Demand on the availability of well-defined reactor experiments for validation
of computer codes for use in nuclear industry and nuclear technology is
everlasting. Users must be confident of the results obtained by the proven
computer codes and nuclear data libraries chosen in the models. The
well-defined (mostly historical) and evaluated reactor experiments (about
5000 in 2015) were collected continuously as the benchmarks within the frame
of the OECD/NEA international projects ICSBEP (since 1995) and IRPhEP (since
2003). The Handbooks of the Projects are published in electronic forms (at
the NEA web site of the OECD and at a DVD media) every year. This study is
aimed to (a) examine and evaluate reactor basic experiments, carried out in
the lattice of the natural uranium metal fuel in the heavy water of the RB
critical assembly first core in 1958, and (b) demonstrate their possibility
for validation of modern nuclear data libraries. These RB reactor basic
experiments include: (1) approach to criticality, (2) determination of the
reactivity gradient at the D2O critical level, (3) measurement of the
dependence of the D2O critical level on the D2O temperature, i. e. dependence
of the reactivity with change in the D2O temperature; (4) the critical
reactor geometrical parameter (buckling) measurements, (5) the migration
length measurements, (6) determination of the neutron multiplication factor
in the infinite lattice, and (7) the safety rods reactivity measurements.
Results of the experiments are compared to the results obtained using modern
nuclear data libraries of the ACE type by applying the MCNP6.1, a well-known
and proven computer code based on the Monte Carlo method. A short overview of
these experiments (done at the RB assembly) is shown. A brief description of
the neutron ACE type nuclear data libraries (created in the LANL, based on
the ENDF/B-VII.0 and ENDF/B-VII.1 files, or created in the OECD/NEA, based on
the JEFF-3.2 evaluated nuclear data files), used in this validation study, is
given. The benchmark models used for this validation study are described and
the obtained results were analyzed. It is concluded that most of these
reactor basic experiments, carried out in the lattice of the natural uranium
metal fuel rods and the heavy water of the RB critical assembly, can be used
as the benchmarks for validation of new nuclear data libraries. It may be
done after further evaluations of influence of missing data, information and
uncertainties in the material composition and geometry dimensions have been
prepared according to the IRPhEP criteria and standards.
A study on the use of the reactor basic experiments in the U-D2O lattices of the RB critical assembly for validation of modern nuclear data libraries
