Target Facilities 6/17
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This Section includes the following interfaces:
2.5.3.1 Target Facilities -Accelerator Facilities interface
In the current IFMIF planning, two targets with a common lithium loop will be constructed in the initial stage. In this stage, only one target is operated at any time with a total heat load of 10 MW (40-MeV deuteron energy).
In future expansion, two additional beam lines of 125 mA each would be added. The two targets could then be operated simultaneously, with up to two beam lines (250 mA) per target. The Target-Accelerator Facilities must take this future expansion into account in the design layout.
Figure 2.5.2-18. Lithium heat exchanger (all dimensions in mm).
The gate valves, which are installed at a point about 4 m from the outside surface of the target/test cell shielding wall, define the boundary between the target and accelerator.
Within this 4-m region, an evacuation system to maintain the low pressure of 10-4 Pa at the gate valve is installed for each of the beam lines. The diameter of the evacuation tubes will be about 20 cm. A lithium vapor/mist trapper and a turbo molecular pump (pumping rate about 5000 L/s) are connected in series to each evacuation tube. These turbo molecular pumps will be set up on the under floor and their outlet will be connected to the building's evacuation system which is able to treat the tritium containing gas. Two horizontal beam lines of the upgrade will be initially plugged and welded closed by shielding material.
2.5.3.2 Target Facilities - Test Facilities interface
There are two interface issues. The first one is gas-tight seals to maintain the test cell pressure to as low as 10-1 Pa for the target with a backwall, and 10-3 Pa for the free jet target. The target assembly has three components which penetrate the test cell vacuum boundary. Two of these are the lithium inlet and outlet of the target assembly, and the third is the end of the beam transport tube. These components will be subjected to the thermal cycling effect during startup and shutdown operations so the flexible seals method will have to be applied. In addition, seals around the edges of the replaceable backwall is needed to maintain different vacuum requirements in the target chamber and test cell.
The second issue is that of a remote handling system for the target assembly. Replacement of the target assembly or the back plate is performed by this system from the upper side of the test cell. This remote handling procedure requires first the removal of the test cell upper shield and the test assemblies. An example of the remote handling operation is illustrated in Figure 2.5.3-1.
Figure 2.5.3-1. Schematic of the remote handling system.
2.5.3.3 Target Facilities - Conventional Facilities interface
Only one interface issue with Conventional Facilities is identified, the tritium evacuation interface. The outlet of the vacuum pumps that are installed for the evacuation of the target-HEBT interface, quench tank, surge tank and drain tank is to be connected to the gas evacuation system of the building. The system is operated to control the level of tritium discharged from the building.
Remote handling capability for insertion and removal of the traps will have to be included as part of the Target Facilities, so has not been included as an interface. The details of the system will be provided in the engineering design phase.
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Target Facilities 6/17 |
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