ML20036B215

Proposed Tech Specs 3.3.8.1, Loss of Power Instrumentation & 3.3.8.2, Vital AC Electric Power Monitoring

ML20036B215
Person / Time
Site:	05200001
Issue date:	05/11/1993
From:	GENERAL ELECTRIC CO.
To:
Shared Package
ML20036B212	List: ML20036B211 ML20036B215
References
NUDOCS 9305180311
Download: ML20036B215 (22)

Text

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• • ' g LOP Instrumentation 3.3.8.1 3.3 INSTRUMENTATION f

3.3.8.1 Loss of Power (LOP) Instrumentation i

LCO 3.3.8.1 The LOP instrumentation for each Function in Table 3.3.8.1-1 shall be OPERABLE.

i APPLICABILITY:

MODES 1, 2, and 3, When the associated diesel generator (DG) is required to be OPERABLE by LCO 3.8.2, "AC Sources--Shutdown."

ACTIONS

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NOTE-------------------------------------

I Separate Condition entry is allowed for each channel.

CONDITION REQUIRED ACTION COMPLETION TIME l'

i A.

One or more channels A.1 Place channel in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> i

inoperable.

trip.

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Required Action and B.1 Declare associated DG Immediately I

associated Completion inoperable.

i Time not met.

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/(BWRf6-STS 3.3-77 Rev.

O, 09/28/92 throu;pleet f 'opler-G 9305180311 930521

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1 LOP Instrumentation 3.3.8.1 i

SURVEILLANCE REQUIREMENTS i

-.--...--------.-..--.-.-.------.-.. NOTES-----..----..---------..--.-..----.-

l 1.

Refer to Table 3.3.8.1 1 to determine which SRs apply for each LOP Function.

2.

When a channel is placed in an inoperable status solely for performance of required Surveillances, entry into associated Conditions and Required Actions may be delayed for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> provided the associated Function maintains DG initiation capability.

SURVEILLANCE FREQUENCY

(

i SR 3.3.8.1.1 Perform CHANNEL CHECK.

12 hocrs i

4 SR 3.3.8.1.2 Perform CHANNEL FUNCTIONAL TEST.

31 days i

SR 3.3.8.1.3 Perform CHANNEL CALIBRATION.

[18] months i

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SR 3.3.8.1.4 Perfons LOGIC SYSTEM FUNCTIONAL TEST.

[18] months l

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BWR/6 STS 3.3-78 Rev.

O, 09/28/92 i

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LOP Instrumentation i

3.3.8.1 Table 3.3.8.1 1 (page 1 of 1)

Loss of Power instrumentation I

PEoJ!aED CKAhWELs PER SURVE!LLANCE ALLOWAsLE FUWCTION DIV!s10N REQUIREMENTS VALUE 1 #A Q wd $ ~ (,.C) KV 3

1 Divisions * ; : - ;. m J Emergency Bus urcervoltage a.

Loss of Voltage -4 rte kV A

[st 3.3.8.1.13 t [M 24) V and s [M 42 V basis

(,.c)

$t 3.3.8.1.2 j

st 3.3.8.1.3 st 3.3.8.1.4 i

b.

Loss of Voltage - Time

[4]

Ist 3.3.8.1.23 2 [0.41 seconds and t

Detsy st 3.3.8.1.3 s (1.01 seconos i

a Q _3.3.8.1.4 h /. Degraced voltape-4.16 kV A)

[St 3.3.5.1.11 t [L441 V and a t&8&Nlr3 V basis st 3.3.8.1.2 st 3.3.8.1.3 st 3.3.8.1.4 i

d.

Degraoed Voltage - Time (4]

Ist 3.3.8.1.22 1 [8.5 ecords and l

De y st 3.3.8.1.3 s. ) seconos l

st 3.3.8.1.4 l

2.

Division 3 -4 Emergency Eus Ordervoltage l

a.

Loss of Voltage -4.16 t (4) st 3.3.8.1.13 2 2964 V and s 3106 V j

basis st 3.3.8.1.2 1

st 3.3.8.1.3 l

SR 3.3.8.1.4 i

b.

Loss of Voltape-Time

[4]

I 3.3.8.1.23 t [2.01 secanos aM Delay st 8.1.3 s [2.51 secanas SR 3.3.. 4 I

c.

D Voltage -4.16 kV I4)

Ist 3.3.8.1.1) a 58.5 V and s 3763.5 V basis st 3.3.8.1.2 st 3.3.8.1.3 st 3.3.8.1.4 d.

