ML20033D226

Forwards Details Re Listed Items to Resolve Open SER Issues, Per 811130 Meeting

ML20033D226
Person / Time
Site:	Clinton
Issue date:	11/30/1981
From:	Geier J ILLINOIS POWER CO.
To:	John Miller Office of Nuclear Reactor Regulation
References
U-0350, U-350, NUDOCS 8112070413
Download: ML20033D226 (29)

Text

__

U-0350

/LLINO/S POWER OOMPANY

- gg L30-81 (11-30)-6 500 SOUTH 27TH STREET, DECATUR, ILLINO's 62525 November 30, 1981 Mr. James R. Miller, Chief

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Standardization & Special Projects Branch Division of Licensing j j _ _

Office of Nuclear Reactor Regulation w

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Washington, D. C.

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Dear Mr. Miller:

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Clinton Power Station Unit 1

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Docket No. 50-461 b

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Attached are details related to the following items whi discussed with James Lazevnick, Power System Branch, during a meeting of November 30, 1981 to resolve issues for the Clinton SER:

ISSUES Diesel Generator Automatic Fast Transfer Capability Diesel Generator Circuit Breaker Trip and Lockout During Test Number of Hours to Charge Batteries Load Sequencer with Offsite Power Separation of Conduit from Open Raceways Containment Building Polar Crane Penetration Thermal Overload Protection Device Bypass Correction to Response for PSB Question 40.107 HPCS ' Diesel Generator Fast Transfer (Verbal ' Question)

HPCS Diesel Generator Automatic Separation from Test Mode (Verbal

. Question) s j"i M.

DC Monitoring Instrumentation Division 3 Off Line Battery Charging f-

-The above items are _ considered by the NRC and -IP to be closed for

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CPS Licensing _ purposes.

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..J Mr. Jamas R. Miller Page #2 The two items listed below are considered by the NRC and IP to be confirmatory for CPS Licensing purposes. As agreed with Mr. Lazevnick.

-c information for the two items is attached.

+

ISSUES Adequacy of Station Electric Distribution System Voltage

- Automatic Transfer from Onsite Source to Offsite Source (Verbal Question)

In addition, additional information pertaining to Reactor Trip A

System Power Supplies is enclosed per Mr. Lazevnick's request.

4 As agreed to during the meeting, FSAR changes to include the pertinent information will be made in a future amendment.

s'

~s Sincerely, t

C O. D. Geier Manager Nuclear Station Engineering 3

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Attachments u

J.H.Wilfiams,NRCClintonProjectManager h

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H. H, Livermore, NRC Resident Inspector w

J.,Lazevnick, NRC Power Systems Branch 3_

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m Issue Diesel Generator Automatic' Fast Transfer Capability (8.3.1)

Response

'In response to'the NRC's position that cetomatic transfer from the onsite source to the-offsite-:n.rce is unacceptable the design of the 1E 4KV buses. control logic is being revised to require operator action to allow ~ transfer from the onsite to the offsite source.

Since automatic transfer, fast or-slow,~is prevented, the. addition of a. synchronizing check

-relay permissive contact is no' longer required, and will not be added.

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Issue Diesel Generator Circuit Breaker Trip and Lockout During Test (8.3.1).

Response

PSL SER issue #7.

Provisions are being provided to separate DG from offsite source on LOOP signal during test.

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GROUAlu FAvLT l

AND OTHER TRIPS GEN DIFF BYPASSED OVERCURRENT ON LOCA ENG OVERSPEED AvX'fELA)I 7O o rt Droj @f l'

LOCA

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$$ CONTACT CLOSED IN ALL POSITIONS

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[ AUX EXCEPT CLOSE AND AFTER CLOSE RLY 47p p3 yy ggg CLINTON POWER STATION DIESEL GENERATOR

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LOCKOUT PREVENTION i

DURING TEST O.

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l Issue Number of Ilours to Charge Batteries (8.3.2)

Response

As submitted at Novembcr PSB meeting.

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Rev. 2;t-040.130 In response to Grand Gulf question 040.31, it was indicated that the lead calcium type of batteries used at Clinton Power Station do not require a periodic equalizing charge.

