A passive decay heat removal system for emergency draining tanks of molten salt reactors.

Highlights • A new passive decay heat removal system has been invented for molten salt reactor emergency draining tank system. • This system is based on the loop heat pipe concept. • It includes an evaporating tank (emergency draining tank), and where the liquid fuel is mixed with a working fluid (sodium) and to vaporizes the working fluid. • The resulting vapor pressure drives the vapor through the pipes to the condensers, where the vapor condenses, releasing its latent heat of vaporization to a provided heat sink. • The condensers are located above the emergency draining tank at a higher elevation than the vaporization tank, so the condensed working fluid can flow back to the emergency draining tank by gravitational force. • Therefore, the system can continuously and passively transport the latent heat of vaporization from the emergency draining tank to the condenser section. Abstract A passive decay heat removal system is proposed that is actuated by the phase change heat transfer method (latent heat of fusion and evaporation) for an emergency draining tank system of molten salt reactors. The emergency draining tank serves an evaporating tank, where the liquid fuel is mixed with an immiscible working fluid and later to vaporize this working fluid. The top header of the vaporizing tank is connected by pipes to a condenser. The resulting vapor pressure of the working fluid drives the vapor through these pipes to condensers, The condensers are located above the reactor, where the vapor condenses, releasing its latent heat of vaporization to a provided heat sink (air heat exchanger). The condensed working fluid flows at first in a Pythagorean cup type collector, which is located just below the condensers, the collected working fluid flows back, in batch, to the emergency draining tank by gravitational force. In this batch manner the working fluid can be strongly mixed with the liquid fuel to enhance the heat transfer between liquid fuel and working fluid without any mechanical or electrical assistance, i.e. a completely passive heat removal process. Therefore the system can passively transport the latent heat of vaporization of the working fluid from the emergency draining tank to the condenser section. This proposed decay heat removal system is described in more detail in this paper. The passive cooling of the liquid fuel to extract the residual heat has been studied. [ABSTRACT FROM AUTHOR]