the staff to com-plete its review in this area (including a confirmatory analysis) we will require the following additional information:

1. A list of the assumptions used in your analysis with a discussion of their conservativeness.

2. The mass and energy release rates to this analysis.

3. The results of your analysis in the form of temperature and pressure profiles as a function of time.

Containment Systems

-Question 1 Page Two

Response

ASSUMPTIONS:

a. The steam inventory between the MSIV, the turbine stop valves and the reheater drain tank check valve will vent 14.6M Btu's through the failed MSIV to the containment.

b. The additional energy of (a) is conservatively added to the containment at the time of peak pressure as calcu-lated in the main steam line break analysis presented in the PVNGS 1, 2 and 3 PSAR without any loss to passive or active heat sinks.

RELEASE RATES:

The conservative mass and energy release rates, presented in Table 6.2.1-24 of CESSAR, were used in the design basis MSL break and the evaluation of the fiSIV f ailure.

P-T PROFILES:

Due to the conservative method used to evaluate the failure of the MSIV, pressure-temperature profiles as a function of time are not available. This information will be available j at the FSAR submittal .

l l

PALO VERDE NUCLEAR' GENERATING' STATION 5

-i UNITS 4 AND 5 00CKET'NOS. STN 50-592-ANDLSTN 50-593 REQUEST FOR ADDITIONAL INFORMATION' ,

• ~!

Containment Systems Question 2

~

. In the qualification review for Palo Verde Units 1, 2 and 3, l e

the question of asymmetric loading on components and supports ,

located within containment subcompartments was addressed -

(item E-29). Although some of the required .information has been provided, the Staff requires additional information to' ,

resolve thisfissue for Palo Verde-4 .and-5.

1. Provide a schematic drawing showing the compartment nodalization 'for the model' used to calculate the maximum a

~ differential pressure loads for;the component supports  ;

evaluation. Provide a tabulation of the nodal' net-free volumes and interconnecting flow path areas. For-each flow path, provide an L/A (ft-I) ratio, where L is the ,

average distance the fluid flows in t6at' flow path and A is the effective cross sectional area. Provide and jus Lify values of vent loss coefficients and/or. friction factors used to cal'culate flow between nodal volumes. When.a loss -

coefficient consists of more than one component, identify each component, its value and the flow area at which the '!

loss coefficient applies.

E

.c h

.44 - - , , , , . , . . ., _. ...,,...,.,.,_..~..,m.,-...._,-.. .-_,--..R.,......,,.-_,..4.-. , , , . . . . .-

, Compartment 1Nodalization

-Question 2 PageLTwo

'2. Describe the,nodalization sensitivity study performed to determine the ' minimum number of volume nodes required to

. conservatively predict the' maximum differential pressure loads acting on the component supports. The nodalization sensitivity study should include consideration of spatial-pressure variation circumferential1y, axial)y, and radially within the compartment.

3. Graphically show the pressure (psia) and differential pres-sure.(psi) responses as' functions of time for each node.

Discuss the basis for establishing the differential pressure on components.

4. Provide the peak and transient loading on the major compo-nents.used to establish the adequacy of the supports' de-sign. This should' include the load forcing functions (e.g., f (t), f (t)) and transient moments (e.g., M (t),

x z x M (t), M (t)) as resolved about a specific,' identified y 7 coordinate system. Provide the projected area used to ca'1culate these loads and identify the location of the i

area prajections on plan and sectior drawings in the selected. coordinate system. This information should be-presented in such a manner that confirmatory evaluations of the loads'and moments can be made.

I 1

Compartment Nodalization Question 2 Page.Three

Response

1. Tne compartment nodalization used to determine the pres-sure loads on components located in the reactor cavity and the steam generator compartment are shown in Figures 6.2-14 and 6.2-14A of the PSAR. The nodal net-free volumes, the interconnection flow path areas, flow path loss coeffi-cients and the L/A ratio for the above models are tabulated in Tables 6.2-14 through 6.2-14F of the PSAR. The methods used to calculate the flow path loss coefficients is given in Section 6.2.1.3.4.2F of the PSAR.

