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System analysis code: HETRAF

Main features

  • Multi-loop, multi-fluid systems with single phase flow
  • Thermal coupling between loops
  • Additional source of mass, momentum and energy in control volumes
  • Pump characteristic for each loop and each cell
  • Capability of bypass simulation
  • Capability of pressure control via pressurizer
  • Capability of control system simulations
  • High flexibility for user interaction

Main applications

  • Super-critical fluids cooled systems
  • Cooling system of spallation targets
  • Safety analysis of HLM cooled nuclear systems

Example (safety analysis of MEGAPIE target)

Figure 1: Cooling system of the MEGAPIE target Transient behavior under protected and unprotected beam interrupt conditions
Figure 1: Cooling system of the MEGAPIE target          Figure 2: Transient behavior under protected and
unprotected beam interrupt conditions

 The right Figure shows the LBE temperature at the heat exchanger exit for beam interrupt transients with and without protection, respectively. In the unprotected case, no actions are taken, whereas in the protected case, the control valve CV2 is opened in 5 s after the start of beam interrupt, and at the same time the control valve CV3 is closed. In the unprotected case, the LBE temperature decreases and reaches the freezing point (123°C) in about 4 minutes. In the protected case, the LBE temperature can be kept far above the freezing point, and blockage of the flow path, subsequently, the damage of the target is avoided.

Main references:

  1. X. Cheng, Numerical analysis of thermally induced transients in forced flow of supercritical helium, Cryogenics, Vol.34 (1994), No.3, 195-201
  2. X. Cheng, Dynamic Behavior of the Heat Removal System of the MEGAPIE Target, IKET Internal Report, October 200