Nuclear Thermal Hydraulics

  • High accuracy flow measurement
  • Research related to the two-phase flow, steam flow, boiling flow
  • Electromagnetic field heat flow coupled simulation (GSMAC-MHD)
  • Instabilities in parallel boiling channel

High accuracy flow measurement (vertical pipe, bent pipe, open channel)

Not only in nuclear power plants, but also in normal power plants and chemical plants, the process flow control is very important for efficiency and safety of the facility. In our laboratory, high-accuracy flow measurement technique using ultrasound flowmeter for vertical pipe, bent pipe and open channel flow is under development.

Research related to the two-phase flow, steam flow, boiling flow

In order to enhance the safety of LWRs, a behavior of two-phase flow is measured. Technology for simultaneous measurement of both liquid and gas phase is developed using different wavelengths of ultrasound. Also, a technology of wire mesh tomography is developed in a way so that it won’t affect the flow.

Electromagnetic field heat flow coupled simulation (GSMAC-MHD)

The High-level radioactive waste is reprocessed into waste liquid, and the waste liquid is mixed into molten glass in a Joule heated glass furnace to make vitrified waste. Thermal-hydraulic behavior must be observed. However, Physical phenomena taking place inside Joule-heated glass melter are quite complex and interrelated. So, it is very difficult to simulate the flow behavior. One of the opportunities is use Generalized Simplified Marker and Cell?Mageto-HydroDynamic-Finite Element Method (GSMAC-MHD-FEM) simply named GSMAC-MHD that combined temperature, flow and magnetic field. GSMAC-MHD is three-dimensional analysis code.

Instabilities in parallel boiling channel

The safety of Natural circulation boiling water reactors is high, but it is important to avoid flow instabilities that interfere with reactor control and cause pipe vibration. Regarding this phenomenon, in our laboratory, instabilities are analyzed using parallel boiling channel experiment. The purpose of obtaining knowledge about these instabilities is to avoid unstable behavior.