ITER: In-vessel Viewing System

The Challenge

ITER is a collaborative international project to build the world's largest tokamak, a magnetic fusion device that has been designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy based on the same principle that powers our Sun and stars. The In-Vessel Viewing System will be deployed after plasma operations, to perform visual inspection and metrology of plasma facing components.

Key challenges

• Ability to operate at 70ºC in magnetic field of 4.6 Tesla
• Survive in 5x10-4Pa vacuum and high temperature (120ºC)
• Operate after exposure of up to 3.8kGy/h in-vessel (gamma)
• Withstand a total lifetime dose of at least 2.5MGy

Veolia's Solution

Veolia Nuclear Solutions (VNS) was contracted to develop the preliminary design of the IVVS by Fusion for Energy (F4E), the body of the European Union that is responsible for the EU's contribution to ITER.

The project included a large quantity of in depth system-level engineering, as well as mechanical and electrical subsystem design, with the intention to gain momentum towards design-decision making.

Once all design activities are completed the main focus moves again towards system-level analyses while remaining technological risks are mitigated through longer-term R&D.

Unique system to be deployed after plasma operations

The IVVS is unique in being the only piece of remote handling equipment that is stored directly inside the ITER vacuum vessel during plasma operations. It is exposed to gamma and neutron radiation along with a high magnetic field and vacuum. VNS used previous experience with the IVVS concept design and developed it using experienced engineers with novel solutions, to achieve the level of technical maturity required for the Preliminary Design Phase.

The benefits for our client

The activities covered by this project led to the point where the main design decisions have been made, the subsystem specifications are developed and mature enough to allow the efficient production of the preliminary design.

Benefits to our client included eight years of experience developing the IVVS design and similar remote handling equipment for the ITER project. This level of familiarity with the system has led to VNS developing a design of the highest quality. This experience is available and is being used to support other projects on the ITER programme.

System overview

The In-Vessel Viewing System (IVVS) in ITER consists of six identical units which will be deployed between pulses or during shutdown, to perform visual examination and metrology of plasma facing components. The system units are installed in vacuum vessel lower ports, each mounted on a deployment arm which positions the measuring equipment into the ITER plasma chamber. It allows for a quick response measuring system which verifies the integrity of the Tokamak plasma facing components without disrupting the planned experimental campaigns.