Chapter 6
Nuclear Transmutation of Minor
Actinide
Cheol Ho Pyeon
Abstract Integral experiments on critical irradiation of neuptium-237 (
237 Np) and
americium-241 (
241 Am) foils are carried out in a hard spectrum core at KUCA with
the use of the back-to-back fission chamber, and Monte Carlo calculations together
with a reference nuclear data library are conducted for confirming the precision of
numerical simulations. Subcritical irradiation of minor actinide (MA) by ADS is a
very important step, before operating actual ADS facilities, in a critical assembly at
zero power, such as KUCA, which is an exclusive facility for ADS that comprises a
uranium-235 (
235 U) fueled core and a 100 MeV proton accelerator. The first significant attempt is made to demonstrate the principle of nuclear transmutation of MA
by ADS through the injection of high-energy neutrons into the KUCA core at a
subcritical state. Here, the main targets of nuclear transmutation of MA by the ADS
experiments are fission reactions of
237 Np and
241 Am, and capture reactions of
237 Np.
Keywords Nuclear transmutation · Minor actinides · BTB fission chamber ·
Neptunium-237 · Americium-241
6.1 Integral Experiments at Critical State
6.1.1 Critical Irradiation Experiments
6.1.1.1 Core Configuration
Critical irradiation experiments [1] were carried out in the A-core (reference core;
Fig. 6.1) that has polyethylene (PE) moderator and reflector rods, and two fuel
assemblies: normal “F” and special “f” (Fig. 6.2a, b, respectively). The normal fuel
assembly “F” is composed of 60 unit cells, and upper and lower polyethylene blocks
about 23
and 21
long, respectively, in an aluminum (Al) sheath (2.1 × 2.1 × 60
).
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_6
157
Nuclear Transmutation of Minor
Actinide
Cheol Ho Pyeon
Abstract Integral experiments on critical irradiation of neuptium-237 (
237 Np) and
americium-241 (
241 Am) foils are carried out in a hard spectrum core at KUCA with
the use of the back-to-back fission chamber, and Monte Carlo calculations together
with a reference nuclear data library are conducted for confirming the precision of
numerical simulations. Subcritical irradiation of minor actinide (MA) by ADS is a
very important step, before operating actual ADS facilities, in a critical assembly at
zero power, such as KUCA, which is an exclusive facility for ADS that comprises a
uranium-235 (
235 U) fueled core and a 100 MeV proton accelerator. The first significant attempt is made to demonstrate the principle of nuclear transmutation of MA
by ADS through the injection of high-energy neutrons into the KUCA core at a
subcritical state. Here, the main targets of nuclear transmutation of MA by the ADS
experiments are fission reactions of
237 Np and
241 Am, and capture reactions of
237 Np.
Keywords Nuclear transmutation · Minor actinides · BTB fission chamber ·
Neptunium-237 · Americium-241
6.1 Integral Experiments at Critical State
6.1.1 Critical Irradiation Experiments
6.1.1.1 Core Configuration
Critical irradiation experiments [1] were carried out in the A-core (reference core;
Fig. 6.1) that has polyethylene (PE) moderator and reflector rods, and two fuel
assemblies: normal “F” and special “f” (Fig. 6.2a, b, respectively). The normal fuel
assembly “F” is composed of 60 unit cells, and upper and lower polyethylene blocks
about 23
and 21
long, respectively, in an aluminum (Al) sheath (2.1 × 2.1 × 60
).
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_6
157