ML19352A032

Proposed Tech Spec Changes to Section 3 Reflecting Mods to Protect Against Degraded Grid Voltage Damage to safety-related Equipment

ML19352A032
Person / Time
Site:	Arkansas Nuclear
Issue date:	02/20/1981
From:	ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML19352A030	List: ML19352A029 ML19352A032
References
NUDOCS 8102250532
Download: ML19352A032 (9)

Text

rm 3.5.1.7 The Decay Heat Removal System isolation valve closure setpoints L) shall be equal to or less than 340 psig for one valve and equal to or less than 400 psig for the second valve in the suction line.

The relief valve setting for the DHR system shall be equal to or less than 450 psig.

3.5.1.8 The degraded voltage monitoring relay settings shall be as follows:

a.

The 4.16 KV emergency bus undervoltage relay setpoints shall be > 3115 VAC.

b.

The 460 V emergency bus undervoltage relay setpoints shall be > 423 VAC.

-42a-sic,sese g3%

~ for protective action from a digital ESAS subsystem will not cause that subsystem to trip.

The fact that a module has been removed will be con-tinuously annunciated to the operator.

The redandant digital subsystem is still sufficient to indicate complete ESAS action.

The testing schemes of both the RPS and the ESAS enable complete system testing while the reactor is operating.

Each channel is capable of being tested independently so that operation of individual channels may be eval-uated.

The Automatic Closure and Isolation System (ACI) is designed to close the Decay Heat Removal System (DHRS) return line isolation valves when the Reactor Coolant System (RCS) pressure exceeds a selected fraction of the DHRS design pressure or when core flooding system isolation valves are opened.

The ACI is designed to permit manual operation of the DHRS re-turn line isolation valves when permissive conditions exist.

In addition,

' the ACI is designed to disallow manual operation of the valves when per-missive conditions do not exist.

Power is normally supplied to.the control rod drive mechanisms from two separate parallel 480 volt sources.

Redundant trip devices are employed in each of these sources.

If any one of these trip devices fails in the untripped state, on-line repairs to the failed device, when practical, will be made and the remaining trip devices will be tested.

Four hours is ample time to test the remaining trip devices and, in many cases, make on-line repairs.

The Steam Line Break Instrumentation and Control System (SLBIC) is designed to automatically close the Main Steam Block valves and the Main Feedwater Isolation valves upon loss of pressure in either of.the two main steam lines.

.The-SLBIC is also designed to be reset from its trip position only when j

the system is shut down or the Main Steam line pressure is below 650 psig.

The Degraded Voltage Monitoring relay se'ttings are based on tha short term

. starting voltage protection as=well as long term running voltage protection.

The14.16 KV undervoltage relay setpoints are based on the allowable starting voltage plus maximum system voltage drops'to the motor-terminals, which

- allows approximately 78% of motor rated voltage at the motor terminals.'The 460V undervoltage. relay setpoint is based on long term ~ motor voltage re-quirements plus the maximum. feeder voltage drop allowance resulting in a

~

92% setting of cotor rated voltage.

REFERENCE 7

FSAR, Section 7.1-T

-43a-4 m

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3.7 Auxiliary Electrical Systems Applicability Applies to the auxiliary electrical power systems.

i Objectives To specify conditions of operation for plant station power necessary to ensure safe reactor operation and combined availability of the angineered safety features.

Specifications 3.7.1.

The reactor shall not be heated or maintained above 200F unless the following conditions are met (except as permitted by para-graph 3.7.2):

A.

Any one of the following combinations of power sources operable:

1.

Startup Transformer No. 1 and Startup Transformer No. 2.

2.

Startup Transformer No. 2 and Unit Auxiliary Transformer provided that the latter one is connected to the 22KV line from the switchyard rather than to the generator bus.

B.

All 4160 V switchgear, 480 V load centers and 480 V motor.

control centers in both of the ESAS distribution systems are operable and are being powered from either one of the two startup transformers or the unit auxiliary transformer.

C.

Both diesel generator sets are operable each with:

i 1.

a separate day. tank containing a minimum of 160 gallons of fuel,.

2.

a separate emergency storage tank containing a minimum of 138 inches (20,000 gallons) of fuel, 3.

'a separate fuel transfer pump, and 4.

a separate starting air compressor.

D.

- Both station batteries are operable and each 'is capable of supplying power to-the 125B d-c distribution system.

At least 2 ofJthe 3 battery chargers are operable.

. E.

A least 2 of 3.d-c' control power sources to the'125V'd-c l

switchyard distribution system are operable.