In section 8. 3. 2.1. 2. 4 of the Clinton FSAR, you state that the battery chargers have a manually inititated equalizing charge timer.

Provide information on the use of the equali-zing charge capability indicating when it will be used, the level it sets the battery voltage to, and whether the loads can tolerate this voltage level if connected to the bus.

Also, indicate whether the battery charger can operate stably as a battery eliminator to supply the de loads without the bat-tery connected to the bus.

Answer:

Division 1, 2, and 4 lead calcium batteries are floated at 2.20 to 2.25V/ cell, which eliminates the periodic equalization of the battery at reg-ular intervals.

However, the batteries are equalized whenever they are. partially or fully discharged due to loss of AC power or testing.

The-manually initiated equalizing charge timer is pro-vided as an option.

It may or may not be used.

The battery charger is set to supply 2.33V/cc11 to equalize the battery.

All the de equipment connected to the de bus can tolerate the de bus equalizing voltage.

The battery chargers may operate stably as a battery-eliminator.

But, they have not been

,Revi qualified by the manufacturer as a battery eliminator.

Division 3 batteries are floated at 2.2V/ cell, which I

eliminates the periodic equalization of the battery at regular intervals.

However, the batteries are equalized whenever they are partially or fully dis-charged due to loss of AC power or testing.

During equalizing, all de equipment, except the NSPS in-verter, is transferred to a separate battery charger and fed at nonnal float voltage.

The inverter is designed to operate at the 140-V de equalizing volt-age.

5 The Division 3 DC loads (except NSPS inverter) are connected to a DC d.istribution bus which is connected via a breaker to the. bat.tery bus.

The battery, normal battery charger and NSPS inverter are connected to the battery bus.

A breaker connected to the DC distribution bus allows ~the spare battery charger to be connected Rev to power DC loads during equalizing.

During equali-2, zing, the breaker which connects the battery bus and the distribution bus is placed in the open position.

The spare battery charger is powered from a non-IE power sourco.

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i Issue Use of Load Sequencer with Offsite Power (8.4.4).

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Response

See attached.

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Action Required None

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3 Issue

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The use of a single load sequencer for sequential loading of the onsite power sources requires the following:

1.

A demonstration of the reliability of the sequencer.

2.

A detailed analysis to show that there are no credible sneak circuits or common mode failures in the sequencer design that could render both onsite.and offsite sources unavailable.

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Response

All 4KV loads for ESF divisions 1 and 2 are tripped on loss of bus voltage, except feeder-s to 480 Volt Unit Substations A, B, lA and 1B.

Drywell Chillers (lVP04CA and IVPO4CB) and Fuel Pool Cooling Pumps (lFC02PA and 1FC02PB) are not automatically sequenced on the bus, but require manual operatdr actio'n to energize.

The LPCS pump motor does not utilize a timer.

(J The remaining loads on these buses are the Shutdown Service Water Pumps (lSX0lPA and 1SX0lPB), and Residual Heat Removal Pumps

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(lE12-c002A, 1E12-C002B, lE12-C002C).

After restoration of bus voltage, these maters are each sequenced on their respective divi-sional buses by electrically independent class lE timers.

t Each Shutdown Service Water Pump utilize's a Westinghouse type TD-5' time located in its respective switchgear cubicle (Cubicle 1AP07ED for 1SX0lPA and Cubicle 1AP09EG for 1SX0lPB).

The RHR pump motors utilize independent class lE solid state timers at their respective divisional panels in thd main control room (Division 1 is at lH13-P661 and Division 2 is at lH13,P662).

All timers on 480 vdit unit sub' stations and motor control centers-will be Agastat Series 7000 and located in the respective 480V

+

CL switchgear or 480V motor control center cubicles.

Note HVAC Control Room Refrigeration Units OVCl3CA and OVC13CB are manually restarted after loss of bus voltage.

n All' timers are independent and are qualified for class lE use.. Since all timers are physically separate and electrically independent, the only common failure mode would be simultaneous individual failures of the timers.

