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Emergency Procedure 21 for Loss of Pressurizer Level Indication
	ML19221A512
Person / Time
Site:	Crane
Issue date:	04/26/1979
From:	; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:	;
References
	OSP-790426, NUDOCS 7905230112
	Download: ML19221A512 (12)
	v • d • e

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EP-21 4/26/79

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LOSS OF PRESSURIZER LEVEL IfiDICATIO!1

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PURPOSE The intent of this procedure is to track pressurizer level af ter a loss of normal level indication utilizing an emperically derived relationship between Make Up Tank level, pressurizer level, and RCS leakage.

Periodic checks and updates will be made every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months utilizing the test equipment installed on the pressurizer water space sample line and pressurizer temperature (RTD)

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voltage output to determine actual level.

1.0 As si.mo t i ons 1.1 Pressurizer level is being maintained at 250 + 25 inches.

1.2 RCS pressure is being maintained between 900 and 1000 psig.

1.3 Summary C group trend including the following data points is being printed at 15 minute intervals.

COMPUTER PT.

38 7 Prz temp.

(Ensure control board selector switch is co2 Prz level sel ected to TT-2) 3S8 Press Loop A 399 Press Loop A 394 RCS Temp A 400 Press Loop B 347 MU Tank Level 1.4 The pressurizer temperature transmitter selector switch on the control panel must be CAUTIOil tagged to require Shift-Supervisor permission to operate.

Af te..

.ny readings taken on TT-1 the switch must be selected to TT-2.

This will allow TT-2 to read out on the pen recorder and provide TT-1 as the point monitored by the computer.

1.5 Pressurizer heater interlocks disabled to prevent level failure from causing loss of heaters.

0 1.6 Temperature of RCS is between 160.and 280 F.

1.7 RC-V2, RC-2 and RC-Vl37 shut.

1.8 Primary leak rate is 2.6 gpm.

1.9 MUV 8 is aligned to the make-up tank.

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EP-21 4/26/79

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m Failed pressurizer level indication.

Ievel instrument should fail to midscale, but may fail high or low.

2.2 Pressurizer level _ annunciator sounds.

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2. 3 Pressurizer level' steady with changing plant parameters. ~

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3.0 liNEDI ATE ACTION (First 5 Min.)

3.1.

Do not secure spray if already initiated.

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3.2.

Do not alter pressurizer heater alignment.

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-4 3.3.

Shut or check shut MUV 17 and 18.

(With a loss of indication it will be necessary to go to sFut on MUV 18 regardless of assumed C. v-y position.

3.4.

Check shut pressurizer vent valve RC V137' and relief valve block valve RC V2 3.5.

Check MU V-8 aligned to the make-up tank and not to the bleed tank.

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3.6.

Record the last valid pressurizer level from the pen recorder prior to -

malfunction of the instrument.

3.7.

Check to ensure sucmary Group B is trending at 1 min. intervals with the data points as'noted in 1.3 above.

3.8.

Record the data listed in data sheet 1 4.0 LONG-TERM ACTIONS ( Af ter 5 Min.)

4.1.

Maintain RCS pressure 900-1000 psig.

00 tiOT EXCEED 1000 psig.

42.

DO NOT VENT THE PRESSURIZER.

4.3.

Maintain constant reactor coolant temperature during first 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months following loss of all pressurizer level indication. Subsequent shrink due 'to cooldown must compensated for by periodic additions per section 5.4.

4.4.

Maintain,, essurizer level 225-275 inches utilizing the following method.

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CAUTION: fionitor pressurizer temperature and pressurizer heater current for evidence of uncovered pressurizer heaters.

A super-heated condition occurs rapidly if the heaters are uncovered.

If 0

either pressurizer temperature increases by 10 F or more in one minute, o' r if a marked Jecrease in pressurizer heater current occurs, secure all heaters and pump borated water to the RCS in accordance with Section 4.8.1.

4.4.1 Compensate for calculated pressurizer level change every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months ,,.

.1 with the following additions to the RCS.

fiOTE: The following additions should be made in batches, i.e.,

open MUV17 and 18, add water to RCS then immediately close MUV 17 & 18.

ADDITION A Add to the RCS from the make-up tank the amount that the make-up tank level increased during the previous two hour period as indicated by the pen recorder trace.

ADDITION B Immediately following Addition A, add another 12 inches from the makeup tank to the RCS to account for the assumed RCS leak rate of 2.6 gpm.