2. The nodalization sensitivity study of . geometrically similar plant arrangement was used to establish the minimum number of nodes to predict the differential pressure loads acting on components and their supports. The study con-sidered three dimensional pressure variations within the compartments. The study showed that differential pressure loads acting on compartment components increased with finer nodalization at an ever decreasing rate. Thus a point of diminishing return is reached, after which increases in the number of model nodes produces changes in the component loads that are small when compared to that load.

L

Compartment Nodalization Question 2 Page Four

3. Nodal pressures for the reactor cavity and steam generator compartment are shown in Figures 6.2-18 and 6.2-20 of the PVNGS_1, 2 & 3 PSAR , respectively. A differential pressure load can be evaluated from these figures. Differential pressure plots have not been provided due to the'very large number of combinations required to represent the loads on all the walls and components that are analyzed.

4. This question implies that' component support design is based solely on pressure differentials acting on the exterior of the component following a portulated break.

To the contrary, the component may be :ubject to dif-ferential pressures acting on the component internals, jet thrust and impingement load in addition to SSE loads.

Bechtel prc~ ides Combustion Engineering external pressure transients, which are combined in their analysis to deter-mine the resultant transient loads acting on the component.

The information provided in Section 6.2.1 of the PVNGS 1, 2 & 3 PSAR is in the form used in the design process (e.g., pressures, affected areas).

/

PALO VERDE NUCLEAR GENERATING' STATION

. UNITS 4 AND 5

DOCKET.NOS. STN150-592 AND'STNI 50-593 J REQUEST FOR~ ADDITIONAL.INFORMATION Power' Systems Question 1 Your. response to' qualification review item E11 regarding'your design.of containment electrical penetration-protection is ,

i inadequate in its present form. We require that the'following requirements'of IEEE-279 be: satisfied with regard-to the pro-tection of.the electrical-penetration,s:

1

a. 'The system shall, with precision ~ and reliability-automatically. ,

disconnect power to the penetration conductors when currents through;the conductors exceed the established protection limits.

b. All primary and backup breaker. overload and short circuit-protection systems shall be qualified for the service environment including seismic. However, the seismic quali-fication for non-Class IE circuit breaker protection systems should as a minimum assure that the protection systems re-main. operable:during an~ operating basis. earthquake. In.addi-tion, the: non-Class IE circuit breaker and protection system shall be of high quality.

ic. LThe circuit breaker protection system trip set points 'and

Powe'r Systems; i

' Question '

Pa ge ? Two :-

4

'f

' b'reaker ' coordination between primary and b'ackup protection 1

sha11'have the: capability for test and calibration'. Pro-visions for test under simulated fault condition; should be provided. For' designs where protection is provided-by a combination of a breaker and a fuse or two fuses in ,

- series,-provisions shal1~be provided for testing fuses.

t

d. - No' single failure shalllcause excessive current in the penetration conductors which will degrade the-penetra-tion seals.

e. Where. external control power is used for tripping breakers',

signals for tripping primary and backup breakers shall be-t independent, physically-separated.and powered from_ separate.

sources. '

Provide modified response'that' includes our above. requirements.

Response

a. The power to the' penetrations 11s automatically disconnected by means of molded case circuit breakers and air-. circuit breakers when a fault occurs. - The Class IE breakers have been manufactured to meet the service' environment re-quirements as outlined in IEEE 323-1974 and IEEE 344-1975.

The non-Class'IE breakers have been manufactured to meet a.high degree oft reliability and are being qualified '

- to a' static seismic loading.of .139.in the horizontal '

ge-J =ap mp r$e<wW-*vvy-" w p-'"-'w- + - Y FT -' y -wry' **^M y - 'v fY * $ W E'+tP* MT"9WF"FTW"'T?' +"W4F** "'4WM:P *^'Y*9*?M ?OT'WiHM*T8 I'#"'II I'#

t

.. . - -r.

