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Titel:
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Status of pseudo fission product cross sections for fast reactors: results of the SWG17, International Working Party on Evaluation Coordination of the Nuclear Science Committee, NEA-OECD
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Auteur(s):
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Gepubliceerd door:
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Publicatie datum:
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ECN
NUCLEAIR
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1-8-1998
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ECN publicatienummer:
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Publicatie type:
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ECN-R--98-014
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Overig
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Aantal pagina's:
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Volledige tekst:
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95
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Niet beschikbaar.
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Samenvatting:
Within the framework of the SWG17 benchmark organized by a Working Partyof the Nuclear Science Committee of the Nuclear Energy Agency (NEA), a
comparison of lumped or pseudo fission product cross sections for fast
reactors has been made. Four institutions participated with data libraries
based on the JEF2.2, EAF-4.2, BROND-2, FONDL-2.1, ADL-3 and JENDL-3.2
evaluated nuclear data files. Several parameters have been compared with each
other: the one-group cross sections and reactivity worths of the lumped
nuclide for several partial absorption and scattering cross sections, and the
one-group cross sections of the individual fission products. Also graphs of
the multi-group cross sections of the lumped nuclide have been compared, as
well as graphs of capture cross sections for 27 nuclides. From two
contributions based on JEF2.2, it can be concluded that the data processing
influences the capture cross section by about 1% and the inelastic scattering
cross section by 2%. The differences between the lumped cross sections of the
different data libraries are surprisingly small: maximum 6% for capture and
9% for the inelastic scattering. Similar results are obtained for the
reactivity effects. Since the reactivity worth of the lumped nuclide is
dominated by the capture reaction, the maximum spread in the total reactivity
worth is still only 5.3%. There is a systematic difference between total,
elastic and capture cross sections of JENDL-3.2 and JEF2.2 of the same order
of magnitude. Possible reasons for this discrepancy have been indicated. The
one-group capture and inelastic scattering cross sections of most of the
important individual fission products differ by less than 10% (root mean
square values). Larger differences are observed for unstable nuclides where
there is a lack of experimental data. For the (n,2n) group cross sections,
which are rather sensitive to the weighting spectrum in the fast energy
range, these differences are several tens of percents. The final conclusion
is that the present status of lumped nuclide cross sections for fast reactors
is satisfactory, although improvements are possible as indicated in this
report. 36 refs.
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