D t&}

tst 3.3.8.1.23

.51 minutes and j

Delay, wo LOCA st 3.3 s (5.52 mirutes j

8.1.4 e.

Degraoed Vol-I41 tst 3.3.8.1.23 a

ecaros and t *7

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BWR/6 STS 3.3-79 Rev.

O, 09/28/92

LOP Instrumentation i

B 3.3.8.1 B 3.3 INSTRUMENTATION j

B 3.3.8.1 Loss of Power (LOP) Instrumentation BASES BACKGROUND Successful operation of the required safety functions of the 2 Emergency Core Cooling Systems (ECCS) is dependent upon the a

availability of adequate power sources for energizing the j

various components such as pump motors, motor operated l

g valves, and the associated con ol components.

The LOP b,gFM /

instrumentation monitors the 4.1 kV emergency buses.

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Off. site power is the preferre source of power for the

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(4.16)kV emergency buses.

If the monitors determine that e

insufficient power is available, the buses are disconnected t from the offsite power sources and connected to the onsite g

diesel generator (DG) power sources.

Each(43kV emergency bus has its own independent LOP g*

instrumentation and associated trip logic. The voltage for l

the Division 1, 2, and 3 buses is monitored at two levels,

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which can be considered as two different undervoltage U

I functions: loss of voltage and degraded voltage.

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The LOP instrumentation comprises tWee Functions for Q

(

and tre Functient for Di"isic' 3, which o

Divisions 1en423 represent different voltage levels that cause various bus y

0 transfers and discoppects.

Each Function is mong ored b y o l j thnc--fe undervoltagi/EWayr, for each emergency busx hos

%, l t w

outputs are arranged in a cre-cut-of-two-taker twice ogic configuration (Ref. 1). The channett include electrcnic h

-equipent (e.g., tr-ip unit:) th:t cc perc: = :sured 4 %

i

-signal: with pre-00tablished setpointh When the setpoint I

is exceeded,

• chenrd -output rel:y actuates, " +h e

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--output-s LOP [ trip signe! to-the trip logic.

o es.ch phne Sen sor

" "'& k APPLICABLE The LOP instrumentation is required for the Engineered SAFETY ANALYSES, Safety Features to function in any accident with a loss of LCO, and offsite power. The required channels of LOP instrumentation t

APPLICABILITY ensure that the ECCS and other assumed-systems powered from the DGs provide plant protection in the event of any of the i

analyzed accidents in References 2, 3, and 4 in which a loss of offsite power is assumed. The initiation of the DGs on loss of offsite power, and subsequent initiation of the (continued)

EWR/6 STS B 3.3-233 Rev.

O, 09/28/92 1

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INSERT A:

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which sends a trip signal to the associated division of Safety System Logic and Control (SSLC). Any two out of the three phase sensor trip signals for an emergency bus results in a LOP trip signal, This trip signal is combined with appropriate time delays and outputs a signal to start the DG from the associated SSLC division.

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LDP Instrumentation B 3.3.8.1 l

BASES a

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APPLICABLE ECCS, ensure that the fuel peak cladding temperature remains SAFETY ANALYSES, below the limits of 10 CFR 50.46.

LCO, and APPLICABILITY Accident analyses credit the loading of the DG based on the (continued) loss of offsite power during a loss of coolant accident (LOCA). The d'esel starting and loading times have been included in the delay time associated with each safety system component requiring DG supplied power following a loss of offsite power.

f The LOP instrumentation satisfies Criterion 3 of the NRC phoe l

Policy Statement.

f sea 8j i

The-OPERABILITY of the LOP instrumentatiop is dependent upon the OPERABILITY of the individual instrupentation channel Functions specified in Table 3.3.8.1-1 f. Each Func ion must have a required number of OPERABLE W..n:6 per V

6, c) emergency bus, with their setpoints within the specified Allowable Values. A channel is inoperable if its actual trip setpoint is not within its required Allowable Value.