Power: Systems j

. Question 11 l Page Three l 1 directionLand .099 in the vertical direction.

l l

b. The primary'and backup. breakers are coordinated such that the operating : time. of .the backup breaker for a .three ghase

. fault:is taken as 'the minimum fault withstand' time for the penetration seal design. These values are specif,ied in the electrical, penetration assemblies specification. .The non-Class IE breakers are designed to seismic conditions as described :inL the response to 1.a. above.  ;

. t

c. The circuit breakers have capability for testing and cali-bration. A fault condition on air circuit ~ breakers is-simulated'by inducing current to the circuit breaker trip coil. It is not necessary to . test molded case circuit-breakers under simulated fault conditions as they are passive devices. The PVNGS design does not have combina-tion of fuse and circuit breaker or two fuses for circuits being fed through electrical penetrations,

d. The penetration assemblies are designed to preclude the failure of penetration seals due to a single failure.of the primary breaker. Any such single failure will be. protected against as indicated in the response to 1.b. above.

e. Where external-control power is used-for tripping breakers

'(RCP motors), separate non-Class IE battery cources are used:to provide tripping signals for primary and backup breakers.

t

-- + ,---- .. .. . . - _ - .

Power Systems Question'l Page Four It should be noted that the PVNGS 1, 2 and 3 design was reviewed against Regulatory Guide 1.63 Revision 0 and approved for con-struction. The PVNGS Qualification Review Letter required a response to Regulatory Guide 1.63, Revision 1. As the changes made by Revision 1 of Regulatory Guide 1.63 did not involve the electrical protection of penetration assemblies, the PVNGS design in this area has not been modified. The responses given to question 1.a. through 1.e. describe the existing design for PVNGS 1, 2 and 3 and will not be modified for PVNGS 4 and 5.

l l

l i

l l

PALO VERDE NUCLEAR GENERATING STATION UNITS 4 AND 5 DOCKET NOS. STN 50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION Power Systems Question 2 It is not clear from the information provided in response to qualification review item E-32 position 1, if a second level of under voltage protection is provided (in addition to the existing under voltage protection) that will automatically perform the function of switching from offsite power (the preferred source) to the onsite power sources in case of sustained degraded voltage conditions at the offsite power source. This second level of protection is a requirement.

Therefore, provide a modified response to this item and include the setpoints and time delays associated with the first and second levels of undervoltage protection.

Response

A second level of voltage protection with time deity would be required for use with an undervoltage protection scheme that utilized instantaneous relays with time delays. The primary undervoltage protection for such a scheme would be typically set to operate at about 70% of nominal voltage with appropriate time delays. Such a scheme would not detect a degraded grid condition between 70% and 100% of the nominal voltage. Monitor-ing this range of voltage would require the use of a second level of voltage protection.

4 4 Power Systems; Question 2' Page'Two o

. The undervoltage protection scheme provided for the PVNGS

~

is -adequate to detect loss of offsite power at 4160 volt ESF b'sses u and to protect the onsite power system from any adverse effects-that could result from a sustained degraded voltage .

condition on the offsite power system. The PVNGS design for the undervoltage protection utilizes induction- disc relays with  ;

inverse- voltage-time relationship measured from approximately.  ;

90% nominal bus voltage down to zero voltage. This system inherently provides a second level of undervol tage protection. ,

Since the Class IE motors for PVNGS are specified to start and i accelerate their loads at 75% rated vo.ltage and to operate con- f tinuously at 90% of rated voltage, any bus voltage that falls j below 75% voltage for short time periods and below 90% for long time periods will- be considered a degraded condition. Such

