ML18038B575

Simulator Four Yr Test Rept.

ML18038B575
Person / Time
Site:	Browns Ferry
Issue date:	12/13/1995
From:	TENNESSEE VALLEY AUTHORITY
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ML18038B574	List: ML18038B573 ML18038B575
References
NUDOCS 9512180209
Download: ML18038B575 (25)

Text

ENCLOSURE TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)

UNITS Iq 2 q AND 3 SIMULATOR FOUR YEAR TEST REPORT TAB E OF CON ENTS I. Introduction II. General Discussion III. Description of Performance Tests Completed A. Steady State Test B. Drift Test C. Transient Test D. Procedures Test E. Malfunction Test F. Real Time Test G. Simulator Fidelity IV. Uncorrected Test Performance Deficiencies and Correction Schedule A. Steady State Test B. Transient Test C. Procedures Test D. Malfunction Test E. Spare Time Test V. Description of Test Differences VI. Simulator Test Schedule TABLES Table 1 Steady State Test Critical Parameters Table 2 Steady State Non-Critical Parameters Table 3 Simulator Transient Test Description Table 4 - Transient Parameters Table 5 Normal and Abnormal Operating Plant Instructions Test Description and Schedule Table 6 Malfunction List and Certification Test Schedule Table 7 Simulator Certification Testing Schedule Table 8 Simulator Exceptions Table 9 - Simulator Limitations

~ l Z~ INTRODUCTION This test report is required by 10 CFR 55.45(b)(5)(ii), to be submitted to NRC every four years on the anniversary of the initial certification report. The four year NRC Form-474 date for certification is December 13, 1995.

Initial Simulator test schedules were given in the certification letter submitted in December 1991 to NRC.

Tests were completed as required by American National Standards Institute (ANSI) 3.5-1985 and were performed each year as outlined in the initial proposed schedule.

This report outlines the methods and the unresolved deficiencies for each test.

ZZ GENERAL DISCUSSION Since the initial certification, the BFN simulator has been used continually for various training at BFN. The simulator has been maintained in accordance with ANSI-3.5, and additional self-imposed requirements. Modifications and tuning adjustments are routinely made as plant data is made available, thus, simulation models are maintained as close to the referenced plant as practical.

ZIZZ DESCRIPTZON OF PERFORMANCE TESTS COMPLETED The following is a summary of the tests completed on the BFN simulator over the past four years. Test results are maintained in the BFN Simulator Services Section. They are maintained per the requirements of 10 CFR 55.45(b)(5)(iii). Any parameter failing these tests had a Simulator Discrepancy Report (SDR) written to correct the simulation calculation of the failed parameter.

Any uncorrected test deficiencies are listed in the Uncorrected Test Performance Deficiencies and Correction Schedule,Section IV of this report.

A. Steady State Test Each year the steady state tests were performed on the simulator at three power levels. Plant critical and non-critical parameters (Tables 1 and 2) were compared to the simulator values at each power level. The differences were calculated automatically for both critical and non-critical parameters. Acceptable differences were calculated based on + 2 percent of span for critical and + 10 percent of span for non-critical parameters for each individual instrument.

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B. Drift Test The drift test was performed each yearto for the past four years. The simulator was reset a 100 percent power initial condition and data was collected for an hour for each of the critical parameters at a rate of one sample per second. Plots were made with this data and checked for stability. A parameter would fail the test if it drifted beyond + 2 percent of the value any time during the hour test.

initial C. Transient Test The required ANSI-3.5 transient tests, listed in Table 3, were performed each year for four years. Test results were compared to the initial certification transients. Data was collected for each of the required parameters listed in Table 4 at a rate of four samples per second. These results were then plotted and compared with the previous year responses.

Problems identified were documented by the initiation of a SDR. Simulation model changes, as a result of corrected simulator problems and plant modifications implemented on the simulator, were taken into account for each transient performed to ensure proper plant behavior.

D. Procedures Test Approximately 25 percent of the procedure tests were performed each year for four years (Table 5). The 25 percent represents the approximate amount of actual work time to perform the test. The following is a summary of the tests performed:

Year 1-General Operating Instructions (GOIs)

Year 2-Surveillance Instructions (SIs)

Year 3-Emergency Operating Instructions (EOIs)

Year 4-Abnormal Operating Instructions (AOIs)

The tests used the latest revision of the BFN Unit 2 plant controlled procedures. Problems encountered during the procedures tests were documented on a SDR.

