Component Testing and Materials Development for Fusion Applications Using Materials Test Reactors
Fusion power plant operation will strongly depend on the economy and reliability of crucial components, such as first wall modules, tritium breeding blankets and divertors. Their operating temperature shall be high to accomplish high plant efficiency. The materials properties and component fabrication routes shall also assure long reliable operation to minimize plant outage. The components must be fabricated in large quantities based on demonstrations with a limited amount of test beds. Mock-ups and test loops will, through iteration processes, demonstrate the reliable operation under reference thermal-hydraulic conditions. 14 MeV neutrons escaping the plasma dominate the nuclear conditions near the first wall. Neutron transport analyses have shown that large portions of the components near the plasma have to cope with a neutron spectrum resembling that of a fission core. MTR's, Materials Test Reactors, have been used successfully to test components for fusion power plants. Their space and availability will also ensure their role as future test bed for (sub) components such as blankets, first walls and divertors. The future generation of MTR's will allow faster testing, because of the higher neutron fluxes possible with advanced driver fuels. The strong limitation of MTR's for fusion testing will remain the limited production of helium and hydrogen, because of the lack of 14 MeV neutrons. Though large parts of the fusion components are subjected to nearly fission neutron spectra, in the domain near the burning plasma 14 MeV neutrons are dominant. IFMIF will produce the 14 MeV neutrons to fill that gap by the end of the next decade. In the meantime the MTR's will generate relevant data for fusion power plant component design. After IFMIF is operational the new generation MTR's will still have a function in testing components in a nuclear environment. The new generation test reactors will also be used for the development of component operating at high temperature in the generation-4 fission power plants. The R&D climate will be most stimulating for cross fertilization of fission and fusion component development, leading to more efficient use of the earth's resources.
Design for in-pile thermal fatigue of first wall mock-ups under ITER relevant conditions
This paper describes the general design and the thermal analysis of an irradiation rig devoted to in-pile thermal fatigue testing of three actively cooled first wall (FW) mock-ups. The temperatures, stress distributions and stress amplitudes at the Be/CuCrZr interface of the mock-ups will be as close as possible to the values calculated for the international thermonuclear experimental reactor (ITER) FW panels. The heat flux will be provided by nuclear heating of high density (W) plates integrated on the Be-side. The assembly will be placed in the pool side facility of the high flux reactor in Petten. Thermal cycling is then arranged by mechanical movement towards and from the core box. As the thermal design of the irradiation rig is very critical, a pilot-irradiation will be performed to crosscheck the models used in the thermal and nuclear design of the rig.
Trouble-shooting dual arch impressions.
Dual arch impression techniques enable the dentist to capture an impression of the prepared tooth, the opposing teeth and the occlusal registration in one procedure. This saves chair time and impression material.