Utilising Electron Beams to Find Design Solutions

Overview

Cambridge Vacuum Engineering (CVE) has commissioned a unique electron beam system for Tokamak Energy Ltd, who will use the machine to find design solutions for divertor components and progress their pioneering work towards making commercial fusion energy a reality.

Fusion Energy

Based in Oxfordshire, UK, Tokamak Energy is striving to deliver a new source of clean energy to the world by utilising the potential of fusion power.

Fusion power is harnessed from the joining of small atomic nuclei to form larger ones, resulting in a release of energy. This is the same process that fuels the Sun, and Tokamak Energy want to recreate it here on Earth in their compact spherical tokamaks.  It is a scalable energy solution that is safe, clean, and plentiful.

Material Properties

As part of the manufacturing process, Tokamak Energy needs to find the best-suited material to use inside the divertor. The divertor is the exhaust system that extracts unwanted particles from the plasma inside of the Tokamak.

To achieve this, they required a solution to test and find materials and coolant configurations which optimise performance under high heat fluxes.

Advanced Electron Beam Technology

CVE designed a unique electron beam system that fit this requirement – a 60kV, 6kW machine able to produce 100mA of beam power.

The electron beam will rapidly deflect over a 30mm2 target,  simulating the heat loads on various components that Tokamak Energy will use in their tokamak.

These prototype tests will then be analysed using thermocouples and an infrared camera.

CVE’s rapid deflection technology and custom pattern generator make this process easier, allowing the beam to fire over the target area in the user’s defined pattern – at speeds of up to 10kHz. Including replicating the quasi-gaussian profile of the heat flux on divertor targets.

Typically, CVE design and manufacture electron beam machines for welding applications, so working on this project provided an exciting opportunity for knowledge transfer and innovation in a new field.

Tokamak Energy hopes to use their spherical Tokamak to form the basis of the commercial module that will deliver electricity into the grid.  You can find out more about their ground-breaking work on their website.

Here, you can download this case study as a PDF.

Figure 1. Custom-built electron
beam system.

Impact of Industry 4.0 in Automotive Manufacturing

What is Industry 4.0?

Industry 4.0, or the fourth industrial revolution, is the transition towards using artificial intelligence, cyber-physical systems, and other digital technologies in manufacturing processes and business models.

An industrial revolution is a transition within the manufacturing industry to a new production process.

The first industrial revolution saw the advent of mass production, utilising water and steam power, the second industrial revolution built on this by introducing electricity and assembly lines, with the third industrial revolution implementing computers and some automation practices.

Industry 4.0, first coined in the early 2010s, builds on all of the previous industrial revolutions by transforming existing manufacturing practices and factories into so-called ‘smart factories’ or ‘factories of the future.’

The Automotive Industry and Industry 4.0

Much of the automotive industry is being driven by the implementation of industry 4.0 technology: such as additive manufacturing (also known as 3D printing), internet of things (IoT), big data or smart machines – resulting in greater efficiency, traceability, and safety throughout the entire supply chain.

This has extended to the industrial internet of things (IIoT), which refers to networks of industrial devices that are all connected to the internet, collecting, exchanging, and analysing new insights.

Below we have explored some areas in which industry 4.0 has impacted the automotive industry and the production of motor vehicles – and how CVE’s welding machines and systems serve these requirements – consistently ensuring optimal production.

Manufacturing Execution Systems (MES)

Manufacturing execution systems (MES) are computerised systems used in manufacturing processes to monitor the transformation of materials throughout their production process.  An MES allows you to track parts, providing traceability throughout the entire product lifecycle and the ability to use big data to improve decision-making processes in the real-world.

This is an effective way to track parts from raw material to a component to use in commercial vehicles.

Figure 1 and 2: Example automotive components with DMX code engraving made using a CVE EB welding machine.

High-Speed Data Capture

CVE’s electron beam and laser welding machines can be enhanced with our high-speed data capture.

A dedicated PC integrates into the welder, enabling high-speed and high-channel-count logging of welding parameters: up to 3m samples per section (single channel), with counts up to 80 channels.

Other benefits include:

  • Capture up to 32 channels of high-resolution data up to 20,000 times per second
  • Data log file and report for traceability
  • Intuitive review programme providing detailed analysis of welds
  • User-definable channels are available, including thermocouples and strain gauges

The data capture logs every weld in its own file for easy review – you can also generate a serial weld report for traceability, with a review programme for easy data review and real-time data export capability to Excel or CSV.

Electrification and Electric Vehicles

A shunt resistor measures electrical current by calculating the voltage drop over the resistor.

The main application for shunts is within the battery management systems of most type of automobiles: including standard fuel, hybrid, and electric vehicles. Shunt resistors ensure the batteries are performing optimally and prolong battery life.

With the global trend in the automotive market towards electrification, the demand for battery and battery-related products has never been greater.

CVE has experience in welding machines for this application and below you can find an example weld of material used for shunt resistors in electric vehicles.

Figure 3: Weld cross-section of copper manganin for electric vehicle shunt resistors.

Electron Beam Welding in Nuclear Industry

The Emergence of Electron Beam Welding in the Nuclear Industry - Is It Viable?

Within the nuclear industry welding of “thick section” components can be completed through various processes that are cost-effective, but the presence of residual magnetism in the materials has hindered the effective application of these processes. For many years the aim has been to find a suitable process that can be used more widely across the nuclear industry.

Even though output within nuclear is low, the safety-critical nature of these components demands a solution. Typically, the welding of “thick section” components such as pressure vessels within the nuclear industry has traditionally been performed using arc-welding techniques, which require multiple weld passes with an interstage non-destructive examination (NDE) and preheating of the component to reduce the risk of hydrogen cracking.