The actual setpoint is calibrated consistent with applicable setpoint methodology assumptions.

j The Allowable Values are specified for each Function in the l

Table. Nominal trip setpoints are specified in the setpoint i

calculations. The nominal setpoints are selected to ensure that the setpoint does not exceed the Allowable Value between CHANNEL CALIBRATIONS. Operation with a trip

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setpoint less conservative than the nominal trip setpoint, l

but within the Allowable Value, is acceptable. Trip setpoints are those predetemined values of output at which an action should take place. The~setpoints are compared to the actual process parameter (e.g., degraded voltage), and when the measured output value of the process parameter exceeds the setpcint, the associated device-(c.g., trip =

-mR)- changes state. The analytic limits are derived from i

the limiting values of the process parameters obtained from the safety analysis. The Allowable Values are derived from the analytic limits, corrected for calibration, process, and some of the instrument errors. The trip setpoints are then detemined accounting for the remaining instrument errors (e.g., drif t). The trip setpoints derived in this manner i

provide adequate protection because instrumentation uncertainties, process effects, calibration tolerances, instrument drift, and severe environment errors (for (continued)

BWR/6 STS B 3.3-234 Rev.

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LOP Instrumentation B 3.3.8.1 BASES APPLICABLE channels that must function in harsh environments as defined SAFETY ANALYSES, by 10 CFR 50.49) are accounted for.

LCO, and APPLICABILITY The specific Applicable Safety Analyses, LCO, and (continued)

Applicability discussions are listed below on a function by Function basis.

bd

-4:% kV Emeroency Bus Undervoltace G. 9 1.a. 1.b. 2.3. 21

• M kV Emeroency Bus Undervoltace (Loss of Voltace) 69 Loss of voltage on a-4-ift kV emergency bus indicates that offsite power may be completely lost to the respective emergency bus and is unable to supply sufficient power for proper operation of the applicable equipment. Therefore, the power supply to the bus is transferred from offsite power to DG power when the voltage on the bus drops below the Loss of Voltage Function Allouable Values (loss of voltage with a short time delay). This ensures that adequate power will be available to the required equipment.

The Bus Undervoltage Allowable Values are low enough to prevent inadvertent power supply transfer, but high enough to ensure power is available to the required equipment.

TAs-.

M e Delay allow bla vainae ere lena enough to provide t4me-

_fer th: Ofh ite power ennnly +n racever te nemal voltages-

-but shert encugh te ensura that nower is available to-the

--r+ qui red e""ipent.,

4 sc. kee ghae ~ o n' 4 " /,9

-Feur ch:nneh of hifriY Emergency Bus Undervoltage (Loss of 3

Voltage) Function per associatea emergency bus are only required to be OPERABLE when the associated DG is required to be OPERABLE to ensure that no single instrument failure of the three DGs.) 3 unctiong O 3.8., " ace ( h e channels input to e can preclude the DG f Refer to LC rces-Operating," and LCO,3.8.2, "AC Sources Shutd n," for gg ApplicabilityBases{fortheDGs.

(.h g,,,e f6 g,5 p v'5; Senec Th ree 1.6

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effr kV Emeroency Bus Undervoltace (Deoraded Voltaae) 6 c) 69 A reduced voltage condition on a *t6 kV emergency bus indicates that while offsite power may not be completely i

lost to the respective emergency bus, power may be j

(continued) j BWR/6 STS B 3.3-235 Rev.

O, 09/28/92

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LOP Instrumentation B 3.3.8.1 BASES I.6 (o.c.)

l APPLICABLE

-4,s. 1. d. ?. :. 2. d. 2. c.

.15 kV Emeroency Bus Undervoltace SAFETY ANALYSES, (Deoraded voltace)

(continued) l LCO, and APPLICABILITY insufficient for starting large motors without risking i

damace to the motors that could disable the ECCS function.

Therefore, power supply to the bus is transferred from offsite power to onsite DG power when the voltage on the bus i

drops below the Degraded Voltage function Allowable Values j

(degraded voltage with a time delay). This ensures that t

adequate power will be available to the required equipment.

j The Bus Undervoltage Allowable Values are low enough to prevent inadvertent power supply transfer, but high enough to ensure that sufficient power is available to the required equipment.

The 'i e Delay ^11cweble '/alues are len; er.cugh-

-to pr;vid; time for th offsit power ;upply te reccser to

-anmal voltages, but :hcrt enough tc :nsrttre-that-tuf#icient

- pow i o n eil:ble te-the required equip :rt._

(Pha s e S e, s o es), c,9

1. ette channels [of-4dFEmergency Bus Undervoltage

--f (Degraded Voltage) Function per associated emergency bus are only required to be OPERABuE when the associated DG is required to be OPERABLE to ensure that no single instrument failure can preclude the DG function.

(Fettr channels input to each of the three DGs.)

Refer to LCO 3.8.1 and LCO 3.8.2 for Applicability Bases for the DGs.