E. Malfunction Test Approximately 25 percent of the certified malfunctions were tested each year for four years. Prior to each test, the Malfunction Cause and Effects document was reviewed by test personnel to identify anticipated simulator responses and to consider appropriate operator actions. The simulator was then initialized E-3

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to an appropriate Initial Condition and the malfunction was inserted. Test personnel observed the simulator responses and took appropriate actions. See Table 6 for BFN simulator's certified malfunctions.

F. Real Time Test The simulator executive used a frame-based scheduling algorithm in which each second of real time was equally divided into a number of smaller units of time called frames. The simulator executive collects frame timing and copies this data to a global region. A non-simulator task collects the global data to a file which is processed later by an offline program which produces plots and tables indicating real time usage.

G. Simulator Fidelity When modifications were initiated in the plant, the design changes were reviewed by the simulator staff for simulator impact and into the simulator.

if applicable, were incorporated In addition, plant and simulator control room photographs were made of all simulated panels after major control room modifications and were compared. Differences were reconciled based on training impact. The photographs helped to capture any additional changes made to the plant that were not detected through the normal design change review process.

Major differences in hardware and software fidelity that remain and are not planned to be corrected, are tracked as Exception Reports. The initial certification identified 14 Exceptions. During the past four years, one exception was closed. See Table 8 for the current list of Simulator Exceptions.

The BFN Simulator imposes six limits of simulation.

Since the exact response of the plant would be unknown beyond these limits, the simulation is stopped automatically or "frozen." This protects the students from negative training. The limits of simulation are listed in Table 9.

IV+ UNCORRECTED TEST PERFORMANCE DEFICIENCIES AND CORRECTION 8CHEDULE The following is a summary of the uncorrected performance test deficiencies encountered during simulator certification testing over the last four years.

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Steady State Test Deficiencies:

DR-2751 Simulator recirculation pump flows were outside the acceptance criteria. The planned correction date for DR-275 is December 13, 1996.

DR-2953 Simulator feedwater temperatures were outside the acceptance criteria. The planned correction date for DR-2953 is December 13, 1996.

Transient Testing Deficiencies:

DR-2951 Slight change in reactor power response between 1994/1995 dual recirculation pump trip. The planned correction date for DR-2952 is December 13, 1996.

DR-2952 Slight change in reactor pressure and feedwater flow response between 1994/1995 for main steam line break. The planned correction date for DR-2952 is December 13, 1996.

Procedures test Deficiencies:

There are no uncorrected performance deficiencies for procedure tests.

Malfunction Test Deficiencies There are no uncorrected performance deficiencies for malfunction tests.

Spare Time Deficiencies DR-2754 During Loss of Offsite power with 100 percent LOCA the simulator will run non-real time momentarily.

The planned correction date for DR-2754 is December 13, 1996.

DESCRIPTION OP TEST DIPPERENCES For the next four years all tests will be performed in the same manner as the previous test period. There will be minor changes made to the parameters collected for the Steady State and the Transient tests which are summarized below.

The Steady State parameter list was changed to show actual Integrated Computer System (ICS) parameters collected. ICS parameters are used in order to enable a direct comparison between plant and simulator data.

The Transient parameter list was changed from three separate lists to one common list of parameters. This simplified the transient data collection process and E-5

C and validation of the transient plots.

Table 4.

A listevaluation enhanced the of the Transient parameters is shown in VI~ SIMULATOR TEST SCHEDULE The next four year test schedule is shown in Table 7.

Annual Test Periods 1 through 4 are for years 1996 through 1999 which comprise the next four year simulator certification cycle. Table 5 lists the procedures to be tested for each year. Table 6 lists the malfunctions to be tested for each year. The Steady State, Drift, Transient, and Real Time tests will be performed each year.

