Stability analysis of passive cooling systems for nuclear spent fuel pool

Abstract

which generate together 2000 MW. Angra 3, the third plant of the nuclear station, is under construction and will supply 1405 MW to the electrical grid. The nuclear fuel assemblies, after a work cycle, are removed from the reactor and stored in the respective storage pool. Each one of the NPPs is provided with a spent fuel pool, which has a limited storage capacity, and do not suffice for the whole lifetime of the plants. Thus, a complementary storage facility must be provided for the nuclear station for the NPPs to keep operation. Facilities for storage of spent fuel assemblies (SFAs) which are not "attached" to the reactor building are referred to as "away from reactor" storage facilities. There are two main types of SFA storage in away from reactor facilities: dry storage and wet storage. In both cases, the installation must be provided with a solution to the remove residual heat generated by the spent fuel.Eletronuclear, the company responsible for construction and operation of NPPs in Brazil, has designed a wet SFA storage facility to fulfill the demand for space. According to the design, this storage facility would be provided with a fully passive cooling system for removal of the residual heat. Worldwide, there is only one installation with a similar solution, which is operating in Gösgen, Switzerland. This decision follows the global trend to increase participation of passive systems in nuclear installations, especially after the events of March 11, 2011, in Fukushima. In that occasion three of the six units of Fukushima Daiichi nuclear station suffered a core meltdown caused by a lossof-coolant accident. The unavailability of external energy supply and emergency diesel generators was the cause for the loss of cooling capacity.Passive cooling systems (PCSs) are engineering solutions to perform the function of heat transfer using the temperature difference between hot and cold sources to generate the driving force for the flow. Their advantages

Experimental Analysis of a Single-Phase Passive Cooling System

“…Figure 8 illustrates this conclusion. It also shows a comparison between numerical simulations using the model described in Lima et al (2016) and the experimental results. It can be seen that the straight line constructed from the numerical simulations are approximately parallel to the one of the experiments, but shifted by a value, which is an effect of the friction model used in the numerical code.…”

Research Progress on Thermal Hydraulic Characteristics of Spent Fuel Pools: A Review

“…The experimental results show that the heat transfer capacity of the heat pipe is improved in the inclined state, while the optimal temperature at the condensing end is about 30 °C. Lima et al [55] studied the thermal hydraulic stability of PCS through linear and nonlinear models. The results show that there is no qualitative relationship between the water volume in the pool and the stability of the system.…”

“…Shandong University [56,57] established a loop heat pipe test bench, studied the heat transfer and resistance characteristics of the passive cooling system of an SFP based on a loop heat pipe, proposed an optimized thermal hydraulic system design Wu et al [44] studied the effects of inlet air volume, inlet air temperature and the angle of inclination on the heat transfer process. The experimental results show that the heat transfer capacity of the heat pipe is improved in the inclined state, while the optimal temperature at the condensing end is about 30 • C. Lima et al [55] studied the thermal hydraulic stability of PCS through linear and nonlinear models. The results show that there is no qualitative relationship between the water volume in the pool and the stability of the system.…”

Avaliação do Índice de Estado Trófico e parâmetros de qualidade da água no reservatório da Usina Hidrelétrica de Sá Carvalho, Minas Gerais, Brasil

“…No período deste estudo observaram-se o florescimento de algas e a depleção de oxigênio na parte central da água no fundo do lago, o que exige a diminuição do aporte de nutrientes. Lima et al (2017) relatam que entre as ações de mitigação está incluído o emprego de processos mecânicos, químicos e/ou biológicos. Ademais, pontuam quanto à importância de práticas capazes de promover a aeração do hipolímnio, a desnitrificação e a remoção de águas profundas e de macrófitas e algas -processos mecânicos capazes de revitalizar o reservatório e melhorar a qualidade da água.…”