7% ae ACTIONS A Note has been provided to modify the ACTIONS related to LOP instrumentation channels. Section 1.3, Completion Times, specifies that once a Condition has been entered, subsequent trains, subsystems, components, or variables expressed in the Condition discovered to be inoperable or not within limits will not result in separate entry into the Condition. Section 1.3 also specifies that Required Actions of the Condition continue to apply for each additional failure, with Completion Times based on initial entry into the Condition. However, the Required Actions for inoperable LOP instrumentation channels provide appropriate compensatory measures for separate inoperable channels. As such, a Note has been provided that allows separate i

Condition entry for each inoperable LOP instr entation channel.

l (continued) t BWR/6 STS B 3.3-236 Rev.

O, 09/28/92

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i LDP Instrumentation B 3.3.8.1 l

1 BASES

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k ACTIONS A.I (continued)

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With one or more channels of a function inoperable, the l

Function may not be capable of perfoming the intended i

i function. Therefore, only I hour is allowed to restore the inoperable channel to OPERABLE status.

If the inoperable l

channel cannot be restored to OPERABLE status within the j

allowable out of service time, the channel must be placed in f

the tripped condition per Required Action A.I.

Placing the inoperable channel in trip would conservatively compensate l

for the inoperability, restore capability to accommodate a single failure, and allow operation to continue.

1 Alternately, if it is not desired to place the channel in trip (e.g., as in the case where placing the channel in trip 4

would result in a DG initiation), Condition B must be entered and its Required Action taken.

2 The Completion Time is intended to allow the operator time to evaluate and repair any discovered inoperabilities. The I hour Completion Time is acceptable because it minimizes risk while allowing time for restoration or tripping of

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channels.

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If any Required Action and associated Completion Time is not-i met, tne associated Function may not be capable of performing the intended function. Therefore, the associated 4

DG(s) are declared inoperable innediately. This requires entry i;ito applicable Conditions and Required Actions of-

- t LCO 3.8.1 and LCO 3.8.2, which provide appropriate actions l

for the inoperable DG(s).

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5 SURVEILLANCE As noted at the beginning of the SRs, the SRs for each LOP l

REQUIREMENTS Instrumentation Function are located in the SRs column of i

Table 3.3.8.1-1.

The Surveillances are modified by a Note to indicate that when a channel is placed in an inoperable status solely for j

~

performance of required Surveillances entry into associated l

l Conditions and Required Actions may be delayed for up to i

2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> provided the associated Function maintains DG j

initiation capability. Upon completion of the Surveillance, 1

(continued) i BWR/6 STS B 3.3-237 Rev.

O, 09/28/92 1

LOP Instrumentation B 3.3.8.1 i

BASES i

i SURVEILLANCE or expiration of the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> allowance, the channel must be REQUIREMENTS returned to OPERABLE status or the applicable Condition (continued) entered and Required Actions taken.

SR 3.3.8.1.1 Performance of the CHANNEL CHECK once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> ensures that a gross failure of instrumentation has not occurred. A CHANNEL CHECK is a comparison of the parameter indicated on one channel to a similar parameter on other channels.

It is based on the assumption that instrument channels monitoring the same parameter should read approximately the same value.

Significant deviations between the instrument channels could be an indication of excessive instrument drift in one of the channels or something even more serious. A CHANNEL CHECK will detect gross channel. failure; thus, it is key to verifying the instrumentation continues to operate properly between each CHANNEL CALIBRATION.

Agreement criteria are determined by the plant staff based on a combination of the channel instrument uncertainties, including indication and readability.

If a channel is outside the match criteria, it may be an indication that the instrument has drifted outside its limit.

The Frequency is based on operating experience that demonstrates channel-failure is rare. Thus, performance of the CHANNEL CHECK ensures that undetected outright channel failure is limited to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The CHANNEL CHECK supplements less formal, but more frequent, checks of channels during normal operational use of the displays associated with the required channels of the LCO.

i SR 3.3.8.1.2 A CHANNEL FUNCTIONAL TEST is performed on each required channel to ensure that the entire channel will perform the intended function.

The Frequency of 31 days is based on plant operating experience with regard to channel OPERABILITY and drift that demonstrates that failure of more than one channel of a given Function in any 31 day interval is rare.

(continued)

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I BWR/6 STS B 3.3-238 Rev.