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Table 1 STEADY STATE TEST CRITICAL PARAMETERS PARAMETER LOW HIGH UNITS DESCRIPTION CALC002 REACTOR POWER NSSS CALCULATED 3-59 850 1050 PSIG RX PRESSURE-NARROWRANGE CALC025 1300 MWE REACTOR POWER ELECTRICAL 3-54 1500 PSIG RX PRESSURE-WIDE RANGE 68-49 120 MLB/HR TOTAL CORE FLOW APRMA 125  % POWER APRM CHANNEL A APRMB 125  % POWER APRM CHANNEL B APRMC 125  % POWER APRM CHANNEL C APRMD 125  % POWER APRM CHANNEL D APRME 125  % POWER APRM CHANNEL E APRMF 125  % POWER APRM CHANNEL F 3-48A 430 DEGF RFW LINE A TEMP 3-50A 100 430 DEGF RFW LINE B TEMP CALC041 MLB/HR MN STM LEAVING REACTOR 68-5A 70 KGPM RECIRC PUMP A FLOW 68-81B 70 KGPM RECIRC PUMP B FLOW CALC040 16 MLB/HR RFW FLOW TO REACTOR 1-81 -15 755 PSIG FIRST STAGE PRESSURE GOV END 2-1 INHGA CNDR A HOTWELL PRESSURE (ABS) 2-5 INHGA CNDR B HOTWELL PRESSURE (ABS) 2-8 INHGA CNDR C HOTWELL PRESSURE (ABS)68-15A MLB/HR RECIRC JET PUMP //1 FLOW 68-25 A MLB/HR RECIRC JET PUMP S6 FLOW 68-38A MLB/HR RECIRC JET PUMP 011 FLOW 68-7A MLB/HR RECIRC JET PUMP //1 6 FLOW 68-45 80 MLB/HR RECIRC JET PUMP LOOP FLOW A 68-47 80 MLB/HR RECIRC JET PUMP LOOP FLOW B 3-53/60 60 INCHES RX LEVEL-NORMALCONTROL RANGE 85-11C 100 GPM CONTROL ROD DRIVE FLOW 85-7-1 600 DEGF CONTROL ROD 02-43 DRIVE TEMP E-7

j Table 2 STEADY STATE NON-CRITICAL PARAMETERS PARAMETER LOW HIGH UNITS DESCRIPTION 2-29A 15 MLB/HR CNDS PMP DISCH HDR FLOW 2-17 150 PSIG CNDS PMP DISCH HDR PRESS 2-48 150 PSIG CNDS BSTR PMP SUCT HDR PRESS 2-70 500 PSIG CNDS BSTR PMP DISCH HDR PRESS 2-105 PSIG RFP SUCTION HEADER PRESSURE 3-20 MLB/HR RFP A FLOW 3-13 MLB/HR RFP 8 FLOW 3-8 ML8/HR RFP C FLOW 3-16 1500 PSIG RFP A DISCH PRESS 3-9 1500 PSIG RFP 8 DISCH PRESS 3-2 1500 PSIG RFP C DISCH PRESS 3-115A 8000 RPM RFPT A SPEED 3-141 A 8000 RPM RFPT 8 SPEED 3-166A RPM RFPT C SPEED 5-6 250 PSIG HTR A1 SHELL STEAM PRESSURE 5-'IO 250 PSIG HTR 81 SHELL STEAM PRESSURE 5-'I 4 250 PSIG HTR C1 SHELL STEAM PRESSURE 5-18 150 PSIG HTR A2 SHELL STEAM PRESSURE 5-22 150 PSIG HTR 82 SHELL STEAM PRESSURE 5-26 150 PSIG HTR C2 SHELL STEAM PRESSURE 5-40 PSIG HTR A3 SHELL STEAM PRESSURE 5-53 100 PSIG HTR 83 SHELL STEAM PRESSURE 5-68 100 PSIG HTR C3 SHELL STEAM PRESSURE 5-33 -16 PSIG HTR A4 SHELL STEAM PRESSURE 5-48 -16 PSIG HTR 84 SHELL STEAM PRESSURE 5-59 -15 PSIG HTR C4 SHELL STEAM PRESSURE 5-29 -15 50 PSIG HTS A5 SHELL STEAM PRESSURE 5-42 -15 50 PSIG HTR 85 SHELL STEAM PRESSURE 5-55 -15 60 PSIG HTR C5 SHELL STEAM PRESSURE 3-45 1600 PSIG RFW PRESSURE TO REACTOR 2-3 80 INCHES CNDR A HOTWELL LEVEL 2-2 150 DEGF CNDR A HOTWELL TEMP 69-358 GPM RWCU DEMIN 2A FLOW 69-608 GPM RWCU DEMIN 28 FLOW 89-BA 600 DEGF RWCU LOOP INLET TEMP 69-6D 800 DEGF RWCU LOOP OUTLET TEMP E-8

