Thesis Open Access

A neutron noise solver based on a discrete ordinates method.

Huaiqian YI

MARC21 XML Export

<?xml version='1.0' encoding='UTF-8'?>
<record xmlns="">
  <datafield tag="041" ind1=" " ind2=" ">
    <subfield code="a">eng</subfield>
  <datafield tag="653" ind1=" " ind2=" ">
    <subfield code="a">Neutron noise</subfield>
  <datafield tag="653" ind1=" " ind2=" ">
    <subfield code="a">nuclear reactor modelling</subfield>
  <datafield tag="653" ind1=" " ind2=" ">
    <subfield code="a">Deterministic neutron transport methods</subfield>
  <datafield tag="653" ind1=" " ind2=" ">
    <subfield code="a">Discrete ordinates</subfield>
  <datafield tag="653" ind1=" " ind2=" ">
    <subfield code="a">Diffusion synthetic acceleration</subfield>
  <datafield tag="653" ind1=" " ind2=" ">
    <subfield code="a">Convergence analysis</subfield>
  <datafield tag="502" ind1=" " ind2=" ">
    <subfield code="c">Chalmers University of Technology</subfield>
  <controlfield tag="005">20220816073601.0</controlfield>
  <controlfield tag="001">3813173</controlfield>
  <datafield tag="700" ind1=" " ind2=" ">
    <subfield code="u">Chalmers University of Technology</subfield>
    <subfield code="4">ths</subfield>
    <subfield code="a">Paolo Vinai</subfield>
  <datafield tag="856" ind1="4" ind2=" ">
    <subfield code="s">2100222</subfield>
    <subfield code="z">md5:62d7415a671e5d26264453cab7149936</subfield>
    <subfield code="u"></subfield>
  <datafield tag="542" ind1=" " ind2=" ">
    <subfield code="l">open</subfield>
  <datafield tag="260" ind1=" " ind2=" ">
    <subfield code="c">2020-04-01</subfield>
  <datafield tag="909" ind1="C" ind2="O">
    <subfield code="p">openaire</subfield>
    <subfield code="o"></subfield>
  <datafield tag="100" ind1=" " ind2=" ">
    <subfield code="u">Chalmers University of Technology</subfield>
    <subfield code="a">Huaiqian YI</subfield>
  <datafield tag="245" ind1=" " ind2=" ">
    <subfield code="a">A neutron noise solver based on a discrete ordinates method.</subfield>
  <datafield tag="536" ind1=" " ind2=" ">
    <subfield code="c">754316</subfield>
    <subfield code="a">Core monitoring techniques and experimental validation and demonstration</subfield>
  <datafield tag="540" ind1=" " ind2=" ">
    <subfield code="u"></subfield>
    <subfield code="a">Creative Commons Attribution 4.0 International</subfield>
  <datafield tag="650" ind1="1" ind2="7">
    <subfield code="a">cc-by</subfield>
    <subfield code="2"></subfield>
  <datafield tag="520" ind1=" " ind2=" ">
    <subfield code="a">&lt;p&gt;A neutron noise transport modelling tool is presented in this thesis. The simulator allows to&lt;br&gt;
determine the static solution of a critical system and the neutron noise induced by a prescribed&lt;br&gt;
perturbation of the critical system. The simulator is based on the neutron balance equations in&lt;br&gt;
the frequency domain and for two-dimensional systems. The discrete ordinates method is used&lt;br&gt;
for the angular discretization and the diamond finite difference method for the treatment of the&lt;br&gt;
spatial variable. The energy dependence is modelled with two neutron energy groups. The&lt;br&gt;
conventional inner-outer iterative scheme is employed for solving the discretized neutron&lt;br&gt;
transport equations. For the acceleration of the iterative scheme, the diffusion synthetic&lt;br&gt;
acceleration is implemented.&lt;br&gt;
The convergence rate of the accelerated and unaccelerated versions of the simulator is studied&lt;br&gt;
for the case of a perturbed infinite homogeneous system. The theoretical behavior predicted by&lt;br&gt;
the Fourier convergence analysis agrees well with the numerical performance of the simulator.&lt;br&gt;
The diffusion synthetic acceleration decreases significantly the number of numerical iterations,&lt;br&gt;
but its convergence rate is still slow, especially for perturbations at low frequencies.&lt;br&gt;
The simulator is further tested on neutron noise problems in more realistic, heterogeneous&lt;br&gt;
systems and compared with the diffusion-based solver. The diffusion synthetic acceleration&lt;br&gt;
leads to a reduction of the computational burden by a factor of 20. In addition, the simulator&lt;br&gt;
shows results that are consistent with the diffusion-based approximation. However,&lt;br&gt;
discrepancies are found because of the local effects of the neutron noise source and the strong&lt;br&gt;
variations of material properties in the system, which are expected to be better reproduced by a&lt;br&gt;
higher-order transport method such as the one used in the new solver.&lt;/p&gt;</subfield>
  <datafield tag="773" ind1=" " ind2=" ">
    <subfield code="n">doi</subfield>
    <subfield code="i">isVersionOf</subfield>
    <subfield code="a">10.5281/zenodo.3813172</subfield>
  <datafield tag="024" ind1=" " ind2=" ">
    <subfield code="a">10.5281/zenodo.3813173</subfield>
    <subfield code="2">doi</subfield>
  <datafield tag="980" ind1=" " ind2=" ">
    <subfield code="a">publication</subfield>
    <subfield code="b">thesis</subfield>
All versions This version
Views 5555
Downloads 1515
Data volume 31.5 MB31.5 MB
Unique views 3939
Unique downloads 1515


Cite as