The maximum failure rate of one of these devices as provided in subsection 4.2.2 of Appendix D to IEEE-Std-500-1977 (based on 3J WASH 1400) is 160 failures per 106 operations.

Therefore, the probability of two timers-(one per division) failing simultaneously would be 2.56x10-8,-which is extremely unlikely.

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i Fusitermore, since all relays will be functionally checked during preoperational testing, the incipiedt failure rate will

' be' practically zero.

In the unlikely event that one of the.four timers fails, this will only result in a loss of one load on one division.

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l Issue Separation of Class lE Cables in conduit from Open Raceways (8.4.7).

Response

The NRC states on page 39 of the SER that separation of Class lE cables in conduit from divisional Class lE and non-Class lE cables in open raceways by a minimum of one inch is acceptable only if the conduit is located below the open raceway.

Section 5.1.4 of IEEE 384-1974 states:

"The minimum distance be-tween these redundant enclosed raceways and between barriers and racewdys shall be one (1) inch."

The Clinton Station caintains a minimum of one (1) inch between the side of an open tray and conduit adjacent to it which contains lE cable.

The tray side and the conduit each form a barrier separated by one (1) inch.

The Clinton design of conduit ad-jacent to tray meets the requirements of IEEE 384.

For Class lE cables in conduit located above redundant divisional Class lE or non-Class lE open raceways, Illinois Power commits to installing cable tray covers on the open trays located below the conduit.

Figure 5 of IEEE 384-1974 will be used as a guide for determining the length of the tray covers.

a)

For conduit traversing open tray at 90 degrees, the tray cover length will be two feet plus the conduit-(or bank of conduit) diameter. (regardless.of plant area) b)

For conduit traversing open tray at less than-90 degrees, the. tray cover length will be long enough such that all points along the' conduit are a minimum of one foot from

.(regardless of plant any ) uncovered portion of the tray.

area Note Covers will be added to open' trays below conduits only where the trays do not meet the IEEE 384-1974 vertical separation criteria of 3 feet from the conduit in cable spreading areas and 5 feet from the conduit in general plant areas.

Action Required None l

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Issue The scheme for protection of the Containment Building polar crane utilizes primary protection consisting of a'480. volt class 1E feeder breaker with a solid state trip device. -Backup pro-tection is provided by the class lE main feed breaker to the 480 volt bus which_is tripped by an inverse time-overcurrent relay we will require in the Technical Specifications.that the feeder breaker to the crane be locked open during. reactor operation.

Response

The attached graph.shows the thermal capability curve for t

a single 350 MCM penetration feedthru.

Also shown plotted on the graph are coordination curves representing actual settings for the polar crane CO-8 overcurrent relay _and the-primary breaker SS-14 solid state trip device.

The graph shows that the coordination curves for both the CO-8 and SS-14 are well below the withstand capability curve of a single 350 MCM cable.

The current input at rated horsepower output of the polar crane is much less than the single 350 MCM cable thermal-capability.

Should the losslof one of the penetration parallel 350 MCM conductors occur,-both the-SS-14 and the CO-8 will adequately protect the remaining 350 MCM cable within the containment penetration.

Therefore, it is not necessary to lock'open the polar crane

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feeder breaker during reactor operation and, as agreed, IP rescinds its' earlier commitment:to add Tech Spec surveillance requirements'on-this feeder breaker.

Action Required None-t

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en Issue ~

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Some thermal overload protection devices (that are integral with the motor starter for electric motors on motor-operated valves) are bypassed in one direction; i.e.,

the "close" cir-cuit.

Some are bypassed in both directions; i.e.,

the "open" and "close" circuits.

Verify that consideration was given to bypassed overloads such that in all cases the motor operated valve will perform its safety function when re-quired.

Response

Regulatory Guide 1.106 " Thermal Overload Protection For Electric Motors On Motor-Operated Valves" describes a method acceptable to the NRC staff of applying thermal overload protection de-

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vices that are integral with the motor starter for. electric-motors on motor-operated valves.

This method ensures that the thermal overload protection devices will not needlessly pre-vent the motor-operated valve from performing its safety-related function.