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Table 3 SIMULATOR TRANSIENT TEST DESCRIPTION Test Number Test Description Initiating Events'est Duration Manual Scram. Depressing both manual scram 10 minutes pushbuttons Simultaneous trip of all feedwater pumps. Malfunctions FW13A-C "S purious RFPT 20 minutes Excessive Thrust Bearing Wear Trip" Simultaneous closure of all Main Steam Malfunction RP11 "Inadvertent MSIV 10 minutes Isolation Valves. Isolation" Simultaneous trip of all recirculation Malfunctions TH03AKB "Recirc Pump 10 minutes pumps. Tnp" Single recirculation pump trip. Malfunction TH03A Reciro Pump Trip" 10 minutes Main turbine trip (maximum power, level Malfunction TC01 "Turbine Trip" 10 minutes which does not result In immediate reactor scram).

Maximum rate power ramp (master Manually rampad master recirc controller 10 minutes recirculation flow oontroller In "manual" ) PIC-98-1 to 75% power demand and let down to approximately 75% and back up set approximately 2 minutes end then to 100%. ramped back to the 100% power demand.

Maximum size reactor coolant system Malfunctions TH21 "Recirc Pump Suction, 10 minutes rupture combined with loss of ell offsite Une Break" et 100% severity and ED01 power. "Loss of all Offsite Power" Maximum size unisolable main steam line Malfunction TH33A "Main Steam Une 10 minutes rupture. Break Inside Containment" 10 Simultaneous closure of all Main Steam Malfunctions RP11 "Inadvertent MSIV 10 minutes Isolation Valves combined with single Isolation" and AD01A Relief Value stuck open safety/relief valve. (Inhibit Failure (PCV-1-5)" with RCIC and HPCI activation of high pressure Emergency disabled.

Core Cooling Systems).

NOTE: 'Initiating events may be changed at the discretion of the test team to accomplish test objective.

Table 4 Transient Parameters PARAMETER LOW HIGH UNITS DESCRIPTION APRM A-METER 125  % POWER APRM CHANNEL A APRM B-METER 125  % POWER APRM CHANNEL B APRM C-METER 125  % POWER APRM CHANNEL C APRM D-METER 125  % POWER APRM CHANNEL D APRM E-METER 125  % POWER APRM CHANNEL E APRM F-METER 125  % POWER APRM CHANNEL F EI-57-50 -e98 1300 MEGAWATTS ELECTRIC FI-68-46 MLB/HR NO 11 THRU NO 20 JET PMP FLOW FI-68-48 MLB/HR NO 1 THRU NO 10 JET PMP FLOW Fl-74-50 25000 GPM RHR SYSTEM I TOTAL FLOW Fl-74-64 25000 GPM RHR SYSTEM II TOTAL FLOW Fl-75-21 10000 GPM CS SYS I FLOW TO REACTOR FI-75-49 GPM CS SYS II FLOW TO REACTOR FIC-71-36A 700 GPM RCIC SYSTEM FLOW FIC-73-33 6000 GPM HPCI SYSTEM FLOW FR-46-5 (FT-3-78) 16 MLB/HR TOTAL STEAM FLOW FR-46-5 (PT-1-78) 16 MLB/HR TURBINE STEAM FLOW FR-68-5 (FT-68-5A) 70000 GPM RECIRC PUMP A DISCH FLOW FR-68-5 (FT-68-81 B) 70000 GPM RECIRC PUMP B DISCH FLOW LI-3-52 -268 32 INCHES RX WATER LEVEL POST ACCIDENT RANGE LI-3-53 eo INCHES NARROW RANGE REACTOR LEVEL LI-3-58A -155 eo INCHES WIDE RANGE REACTOR LEVEL PR-3-53 (PT-3-59) 1500 PSIG NARROW RANGE REACTOR PRESSURE PR-3-53 (PT-3-53) 850 '050 PSIG WIDE RANGE REACTOR PRESSURE Tl-64-1 61 30 230 DEGF SUPPRESSION POOL BULK TEMPERATURE XR-3-53 (FT-3-78) 16 MLB/HR TOTAL FEEDWATER FLOW XR-64-50B -15 e5 PSIG DRYWELL PRESSURE XR-64-52 (TE-64-52) 400 DEGF SUPPRESSION POOL TEMPERATURE XR-64-50 (TE-64-50) 400 DEGF DRYWELLTEMPERATURE FR-68-50 (FT-3-78) 12 ML8/HR CORE FLOW E-10

