The Target Station 1 (TS1) Project has been put in place to ensure sustainability for TS1, and its continued operation for many years into the future, as it has run for over 35 years without significant maintenance or development work. The project will see many changes to the heart of TS1, including the design of the target and its cooling systems, the moderators, the reflector and all their associated services. This includes the monitoring instrumentation within the target station vessel; the target station controls; the trolley that the target, moderator and reflectors sit on; and the large area of plant that sits behind the target station.
The actual installation work will occur over a period of about a year, and the facility will have an extended shutdown during this period: TS1 will be shut down for 14 months for the work to happen. At the same time, work will be taking place to replace part of the linear accelerator, and this will take TS2 off for around 8 months from January 2021. Further details of planned proposal rounds and run cycles can be found on the Apply for Beamtime page.
2019 saw many milestones for the project, including the first time the new target was assembled. Its design, with ten individual plates of tantalum-clad tungsten electron beam welded together, took over a year to design and another year to build. Not only is the new target itself different, but the surrounding assembly also needed to be updated. The associated tooling and jigs used for handling the target during manufacture, installation and maintenance in the remote handling cell also needed updating.
Design engineering group with the new TS1 target
The design of the new water circuits was completed in 2018 based on the concept of four modules (skids) that can be fully and individually built in the new Harwell Facilities Building (R106), partially dis-assembled, and transported to the Target Services Area to form the basis of the new services trolley. The water plant and equipment was delivered over the following months, along with the skid bases, whilst design on the ancillary services and integration with existing infrastructure was progressed. In the first part of 2019, the build area in R106 was established, followed by the skid structures being assembled and the water plant being mounted ready for the pipework build. The welding of the pipework
for the main circuits is now nearing completion and is in the process of being
installed onto the modules, ready for testing.
The new design of the target, reflector and moderators (TRaM) for TS1 features pre-moderators for the first time, which are designed to improve performance and lifetime of the cryogenic moderators they sit above. The first set of pre moderators for the TS1 project are now complete, with spares currently in manufacture. Both the methane and hydrogen pre moderators have been tested and are assembled onto a full-scale mock-up of the TRaM for alignment checks. Both pre moderators have been designed to provide an optimal internal water flow and to ensure integrity of the vessel under the TS1 operating conditions.
All the joints of the vessels are made using the specialist technique Electron Beam Welding to ensure a minimal distortion of the assembly and a minimal heat affected zone on the materials. This contributes to a safer equipment and ensures a good fit of the Pre Moderators inside the Reflector due to the tight tolerances of the assembly.
Dan Blanco Lopez working on the pre-moderators
At the end of December 2019, the project hit another milestone: the delivery of the critical reflector assembly. The £3.4 million reflector, a core component in the centre of the target station, is made from nickel-plated solid beryllium blocks similar to the one used on Target Station 2. It has been developed to improve neutronic performance and to improve access to the cryogenic moderators. It was manufactured by Leading Metal Mechanic Solutions in their specialist beryllium manufacturing facility based just outside Santander in northern Spain.
ISIS Target Station 1 project team members in building R106.