Clinton Power Station has committed to R.G. 1.106 (Rev.

1, March,1977) and FSAR section 8.1.6.1.19' describes our con-formance.

Basically, the safety function and it's " direction" (i.e.,

open circuit or close circuit or both circuits).of each 1E MOV is determined. :The thermal overload is continuously by-passed in~that safety direction unless the motor-is placed in the. test position.

In the test mode, the' thermal overloads are temporarily _placed in the circuit. LTherefore, IP does state that consideration was given to bypassed overloads such that in all cases, the motor-operated' valve will perform its safety function when required.

Action Required i

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Rev. 1

.V Safety Evaluation Report Open Issue #5 s)

' Page 19 PSB 40.107 Issue Identify' blocks of'lE load's and the times'they are

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sequenced onto their respective 1E bus.

Response

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Thisissueisclosedby.thereviseqre.tponsetoPSB question 40.107.

.The following revisions to the response to PSB question 40.107 will be made in response to. additional verbal.

questions on Division 1 and Division 2 loads.

1.

Revise starting KVA for Division 2 at time'0 secondsl

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to be 6,975.

2.

Revise 4.16. KV switchgear 1B1 RHR Pumps 1B,1C load at time 5 ~ seconds to be 760.9 (Page 1 of 12, Div-Rev. 1

]

ision 2).

3.

Revise totals for 4.16 KV switchgear 1B1 at time 0 seconds to be 1178.3 and at t,ime 5 seconds to be 801.0.

4.

Revise 480 V Unit Substation 1B switchgear 1 Heat re-moval Condition Unit. Motor Efficiency to be 92, load at time 0 seconds to be 108.69.

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5.

Revise totals for 480 V Unit substation 1B for time 0 seconds to be.360.88.

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'w' l-Additional Verbal Question l

Question:

Does the llPCS Diesel Generator utilize a fast transfer scheme similar to the Division 1 and Division 2 Diesel Generator?

The logic diagrams do not show this.

i.

Response

Division 3 does utilize a fast transfer scheme similar to Divisions.1 and 2.

The E02-1HP99 drawings show this.

Division 3 will be revised to prevent auto transfer from the Diesel Gen-s t

erator to an offsite. soured.

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Additional Verbal Question Question:

Will the IIPCS Diesel Generator automatically separate from the test mode upon receipt of l

a safety injection signal?

The FSAR indicates i

this is true, but the logic diagrams do not show this.

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Response

The llPCS Diesel Generator will separate from the test mode upon receipt of a safety injec--

_ tion. signal.

E02-1HP99 Sheet 109 shows the circuits to i

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accomplish this separation.'

The logic diagrams will be revised to reflect this feature.

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Issue DC Monitoring Instrumentation

Response

Additional response to 40.133 The Division 3 alarms and indications listed above will be changed to include the following:

A battery charger failure alarm which monitors the battery charger DC output voltage for high voltage, low voltage, and battery charger output current for no/ low current, will be provided.

This alarm will be grouped with other HPCS DC alarms and will. alarm in the main control room. The low voltage alarm set point will be selected to allow prompt indication of a off normal battery float voltage condition.

.This addition to the Division 3 alarms and indications, allows the Division 3 DC system to be monitored to the extent necessary to assure that it will be available to perform its safety' function.

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l Issue Division 3 off-line battery. charging.

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Response

l-Division 3 batteries are floated at 2.2V/ cell,.which eliminates the-periodic equalization of the battery at reg-i l

ular intervals.

However, the batteries are equalized whenever they are partially or fully discharged due to loss of AC power

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l or testing.

During equalizing, all de equipment, except the

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L NSPS inverter, is transfered to a separate battery charger.and-fed at normal float voltage.

The inverter is; designed to.

operate at the 140-V de equalizing' voltage.

In response to additional questions on the spare charger alarms and' loads,'the following response was'provided.

Local indication of DC current and DC voltage is provided.

High DC voltage will trip AC source breaker.and provide an alarm.. Low DC voltage will. provide an alarm.