. degraded' conditions will be monitored by induction disc relays and will generate a loss of voltage signal. Section 8.3.1.1.2.11 B of the PVNGS 1, 2 & 3 PSAR summarizes the setpoint and design criteria for these relays. I Reliability of the undervoltage detection is assured by the use of four relays, with 2 out of 4 coincidence logic, on each of the 4160 volt Class IE busses.

e f

t

-i

• i PALO VERDE' NUCLEAR GENERATING STATION l UNITS 4 AND 5 DOCKET NOS. STN 50-592 AND STN:50-593 REQUEST FOR-ADDITI0lvAL INFORMATION Power Systems Question 3 Your response to position-2 of item E32 isfunacceptable'because

.1 ) your design does not prevent load shedding of the emergency buses once the onsite sources are. supplying power to all.se-quenced loads on the. emergency busses and, 2) your design does. r not. include the capability of the load shedding feature to be ,

automatically reinstated if the'onsite source supply' breakers -

are tripped.- Provide a modified response to this. item that meets our requirements or provide full justification for your .,

proposed design.on some other defined bases.

Response: ,

l-

1) Prevention of the load shedding feature for the Class IE 4.16kv buses would be required if an undervoltage protection system design were' based on the utilization of undervoltage relays with instantaneous characteristics. The undervoltage j relays utilized.for PVNGS as described in Section 8.3.1.1.2- .

t U.B of the PVNGS PSAR have inverse voltage-time characteristics. ,

On a two-out-of-four coincidence logic a' single pulse load

.shed signal is generated for

~

degraded bus voltage condition ,

or.for...a. loss of offsite power.

l

Power-Systems q Question 3 )

Page Two l The undervoltage relays are adjusted to initiate a load shed- ,

l when conditions are present such that there is insufficient bus voltage available to accelerate a motor (less than 75%

of rated voltage for short period of time) or a sustained undervoltage condition exists (less than 90% of rated voltage for long duration). The diesel generators.are designed to be consistent with the recommendations of Regulatory Guide 1.9.

The undervoltage relays are not expected to generate an under-voltage signal during normal bus sequencing due to the time delay inherent in their inverse voltage-time operation.

2) Section 8. 3.1.1. 3. 6 of the Unit l', 2 & 3 PSAR states:

"After load shed, tripping of-the Class IE 4.16 kV bus s

offsite supply breaker and subsequent closing of diesel generator breaker to the Class IE 4.16kV bus, the under-  ;

voltage relays monitor the standby (onsite) power supply for an undervoltage occurrence. Should an undervoltage P

occur, the Class IE 4.16kV loads are shed and the loading sequence restarted."

This indicates that there is no need for reinstatement of the load shed feature since it is never disconnected from the Class IE 4.16kV busses. If the onsite source supply breakers are tripped, the undervoltage relays detect the subsequent bus undervoltage and initiate a load shed.

l L _ . _ _ _ . , _ _ ~ , _ . . . _ , - . , , . _ _ _ _ _ , . . _ _ . . . . _ _ _ . _ _ , _ _ _ _ _ _ _ _ . . _ _ . . _ _

Power Systems-Question 3 Page Three The load shed feature is retained 'in the PVNGS design when the onsite (standby) source is supplying power to'the Class IE 4.16kV bus for the following reasons.:

A. If a load shed is not generated during a. degraded voltage condition, then a condition could exist where there is insufficient voltage on the bus for either accelerating ClassLIE motors or for the continuous operation of Class IE motors. If the load shedding feature was prevented, the affected motors and subsequent motors sequenced onto the bus would remain at approximately a locked rotor cur-

. rent condition, eventually tripping their associated circuit breakers. Allowing the load shed feature to clear the bus will enable the diesel generator to recover and be reloaded through the load sequencer. Without this feature tripping of the motor circuit breakers on locked rotor current conditions would lock-out the circuit breakers .,

so they would have to be manually reclosed. This would l

-result in their not being readily available when needed and could result in damage to the motors.

