steady state, and two kinds of calculation modes in steady state are compared and
discussed: the k-eigenvalue mode and the alpha-eigenvalue mode.
Chapter 2 shows a brief explanation of KUCA experiments and the major
results. Analyses of the experiments and discussion are described in Chap. 3, and
the conclusions are summarized in Chap. 4.
13.2 Experiment at KUCA and Measured Results
This chapter shows a brief explanation of experiments performed at KUCA for the
convenience of easy understanding of the analysis described in the next chapter.
Experiments modeled on the ADSR were performed at the A-core with adjacent
D+ accelerator. A typical core configuration is shown in Fig. 13.1 for the case of
13 fuel rods. Each square cell is 2 in. Â 2 in. in size, with size in the horizontal
direction about 1.5 m, composed of a central 40-cm-thick fuel region and upper and
lower polyethylene reflector regions. All control rods are inserted through the
experiment. Accelerated D+ ions are hit with tritium target, depicted as T-target
in Fig. 13.1, and 14 MeV neutrons produced by D-T reaction at T-target are injected
into the core region composed of the fuel rods, polyethylene reflector, etc. Neutrons
are injected from outside the core region in this experiment.
The target subcriticality was widely changed by changing the number of fuel
rods from 19 to 6 to check the validity of the fiber scintillation counter used in the
measurement. The subcriticality of the system was evaluated by the so-called
extrapolation area ratio method proposed by Gozani [1]. The counters used in the
experiments were set at several positions inside the core, and the measured results
summarized in Table 13.1 are the results obtained at the core central area, where the
most reliable results are expected. Measured subcriticality is from 2.3 [$] (19 fuel
rods case) to 49 [$] (6 fuel rods case).
13.3 Analysis and Discussion of Neutron Flux
The analysis results of neutron flux distribution and neutron spectrum are summarized in this chapter with some discussion. Neutron flux distribution and spectrum
in the core are shown in Sects. 13.3.1 and 13.3.2, respectively. All analyses are done
by a continuous energy Monte Carlo code named MVP-II [2] with JENDL-4.0 [3]
library. The code has the function to simulate the experiment not only in eigenvalue
mode but also in time-dependent mode, where the necessary time of neutron flight
is used to account for the elapsed time after the injection of DT neutrons.
In this chapter, fast and thermal neutrons are in the energy range less than 4 eV
and more than 100 keV, respectively.
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discussed: the k-eigenvalue mode and the alpha-eigenvalue mode.
Chapter 2 shows a brief explanation of KUCA experiments and the major
results. Analyses of the experiments and discussion are described in Chap. 3, and
the conclusions are summarized in Chap. 4.
13.2 Experiment at KUCA and Measured Results
This chapter shows a brief explanation of experiments performed at KUCA for the
convenience of easy understanding of the analysis described in the next chapter.
Experiments modeled on the ADSR were performed at the A-core with adjacent
D+ accelerator. A typical core configuration is shown in Fig. 13.1 for the case of
13 fuel rods. Each square cell is 2 in. Â 2 in. in size, with size in the horizontal
direction about 1.5 m, composed of a central 40-cm-thick fuel region and upper and
lower polyethylene reflector regions. All control rods are inserted through the
experiment. Accelerated D+ ions are hit with tritium target, depicted as T-target
in Fig. 13.1, and 14 MeV neutrons produced by D-T reaction at T-target are injected
into the core region composed of the fuel rods, polyethylene reflector, etc. Neutrons
are injected from outside the core region in this experiment.
The target subcriticality was widely changed by changing the number of fuel
rods from 19 to 6 to check the validity of the fiber scintillation counter used in the
measurement. The subcriticality of the system was evaluated by the so-called
extrapolation area ratio method proposed by Gozani [1]. The counters used in the
experiments were set at several positions inside the core, and the measured results
summarized in Table 13.1 are the results obtained at the core central area, where the
most reliable results are expected. Measured subcriticality is from 2.3 [$] (19 fuel
rods case) to 49 [$] (6 fuel rods case).
13.3 Analysis and Discussion of Neutron Flux
The analysis results of neutron flux distribution and neutron spectrum are summarized in this chapter with some discussion. Neutron flux distribution and spectrum
in the core are shown in Sects. 13.3.1 and 13.3.2, respectively. All analyses are done
by a continuous energy Monte Carlo code named MVP-II [2] with JENDL-4.0 [3]
library. The code has the function to simulate the experiment not only in eigenvalue
mode but also in time-dependent mode, where the necessary time of neutron flight
is used to account for the elapsed time after the injection of DT neutrons.
In this chapter, fast and thermal neutrons are in the energy range less than 4 eV
and more than 100 keV, respectively.
130
T. Kitada et al.