Natural Circulation Nuclear-thermal Coupling Characteristics Research Under Rolling Motion

With the respect of the primary loop of natural circulation under marine ocean conditions,based on the thermal-hydraulic experiments of natural circulation under rolling motioncondition, this investigation aims to establish rolling motion condition mathematical model,natural circulation system thermal-hydraulic calculation model under rolling motion conditionand nuclear feedback computing model, and analyze the nuclear thermal couplingcharacteristics of natural circulation system under rolling motion condition.The natural circulation thermal-hydraulic calculation model considers the impact of thesystem friction factor and heat transfer coefficient under rolling motion condition, and thenuclear feedback calculation model calculates the system power using six groups of delayedneutrons point reactor neutron kinetics model. the corresponding computer calculationprogram is developed in Matlab platform. And then, the analysis is established about naturalcirculation system nuclear thermal coupling characteristics under rolling motion condition.The main conclusions are as follows:(1) The nuclear thermal coupling has a certain extent effect on the natural circulationsystem operating parameters. The rolling parameter is not the same, the degree of influencewill be different. As the rolling frequency and amplitude increases, the degree of influenceenhanced. The mechanism analysis shows which is caused by the flow fluctuation amplitudeincreases with increasing rolling amplitude and frequency.(2) With the different nuclear feedback manner but the same rolling parameter and thenatural circulation operating conditions, the nuclear thermal coupling effect on the naturalcirculation system parameters will be different. When the absolute value of the nuclearfeedback factor increases, the nuclear thermal coupling effect on the natural circulationsystem parameters will be enhanced at the same time.(3) The mechanism analysis of the impact of nuclear-thermal coupling effect on the fueltemperature and coolant temperature shows that the fuel temperature fluctuations affects notonly by the flow fluctuations, but also by power fluctuations caused by the nuclear feedbackeffect after considering the nuclear feedback effect. The coolant temperature fluctuations ismainly affected by flow fluctuations and fluid power fluctuations.