Molten Salt System

Molten Salt Reactor (MSR) is one promising Generation IV nuclear reactors due to its improved safety design, near the atmospheric working pressure, and high electric power conversion efficiency. MSR-related research activities have significantly increased in recent years, but a number of key technology gaps or issues still exist for MSR thermal hydraulics. One key phenomena that need further investigation is molten salt natural circulation in passive decay heat removal systems. It is necessary to design and construct an Integral-Effect Test (IET) facility for experimental demonstration of the functionality of the passive decay heat removal system as well as to provide experimental data for code validation.

 

An IET facility, also known as the high-temperature FLUoride Salt Test FAcility (FLUSTFA), is designed to replicate, at a reduced-scale, a passive decay heat removal system, such as the Direct Reactor Auxiliary Cooling System (DRACS). A prototypic DRACS design is initially proposed and a scaling analysis is then carried out to support the design of the FLUSTFA. The FLUSTFA is designed and constructed to have a 1/10 height scaling and a 1/1,250 power scaling relative to its prototype. 

 

The FLUSTFA is comprised of: a reservoir tank for salt melting and storage, a primary molten salt loop that simulates the reactor primary coolant system, a secondary molten salt loop that represents the DRACS salt loop, an air loop for removing decay heat from the DRACS salt loop, and a chilled water loop.The FLUSTFA utilizes FLiNaK salt (46.5LiF-11.5NaF-42.0KF mol%) and can operate up to 700 °C at near the atmospheric pressure.

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In addition, a thermal-hydraulic system-level code, known as NAtural Circulation COde (NACCO), is developed to predict the steady-state/transient behavior of coupled molten salt forced- and natural-circulation systems, such as FLUSTFA.