O, 09/28/92 i

LOP instrumentation B 3.3.8.1 BASES SURVEILLANCE SR 3.3.8.1.3 REQUIREMENTS (continued) k CHANNEL CALIBRATION is a complete check of the instrument loop and the sensor.

This test verifies the channel responds to the measured parameter within the necessary range and accuracy. CHANNEL CALIBRATION leaves the channel adjusted to account for instrument drifts between successive calibrations. Measurement and setpoint error historical deteminations must be perfomed consistent with the plant specific setp-int methodology. The channel shall be left calibrated coi. istent with the assumptions of the setpoint methodology.

If the as found setpoint is not within its required Allowable Value, the plant specific setpoint methodology may be revised, as appropriate, if the history and all other pertinent infomation indicate a need for the revision. The setpoint shall be left set consistent with the assumptions of the current plant specific setpoint methodology.

The frequency is based on the assumption of an 18 month calibration interval in the determination of the magnitude of equipment drift in the setpoint analysis.

SR 3.3.8.1.4 The LOGIC SYSTEM FUNCTIONAL TEST demonstrates the OPERABILITY of the required actuation logic for a specific channel. The system functional testing performed in LCO 3.8.1 and LCO 3.8.2 overlaps this Surveillance to provide complete testing of the assumed safety functions.

The 18 month Frequency is based on the need to perfom this Surveillance under the conditions that apply during a plant outage and the potential for an unplanned transient if the Surveillance were performed with the reactor at power.

Operating experience has shown these components usually pass the Surveillance when performed at the 18 month Frequency.

/t & v A S M R REFERENCES

1. -fSAR. Fi m [ h 5 ' c N o #* #' /

5 ESAR,Section/5.2[

2.

/

aw #5a (Continued)

BWR/6 STS B 3.3-239 Rev.

O, 09/28/92

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LOP instrumentation B 3.3.8.1 BASES REFERENCES

3. (FSAR,Section 6.3[

(continued) 4.(,FSt.R,Chapte IS[

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t BWR/6 STS B 3.3-240 Rev.

O, 09/28/92

\\Nf.tl AC

-RPS-Electric Power Monitoring

&rs 4o-p 3.3.8.2 b&J 3.3 INSTRUMENTATION 3.3.8.2 Rco;^er Notecticc, Sy::te: (RPSP Electric Power Monitoring UVaf Ac LCO 3.3.8.2 Two4PE electric power monitoring assemblies shall be OPERABLE for each inservice APS meter scr,cret'r set om

- clicen t power supply.

cl.'vs' dona / v,+a / A c-APPLICABILITY:

MODES 1, 2, and 3, MODES 4 and 5 {with any control rod withdrawn from a core 7

cellcontainingoneormorefuelassembliesM-ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME m or'C-A.

One orDtti inservice A.1 Remove associated 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> power supplies with inservice power one electric power supply (s) from monitoring assembly service.

inoperable.

mCYG B.

One orJoth inservice B.1 Remove associated 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> power supplies with inservice power both electric power supply (s) from monitoring assemblies service.

inoperable.

3 C.

Required Action and C.1 Be in MODE 3.

12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> associated Completion Time of Condition A AND or B not met in MODE 1, 2, or 3.

C.2 Be in MODE 4.

36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> (continued) a hBWR/6-STS 3.3-80 Dav

n. ^9/26/92-m,,a g s e 64<)

RPT. Electric Power Monitoring 3.3.8.2 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME i

D.

Required Action and D.1 Initiate action to Immediately associated Completion fully insert all Time of Condition A or insertable control B not met in MODE 4 rods in core cells or 5/with any control containing one or rod withdrawn from a more fuel assemblies.

core cell containing one or more fuel AND assemblies %

D.2.1 Initiate action to Immediately restore one electric power monitoring assembly to OPERABLE

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status for inservice

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power supply (s) supplying required instrumentation.

OE D.2.2 Initiate action to Innediately isolate the Residual

_g, Heat Removal Shutdown

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Cooling System s.

g SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.3.8.2.1

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..-.--.---. NOTE-----------...--...

Only required to be performed prior to entering MODE 2 or 3 from MODE 4, when in MODE 4 for a 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Perform CHANNEL FUNCTIONAL TEST.

184 days (continued)

BWR/6 STS 3.3-81 Rev.

O, 09/28/92

RPS Electric Power Monitoring 3.3.8.2 i

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.3.8.2.2 Perfom CHANNEL CALIBRATION.

The

[18] months Allowable Values shall be:

a.

