Key Enabling Design Features of the ITER HNB Duct Liner

Key Enabling Design Features of the ITER HNB Duct Liner

Key Enabling Design Features of the ITER HNB Duct Liner 150 150 Mathew
CCFE-PR(17)38

Key Enabling Design Features of the ITER HNB Duct Liner

The Duct Liner (DL) for the ITER Heating Neutral Beam (HNB) is a key component in the beam transport system. Duct Liners installed into equatorial ports 4 and 5 of the Vacuum Vessel (VV) will protect the port extension from power deposition due to re-ionisation and direct interception of the HNB. Furthermore, the DL contributes towards the shielding of the VV and superconducting coils from plasma photons and neutrons. The DL incorporates a 316L(N)-IG, deep-drilled and water cooled Neutron Shield (NS) whose internal walls are lined with actively cooled CuCrZr Duct Liner Modules (DLMs). These Remote Handling Class 2 and 3 panels provide protection from neutral beam power. This paper provides an overview of the preliminary design for the ITER HNB DL and focusses on critical features that ensure compatibility with: high heat flux requirements, remote maintenance procedures, and transient magnetic fields arising from major plasma disruptions. The power deposited on a single DLM can reach 300 kW with a peak power density of 2.4 MW/m2. Feeding coolant to the DLMs is accomplished via welded connections to the internal coolant network of the NS. These are placed coaxially to allow for thermal expansion of the DLMs without the use of deformable connections. Critically, the remote maintenance of individual DLMs necessitates access to water connections and bolts from the beam facing surface, thus subjecting them to high heat flux loads. This design challenge will become more prevalent as fusion devices become more powerful and remote handling becomes a necessity. The novel solutions implemented to overcome this are detailed and their performance scrutinised. The designs presented include tungsten caps that protect bolted and remotely welded connections by radiating heat away, and explosion bonded CuCrZr/Stainless Steel panels designed to reduce by a factor of 10 the eddy current torques caused by plasma disruptions.

Collection:
Journals
Journal:
Fusion Engineering and Design
Publisher:
Elsevier
Published date:
10/01/2015