SPEED-ASTIR: material irradiation in Lead Bismuth Eutectic (LBE)

ADS STeel IRradation

Speed-Astir is one of the material experiments defined in the MYRRHA R&D support programme in which structural materials such as martensitic T91-steel (~9% Cr, 1% Mo) are assessed in contact with lead-bismuth at 450°C and simultaneously exposed to high energy neutrons.

Design

Speed-Astir consists of a double wall capsule with a thin gap filled with helium. To achieve the highest possible fast flux (SPEED) the experimental rig will be loaded in a BR2 fuel element.

The innovative and challenging features of this experiment are:

• A variable gap with from 80µm to 500µm at room temperature to minimize the axial temperature gradient
• A brazed instrumentation feed-through with 14 penetrations in a diameter of 18mm which will be placed in the irradiated part of the experiment
  
  
  

• The use of rarefied gas conduction for the temperature control
• The safety and technological issues of polonium
  
  
  

Characteristics

• Temperature: 450°C (controlled)
• Irradiation dose: 0.2 to 0.7 dpa/cycle, dependent on the location in the rig
• Flux:
  • Thermal: 3.5…4.0 x10 ¹⁴n/cm².s (maximal)
  • Epithermal: 6.5…6.6 x10 ¹⁴n/cm².s (maximal)
  • Fast (>0.1MeV): 6.1…6.6 x10 ¹⁴n/cm².s (maximal)
  • Fast (>1MeV): 3.1…3.3 x10 ¹⁴n/cm².s (maximal)
• Expected irradiation: 5 cycles

Loading

The capsule will contain:

• 8 pressurized tubes to asses the creep behaviour of the structural material
  
  
• 20 compact toughness discs of which 10 in contact with lead-bismuth and 10 wrapped in a foil
  
  

• 52 tensile specimens
  
  

• 22 mini-Charpy's
  
  

For further information please contact:

Dekeyser Jean