B. A load shed will not be generated if a short circuit occurs on motor feeders since the resultant voltage dip will not be l detected by the load shed undervoltage relays by the time the fault is cleared by the motor circuit breaker and the voltage returns to normal on the bus. For complete descrip-

~

tion of electrical circuit protection refer to PVNGS PSAR Section 8.3.1.1.2.11.

PALO VERDE NOCLEAR GENERATING STATION UNITS 4 AND 5 DOCKET NOS. STN 50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION Power Systems Question 4 Section 8.3.1.1.2.8 of the PS AR s ta tes tha t, "If preferred power is available to the Class IE bus following an engineered safety feature actuation signal, the required Class IE loads will be started through a sequencer." Provide your basis and justification for sequencing safety loads when preferred (offsite) power is available during the accident.

Provide a comparison on a bus by bus basis for all emergency buses of the voltage and motor starting transients associated with sequenced versus instantaneous loading for the condition of grid voltage at the low end of its normal range and maximum plant auxiliary load. In addition, address the loss of one startup transformer and the capability to fast transfer to the other startup transformer during this transient.

Provide a description of what would be required to remove this non-standard design feature from your design and the associated safety implications, if any.

PowerfSystems Question 4 Page Two

Response

Justification of sequencing.the LOCA loads with offsite' power

~

available is that the simultaneous starting of these loads will depress the voltage.at motor terminals below:75% on 480 volt loadcenters and MCC's. This is below the. minimum to start and accelerate the motors. This conclusion is based on the attached calculations of' voltage drop on starting.all safety loads simultaneously.

We have investigated the use of this sequencing feature with fifteen other applicants, representing forty PWR's which are either under construction or have beg'un commercial operation within the last several years. Of these, twelve applicants, representing twenty-five units, sequence with offsite power available, either through the use of a sequencer or with in-dividual time delay relays, while three applicants, representing i fif teen units, do not sequence. This demonstrates that this should not be considered a non-standard design feature, but rather a standard alternative way of starting emergency loads with offsite power available.

The PVNGS design does not provide for automatic fast transfer from one start-up transformer source to another. This transfer is performed manually. Should one start-up transformer source '

be lost the ESF loads of the redundant train will be available o

l to mitigate the consequences of an accident. This is in accordance with GDC 17. Per R.G. 1.93, operation is allowed for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> in .this LC0 before proceeding to cold shutdown.

l

d

~-

Power.' Sys tems ~

Question' 4:

Page Three' The PVNGS ESF transformers are sized to simultaneously hand.le ~

-l

'I t is, therefore,_ sized'twice the loads of both ESF trains.

' ~

as large-as required for steady state operation. In addition, the transformer impedance has been specified as 5% to minimize the voltage drop effects.

The sequencer for PVNGS utilizes, solid state logic with self- ,

test features to enhance the reliability of sequencer operation.

1-G 1

l l

1 J 3

PALO' VERDE NUCLEAR GENERATING STATION UNITS:4 AND 5 00CKET'NOS. STN 50-592 AND STN 50-593-

-REQUEST' FOR-ADDITIONAL INFORMATION Power Systems ,

Question 5'

. Provide physical layout drawings of the circuits that connect the Units 1,.'2 & 3-switchyard to.the Units 4 and 5. switchyard and the onsite distribution system to the preferred power supply. In addition, provide assu'rance that physical separa-tion of overhead bus extension lines that connect'the' Units 4 and 5. switchyard to the Units 1, 2 and:3 switchyard is sufficient so as'to minimize the likelihood of simultaneous failure of both lines.

Response

The o'verhead bus extension lines that connect the Units 4 and 5 switchyard to the Units 1, 2 and 3 switchyard will maintain the same 570 foot centerline to centerline spacing as the switch-

[

yard busses to which they connect. They wit: pull straight off the busses and will not exceed the phase spacing and tower height of the plant to switchyard 500kv line segments, which are 46 feet

! and 127 feet, respectively.

