The Indian Test Blanket Module（TBM） program in ITER is one of the major steps in its fusion reactor program towards DEMO and the future fusion power reactor vision. Research and development（RD） is focused on two t...The Indian Test Blanket Module（TBM） program in ITER is one of the major steps in its fusion reactor program towards DEMO and the future fusion power reactor vision. Research and development（RD） is focused on two types of breeding blanket concepts： lead–lithium ceramic breeder（LLCB） and helium-cooled ceramic breeder（HCCB） blanket systems for the DEMO reactor. As part of the ITER-TBM program, the LLCB concept will be tested in one-half of ITER port no. 2, whose materials and technologies will be tested during ITER operation. The HCCB concept is a variant of the solid breeder blanket, which is presently part of our domestic RD program for DEMO relevant technology development. In the HCCB concept Li_2TiO_3 and beryllium are used as the tritium breeder and neutron multiplier, respectively, in the form of a packed bed having edge-on configuration with reduced activation ferritic martensitic steel as the structural material. In this paper two design schemes, mainly two different orientations of pebble beds, are discussed. In the current concept（case-1）, the ceramic breeder beds are kept horizontal in the toroidal–radial direction. Due to gravity, the pebbles may settle down at the bottom and create a finite gap between the pebbles and the top cooling plate, which will affect the heat transfer between them. In the alternate design concept（case-2）, the pebble bed is vertically（poloidal–radial） orientated where the side plates act as cooling plates instead of top and bottom plates. These two design variants are analyzed analytically and 2 D thermal-hydraulic simulation studies are carried out with ANSYS, using the heat loads obtained from neutronic calculations.Based on the analysis the performance is compared and details of the thermal and radiative heat transfer studies are also discussed in this paper.展开更多
Electrothermal metasurfaces have garneredconsiderable attention owing to their ability to dynamicallycontrol thermal infrared radiation. Although previousstudies were mainly focused on metasurfaces with infiniteunit c...Electrothermal metasurfaces have garneredconsiderable attention owing to their ability to dynamicallycontrol thermal infrared radiation. Although previousstudies were mainly focused on metasurfaces with infiniteunit cells, in practice, the finite-size effect can be a criticaldesign factor for developing thermal metasurfaces withfast response and broad temperature uniformity. Here, westudy the thermal metasurfaces consisting of goldnanorods with a finite array size, which can achieve aresonance close to that of the infinite case with onlyseveral periods. More importantly, such a small footprintdue to the finite array size yields response time down to ananosecond level. Furthermore, the number of the unitcells in the direction perpendicular to the axis of nanorodsis found to be insensitive to the resonance and responsetime;thus, providing a tunable aspect ratio that can boostthe temperature uniformity in the sub-Kelvin level.展开更多
文摘The Indian Test Blanket Module（TBM） program in ITER is one of the major steps in its fusion reactor program towards DEMO and the future fusion power reactor vision. Research and development（RD） is focused on two types of breeding blanket concepts： lead–lithium ceramic breeder（LLCB） and helium-cooled ceramic breeder（HCCB） blanket systems for the DEMO reactor. As part of the ITER-TBM program, the LLCB concept will be tested in one-half of ITER port no. 2, whose materials and technologies will be tested during ITER operation. The HCCB concept is a variant of the solid breeder blanket, which is presently part of our domestic RD program for DEMO relevant technology development. In the HCCB concept Li_2TiO_3 and beryllium are used as the tritium breeder and neutron multiplier, respectively, in the form of a packed bed having edge-on configuration with reduced activation ferritic martensitic steel as the structural material. In this paper two design schemes, mainly two different orientations of pebble beds, are discussed. In the current concept（case-1）, the ceramic breeder beds are kept horizontal in the toroidal–radial direction. Due to gravity, the pebbles may settle down at the bottom and create a finite gap between the pebbles and the top cooling plate, which will affect the heat transfer between them. In the alternate design concept（case-2）, the pebble bed is vertically（poloidal–radial） orientated where the side plates act as cooling plates instead of top and bottom plates. These two design variants are analyzed analytically and 2 D thermal-hydraulic simulation studies are carried out with ANSYS, using the heat loads obtained from neutronic calculations.Based on the analysis the performance is compared and details of the thermal and radiative heat transfer studies are also discussed in this paper.
文摘Electrothermal metasurfaces have garneredconsiderable attention owing to their ability to dynamicallycontrol thermal infrared radiation. Although previousstudies were mainly focused on metasurfaces with infiniteunit cells, in practice, the finite-size effect can be a criticaldesign factor for developing thermal metasurfaces withfast response and broad temperature uniformity. Here, westudy the thermal metasurfaces consisting of goldnanorods with a finite array size, which can achieve aresonance close to that of the infinite case with onlyseveral periods. More importantly, such a small footprintdue to the finite array size yields response time down to ananosecond level. Furthermore, the number of the unitcells in the direction perpendicular to the axis of nanorodsis found to be insensitive to the resonance and responsetime;thus, providing a tunable aspect ratio that can boostthe temperature uniformity in the sub-Kelvin level.