Overvoltage Bus A 5 HO 9.V Bus B 5 W V

% c,b b.

Undervoltage Bus A E 4H:01 V us B t lH64[ V

> c, D

• e c.

Underfrequency (with time delay set to [zero])

Bus A E W Hz Bus B t lEr7[ Hz l

%> c, b SR 3.3.8.2.3 Perfom a system functional test.

[18] months BWR/6 STS 3.3-82 Rev.

O, 09/28/92 l

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--4P9 Elec2ric Power Monitoring B 3.3.8.2

(-//ry oE b rah d

f B 3.3 INSTRUMENTATION B 3.3.8.2 hter Fi vicctier. Sptcia (RF37 Electric Power Monitoring VMa /

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BASES t

BACKGROUND The xP Elec ric Power Monitoring System is provided to I

isolate the RP bus from the motor generator (MG) set or an alternate power supply in the event of overvoltage, l

g.g f undervoltage, or under uency.

This system protects the loads connected to th bus against unacceptable voltage AC-and frequency conditions Ref.1) and forms an important part of the primary success path for the essential safety (C W)c, d) circuits. Some of the essential equipment powered from the go J h,q RPS buses includes the RPS logic, scram solenoids, and various valve isolation logic.

7,fjer ThehElectric Power Monitoring assembly wil detect any abnomal high or low voltage or low frequency condition in the output of the -two "C 3Et3 or t a 'lterete; power supply A)Mid M and will

-energize its respective bus, thereby causing g

th6, all safety functions nomally powere y this bus to g.j7go a de-energize.

[In-t vent of failure of an RPS Electric Power Mo "tering)

System (e..,

th inseries electric o-oring assemblies, the s

xpe ience significant Y

effects from the u trt1 e supply. Depending on the i

deviation e nominal condition ause potential (damag o the scram solenoids and other Class vices.

In the event of a low voltage condition for an extended period of time, the scram solenoids can chatter and potentially lose their pneumatic control capability, resulting in a loss of primary scram action.

i In the event of an overvoltage condition for an extended period of time, the RPS logic relays and scram solenoids, as well as the main steam isolation valve solenoids, may experience a voltage higher than their design voltage.

If the overvoltage condition persists for an extended time 1

period, it may cause equipment degradation and the loss of plant safety function.

M edundant Class 1 brea re co nd between eac b series between each RJPSw RPS bus and p h Frnate power supply.

Ea of these (continued)

BWR/6 STS B 3.3-241 Rev.

O, 09/28/92

_ ~.

RPS Electric Power Monitoring l

B 3.3.8.2

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BASES l

1 BACKGROUND circuit breakers has an associated indep,endent set of (continued)

Class 1E overvoltage, undervoltage, underfrequency i

sensing lo Together, a ci breaker and its sensing

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i logic constitute a tri power monitoring assembly.

If l

l the output of the M e

the predetemined limits of overvoltage, rvoltage, or un quency, a trip coil driven h is logic circuitry opens t circuit breaker,

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which removes the associated power supply from service.

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APPLICABLE RPS. electric power monitoring is necessary to meet the SAFETY ANALYSES sumptions of the safety an ses by ensuring that the

(

equipment powered fr th PS buses can perform its j

intended function. RPS elec ric power monitoring provides protectio o the RP and other systems that receive power I

supply un er specified conditions that c@ould damage the from the RP buses, by disconnecting the P from the pow r

)

PS l

bus powered equipment.

L ORPelectric power monitoring satisfies Criterion 3 of the i

NRC Policy Statement.

j I

The OPERABILITY of eachh electric power monitoring i

LCO assembly is dependent upon the OPERABILITY of the overvoltage, undervoltage, and underfrequency logic, as well as the OPERABILITY of the associated circuit breaker. Two electric power monitoring assemblies are required to be OPERABLE for each inservice power supply. This provides l

redundant protection against any abnormal voit or 3

frequency conditions to ensure that no single electric i

po monitoring assembly failure can preclud e function

{

i of RP bus powered components. Each inservice electric i

i power monitoring assembly's trip logic setpoints are

)

required to be within the specific Allowable Value. The l

actual setpoint is calibrated consistent with applicable i

setpoint methodology assumptions.

l Allowable Values are specified for each electric power l

monitoring assembly trip logic (refer to R 3.3.8.2.2).

e Nominal trip setpoints are specified in the setpoint 4

calculations. The nominal setooints are selected to ensure i

that the setpoints do not exceed the Allowable Value between

~

CHANNEL CALIBRATIONS. Operation with a trip setpoint less l

(continued) i BWR/6 STS B 3.3-242 Rev.