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Table 5 - NORMAL AND ABNORMAL OPERATING PLANT INSTRUCTIONS TEST DESCRIPTION AND SCHEDULE Test Annual Test Test Description Test Date Number Period Planned Start 1st yr. Plant start up from cold shutdown to 100% power and plant 11/199B shutdown from 100% power, using the BFNP Unit 2 General Operating Instructions (GOls).

2nd yr. Perform the BFNP Unit 2 Surveillance Instructions (Sls). 11/1 997 3rd yr. Perform the BFNP Unit 2 Emergency Operating Instruct(ons (EO!s) 11/1998 including appendicies.

4th yr. Perform the BFNP Unit 2 Abnormal Operating Instructions (AOls). 10/1999

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Table 6 MALFUNCTION LIST AND CERTIFICATION TEST SCHEDULE Malfunction Doser(Ption Annual ANS 3.5 Test Item Malf Section 3.1.2 Test Data Period Number Malfunction Definition Name Reference Planned Start MAIN STEAM LINE BREAK INSIDE CONTAINMENT TH33 3.1.2(1b,20) 9/1996 RWCU SYSTEM SUCTION LINE BREAK CU04 3.1.2(lb) 9/1996 RECIRC PUMP SUCTION LINE BREAK TH21 3.1.2(1c) 9/1996 COOLANT LEAK INSIDE DRYWELL TH22 3.1.2(1c) 9/1996 RELIEF VALVEFAILURES AD01 3.1.2(1d) 9/1996 LOSS OF CONTROL AIR IA01 3.1.2(2) 9/1996 DG TRIP DG02 3.1.2(3) 9/1996 LOSS OF OFFSITE POWER ED01 3.1.2(3) 9/1996 9 LOSS OF 4KV SHUTDOWN BOARD ED09 3.1.2(3) 9/1996 10 LOSS OF 250V BATTERY BOARD 2 ED17 3.1.2(3) 9/1996 11 LOSS OF UNIT PREFERRED ED19 3.1.2(3) 9/1996 12 RECIRC PUMP TRIP TH03 3.1.2(4) 9/1997 13 LOSS OF CONDENSER VACUUM OG02 3.1.2(5) 9/1997 14 CONDENSER HOTWELL LEVEL AUTOMATICMAKEUP FAILURE FW20 3.1.2(5) 9/1997 15 RCW PUMP TRIP SW04 3.1.2(6) 9/1997 16 PARTIALLOSS OF PLANT PREFERRED SYSTEM SW06 3.1.2(6) 9/1997 17 FAIL THE FOLLOWING PRESS INSTRUMENTS TH31 3.1.2(7) 9/1997 18 LOSS OF RBCCW FLOW TO THE DRYWELL SW01 3.1.2(8) 9/1997 19 CONDENSATE PUMP TRIP FW01 3.1.2(9) 9/1997 20 SPURIOUS RFPT LOW SUCTION PRESS TRIP FW22 3.1.2(10) 9/1997 21 RCIC LOW SUCTION PRESS TURBINE TRIP RC03 3.1.2(10) 9/1997 22 RPS CHANNEL MG SET FAILURE RP01 3.1.2(11) 9/1998 23 DRIFT ANY CONTROL ROD OUT RD04 3.1.2(1 2) 9/1998 24 UNCOUPLE ANY CONTROL ROD RD05 3.1.2(1 2) 9/1998 25 STICK ANY CONTROL ROD RD06 3.1.2(12,13) 9/1998 26 DRIFT ANY CONTROL ROD IN RD07 3.1.2(1 2) 9/1998 27 RMCS TIMER FAILURE RD13 3.1.2(13) 9/1998 28 FUEL CLADDING DAMAGE TH23 3.1.2(14) 9/1998 29 TURBINE TRIP TC01 3.1.2(1 5) 9/1998 30 GENERATOR LOCKOUT DUE TO TRANSFORMER FAULTS EG01 3.1.2(16) 9/1998 31 RECIRC SYSTEM SPEED DEMAND FAILURE TH15 3.1.2(17) 9/1 998