Refill the makeup tank 12 inches by an addition from an external water source (RC bleed tank, Demin. water, BA batching tank, etc).

Reoeat Additions A and B every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months .

The makeup. tank level trace should approximate the following:

A n.,.. A g

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Rev.u a renv-e oP N 1

nm am a w m cc dE 1

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-p 4.4.2 If RCS temperature increasesor decreases by 100F campensate for system vo'ume changes as follows:

U For every 10 rise in RCS temprature, allow the make-up tank level to increase 16 inches from normal letdown, i.e., during the period that the M/_U. tank level rises or for every 100F decrease in RCS temperature, lower the makeup tank level by 16 inches, by pumping from the makeup tank-to the RCS.

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These cha. ges will be made in addition to Additions A & B.

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EP-21 4/26/79 W

4 '. 5 Maintain a record of additions (other than letdoven) to the make-up tank by completing data sheet 2 whenever an addition is made.

D0 GOT use totalizer.

Use the change in level as indicated on the pen recorder on the console.

4.6 Establish a plot of pressurizer level vs. time utilizing the following method:

Update plot immediately following the additions made per section 4.4 every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months .

4.6.1 Transfer the data collected initially following loss of LT-3 to data sheet 3 in the blanks provided under "TOF" (Time of failure).

4.6.2 Collect data for time "t)" when last addition A+B were made.

4.6.3 Subtract values at TOF from values at tj to generate the values identified in equation 1 on data sheet 3.

Maintain consistent sign convention throughout i.e. 5-6=-1.

4.6.4 Insert the values determined in 3 above into equation 1 and calculate pressurizer level at the time the addition A&B were nade.

4.6.5 Plot this value on graph attached to this procedure.

4.7 Every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months determine actual pressurizer level utilizing the test

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equipment installed on the pressurizer water space sample line and y

t pressurizer temperature RTD as follows:

4.7.1 Immediately following the periodic addition secure spray flow and allow condi.tions to stabilize for approximately 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

4.7.2 Stabilize pressure between 900-1000 psig uti.lizing SCR controlled pressurizer heate,rs.

4.7.3 If a primary sample has been taken since the last level measurement verify that the line-up has been returned to normal by lining up per Z-107 to read both the beise gage and pressure transmitter.

If no sample has been taken, open or check open CAV3, CAV10, SN VT1, 2, 4, & 5.

4.7.4.. Start 1 min. trend interval on Summary B.

4.7.5 Establish communications between the control roem and the cable spreading room.

4.7.6 Read and record the DVM readout (in trie control room) and the Heise Gage (on the pressurizer water space for pressurizer water space pressure oJ"6ata sheet 4.

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'.- EP-21 4/26/79 a.

4.7.7 Read and record the DVM readout (in cable spreading room) for pressurizer water space temperature on cata sheet 4.

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4.7.8 Re-perform step 4.7.5, 4.7.6, 4.7.7.

4.7.9 Complete data sheet 4 by performing the conversions listed on the bottom of the sheet.

4.7.10 Subtract P from Pdvm nd P (Heise)'to obtain 6 P.

.y sat 4.7.11 Determine actual level from the attached ;urve.

Record this value on data sheet 4.

4.7.12 Plot value on pressurizer level plot.

Plots over extendec period are shown typically as below:

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r 4.7.13 If measured pressurizer level is less than 140 inches or greater than 350 inches notify the shift supervisor and perform

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the following:

4.7.13.1 If level is 4.140 inches make a batch addition to the pressurizer from the mekeup tank with an amount calculated as follows:

/L MU Tank Level = 225 - measured level 1.227 f

4.7.13.2 If level is >> 350 inches reduce the amount pumped back into the RCS at the next 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months addition, by the following amount.

LL MU Tank Level = measured level - 275 1.227 4.7.13.3 These adjustments to level should not be added to equation 1 or data sheet 2.

4.7.14 If measured level is less than 225" but greater than 140" or If measured level is greater than 275" but less than 350" 6

.} } j Repeat the level measurement per steps 4. 7.1 - 4.7.12, prior o the next periodic 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months addition.

If the level is confirmed, make an adjustment per 4.7.13.

This addition should not be added to equation 1 or data sheet 2.

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4.8 Loss of Pressurizer level control (indication of high or icw level in the pressurizer) 4.8.1 Low pressurizer level:

Indicated by increasing pressurizer temp-erature and/or marked decrease in pressurizer heater amps.

a.

Secure all pressurizer heaters.

b.