O, 09/28/92 i

i

RPS Elec%ric Power Monitoring B 3.3.8.2 BASES LCO conservative than the nominal trip setpoint, but within its (continued)

Allowable Value, is acceptable. A channel is inoperable if its actual trip setpoint is not within its required Allowable Value. Trip setpoints are those predetemined values of output at which an action should take place. The setpoints are compared to the actual process parameter (e.g., overvoltage), and when the measured output value of the process parameter exceeds the setpoint, the associated device (e.g., trip unit) changes state. The analytic limits are derived from the limiting values of the process parameters obtained from the safety analysis.

The Allowable values are derived from the analytic limits, corrected for calibration, process, and some of the instrument errors.

The trip setpoints are then determined, accounting for the remaining instrument errors (e.g., drift). The trip i

setpoints derived in this manner provide adequate protection because instrumentation uncertainties, process effects, calibration tolerances, instrument drift, and severe environment errors (for channels that must function in harsh environments as defined by 10 CFR 50.49) are accounted for.

The Allowable Values for the instrument settings are based on the RPS providing a 57 Hz, 120 V

• 10% {to all equipment), and 115 Y t 10 V (to scram and MSIV solenoids).

The most limiting voltage requirement determines the settings of the electric power monitoring instrument channels. The settings are calculated based on the ioads on the buses and P"5 "C :et er al.

tw power supply being 120 VAC and 50 Hz.

the reder feeder APPLICABILITY The operation of the RP electric power nitoring assemblies is essentia to disconnect the RPS bus powered components from the 4G-set ce alternatefpower supply during abnomal voltage or frequency conditions. Since the radation of a nonclass 1E source supplying power to the RPS us can occur as a uit of any random single failure, e OPERABILITY of the RPS electr'c power monitoring assemblies is required w en the 'PS bus powered co Rpnents are required to be OPERABLE. This results in the RPS Electric Power Monitoring System OPERABILITY being equired in HDDES 1, 2, and 3, and MODES 4 and 5 with any control rod withdrawn from a core cell containing one or more fuel assemblies or with both residual heat removal (RHR) shutdown cooling ite!at ka valves open.

a s e,,,

s'y [4 [jh4 (Continued) t/4/ves Rev.

O, 09/28/92 BWR/6 STS B 3.3-243

<r a

RPS Electric Power Monitoring B 3.3.8.2 i

BASES (continued) i ACTIONS A.1 i

If one RPS electric power monitoring assembly for an i

inservi power supply iM2 at or alternete)~ is inoperable, or one RPS electric power monitoring assembly on each inservice power supply is inoperable, e OPERABLE assembly will still provide protection to the RPS bus powered components under degraded voltage or frequency onditions.

However, the reliability and redundancy of the RP Electric Power Monitoring System are reduced and only a imited time (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) is allowed to restore the inoperable assembly (s) i to OPERABLE status.

If the inoperable assembly (s) cannot be restored to OPERABLE status, the associated power supply must be rem d from service (Required Action A.1).

This l

places the RP bus in a safe condition. An alternate power i

supply with PERAB ower monitoring assemblies may then be used to power the bus.

The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the remaining

(

OPERABLE electric power monitoring sembly and the low probability of an event requiring PS Electric Power Monitoring protection occurring during this period.

It allows time for plant operations personnel to take corrective actions or to place the plant in the required condition in an orderly manner and without challenging plant systems.

Alternatively, if it is not desired to remove the power supply (s) from service (e.g., as in the case where removing the power supply (s) from service would result in a scram or isolation), Condition C or D, as applicable, must be entered and its Required Actions taken.

E.d If both power monitoring assemblies for an inservice power supply (MC nt or alter =td are inoperable, or both power i

monitoring assemblies in each inservice power supply are inoperable, the system protective function is lost.

In this condition, I hour is allowed to restore one assembly to OPERABLE status for each inservice power supply.

If one inoperable assembly for each inservice power supply cannot be restored to OPERABLE status, the associated power supplies must be removed frr.m service within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (Required Action B.1). An alternate power supply with t

(continued)

BWR/6 STS B 3.3-244 Rev.

O, 09/28/92

RPS Electric Power Monitoring B 3.3.8.2 i

BASES ACTIONS B.1 (continued)

OPERABLEassembliesmaythenbeusedtopoweroneORe5 bus.