If one line were to physically fail, with a tower falling directly l

l <toward the other line, there would still be 351 feet of clearance

'(minimum).between the top of the tower and the nearest phase of  ;

• - *ewetee--u e r-- TT g-+$---Wfewe+ w er * :s afa+-g--as qr %-+ =s rgr- gr rg *r aqu, yTW- 3 0 -*y- g* 9 gtv-+- '--+9- - - g

a c,

' Poter Systemst

. Question;5:

, ' Page: Two the second line.

' In, addition, due toLtheir. location, immediately.. adjacent'to the-switchyardson.theplantsith,Ltheselinesaresubjectonlyto the. sam occurences which could be' postulated for the switchyards, the risks of? which .have already:been judged to be acceptable'.by the NRC on Units.1, 2'and 3.

This, $herefore, provides: assurance that'the physical separation of these bus extension lines is sufficient to minimize-theLiikeli-hood of their simultaneous ' failure. .

Revised'PVNGS-425 PSAR-Figure 8.2-5,'at'tached, dep'icts1the layout of. th'ef offsiteLto onsite' power system connections.

i-1 :.

l 4

. . . . ,-~..;..- . .

- ~ . - - - - -- =- ~-- "

stoavges

,/*(^)",, ras, g uni r I

( !s our switcuasae

f. ?N'cl0" g staa* se . aausroeus.a s

/

f y$v','y g s'dar "avo

/ , sr.sar vo -aansmeura reso g casac roe sa.srs .

3

=

I, ernce o UN/ f 2

/. #

r

\

'n

• j

} ' '.j g j / / . ' 4' ,

<..f . . q s nu . se o was ~~.

/

' 2',wrs ?sor sesus une -o westwise vr* m ) \ -us a . ,e , a raan, s . ,

/

s,vir J l s

\\

N

~

~

x criev 4:sa to saauseo

\ 5tSer dise O(ktas s

sewar recaruarr

1. 4JN7 i d \

\

L / j -

\

\\

L

[

4

.va a , . .

, ,\ $

i ,

/

hfi,b, Palo Verde Nuclear Generating Station

^"'

\ Units 4 & 5

% f 525 KV SWITCHYARDS MD TRANSMISSION LINES Figure 8.2-5 f  % i'4'+* Iw"'* M"9"FS t 9" -^W H- "f*"'"t+*&

. v- " 9 + 9 4

• 4

i 4 '4 .

PALO VERDE4NUCLEAR GENERATING' STATION i: UNITS 4'AND 5 DOCKET NOS. STN 50-592'ANDTSTN-50-593 REQUEST FOR ADDITIONAL INFORMATION:

4 Power'Sy' stems Question;6 Your response to, qualification review item A4b regarding capac-ity of the startup tranformers is not clear. We require that each startup transformer-th'at.is shared.between^the two units must have sufficient-capacity to supply all accident. loads in-one unit and normal shut'own d loads i.n the other' unit plus mar-gin. Provide a discussion of your design: criteria of sizing the-startup transformers and demonstrate how your design meets our_ position.-

Response:  ;

The PVNGS-start-up loads 1are estimated to'be approximately 91 MVA and the accident loads per unit (2 redundant trains) to be approximately 1.1 MVA. The~ total of start-up load and acci-dent loads is approximately-102 MVA. With the start-up trans-former rize of 140;MVA there will be more than 38 MVA of mar-gin,  ;

A 5

' 'b r 1

A

, . . . , , , . .-- . . - . - - .  :.- .  :.~... . . . - . . . - . . . . . . . . - - . . . . - . .

