Fine distributed moderating material to enhance feedback coefficients in lead cooled fast reactor experiment


Fine distributed moderating material to enhance feedback coefficients in lead cooled fast reactor experiment

Merk, B.

Recently, the use of moderating materials in fuel assemblies for Sodium cooled fast reactors (SFRs) has been investigated and published in several papers (Annals of Nuclear Energy 38, 5, Annals of Nuclear Energy 38, 11 (2011)). Especially the fine distribution of the moderating material has shown very promising results for the enhancement of the feedback coefficients in Sodium cooled fast reactors. The validity of the HELIOS results has been demonstrated in a comparison with MCNP and the transferability of the effect to full core calculations has been shown.
In a new attempt, it will be demonstrated, that the concept of enhanced feedback coefficients is transferable to lead cooled fast reactors (LFRs). The demonstration is based on a test for the configuration of the zero power experimental setup GUINEVERE in the VENUS facility at SCK•CEN in Mol/Belgium, since this experiment could serve for a first real experimental test to confirm the simulations. The calculations are based on the preliminary design of the fuel assemblies of the currently running subcritical experiments at GUINEVERE. The effect of the moderating material on the neutron spectrum, on the kinf, and on the fuel temperature feedback of the zero power facility is shown, discussed and compared to SFRs. The thermal stability of the hydrogen bearing compound is of paramount importance for the use of moderating material in a LFR. An insight will be given into the relationship of the hydrogen content of the compound and the resulting thermal stability. Thermal stability of the moderating material up to more than 1300°C can be ensured by the use of Yttrium-mono-hydride as moderating material.
Over all it is demonstrated, that the use of fine distributed moderating material has the potential to open the stage for designable feedback coefficients not only in sodium cooled fast reactors, but also in lead cooled fast reactors. An important point is that the enhanced feedback effects can be achieved without creating a major influence on the operational parameters and core coolability.

Keywords: Lead Cooled Fast Reactor; Fast Reactor; Enhanced Feedback Effects; Moderating Material; Yttriumhydride; GUINEVERE

  • Contribution to proceedings
    2013 International Congress on Advances in Nuclear Power Plants (ICAPP '13), 14.-18.04.2013, Jeju, Korea
    Proceedings of ICAPP'13
  • Lecture (Conference)
    2013 International Congress on Advances in Nuclear Power Plants (ICAPP '13), 14.-18.04.2013, Jeju, Korea

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Publ.-Id: 17892