.32 APRM FAILURE NM09 3.1.2(19,21) 9/1999 33 FEEDWATER UNE BREAK IN STEAM TUNNEL FW19 3.1.2(20) 9/1999 34 IRM FAILURE NM05 3.1.2(21) 9/1999 35 MASTER FEEDWATER LEVEL CONTROLLER AUTO FAILURE FW03 3.1.2(22) 9/1999 36 PRESSURE REGULATOR FAILS OPEN (DEPRESSURIZATION) TC06 3.1.2(22,25) 9/1999 37 CORE SPRAY LOGIC POWER FAILURE CS04 3.1.2(23) 9/1 999 38 RCIC LOGIC POWER LOSS RC07 3.1.2(23) 9/1 999 39 AUTO SCRAM CHANNELS FAIL (MANUALSTILL FUNCTIONAL) RP06 ,3.'1.2(24) 9/1999 TURBINE BYPASS VALVES CONTROL UNIT FAILURE TC02 3.1.2(25) 9/1 999

Table 7 SIMULATOR CERTIFICATION TESTING SCHEDULE Four-Year Test Schedule Dece ber 6 December 13 1999 Annual Test Test Description Test Date Period Planned Start A) Simulator Steady State Test. 08/01/98 B) Simulator Normal and Abnormal Operating Plant (GOls) 07/01/98 C) Simulator Transient Performance Tests. 10/01/98 D) Simulator Malfunction Tests. 09/01/98 A) Simulator Steady State Test. 08/01/97 B) Simulator Normal and Abnormal Operating Plant (Sls) 07/01/97 C) Simulator Transient Performance Tests. 10/01/97 D) Simulator Malfunction Tests. 09/01/97 A) Simulator Steady State Test. 08/01/98 B) Simulator Normal and Abnormal Operating Plant (EOls) 07/01/98 C) Simulator Transient Performance Tests. 10/01/98 D) Simulator Malfunction Tests. 09/01/98 A) Simulator Steady State Test. 08/01/99 B) Simulator Normal and Abnormal Operating Plant (AOls) 07/01/99 C) Simulator Transient Performance Tests. 10/01/99 D) Simulator Malfunction Tests. 09/01/99 E-13

Table 8 SIMULATOR EXCEPTIONS Exception Open Date Close Date Exception Description Number 11/22/91 No camera equipment mounted at top of panels or ceiling at plant.

11/22/91 Simulator room lighting does not match the plant.

11/23/91 11/09/95 Side panels 2-9-2, 2-9-10, 2-9-11, 2-9-12, 2-9-13, 2-9-14, 2-9-53, 2-9-54, 2-9-55, 2-9-21, 2-9-20, 1-9-20, 0-9-23-2, 0-9-23-4, 0-9-23-3, 0-9-23-4, 0-9-23-5, 0-9-23-6, 0-9-23-7, 0-9-23-8 and 2-9-22A are located on the opposite sides of the room in respect to Unit 2 horseshoe.

11/23/91 Panel 2-9-47 is only partially simulated.

12/03/91 Panel 0-9-56 is not simulated.

12/03/91 Panel 2-9-9 is not simulated.

12/03/91 Panel 2-9-46 is not simulated.

12/03/91 Panel 2-9-24 is not simulated.

12/03/91 Panel 2-9-44 is not simulated.

10 12/03/91 Panel 2-9-59 is not simulated.

12/03/91 Panel 2-9-22 ls not simulated.

12 12/03/91 Electrical operator typer is not simulated.

13 12/03/91 Drywall TV Monitor is not simulated.

14 12/03/91 Panel 2-9-54 has additional instruments.

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Table 9 SIMULATOR LIMITATIONS The following simulator limitations have been imposed to prevent training from occurring when the simulator is operating beyond the planned scope of simulation.

1. Drywell pressure exceeds design limit (,( -2 pslg or ) 63 psig).

2. Fuel clad temperatures exceed clad malt point f2200 deg F).

3. Reactor vessel pressure exceeds design limit (1375 psig).

4. Water entering steam turbines.

5. Suppression pool temperature exceeds boiling point.

6. Core average void fraction > 90% and water level < -400 inches If any above limit is reached, the simulator will freeze and the Instructor station will display a "SIMULATOROUT OF BOUNDS" popup explaining the limit.

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