1 Introduction
7
burning plutonium and nuclear waste. An outstanding advantage of its use is the
anticipated absence of reactivity accidents when sufficient subcriticality is ensured.
Also, ADS is expected to provide capabilities for power generation, nuclear waste
transmutation, and a reliable neutron source for research purposes.
The ADS experimental facilities are being prepared for the investigations of
nuclear transmutation of MA and LLFP, as are the Transmutation Experimental
Facility (TEF) [6] at the Japan Atomic Energy Agency and the Multi-purpose
Hybrid Research Reactor for High-tech Applications (MYRRHA) [7] at SCK/CEN in
Belgium. Research activities on ADS involved mainly the experimental feasibility
study using critical assemblies and test facilities: MASURCA in France [8–10],
YALINA-booster and-thermal in Belarus [11–13], VENUS-F in Belgium [14–17],
and KUCA in Japan [18–78]. At these facilities, feasibility studies on ADS have
been conducted by combining a reactor core (fast or thermal core) with an external
neutron source by the D-T accelerator (14 MeV neutrons) or 100 MeV proton accelerator (KUCA only), through experimental and numerical analyses of reactor physics
parameters, including statics parameters: reaction rates, neutron spectrum, and
subcritical multiplication factor; kinetics parameters: subcriticality, prompt neutron
decay constant, effective delayed neutron fraction, and neutron generation time.
Here, to ensure measurement methodologies of the statics and kinetics parameters
and confirm numerical precision by stochastic and deterministic calculations, many
attempts were made for uniquely developing new-type and high-precision detectors,
and interestingly for introducing advanced-numerical approaches, respectively.
1.2.2 Feasibility Study at KUCA
At KURRI, a series of preliminary experiments on the ADS with 14 MeV neutrons
was officially launched at KUCA in 2003, with sights on a future plan (Kart & Lab.
Project) [79, 80]. The goal of the plan was to establish a next-generation neutron
source, as a substitution for the current 5 MW Kyoto University Research Reactor
established in 1964, by introducing a synergetic system comprising a research reactor
and a particle accelerator. High-energy neutrons generated by the interaction of highenergy proton beams (100 MeV) with heavy metal was expected to be injected into
the KUCA core, and finally, the world’s first injection [21] of high-energy neutrons
obtained by a new accelerator was successfully conducted into the KUCA core in
2009. The new accelerator is called the FFAG accelerator of the synchrotron type
developed by the High Energy Accelerator Research Organization in Japan.
Prior to actual ADS experiments with 100 MeV protons, it was requisite to establish measurement techniques for various neutronics parameters and the method for
evaluating neutronic properties of the ADS with 100 MeV protons. Uniquely, KUCA
has outstanding features of two external neutron sources (14 MeV neutrons and
100 MeV protons) and a variety of neutron spectrum cores, although the KUCA cores
provide almost a thermal neutron spectrum. For the accomplishment of research
objectives, a series of basic experiments with 14 MeV neutrons obtained by the
7
burning plutonium and nuclear waste. An outstanding advantage of its use is the
anticipated absence of reactivity accidents when sufficient subcriticality is ensured.
Also, ADS is expected to provide capabilities for power generation, nuclear waste
transmutation, and a reliable neutron source for research purposes.
The ADS experimental facilities are being prepared for the investigations of
nuclear transmutation of MA and LLFP, as are the Transmutation Experimental
Facility (TEF) [6] at the Japan Atomic Energy Agency and the Multi-purpose
Hybrid Research Reactor for High-tech Applications (MYRRHA) [7] at SCK/CEN in
Belgium. Research activities on ADS involved mainly the experimental feasibility
study using critical assemblies and test facilities: MASURCA in France [8–10],
YALINA-booster and-thermal in Belarus [11–13], VENUS-F in Belgium [14–17],
and KUCA in Japan [18–78]. At these facilities, feasibility studies on ADS have
been conducted by combining a reactor core (fast or thermal core) with an external
neutron source by the D-T accelerator (14 MeV neutrons) or 100 MeV proton accelerator (KUCA only), through experimental and numerical analyses of reactor physics
parameters, including statics parameters: reaction rates, neutron spectrum, and
subcritical multiplication factor; kinetics parameters: subcriticality, prompt neutron
decay constant, effective delayed neutron fraction, and neutron generation time.
Here, to ensure measurement methodologies of the statics and kinetics parameters
and confirm numerical precision by stochastic and deterministic calculations, many
attempts were made for uniquely developing new-type and high-precision detectors,
and interestingly for introducing advanced-numerical approaches, respectively.
1.2.2 Feasibility Study at KUCA
At KURRI, a series of preliminary experiments on the ADS with 14 MeV neutrons
was officially launched at KUCA in 2003, with sights on a future plan (Kart & Lab.
Project) [79, 80]. The goal of the plan was to establish a next-generation neutron
source, as a substitution for the current 5 MW Kyoto University Research Reactor
established in 1964, by introducing a synergetic system comprising a research reactor
and a particle accelerator. High-energy neutrons generated by the interaction of highenergy proton beams (100 MeV) with heavy metal was expected to be injected into
the KUCA core, and finally, the world’s first injection [21] of high-energy neutrons
obtained by a new accelerator was successfully conducted into the KUCA core in
2009. The new accelerator is called the FFAG accelerator of the synchrotron type
developed by the High Energy Accelerator Research Organization in Japan.
Prior to actual ADS experiments with 100 MeV protons, it was requisite to establish measurement techniques for various neutronics parameters and the method for
evaluating neutronic properties of the ADS with 100 MeV protons. Uniquely, KUCA
has outstanding features of two external neutron sources (14 MeV neutrons and
100 MeV protons) and a variety of neutron spectrum cores, although the KUCA cores
provide almost a thermal neutron spectrum. For the accomplishment of research
objectives, a series of basic experiments with 14 MeV neutrons obtained by the