'Open MU-V18 and close MU-V5.

c.

Place MU-V17 in manual control and pump 30 inches of make-up tank level to the RCS.

d.

Energize the Bank l heaters and observe pressurizer tempera-ture.

e.

If pressurizer temperature stabilizes, establish normal pressurizer level using MU-V5 and MU-V17.

f.

If pressurizer temperature continues to increase above Tsat, secure the bank 1 heaters and perform steps b thru d again.

g.

Restore pressurizer level to mid-scale ( 225-275 inchesl by making several (5-6) additions (?:30 inches ot' make-up tank level) from the make-up tank to the RC5.

4.8.2 High pressurizer level:

Indicated by increasing RCS pressure Q,

(greater than Psat).

This indication only occurs if for existing PZR temperatures the pressurizer i.1. near solid.

a.

Take manual contro] of MU, V17 (if being used) and maintain the existing make-up flow rate.

Use MU-V5 for pressure control.

b.

Shut /checkshutRC-VT,RC-V2andRC-V137.

c.

Secure all pressurizer heaters, record the RCS pressure and mark the pressure recorder chart.

d.

Slowly increase the make-up flow rate to raise pressure to

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50 psi above the value recorded in step c.

Maintain the RCS pressure at this value to completely collapse the bubble and take the pressurizer to a solic water condition.

Pressure shculd a.lways be kept above 500 psi.

tiOTE:

The indication that the pressurizer is solid is a sudde.,

increase in RCS pressure when making up at a constant rate.

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CAUTIO3:

When operating in a solid condition, RCS temperature ch,inges and/or net addition or removal of RCS water cause large changes in RCS pressure.

A net addition or removal of 10 gallons resul ts in a pressure change of approximately 50 psig.

A RCS temperature change of 10F results in a pressure changa of approxi-mately 130 psig._._.

Maintain pressure by varying make-up and/or. letdown flow c.

ra te using MU-V5 and MU-V17.

f.

If RCS pressure continues to increase with MU-V17 and MU-V18 shut and MU-V5 closed, jog open RC-V137 to decrease pressure bec-to the original control points (pressure in section 2 +

50 psi). When pressure returns to the value being maintained previcusly, shut RC-V137 and revert to varying make-up/ letdown flow rate for pressure control..If contir.uous venting through RC-V137 is necessary, minimize the flow rate through the vent valve by keeping the make-up addition rate as low as possible.

Adjust make-up tank level as requiret;.

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DATA SHEET 1 Values at A s-Time of Failure (TOF) o._

lonsole Pen Recorder

.<CS Pressure Console Pen Recorder PRZ Temperature Console Pen Recorder

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Th Console Pen Recorder Tc Console Pen Recorder MU Tank Level Console MU Tank Temperature l

Console MU Tank Press OSTG Operating Range A Level

'STG Operating Range

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Level OSTG A Temperature OSTG B Temperature I

Upper Cavity Press RCP1A RCPlB

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RCP2A iiCP2B Seal Leakage prD 1A PPD 7A PPD 1R RCP 2S Seal Injection.

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} }/4 RCP 1A RCP 2A RCP 18

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ty-tt 4/40/l'd RECORD OF ADDITIONS

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DATA SHEER 2 4

IfilTIAL f4EW THANGE Ifi CUtiUL A fl VE

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f%KE-UP MAKE-UP MAKE-UP TOTAL ADDITION TIME /

TAtlK LEVEL TANK LEVEL TAf!K LE'/EL TO MU TK Sif1CE DATE (If!CHES)

(IllCHES)

(I!!CHES)

TOF -(INCHES)

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Data Sheet 3 PRZ LEVEL CALCULATIOT bserve all sign conventions, i.e., S-6=-1

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Time Date t)

TOF O

Temp Pzr F

=

AT PRZ (OF)

,_. values at __

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.a Make-Up TK Level

=

A L MUT (inches)

(utilize pen recorder) values at

( inch.2s )

T0F T-( F)

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6Tc ( f) values at TOF A = Total additions to MU TK since TOF (obtain from dats sheet 2) inches L (PZR TOF) =

inches take from value recorded on data sheet 1.

Equation 1 L Ezr L pzr + 2.07 (o Tc,! - 1.227 (o LMUT - A)

=

TOF 1

+.287 (A T pZR)

L PZR

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IPZR o Tc A LMUT A

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Record and Plot AT PZR 0

Assumptions:

T between 160 and 280 F c

RCS pressure between 800 and 1000 psig.

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