The nuclear power and energy storage company, alongside scientific instruments manufacturer Anton Paar, has installed the rheometer inside a climate-controlled inert gas glovebox at the MoltexFLEX laboratory in Warrington, Cheshire. The test rig is now operational and has started providing data.
Rheometers measure the viscosity and density of different materials at varying temperatures. MoltexFLEX is using the technology to test the fluoride salts the company is planning to use as the fuel and coolant for its novel FLEX reactor.
“The FLEX reactor relies on natural convection rather than pumps to circulate the molten salt coolant, and this is sensitive to viscosity and density, so accurate information of these parameters at different temperatures is vital,” said MoltexFLEX lead chemist Phil Quayle. “This one-of-a-kind installation will go a long way towards delivering a FLEX reactor this decade.”
There is little available information on how the kinds of fluoride salts used in the FLEX reactor behave at high temperatures.
Few companies and research institutions have investigated their density and viscosity, as this data is difficult to gather reliably as the salt can easily become contaminated by oxygen and water, which affects its material properties, MoltexFLEX said.
The company added that installing the rheometer inside the glovebox, which is filled with pure nitrogen gas, solves the problem and enables scientists to get accurate results. The team has calibrated the rheometer with lower-temperature chloride salts and is now generating viscosity data for the FLEX salts.
Quayle said that the in-house rheometer is a huge step forward in MoltexFLEX’s analytical capability, enabling the company to rapidly develop experimental protocols and generate good data sooner.
“As far as we and Anton Paar know, no-one in the UK has installed a high-temperature rheometer inside a climate-controlled environment like this,” said MoltexFLEX chemist Beth Mapley, who is developing procedures for use with surrogate uranium fluoride fuel salt. “It’s really exciting to be able to work on such cutting-edge research,” she added.