4 PALO VERDE NUCLEAR GENERATING STATION UNITS 4 AND 5 DOCKET NOS. STN 50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION Structural Engineering Question 1 Clarify whether or not both the lumped parameter and the finite element methods are to be used for the dynamic responses of all Category 1 structures. Explain how these two metheda are to ,

be used in the design. If both are used, is a t- . son of dynamic responses available? -

Response

Refer to PVNGS 4 and 5 PSAR Section 3.7.1.6 and PVNGS 1, 2 and 3 PSAR Section 3.7.1.6 for a discussion of the calculational methods. Refer to PVNGS SER Section 3.7.2 for NRC acceptance of these methods. Response spectra are calculated using both the lumped parameter and finite element methods for all Seismic Category I buildings. In each case a higher response spectrum is calculated using the lumped parameter method. Structures are designed using the lumped parameter method.

Under the replication policy the design of PVNGS 4 and 5 safety related structures will be identical to that of PVNGS 1, 2 and

3. As no reference was made to this matter in either the Palo

Structural Engineering Question 1 Page Two Verde Qualification Review Letter, dated December 12, 1977 or the " final listing of the issues originally addressed in Cate-gory E of the qualification review letter," dated October 12, 1978, the design of safety related structures for PVNGS 1, 2 ,,

and 3 is considered acceptable for replication by PVNGS 4 and 5.

4 I

i

(

l I

l l

PALO VERDE NUCLEAR GENERATING STATION' UNITS 4 AND 5-DOCKET NOS. STN 50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION S t r u c tu ra'l Engineering Quest' ion 2 Clarify whether or not one complete set of seismic .instrumenta-tion is to be installed for Palo Verde Units 4_and'5. Explain how the peak strain gages pr' ovide the required information as  ;

opposed toithe accelerograph recommended by Regulatory Guide .

1.18.

Response: ,

Only one set of seismic instrumentation will be' installed for all the five units since tise same seismic response is expected j at all the units based on the seismic analysis used in the ,

seismic design of the plant. This is in conformance with ANSI Standard N18.5, Section 4.4.

Peak strain gages are not being implemented in the.PVNGS seismic instrumentation. design. The requirements of Regulatory Guide  ;

1.12 are being met by usingEstrong motion accelerometers.

Section.3.7.4 of the PVNGS 1, 2 and 3 PSAR, as referenced by the PVNGS 4 and 5 PSAR, will be revised in a future amendment to clarify _the use of strong motion accelerometers in lieu of peak- l

' strain gages.

v

.~.,,,.,.s ,,, _, , _, _ _ _ . , . , , _ ,

?

PALO' VERDE NUCLEAR GENERATING' STATION UNITS 4 AND 5' DOCKET NOS.'STN S0-592 AND STN 50-593 ,

REQUEST FOR. ADDITIONAL INFORMATION Structural Encineering Ques t'i on ' 3 Section 3.8.'1.2.2: Indicate the reason for deleting ASME code .

date. State'what year ASME code the relevant components have been designed and constructed.

Response: .

The ASME code date was' deleted from the PVNGS-1, 2 and 3 PSAR Section 3.8.1.2.2 because ASME Section III Division I.is not  ;

applicable to containment design except for'the access hatch and locks. The'ASME Section III Division I code date for the t access hatch and locks is the 1974 edition, Winter 1974 Addanda.  ;

-t i

s

. , - , , - , ,. ..c,. , ..-vc, ,. -- ,,-..,,.,-,--n., ~, ., _ , . . . - , . . , , ...-v. . . . , , . . - , . , ..,- . . ~ , ,

e .

'PALO VERDE NUCLEAR GENERATING STATION UNITS'4 AND 5 DOCKET-NOS. STN 50-592 AND STN 50-593 l REQUEST FOR ADDITIONAL INFORMATION j Structural Engineering Question 4' Section 3.8.1.6.1, 3.8.3.6.1 and-3.8.4.5: The concrete strength- ,

age requirement was deleted. The age corresponding'to'the Furthermore, clarify ~whether i value of'f'c should be specified.

fly ash is used and othe' amount used.

Response

The concrete strength age requirement -varies with the mix design.

