TEF-P is designed with referring to FCA, the horizontal table–split type critical
assembly with a rectangular lattice matrix. In this concept, the plate-type fuel for
FCA with various simulation materials such as lead and sodium for coolant,
tungsten for solid target, ZrH for moderator, B 4 C for absorber, and AlN for
simulating nitride fuel can be commonly used at TEF-P. Therefore, previous
experiments can be correlated with TEF-P experiments. The proton beam will be
introduced horizontally at the center of the fixed half assembly, and various kinds of
spallation targets can be installed at various axial position of the radial center of the
subcritical core. Application of MA fuel is one of the promising characteristics of
TEF-P. Installation of a partial mock-up region of MA fuel with air cooling is
considered to measure the physics parameters of the transmutation system. R&D to
utilize MA fuel by remote handling systems is under way.
8.3 Design of Spallation Target for TEF-T
To evaluate the feasibility of a designed beam window of TEF target, numerical
analysis with a three-dimensional (3D) model was performed. The analysis was
done by considering the current density and shape of the incident proton beam to the
target and the thermal fluid behavior of Pb-Bi around the beam window as a
function of flow rate and inlet temperature. The thickness of the beam window is
also considered from 2 to 3 mm. After the temperature distribution analysis,
structural strength of the beam window is determined to evaluate soundness of
the target. A concave shape beam window was used for this analysis. The prototype
design of the beam window for TEF target system is shown in Fig. 8.2.
The material of the beam window would be a type 316 stainless steel. The
concave section in the center part of the target was connected to the convex section
in the terminal part, and then it was connected to the straight tube. A straight tube
part has coaxially arranged annular and tube-type channels. The inner diameters of
the outside tube and inside tube were set to 150 and 105 mm, respectively. The total
length of the analysis region was 600 mm, which corresponds to an effective target
depth for the 400 MeV proton. An irradiation sample holder, which was installed in
the inner tube, holds eight irradiation specimens in the horizontal direction. The
size of each specimen was 40 Â 145 Â 2 mm. The rectification lattice having the
aperture of the plural squares type was installed at the front end of the sample
holder. A slit 2 mm in width was arranged along the side of the rectification lattice
to cool the sample holder by flowing Pb-Bi.
The thermal-fluid behavior of the target was analyzed by the STAR-CD. The
quarter-part model was set to tetra metric type and the divided face was set to a
reflected image condition. At first, Pb-Bi flowed through the annular region and
joined in the center of the beam window, and then, turned over and flowed in the
inner tube after having passed a rectification lattice and an irradiation sample. In a
default condition, flow rate at the inlet of annulus region was set to 1 l/s, and this
was equivalent to the flow velocity of 0.125 m/s. Because the Pb-Bi flow forms a
76
T. Sasa
assembly with a rectangular lattice matrix. In this concept, the plate-type fuel for
FCA with various simulation materials such as lead and sodium for coolant,
tungsten for solid target, ZrH for moderator, B 4 C for absorber, and AlN for
simulating nitride fuel can be commonly used at TEF-P. Therefore, previous
experiments can be correlated with TEF-P experiments. The proton beam will be
introduced horizontally at the center of the fixed half assembly, and various kinds of
spallation targets can be installed at various axial position of the radial center of the
subcritical core. Application of MA fuel is one of the promising characteristics of
TEF-P. Installation of a partial mock-up region of MA fuel with air cooling is
considered to measure the physics parameters of the transmutation system. R&D to
utilize MA fuel by remote handling systems is under way.
8.3 Design of Spallation Target for TEF-T
To evaluate the feasibility of a designed beam window of TEF target, numerical
analysis with a three-dimensional (3D) model was performed. The analysis was
done by considering the current density and shape of the incident proton beam to the
target and the thermal fluid behavior of Pb-Bi around the beam window as a
function of flow rate and inlet temperature. The thickness of the beam window is
also considered from 2 to 3 mm. After the temperature distribution analysis,
structural strength of the beam window is determined to evaluate soundness of
the target. A concave shape beam window was used for this analysis. The prototype
design of the beam window for TEF target system is shown in Fig. 8.2.
The material of the beam window would be a type 316 stainless steel. The
concave section in the center part of the target was connected to the convex section
in the terminal part, and then it was connected to the straight tube. A straight tube
part has coaxially arranged annular and tube-type channels. The inner diameters of
the outside tube and inside tube were set to 150 and 105 mm, respectively. The total
length of the analysis region was 600 mm, which corresponds to an effective target
depth for the 400 MeV proton. An irradiation sample holder, which was installed in
the inner tube, holds eight irradiation specimens in the horizontal direction. The
size of each specimen was 40 Â 145 Â 2 mm. The rectification lattice having the
aperture of the plural squares type was installed at the front end of the sample
holder. A slit 2 mm in width was arranged along the side of the rectification lattice
to cool the sample holder by flowing Pb-Bi.
The thermal-fluid behavior of the target was analyzed by the STAR-CD. The
quarter-part model was set to tetra metric type and the divided face was set to a
reflected image condition. At first, Pb-Bi flowed through the annular region and
joined in the center of the beam window, and then, turned over and flowed in the
inner tube after having passed a rectification lattice and an irradiation sample. In a
default condition, flow rate at the inlet of annulus region was set to 1 l/s, and this
was equivalent to the flow velocity of 0.125 m/s. Because the Pb-Bi flow forms a
76
T. Sasa