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| ITER Test Blanket Design |
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| ITER Test Blanket Design |
This is a project to help define what a Demo-relevant, power-producing blanket for a fusion power plant will look like and act like.
OK, so what is a "Blanket" for a power plant?A blanket is basically a form of a heat exchanger to convert the energy in the high-energy neutrons (14 MeV) formed in the fusion process into a useful form of thermal energy. Also this blanket generates one of the fuel elements, tritium, necessary to sustain the fusion reaction. The other fuel element, deuterium, is abundant in all water. So this is one of the inherent advantages of fusion - one of the fuel elements is abundant and the other is made while it is being consumed. When two atoms of hydrogen are fused together to form an atom of helium, some of the mass of the hydrogen is converted into energy, see figures below. The easiest fusion reaction to make happen is combining deuterium (or heavy hydrogen) with tritium (or heavy-heavy hydrogen) to make helium and a neutron. Tritium can be produced by combining the fusion neutron with the light metal lithium. Thus fusion has the potential to be a source of energy.
These experimental blankets are being designed by several industrial nations to be placed in the International Thermonuclear Experimental Reactor (ITER). The Boeing Company has been awarded multi-year contracts by the U.S. Department of Energy to help design the blankets and to correctly interface with the ITER device test ports. This Boeing team from St. Louis, MO, and Canoga Park, CA (Rocketdyne Division of Boeing North American, Inc.) is technically directed by Professor Mohamed Abdou from the fusion group in the University of California, Los Angeles within the School of Engineering and Applied Science, Mechanical and Aerospace Department. We also collaborate with Argonne National Laboratory and Idaho National Engineering Laboratory on these test blankets.
McDonnell Douglas also participates in the multi-national Test Blanket Working Group, consisting of representatives from the European Union, Japan, Russian Federation, and the United States.
The picture shown below illustrates how the test blankets will be installed into the horizontal test ports of ITER. There are twenty such ports that will house test blankets, remote maintenance equipment, plasma heating systems, and diagnostic systems. The test modules are inserted from the outside of the reactor (right to left on the picture), through the bioshield, and cryostat, and into the extension of the vacuum vessel. The test module is attached and supported from the backplate, a portion of which is shown. All the adjacent shielding blanket modules are not shown, but are mounted flush to form the torus-shaped first wall. The plasma would be at the extreme right hand side of the figure. This figure was constructed to examine the mounting scheme and the routing of the piping through the extension area and around or through the several layers of doors.
The above figure represents work in progress on ITER. It was presented to the Third ITER Test Blanket Working Group meeting held at Paris France, 23-25 September 1996. The general design concepts of the test blanket interfaces and maintenance approaches were adopted for use by ITER and the four parties that are developing test blankets. But work is continuning to refine these designs and interfaces.
A more recent example of the interface between the test blanket module and the ITER device is shown below. In order to assure that the test blanket assembly could be removed in a timely manner so as to not affect the operational availablity of the basic ITER device and to assure that the module could be installed as a fully tested assembly, the ITER project decided to mount most equatorial port systems from the vacuum vessel extension as opposed to the prior approach of mounting to the shielding blanket backplate. This will allow a complete assembly be installed in the vacuum vessel with the primary vacuum seal at the outer end of the vacuum vessel extension. Remote handling equipment can disconnect piping outside this interface and then remove the entire assembly and replace it with a new or refurbished assembly. This schematic is being used to examine interfaces and provide insight for more detailed design drawings.