The I hour Completion Time is sufficient for the p Fant operations personnel to take corrective actions and is i

acceptable because it minimizes risk while allowing time for l

restoration or removal from service of the electric power monitoring assemblies.

Alternately, if it is not desired to remove the power supply (s) from service (e.g., as in the case where removing l

the power supply (s) from service would result in a scram or isolation), Condition C or D, as applicable, must be entered and its Required Actions taken.

C.1 and C.2 If any Required Action and associated Completion Time of Condition A or B are not met in MODE 1, 2, or 3, a plant shutdown must be performed. This places the plant in a condition w re minimal equipment, powered through the inoperable RP electric power monitoring assembly (s), is required an ensures that the safety function of the RPS (e.g., scram of control rods) is not required. The plant shutdown is accomplished by placing the plant in MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in MODE 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completinn Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.

sh h

hpl/#5 D.1. D.2.1. and 0.2.2 If any Required Action and associat d Completion Time of Condition A or B are not met in E 4 or 5, with any ccntrol rod withdrawn from a core ell containing one or g

more fuel assemblies or with both RHR shutdown cooling p ]deM A

u & c2 open, the operator must immediately initiate action v

to fully insert all insertable control rods in core cells containing one or more fuel assemblies (Required Action D.1).

This Required Action results in the least reactive condition for the reactor core and ensures that the safety function of the RPS (e.g., scre of control rods) is not required.

(continued)

BWR/6 STS B 3.3-245 Rev.

O, 09/28/92

~

RPS Electric Power Monitoring B 3.3.8.2 1

BASES ACTIONS D.1. D.2.1. and D.2.2 (continued)

In addition, action must be imediately initiated to either restore one electric power monitoring assembly to OPERABLE status for the inservice power source supplying the required instrumentation powered from the RPS bus (Required Action D.2.1) or to isolate the RHR Shutdown Cooling System (Required Action D.2.2).

Required

'on D.2.1 is provided because the RHR Shutdown Cooling ystem ay be needed to provide core cooling. All action us continue until the applicable Required Actions are completed.

SURVEILLANCE SR 3.3.8.2.1 REQUIREMENTS A CHANNEL FUNCTIONAL TEST is perfomed on each overvoltage, undervoltage, and underfrequency channel to ensure that the entire channel will perfom the intended function.

As noted in the Surveillance, the CHANNEL FUNCTIONAL TEST is only required to be perfomed whil plant is in a condition in which the loss of the bus will not jeopardize steady state power opera ion (the design of the system is such that the power source must be removed from i

service to conduct the Surveillance). The 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is intended to indicate an outage of sufficient duration to allow for scheduling and proper perfomence of the Surveillance. The 184 day Frequency and the Note in the Surveillance are based on guidance provided in Generic Letter 91-09 (Ref. 2).

SR 3.3.8.2.2 CHANNEL CALIBRATION is a complete check of the instrument loop and the sensor.

The Frequency is based upon the assumption of an 18 month calibration interval in the detemination of the magnitude of equipment drift in the setpoint analysis.

l (continued)

BWR/6 STS B 3.3-246 Rev.

O, 09/28/92 i

RPS Electric Power Monitoring B 3.3.8.2 i

i BASES SURVEILLANCE SR 3.3.8.2.3 REQUIREKNTS (con'.inued)

Perfomance of a system functional test demonstrates a required system actuation (simulated or actual) signal.

The logic of the system will automatically trip open the associated power monitoring assembly circuit breaker.

Only one signal per power monitoring assembly is required to be tested. This Surveillance overlaps with the CHANNEL CALIBRATION to provide complete testing of the safety function. The system functional test of the Class 1E circuit breakers is included as part of this test to provide complete testing of the safety function.

If the breakers are incapable of operating, the associated electric power monitoring assembly would be inoperable.

The 18 month Frequency is based on the need to perfom this Surveillance under the conditions that apply during a plant outage and the potential for an unplanned transient if the Surveillance were perfomed with the reactor at power.

Operating experience has shown that these components usually pass the Surveillance when perfomed at the 18 month Frequency.

ASJA 55AA REFERENCES 1.

4SAR, Section 8.3.1.1.SK o

2.

NRC Generic Letter 91-09, " Modification of Surveillance Interval for the Electric Protective Assemblies in Power Supplies for the Reactor Protection System."

I BWR/6 STS B 3.3-247 Rev.

O, 09/28/92

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