Abstract
To support the design of an external filtering and conditioning system for the lead-bismuth cooled MYRRHA reactor, the formation and transport of iron oxide
particles from corrosion products in the reactor primary system have been investigated for normal operating conditions.
The regions of the reactor with the highest probability of oxide formation are identified by a local chemical equilibrium model for magnetite formation. This
analysis reveals that magnetite precipitation generally occurs in regions with large temperature gradients. For the specific case of the MYRRHA reactor, these regions
correspond to the transition region between the barrel and the upper plenum, mainly at the location of the holes in the top part of the barrel.
The transport behaviour of solid oxides from these regions is then investigated with a multi-phase Euler-Lagrange particle tracking model of the MYRRHA primary
system. The simulations show that the majority of large oxide particles (above 100 μm) will eventually move to the free surface without passing through the reactor
core, thereby allowing their removal by an external filtering system with surface extraction. This indicates that such large particles present a minimal risk for sudden
core blockage, which does not compromise reactor safety.
On the other hand, particles below a threshold diameter identified at 40 μm cannot be efficiently filtered out by an external system since the majority follows the
carrier liquid and re-enters the core during each LBE flow-through cycle. The continuous purification of the coolant is therefore necessary to avoid undesired build-up
of suspended particles in the primary system. A preliminary design value of the required mass flow rate through the filters is identified with the support of numerical
simulations.
Original language | English |
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Pages (from-to) | 199-208 |
Number of pages | 10 |
Journal | Nuclear Engineering and Design |
Volume | 338 |
DOIs | |
State | Published - 27 Aug 2018 |