F.~

The off-site power undervoltage.and protective relaying in-

- terlocks associated with required startup transformer power sources shall be operable per Table 35.1-1.

G.

-The selective load-shed features associated with Startup Transformer No. 2 shall.be operab e if, selected for. auto l

- transfer.

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3.7.2 A. The specifications in 3.7.1 may be modified to allow one of the following conditions to exist after the reactor has been heated above 200F.

Except as indicated in the following conditions, if any of these conditions are not met, a hot shutdown shall be initiated within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

If the condition is not cleared with-in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the reactor shall be brought to cold shutdown within an additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

B. In the event that one of the offsite power sources specified in 3.7.1.A (1 or 2) is inoperable, reactor operation may continue for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if the availability of the diesel generators is immediately verified.

C. Either one of the two diesel generators may be inoperable for up to 7 days in any month provided that during such 7 days the opera-bility.of the remaining diesel generator is demonstrated immedi-ately and daily thereafter, there are no inoperable ESF components associated with the operable diesel generator, and provided that the two sources of off-site power specified in 3.7.1.A(1) or 3.7.1.A(2) are available.

D. Any 4160V, 480V, or 120V switchgear, load center, motor control center, or distribution panel in one of the two ESF distribution systems may be inoperable for up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />', provided that the operability of the' diesel generator associated with the operable i-ESF distribution system is demonstrated immediately and all of the I

components'of the operable distribution system are operable.

If the ESF distribution system is not returned to service at the end of the 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period, specification 3.7.2. A shall apply.

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E. Two station battery chargers may be inoperable for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, after-which specification 3.7.2.A shall apply.

F. One of the two station _ batteries and the associated distribution system may be inoperable for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> provided that there are no inoperable safety related components associated with the remaining L

station battery which are redundant'to the inoperable station

{-

battery and the operability of the diesel generator is verified immediately.

If the battery is not returned to service at the end e

of. the 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period, specification 3.7.2.A shall apply.

'G.-Two contro.1 power sources from the plant to the switchyard and the p

l attendant distribution system may be inoperable for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, after~

which specification 3.7.2.A shall apply.

H. If the requirements' of specification ~ 3.7.1.G cannot be' met, either:

L (1) place all Startup' Transformer No. 2 feeder breakers in " pull-to-lock" within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, ' restore-the inoperable interlocks to operable status within 30 days or: submit a special report pur-suant to specification 6.-12.3.2 outlining cause of the failure,

_ proposed corrective action and schedule for implementation; or (2)' apply the action requirements of_ Table 3.5.1-1, Note 11.

6 h'

3.7.3 Any degradation beyond those conditions specified in 3.7.1 and 3.7.2 shall be cause to initiate a reportab!' occurrence report per speci-fications 6.5 and 6.12.

Bases The electrical system is designed to be electrically self-sufficient and provide adequate, reliable power sources for all eier.trical equipment during startup, normal operation, safe shutdown and handling of all emer-gency situations.

To prevent the concurrent loss of all auxiliary power, the various sources of power are independent of and isolated from each other.

In the event that the offsite power sources specified in 3.7.1. A (1 or 2) are inoperable, the required capacity of one emergency storage tank plus one day tank (20, 160 gallons) will be sufficient for not less than three and one-half days operation for one diesel generator loaded to full capa-city.

(ANO-1 FSAR 8.2.2.3)

The underground emercency storage tanks are gravity fed from the bulk storage tank and are normally full, while the day tanks are fed from transfer pumps which are cacable of being cross connected at their suction and discharges and autcmatically receive fuel oil when their inventory is less than 180 gallons.

Thus, at least a seven day total diesel oil inventory is available onsite for emergency diesel generator operation during complete loss of electric power conditions.

Technical Specification 3.7.2 allows for the temocrary modification of the specifications in 3.7.1 provided that backup system (s) are operable with safe reactor operation and combined availability of the engineered safety features ensured.

Technical Specifications 3.7.1.F and 3.7.1.G provide assurance that the Startup Transformer No. 2 loads will not contribute to a sustained de-graded grid voltage situation.

This will protect ESF equipment from damage caused by sustained undervoltage.

-57a-

4.6 AUXILIARY ELECTRICAL SYSTEM TESTS Applicability Applies to the periodic testing and surveillance requirements of the auxil-iary electrical system to ensure it will respond promptly and properly when required.

Specification 4.6.1 Diesel Generators

1. Each diesel generator shall be manually started each month and demonstrated to be ready for loading within 15 seconds.

The signal initiating the start of the diesel shall be varied from one test to another (start with handswitch at control room panel and at diesel local control panel) to verify all starting circuits are operable.

