Optimization of the Overall Heat Transfer Coefficient of the Frozen Seal Valve Fin Tube Assembly for Fast Reactors

Sodium is used as a coolant in the fast reactor’s primary and secondary loops to transfer enthalpy from the reactor and transport it to the expander. However, handling sodium is difficult, and it can be hazardous if it comes into contact with air, which causes an exothermic reaction. During maintenance of sodium loop components, isolation is typically accomplished with valves. The valve leaking is caused by the seal or the gland. Seal leakage is compensated because it occurs within the line, but gland leakage should be zero because the liquid is harmful. To address this requirement, the author attempted to design a special type of valve in which sodium is allowed to rise through an annular path along the stem and heat transfer is augmented in such a way that the required enthalpy is evacuated to freeze sodium inside the annular path, confirming the fail-safe zero gland leakage. A finned tube assembly is fitted around the stem to achieve this concept of expanded surface heat transfer. However, the issue is to design the fin tube assembly, as well as the number of fins and their dimensions. Normally, these things are done through a series of physical model studies, which is inefficient. In our study, we used conjugate heat transfer analysis to design the fin tube assembly, which was then tested using a physical model.