Investigation of passive evaporative condensing heat transfer systems to improve the safe operation of nuclear power equipment

Formulation and conduct of this work due to the urgent need to increase the security level of nuclear power equipment operations. The use of passive systems that operate mainly due to natural forces and phenomena and which include the heat transfer systems of evaporating-condensing type (ЕСT) will dispense with equipment at work which may refuse, reduce dependence on operator's actions during transients and accidents.

For the first time on the basis of comprehensive studies of thermal heat transfer characteristics of heat transfer systems CGT developed scientifically based methods of rational design and patents new specific scientific and technical decisions regarding these systems proved that the evaporating-condensing system (ECS) heat transfer by complex inherent thermal and technological and operational advantages, advantages, features and seamlessly meet the conditions that apply to passive systems of cooling and thermal protection in nuclear power.
As a result of detection, research and the analysis of several thermal factors restricting heat-transmitting ability of evaporating-condensing type’s systems derived regularities and dependencies which define the values of the maximum heat fluxes as functions of design parameters, regime characteristics of processes, thermophysical properties of the environments, between which heat exchange is carried out and intermediate heat-carrier.

Methods of improving of heat-transportation ability of evaporating-condensing systems, which based on creation of an effective capillary-arterial system and separation of the channels for passing of steam and condensate flows are researched and analyzed. The problem of optimization of parameters of capillary structure heat-transmitting element (HE) ECT from the point of view of minimization of its thermal resistance is set and decided. On the basis of regularities analysis of heat exchange processes are received dependences for determination of optimal ratio of the lengths of zone of evaporation and condensation HE of trumpet packet of heat-exchanging system, at which the system has minimal thermal resistance of heat transfer. The basic provisions of the methodology for thermal calculation of passive systems of heatsink ECT in relation to typical thermal schemes of heat transfer are received.
The complex of works on development of specific technological solutions on support of efficiency and reliability of heat transfer systems ECT functioning is carried out.

Developed original schematic-constructive decisions ECT for heatsink from the power generating equipments, fulfilled nuclear fuel and thermal protection of metal constructions, which are confirmed by patents of Ukraine. The organization of manufacture and implementation of such heat transfer systems will ensure improved reliability of systems of heatsink in nuclear power; to improve the security of nuclear power equipment operations, to reduce technogenic impacts on the environment.