polaris, a tool for generating "real" thermal margins in the oyster creek simulator

POLARIS, a Tool for Generating "Real" Thermal Margins in the Oyster Creek Simulator

Alan Cheng and Robin Brown, Exelon CorporationLotfi Belblidia, Studsvik Scandpower

Power Plant Simulation ConferenceFebruary 14-18, 2011 Tampa, Florida

Core Monitoring• Almost all BWRs and many PWRs use a core monitoring

system in the plant control room. • Core monitoring systems combine measured data and

physics calculations to ensure compliance of fuel thermal limits as part of the Technical Specification requirements.

• These systems are frequently not available in the simulated control room or are available only via a simplified emulation.

• Short of providing a complete core monitoring system, POLARIS offers a way to implement a rigorous thermal limits monitoring system in the training simulator of the same quality and reliability as what is available to the operator in the actual control room.

POLARIS – “Real” Thermal Margins / Tampa, Florida – Feb 14-18, 2011

Overview• All core monitoring start at the process computer, which

collects measured plants signals. • In BWRs, signals from the process computer include:

– State point conditions: core thermal power, core coolant flow rate, feedwater temperature, recirculation flow and temperature, control rod positions, reactor pressure.

– Fixed incore signals– Pressure indications, pump speeds

• These signals are used as inputs to a reactor physics computational module.

• The physics model is invoked manually or automatically, either on a fixed interval or in response to a change in plant condition.


Benefits of Plant Core Monitoring• Extend the amount of core information available to the

operators and reactor engineers. • Core Monitoring System acquires measured data from the

plant computer and uses that data as input to core analysis software.

• Core analysis software provides 3D and scalar results as printed text or via a GUI. Extensions beyond the pure surveillance of Technical Specification limits include:– 3D distributions (anything you want and more than you know what

to do with)– Margin to limits (Power distribution, CPR, MAPLHGR, MAPRAT)– Heat balance– Reactivity balance


Thermal Margins Monitoring on the Simulator• Licensing authorities in many countries are requesting fidelity

between the full scope training simulator control room and the actual control room, which may require the core monitoring system to replicate reference plant data.

• Exelon core test procedures includes comparison of power distributions and thermal margins

• Without implementing a complete core monitoring system, POLARIS provides a reliable way to fulfill the surveillance part of Technical Specification limits without the cost of a full-fledged core monitoring system.

• It uses “measured” data from the simulator and includes design code SIMULATE-3 as the core analysis software.


Implementation in Oyster Creek (1)• POLARIS requires the usual restart and library files used by

S3R as well as an additional thermal margin library generated by SIMULATE-3 as part of the core depletion calculations.

• The following information is passed from the simulator to POLARIS:– Core power, flow, and inlet temperature– Control rod positions– LPRM signals– Xenon and samarium nodal concentrations

• This information is used to automatically generate a SIMULATE-3 input file.


Implementation in Oyster Creek (2)• A call to SIMULATE-3 is made on demand.• After completion of the SIMULATE-3 calculation, all the

thermal margins and data needed to generate a P1-like report are gathered.

• A P1-like report is generated and relevant information is passed to the simulated process computer for display to the operator (3DM Display).


