Chapter 7
Neutronics of Lead and Bismuth
Cheol Ho Pyeon
Abstract Cross-section uncertainties of Pb and Bi isotopes could consequently
affect the precision of nuclear design calculations of preliminary analyses, before the
actual operation of upcoming ADS, since Pb and Bi are composed partly of coolant
material (lead-bismuth eutectic: LBE) in ADS facilities. The main characteristics
of LBE in ADS are recognized as follows: chemically inactive; high boiling point
mechanically; excellent neutron economy caused by large scattering cross sections.
From the viewpoint of neutronics, LBE exerts considerable impact on nuclear design
parameters for numerical simulations of neutron interactions of Pb and Bi isotopes.
As a suitable way of investigating cross-section uncertainties, sample reactivity worth
measurements in critical states are considered effective with the use of reference and
test materials in a zero-power state, such as a critical assembly, because integral
parameter information on cross sections of test materials can be acquired experimentally. For the required experimental study on Pb and Bi nuclear data uncertainties, the sample reactivity worth experiments are carried out at the KUCA core by
the substitution of reference (aluminum) for test (Pb or Bi) materials, and numerical simulations are performed with stochastic and deterministic calculation codes
together with major nuclear data libraries.
Keywords Sensitivity · Uncertainty · Sample reactivity worth · Lead · Bismuth
7.1 Sample Reactivity Worth Experiments
7.1.1 Core Configuration
7.1.1.1 Lead Sample Reactivity Worth
The lead (Pb) sample reactivity experiments [1, 2] were carried out in the A-core
(Fig. 7.1) that has polyethylene moderator (polyethylene “p” in Fig. 7.1) and reflector
C. H. Pyeon (B)
Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
e-mail: pyeon.cheolho.4z@kyoto-u.ac.jp
© The Author(s) 2021
C. H. Pyeon (ed.), Accelerator-Driven System at Kyoto University Critical Assembly,
https://doi.org/10.1007/978-981-16-0344-0_7
177
Neutronics of Lead and Bismuth
Cheol Ho Pyeon
Abstract Cross-section uncertainties of Pb and Bi isotopes could consequently
affect the precision of nuclear design calculations of preliminary analyses, before the
actual operation of upcoming ADS, since Pb and Bi are composed partly of coolant
material (lead-bismuth eutectic: LBE) in ADS facilities. The main characteristics
of LBE in ADS are recognized as follows: chemically inactive; high boiling point
mechanically; excellent neutron economy caused by large scattering cross sections.
From the viewpoint of neutronics, LBE exerts considerable impact on nuclear design
parameters for numerical simulations of neutron interactions of Pb and Bi isotopes.
As a suitable way of investigating cross-section uncertainties, sample reactivity worth
measurements in critical states are considered effective with the use of reference and
test materials in a zero-power state, such as a critical assembly, because integral
parameter information on cross sections of test materials can be acquired experimentally. For the required experimental study on Pb and Bi nuclear data uncertainties, the sample reactivity worth experiments are carried out at the KUCA core by
the substitution of reference (aluminum) for test (Pb or Bi) materials, and numerical simulations are performed with stochastic and deterministic calculation codes
together with major nuclear data libraries.
Keywords Sensitivity · Uncertainty · Sample reactivity worth · Lead · Bismuth
7.1 Sample Reactivity Worth Experiments
7.1.1 Core Configuration
7.1.1.1 Lead Sample Reactivity Worth
The lead (Pb) sample reactivity experiments [1, 2] were carried out in the A-core
(Fig. 7.1) that has polyethylene moderator (polyethylene “p” in Fig. 7.1) and reflector
C. H. Pyeon (B)
Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
e-mail: pyeon.cheolho.4z@kyoto-u.ac.jp
© The Author(s) 2021
C. H. Pyeon (ed.), Accelerator-Driven System at Kyoto University Critical Assembly,
https://doi.org/10.1007/978-981-16-0344-0_7
177