The generator shall be synchronized from the control room and loaded to full rated load and allowed to run until diesel generator operating temperatures have stabilized.

2. A test shall be conducted once every 18 months to demonstrate the ability of the diesel. generators to perform as designed by:

a.

simulating a loss of off-site power, b.

simulating a loss of off-site power in conjunction with an ESF

signal, c.

simulating interruption of off-site power and subsequent re-connection of the on-site power source to their respective busses, and d.

operating the diesel generator for g 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> after operating temperatures have stabilized.

3. Each diesel generator shall be given an inspection once every 18 months-following the manufacturer's reccmmendations for this class of standby service.

4. During the monthly diesel ge.nerator test specified in paragraph 1 above, the following shall be performed:

a'.

.The diesel generator starting. air ccmpressors shall.be checked for operation and their ability to recharge the air receivers.

b.

The diesel oil transfer pumps shall be checked for operability and their ability to transfer oil to~the day-tank.

c.

The_ day tank fuel level-shall be verified.

d.

The emergency storage tank fuel level shall be verified.

-100-

Table 3.5.1-1 (Cont'd)

OTHER SAFETY RELATED SYSTEMS 1

2 3

4 5

No. of Operator action channels Min.

Min.

if conditions of No. of for sys-operable degree of column 3 or 4 Functional Unit channels tem trip channels redundancy cannot be met

2. Steam line break instrumentation control system (SLBIC)

a. SLBIC Control & Logic channels 2

1 2

1 Notes 9, 5

3. Degraded Voltage Monitoring

a. 4.16 KV Emergency Bus Undervoltage 2/ Bus 1/ Bus 2/ Bus 0

Note 11

b. 460 V Emergency Bus Undervoltage 1/ Bus 1/ Bus 1/ Bus 0

Note 10, 11 j,

Notes:

1.

Initiate a shutdown using normal operating instructions and place the reactor in the hot shutdown gp -

condition.if the requirements cf Columns 3 and 4 are not met within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

e 2.

.When 2 of 4 power range instrument channels are greater than 10% rated power, hot shutdown is not required.

3.

When 1 of 2 intermediate range instrument channels is greater than 10 H3 amps, hot shutdown is not required.

4.

For channel testing, calibration, or maintenance, the minimum number of operable channels may be two and a degree of redundancy of one for a maximum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, af ter which Note 1 applies.

5.

If the requirements of Columns 3 or 4 cannot be met within an additional 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, place the reactor in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

6.

The minimum number of operable channels may be reduced to 2, provided that the system is reducer co 1 out of 2 coincidence by tripping the remaining channel.

Otherwise, Specification 3.3 shall apply.

7.

These channels initiate control rod withdrawal inhibits not reactor trips at 10% rated power. Above 10% rated power, these inhibits are bypassed.

8.

If any one component of a digital subsystem is inoperable, the entire digital subsystem is considered inoperable.

Hence, the associated safety features are inoperable and Specification 3.3 applies.

Table 3.5.1-1 (Cont'd) d

. Notes:

(cont'd)

-9. The minimum number of. operable channels may be reduced to one and the minimum degree of redundancy to zero for a maximum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, after which Note 1 applies.

16. Channels may be bypassed for not greater than 30 seconds during reactor coolant pump starts.

If the automatic bypass circuit or its alarm circuit is inoperable, the undervoltage protection shall be restored within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, otherwise, Note 11 applies.

.11. With the number of channels less than required, restore the inoperable channels to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in hot shutdown within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

Table 4.1-1 (Cont'd)

Channel Description Check Test Calibrate Remarks

30.. Decay Heat Removal System S(1)(2)

M(1)(3)

R (1)

Includes RCS Pressure Analog Channel Isolation Valve Automatic

. Closure and Interlock (2)

Includes CFT Isolation Valve Position System (3) Shall also be tested during refueling shutdown prior to repressurization at a pressure greater than 300 but less than 470 psig.

31. ' Turbine Overspeed Irip

.NA R

NA Mechanism

32. -Steam Line Break Instru-W Q

R mentation and Control System Logic Test and

?

. Control Circuits

33.. Diesel Generator Protec-M Q

NA tive Relaying, Starting Interlocks'and Circuitry

'34.

Offsite Power Undervoltage W

R(1)

R (1) Sna11 be tested during refueling shutdown

.and Protective Relaying to demonstrate selective load shedding Interlocks and Circuitry interlocks function during manual or auto-matit transfer of Unit I auxiliary loads to Startup Iransformer No. 2.

-35.

Borated Water Storage tank W

NA R

Level Indicator 36.

Degraded Voltage Monitoring W

R R