Project Details
Problem Statement
The HFIR-MFE-RB-19J materials irradiation experiment is a collaborative effort between both the US and Japan fusion programs to research tungsten as plasma facing components under divertor conditions and to evaluate blanket structural materials for DEMO Reactors. The objective of this experiment is to irradiate tungsten and RAFM steel specimens at controlled temperatures of 300°C, 500°C, 800°C and 1200°C in the Removable Beryllium (RB) position of the High Flux Isotope Reactor (HFIR). The capsule has a Gadolinium shield inside the capsule housing to reduce thermal neutron material interaction.
Technical Approach
The RB19J capsule contains six cylindrical holders located in four temperature zones 300°C, 500°C, 800°C and 1200°C. The lower 300°C temperature zone uses a DISPAL (dispersed oxide aluminum) holder and contains only F82H alloy specimens, while the upper three temperature zones use a POCO graphite AXF-5Q holder and contain tungsten and tungsten alloy specimens.
The temperature regions are separated by three 20mm Grade 5 Titanium holder spacers filled with grafoil inserts. Each holder spacer also contains a flux wire dosimetry specimen. The three dosimetry specimens 8A, 2U and 5H are located between holders 300°C & 800°C, 800°C & 1200°C and 1200°C & 500°C, respectively.
The effective internal subcapsule length is 480mm in total, with the reactor midplane crossing approximately 2 cm above the bottom of the 800°C holder. The bottom of the 300°C holder (position 3) is 217.9mm below the midplane while the top of the 500°C holder is 261.1mm above the midplane position.
The assembly of the RB19J capsule was completed in May 2016 and installed in HFIR in June 2016. The first irradiation cycle, 466, started June 14th 2016. Starting temperatures stabilized within design range for the 500°C and the 800°C. The 1200°C and the 300°C were lower and higher by about 50°C to 100°C respectively, than designed.
Benefit
This project will provide critical information on the use of tungsten for fusion reactor plasma facing components under divertor conditions and on the of F82H steel on blanket structural materials for DEMO Reactors.
Sponsor
This experiment was sponsored jointly by both the US and Japan Fusion Energy Programs.
Partners
Materials Science and Technology Division and the Fusion Materials for Nuclear Systems Division.