The setpoints of'the-voltage-alarm relays'will provide prompt alarming of an'off normal DC' voltage condition.-

Division 3 DC' load bus supplies HPCS instrumentation and control. -It'alsoEsupplies 125 VDC power.to the: Division.3.. portion

,of the NSPS.' Division 3 battery offline equalizing'will be performed:

in accordance with. written procedures.

l Action Required L

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Adequacy of Station Electric Distribution System Voltage (8.2.4)

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Response

As submitted at November PSB meeting, Bethesda, and additional response sent to Jim.Lazevnick 11-24-81.

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.s Safety Evaluation Report l

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Open Issue #3 l

Page 15~

PSB 40.135 Additional Response to PSB Question 40.135 i

1.

All continuous duty motors which are susceptable to voltages less than 90% of rated motor voltage under degraded voltage conditions either have a 1.15 service factor or are designed with rated horsepowers at least 10% higher than the required k-brake horsepower.

2.

The first level of under voltage relays will be set-at 78%

of 4160 volts (time dial 2) for Divisions 1 & 2.

A similar characteristic will be created for Division 3 using the instantaneous under voltage relays with a timer.

When the diesel genera, tor is supplying the loads, load shedding will be blocked.

Spurious transfers are precluoed by the 78%

setting, which is sufficiently lower than the minimum tran-sient voltages which occur while starting motors from offsite i

sources.

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One timer will be utilized for the 2nd level under voltage scheme.

Preliminary data lists..the startin' ' tige of the g

largest 1E motor wi,th worst case' source voltage,as approxi-

.u 49 mately 10 second,s or les's.' Based'on this information, the timecuill'be set at 15 seconds.

Motor starting time'in pre-sently'being ve.4.fied.

After'this timer has' timed out,'tha.

loads will aut'omatic. ally transfer to the onsit'e power.souree.

Instrumentation and controls vill not be damaged by thin -

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degraded voltage for this.short tiuc-period.

l 3.

See attached table I.

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4.

The minimum and maximum voltage ranges of the offsite sources used for the voltage drop calculation are as follows:

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a.

Normal Operating Voltage Range During Plant Life for 345 kV system:

355.4 kV to 362.2 kV.

b.

Normal Operating Voltage Range During Plant Life for -

138 kV system:

135.5 kV to 142.6 kV.

c.

Minimum voltage during most severe contingency (i.e.,

single or doubic line circuit failure). under which the -

RAT would be required to successfully/or. shutdown.

start up~Clinton and the ERAT supply Clinton LOCA and 345 kV System = 1.010 per unit 138 kV System =. 935 per unit l-

)

.+

Safety Evaluation Report Open Issue #3 C~-

Page #2 1

See attac1ed Table I.

5.

3 6.

Since only.one timer is provided (setting discussed in.

item 2), there will be no LOCA bypass.

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7.

Therc kE11 be Eo' automatic transfer from the ohsite source'"

to.off' site source.

8.

See item 2...

7 3

9.

Startup of the 270 HP control room HVAC chiller OVC13CA on 480V ESF'switchgear Bus A when ERAT is carrying LOCA loads will cause the most severe voltage dip at the 480V level.

The effect at the 480V level is more severe under this condition than starting t he largest 4kV motor.

Th5 starting voltage at the chiller is expected to be 364V and the bus voltage will be 367V.

This 367V at the switch-gear bus will cause the following minimum voltages at other equipment terminals:.

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1. OF EQUIPMENT EQUIPMENT RATED VOLTAGE VOLTAGE

1. 480V MCC 364 75.8%

2. 460V MCC

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~3521 76.5%

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3.~480/120 366 76.25%

.. Regulated Transformers 4'.'480-120/208

. 94/163 78'.'3%

Non-Regulated All motors are designed to deliver rated full rated torque without damage for infrequent one-minute intervals at 75%

of rated motor terminal voltage.

Under voltage relays and overcurrent relays at the 4160V and 480V 1cvel are set to override motor starting transients and, therefore, will not cause spurious trips during motor starting.

Note 480V under voltage relays _are~for alarm only.