The following table indicates the age at which the required strengths are. developed. Fly ash is not'used.- Calcined natural pozzolon is utilized in mixes containing' approximately 15% replace-  !

ment of portland cement with pozzolan, by weight.  :

I f'c Age ,

G psi . without pozzolan 28 days l 4000 '"

with "

91~ days l  ?

5000 "

without "

28 days-5000- "

with 91 days-

?

6000 with 91 days-

!~..~ . . ., -.;_,.._.._..., , , _ , , , . . , _ . ...; 2.. _ . _ _ _ , _ , _ , , . __,

PALO VERDE NUCLEAR GENERATING STATION  :

UNITS 4-AND 5 '

DOCKET NOS.<STN'50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION Structural Engineering  ;

' Question 5 Section 3. 8.1. 6. 6.1 : This section indicates that:the minimum.

curingfperiod will be 7 days or the time necessary to attain 70% of the specified design strength,'whichever is less. Indi-cate how-the 70% of f'c is verified.

Response

The 70% of f'c is verified by strength tests on test cylinders.

- Strength tests are accomplished in accordance with ASTM C39, Standard Method of Test for Compressive Strength of Cylindrical

- Concrete Specimens.

I r

l l

l l'

i L <

! I i

I F b

l I.

e- ,-.

y 9 , ei--- r +*g-4y-, 9- y y g-- r-g -we.p ,,r. y..rg, y,,-+-- -,

i PALO VERDE NUCLEAR' GENERATING STATION UNIT 5 4 AND 5 1

DOCKET NOS.-STN 50-592'AND STN 50-593 i REQUEST FOR ADDITIONAL INFORMATION Structural 1 Engi,neering Question 6 Section 3.8.3.6.1: Clarify what is meant by the . statement "The

. containment internal concrete structurenhas a design compressive strength of 5000-psi or. greater, as determined by design' analysis.

Response

The results of the design anc ysis determined the concrete desige strengths required for. containment internal' con' rete structure.

The actual strength attained'is verified by strength tests.on test cylinders.

e 4

, i w-p = ,,,www -mr s , e -y -n , ,,-.h we we- ,-v,-ev-w n.m , e

PALO VERDE NUCLEAR GENERATING STATION ,

UNITS 4 AND 5 00CKET NOS. STN 50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION Structural Engineering i

Question 7 Section 3.8.1.6.1, Item 2a, page 3.8-68A: Indicate the method of transporting'th'e concrete-and the time elapsed between the ,

discharge of-the batch plant' stationary mixer and the place-ment-of the concrete into the forms. Clarify why correlation tests need not be performed between.the mixing point and the.

I placement point.

i

Response

Concrete is transported from.the batch plant to the placement area by truck mixer where.it is discharged to a belt conveyor or concrete pump. The elapsed time between the dischkrge. of the batch plant stationary' mixer and the placement of .the c'ncrete o into the forms is a maximum of 45 minutes. Correlation' tests'are performed as-indicated in. items 2d and 2c of PVNGS 1,.2 & 3 PSAR Section' 3.8.1.6.6.1.H (Page 3.8-688).

v

.;s $

. . . . - - .. . -.+ -~. .... .

+

. . ;6

~

PALO VERDE' NUCLEAR GENERATING' STATION UNITS 4 AND 5 DOCKET N05. STN 50-592 AND STN 50-593 REQUEST FOR ADDITIONAL INFORMATION Materials Engineering Question 1 Your' response to Regulatory Guide 1.99.in Appendix 3J. stated that: "This guide is not applicable toithe balance of plant design. 'e will review the response'to this guide when it is.

W .

1 addressed ~in'CESSAR, however you' shou 1d be aware that. heat-up and cool-down curves and technical specifications applicable to Palo Verde must utilize the recommendation of Regulatory Guide 1.99.

Response

Palo Verde will use the heat-up and cool-down curves and ' technical specifications resolved between the NRC staff and APS in the FSAR.

44