Research On Simulation Of Primary Coolant System Of Sodium Cooled Fast Reactor

CEFR is a65MW,25MW, sodium cooled, and pool type experimental fast reactor..It hasachieved the first criticality on21July2010. It is in dire need of developing a full-scope fastreactor system simulator for analysis of accidental condition, ensuring the operation safetyand personnel training. The existed codes for sodium cooled fast reactor are developed forspecial fast reactors, and can’t be applied for other fast reactors. However, up to now, there isno thermal-hydraulic analysis codes for PCS of China Experimental Fast Reactor(CEFR).Based on the structure and operation characteristics of PCS of CEFR, a series ofreasonable mathematical and physical models were set up. The models include: basicthermal-hydraulic model of coolant, hydraulic model of primary pump, heat conductionmodel of fuel rod, thermal model of IHX, thermo physical properties of liquid sodium, heattransfer and flow correlations for liquid sodium. Gear method was applied to solve thedynamic model of the system. It contributes to the accurate and effective of calculation tomeet the requirement of real-time simulation. Gear method is a numerical integration methodwhich is suitable to solve stiff differential equations. It adopts an implicit back differencemethod and designs a abnormal steady strategy to realize automatic variety of step-size andorder.The dynamic simulation code is developed with modularized method by FORTRANlanguage. The design parameter of CEFR was used to validate the rating condition. And threedynamic conditions analyzed in final safety analysis report of CEFR had been selected forvalidation of the dynamic model. They were a loss of power to one primary pump whileoperating under rated condition, withdrawal of adjust rod without scram and the accidentalclosure of primary pump check valves respectively.. During the three transients, the peak ofcoolant temperature and fuel temperature satisfied the safety criteria, and the trend of mainparameters vs time agreed with the safety report. Thus the validity and applicability of thiscode was proved. Then the code was applied to analyze two imaginary transients. The resultsshowed that the trend of simulation curves for transient condition were reasonable.