Example (Page 1 excerpt) PAGE 1

OYSTER CREEK CY-23 SEQUENCE NO 12CORE PARAMETERS 3DM (POLARIS) 05-FEB-2011 12:33 CALCULATEDPOWER MWT 1912.2 PERIODIC LOG 05-FEB-2011 12:33 PRINTEDPOWER MWE 650.0 AUTOMATIC CASE ID FMLD1110205123302FLOW MLB/HR 57.541 CALC RESULTS RESTART FMLD1110205123301FLAPDR 0.881 LPRM SHAPE - FULL CORESUBC BTU/LB 33.29 KEFF 1.0017PR PSIa 1034.14 XE WORTH % -2.30 LOAD LINE SUMMARYCORE MWD/ST 23945.4 XE/RATED 1.000 CORE POWER 99.1%CYCLE MWD/ST 6900.0 AVE VF 0.336 CORE FLOW 94.5%MCPR 1.658 FLLLP 0.944 LOAD LINE 102.9% CORRECTION FACTORS: MFLCPR= 1.000 MFLPD= 1.000 MAPRAT= 1.000OPTION: PRE_ARTS 4 LOOPS ON MANUAL FLOW MCPRLIM=1.658 MOST LIMITING LOCATIONS (NON-SYMMETRIC)MFLCPR LOC MFLPD LOC MAPRAT LOC PCRAT LOC0.917 38-31 0.806 32-35-12 0.810 34-33-12 0.000 00-00-000.916 32-15 0.806 36-31-12 0.809 36-31-12 0.000 00-00-000.915 34-33 0.804 32-31-12 0.808 32-35-12 0.000 00-00-000.915 32-37 0.803 32-17-12 0.805 32-17-12 0.000 00-00-000.914 16-21 0.801 18-21-12 0.804 36-35-12 0.000 00-00-000.900 36-15 0.793 36-35-12 0.803 18-21-12 0.000 00-00-000.900 38-35 0.790 36-17-12 0.800 36-17-12 0.000 00-00-000.899 18-15 0.787 18-17-12 0.798 18-17-12 0.000 00-00-000.894 16-35 0.785 18-35-12 0.795 18-35-12 0.000 00-00-00

…/…


Example (Page 2 excerpt) PAGE 2

OYSTER CREEK CY-23 INSTRUMENT READINGS/STATUS SEQUENCE NO 12 CALIBRATED LPRM READINGS 05-FEB-2011 12:33 CALCULATED 05-FEB-2011 12:33 PRINTED 49D 24.7 25.0 19.9 CASE ID FMLD1110205123302 C 33.4 35.8 24.9 B 28.2 31.4 18.0 LPRM SHAPE - FULL CORE A 19.4 23.7 11.7 FAILED SENSORS 41D 24.8 29.6 29.6 28.9 24.4 LPRM ( 0 SIGNALS FAILED) C 40.1 39.6 53.2 40.3 38.1 B 44.1 42.7 59.0 43.5 37.4 A 42.8 44.5 59.7 44.0 26.9

33D 24.5 29.4 30.6 33.0 32.3C 26.3 C 33.6 40.0 54.0 43.4 57.5 34.8 B 28.5 43.2 60.4 47.7* 63.0 36.6 A 20.0 45.8 52.6 42.7 61.2 32.1

25D 25.0 29.6 32.9 32.1 33.1 26.9 C 35.9 53.2 43.3 50.5 43.6 48.0 B 31.5 58.9 47.4 55.2 48.5 52.3 A 24.3 61.0 43.1 50.2 41.9 55.1 T = TIP RUN RECOMMENDED C = MFLCPR LOCATION 17D 19.8 28.8 32.2 33.0 30.3 27.1 M = MAPRAT LOCATION C 24.8 40.0 57.2 43.5 53.7 33.7 P = PCRAT LOCATION B 18.0 43.1 62.6 48.3 58.6 34.6 D = MFLPD LOCATION A 12.0 45.4 62.5 42.3 61.5 26.0 * = MULTIPLE LIMIT

09D 22.6 26.2 26.8 27.0 17.2 C 34.5 34.6 47.8 33.5 23.5 B 35.2 36.4 52.0 34.5 18.6 A 27.5 33.1 56.1 26.2 12.6

04 12 20 28 36 44 POLARIS – “Real” Thermal Margins / Tampa, Florida – Feb 14-18, 2011

Example (Reactor Core State Display)


Summary• There are two requirements for implementing POLARIS:

– Up-to-date CASMO/SIMULATE core files– The use of a high fidelity simulator core model such as S3R

• Since POLARIS uses a well established design code (SIMULATE-3) for the calculation of thermal margins, there is no need for any assumption or simplification.

• The results from POLARIS can be presented with the same format as existing plant reports.

• Exelon is pushing to have site Reactor Engineers participate in licensed operator requalification simulator training. POLARIS will be a great aid in supporting this.


PROPRIETARY October 2008 - Arizonatitle

polaris, a tool for generating "real" thermal margins in the oyster creek simulator

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