Dropout voltage 'for relays and contractors are substantially

' r-lower than the minimum expected voltage during this tran-(.

sient conductor.

Therefore, relays and contactors.will not-

- drop out.

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.-c Safety Evaluation Report

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Open Issue #3

!O Page #3 l

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The instrumentation will not be damaged during anticipated low voltage,n:ransi.ents.

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10.

The Technical Specifications (Section 3/4 3.3) allow tolerance at 4kV for second level under voltage relay which corresponds to'about 19 volts based on the setpoint of 3715 volts.

Therefore, the setpoint in the technical specifica-tion for second level will be specified as 3734 19 volts which will correspond to a relay setpoint of 106.2 +.5 volts (based on 4200-120V potential trahsformers).

1 The low tolerance of the setpoint' corresponds t> 3715 volts at the 4kV leyel which is the minimum value for successful operation of equipment at all levels.

The high tolerance corresponds to 3753 volts at the 4kV level and is substantially lower than the worst case minimum expected voltage of 3848 l

volts to preclude spurious trips.

l We have co'ntacted relay inanufacturer, and he has advised u's that there is no draft in setpoint of 2nd level of UV relays.

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NO LOAD VOLTAGE AT MINIMUM RUN VOLTAGE AT 120V NSPS and 208/120V Non-120V NSPS and 208/120V Non-Regulated Bus Regulated Bus Regulated Bus Regulated Bus CASE Volt Volt Volt Volt 120V 2%

228/131 109-120V 2%.

194/112 93.3 Start Up From RAT (Guaranteed (Guaranteed Output)

Output)

,LOCA Operation 120Vt2%

228/131 109 120V 2%

197/114 95.0 From RAT (Guaranteed (Guaranteed Output):

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Output)

Shutdown 120V 2%

228/131 109 120V 2%

191/110 91.7 (Guaranteed From RAT (GuarantdEd

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Output)

Normal ESF 120V 2%

228/131h 109 120V*2%

203/117 97.5 Load + DG Test (Guaranteed (Guaranteed Output)

From RAT Output)

LOCA Operation' 120V 2%

232/134 *111.7 120V 2%

189/109 90.E From ERAT (Guaranteed (Guaranteed Output)-

Output)

Shutdown N

120V 2%,

232/134'*111.7 120V*2%

194/112: 93.3 (Guaranteed (Guaranteed From ERAT Output)

Output)'

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DG Test From'g 120V 2%.

232/134,*111.7 120V 2%

194/112 93.3 (Guaranteed ERAT (Guaranteed 0utput)

Output) d' NOTE i.:

• No-load voltage has.been calculated without considering any voltage drop through the ERAT, 480V substation, or in the feeder.

Since there will always be some drop in this equipment, 111.7% at 480-208/120V.non-regulating transformer is considered acceptabic.

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1 Draft SER 3

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Additional SER Clarification Page 17 Per discussion with the NRC on November 4th and 5th, 1981, the. capability for the Clinton IE 4KV buses to auto trans-

'fer from theonsitY~ source't'o an offsite source is not l

acceptabic.

The NRC's requires.that an acceptable design include the capability for restoring preferred power to

.the respective safety bus by manual actuation only.

To meet this requirement, the Clinton IE 4KV bus control logic will be revised to require operator. action to. allow transfer from the onsite source to !an offsite source.

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Issue The.RPS and MSIV-solenoid circuit wiring is run in conduit and

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the conduits may be run with divisional wiring.

Tests and analyses-have-been performed which show that the conduit (with no separation) provides adequate separation between' Class lE circuits and the non-lE special solenoid circuits.

Also, non-lE fire detection, intercom and utility services wiring in PGCC floor sections are in conduit and the conduit

.may runiin any divisional duct.

All conduits are grounded to -ensure that hot shorts in internal wiring will' melt up-stream fuses which will provide short circuit protection that limits the fault to the non-divisional cables.

L Additional information is required from the applicant describing.

the tests and analyses performed to show that the RPS and MSIV conduits 1 provide adequate separation when routed with divisional circuits.

Test data is also required from the applicant to show adequate separation is maintained in PGCC conduits..The test must L

l be performed assuming the upstream fuses-fail.

i Af ter discussing by phone with the applicant 'and GE -(on ll-17-81),.

L the test report for electr'ical fire. separation capability of-flexible' conduit, the following information was requested:

'l.

Was the conduit under test-closed at one end or.both?

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Was the. selection of a 2/c #10 AWG' wire in the 2.

worst case for_both-RPS/MSIV and PGCC and why?~te'st the Include cables sizes for PGCC and RPS/MSIV.

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3.

-State'how the~ test l(which wasjperformed.iniopen air).was-corrected for different heat rate characteristics'en-.

. countered by-the_ conduits for RPS/MSIV and PGCC which would beLhuried by-energized cables.

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4.

"For the test. cable not'in~ conduit,swhat size conductor and

insulation voltage.was used?

s See attached telecon memo of;11/17/81.-

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Issue 5.

State how the test showed no damage to cable outside the conduit if the cable and conduit were buried in other energized cable would be encountered by-the divisional cable around PGCC and RPS/MSIV.

6.

Where did the test cabic fail?

For an arcing fault, a concentrated heat rise at that 7.

_po' int on the conduit could c cur.

Describe how the test covered this.

U.

State how the test corrected for the ambient-temperature encountered by conduits buried by energized cables.

Response

The information requested by the NRC is being investigated.

The test report as written does not give details to answer the questions.

Personnel in Daytona Beach, Florida who were involved with the actual test are gathering information.

An additional conference call to the NRC is planned the week of November 30, 1981.

Action-Required Obtain answers to the questions presented by the NRC.

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NUCLEAR POWER SYSTEMS DIVISION - -

I San Jose, California fj y

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' November 17, 198f

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SUBJECT:

TELECON 11/17/81 Participants

/

Tom Spry ~,

IPC Jim Lazevnick NRC-F.

C.

Downey

'UE' W. H. Hendrix 'GE '

D. L. Foreman 'GE 1

This is.to document discbssion of' kC questions on the Clinton NSPS power distribution in a.telecon'with the above listed individuals.

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Relay Plant. Reference Design

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As discussed, a reference plant for power distribution is any of o

l the BWR relay designs.

Hatch would be the best reference since this is the plant where questions concerning the protective circuitry first came up.

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i Therelaydesignsusetwonon-1EMGsetstosuphlyRPSandMSIV solenoids and logic.

Outputs of these MG sets to the busses are now through the protective circuitry to ensure that the busses re-main within class 1E parameters.

2)

Description of ClInton Inverter Design The power arrangement for.Clinton will be similar to the relay plant power distribution.

The inverters, which will be class lE equipment, will be the equivalent'of the MG set, which is non 1E on the relay i

plants.

Each inverter output will power a' solenoid bus for normal i

operaton.

The A bus will power all "A" solenoids and the~B bus will l

power'all "B" solenoids.

During bypass mode the bus is powered through a regulating transformer (class 1E) from a non 1E power source.

-3)

Description of. Power Monitor for the Inverter Output The inverter output will hava-a power monitor system to disconnect its output should the inverter controls fail to maintain the class 1E voltage parameters':

lThe donitorfwil'1 trip the inverter output breaker j

upon-sensing an over voltage, undervoltage,or underfrequency con -

.dition at the inverter outputc (The poweg_ monitor system is also class lE.)

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Telecon. 3.1/17/81 4.

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m The power monitor circuits will be circuitry other than that used for. inverter controls.

The monitor will trip the output

_ breaker during normal or bypass operation of the inverter.

4)

Logic _ comparison The 1bgic for fina.1 actuation will be the sane as on the relay plants, 1 out of 2 twice.

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5)

Tech Specs b

.f [A Tech Spec limit will be imposed when on the bypass to limit. opera-r-

tion in the bypass mode.

Only one bus wilf be allowed to be on the A>yphss at any one time.

The time limit for the bypass mode will be

,I,,affected'by the. fact that.the power monitor'.is not redundant when.on-the bypass._.

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The, tech spec time limit is still to be determined.

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