For a nuclear plant, the joining of components is currently used through the use of the tungsten inert gas (TIG) process. TIG welding of “thick-section” pressure vessels such as the reactor pressure vessel is an expensive and time-consuming practice involving extensive pre-work including fixtures, tooling, pre-heating of the components and multiple weld passes. Another drawback to using the TIG process is that it can only penetrate to a certain depth so thick-section welding is executed by filling the weld groove with several passes. Typically, this involves up to 100 runs of weld for a typical reactor pressure vessel section of 140mm or greater.

Consequently, there are a few disadvantages of using this process, namely multiple runs requiring preheating, inter-pass temperature control and inter-stage inspection by NDE throughout the whole process. The welding, inspection and completion of an RPV, therefore, takes many weeks, even months thus accounting for a vast proportion of the fabrication cost and component lead-time. Historically, there have been many attempts to deploy electron beam welding (EB) with local vacuum pumping, but most were hampered by the need to work at a high vacuum.

Previously, trade organisation, The Welding Institute has demonstrated that operating the EB process in the pressure range of 0.1-10m bar, so-called ‘reduced pressure’ in preference to high vacuum ~10-3mbar offers possibilities of more reliable deployment of local sealing and pumping for EB welding on a large structure. In the late 1990s, TWI developed a high power (60kW) EB welding system for girth welding of long offshore oil and gas transmission pipelines.

Excellent weld quality was achieved consistently with rudimentary pumping and flexible rubber seals and the process showed that there was a good tolerance to material cleanliness, fit-up, surface condition and working distance with the potential to fully girth weld 40mm wall thickness, 711mm diameter pipe sections, in less than five minutes.

Recent Developments of Electron Beam Welding - Ebflow

The more recent developments of electron beam welding technology offer the opportunity to weld “thick-section” components in a single pass and negate the need for (NDE), which means there’s a significant saving in time and cost in the fabrication of nuclear pressure vessels. Furthermore, elimination of the preheating step is possible since the EB process is carried out in a vacuum environment.

Compared with other welding processes there are many advantages of using electron beam welding within the nuclear industry. It can offer significant savings in cost and time for “thick-section” fabrication due to the rapid joining rate resulting from the process of welding the full joint thickness in one single pass.

However, due to the physical size and geometry of nuclear pressure vessels, traditional vacuum chambers would be prohibitively expensive when considering the low volume of output in the nuclear industry. Currently being pioneered in Britain, Cambridge Vacuum Engineering has recently launched a revolutionary local vacuum EB technology called Ebflow.

The EBManPower project, which is a joint- collaboration between CVE, TWI, U-Battery and Cammell Laird, will implement and validate the first Ebflow system within a large-scale fabrication facility for cost-effective manufacture of large-scale power generation infrastructure.

The Ebflow technology will specifically focus on reducing the cost of “thick section” steel structures applicable for both nuclear and off-shore wind structures. The collaborative partners are hopeful that their project will be critical in helping Ebflow to reach the marketplace and work in a real-world environment.

Compared with other welding processes there are many advantages of using Ebflow technology within the nuclear industry.

This particular project aims to manufacture components for nuclear power plants. Similar processes have been successfully applied in other industrial sectors, but this is the first time this approach has been applied within the power sector.

Thick Section Steel Structures

The demand for “thick section” steel structures in the power generation is already strong and will continue to grow over the years. Currently to produce a typical 100-metre long monopile (100mm thick) it can take more than six thousand hours of ‘arc-on’ welding time. However, the Ebflow system, based on high productivity electron beam welding can reduce the welding time involved to less than 200 hours equivalent to a 85% cost reduction.

Due to complete in 2021, the EBMan Power project aims to will resolve many years of development of trying to attempt and deploy electron beam welding within the global industry.

This will become a reality, rather than a possibility and may help to relieve some of the production pressures the world currently faces as well as contributing to the solution of what is known as the “energy trilemma” (low carbon, secure and affordable energy) and enabling a low carbon economy.

EBManPower Project – Modular Reactor

Background to the Emerging MMR Market

Micro modular reactors (MMRs) are a type of nuclear fission reactor that are smaller than conventional reactors and manufactured at a plant and then brought to a site to be fully constructed. Modular reactors allow for less on-site construction, increased containment efficiency, and heightened nuclear materials security. MMRs have been proposed as a less expensive alternative to conventional nuclear reactors.

U-Battery is a micro modular reactor (MMR) that will be able to produce local power and heat for a range of energy needs. The original challenge was to design an economically viable, modular nuclear power generation system that is intrinsically safe. Putting this into context, large scale nuclear reactors require high capital investment and heavily rely on the infrastructure of nuclear sites.

Designers were therefore motivated to develop smaller-scale reactors, especially for developing countries and remote areas off main power grids. The development of micro modular reactors presents a host of economic, industrial and environmental opportunities, contributing to the solution of what is known as the “energy trilemma” (low carbon, secure and affordable energy) and enabling a low carbon economy.

The Welding Challenge

Globally, 79% of electricity is generated by thermal processes, in which conventional power plants provide over 62% of the global electricity supply and the remaining 17% is by nuclear fission processes and this is expected to increase further (IEA, 2015).

Thermal power plants make use of a large number of thick section (greater than 20mm) components for many parts of the primary circuit; pump and valve bodies, ancillary systems and other safety-critical components. Furthermore, offshore wind demand in the UK requires more than one thousand structures (towers and foundations) or 1 million tonnes of steel to be cost-effectively fabricated on an annual basis.

The demand for “thick section” steel structures in power generation is already strong and continues to grow. The ability to fabricate these thick section structures cost-effectively is in part limited by the welding time and associated cost; to produce a typical 40-metre long monopile (60mm thick) can take more than six thousand hours of ‘arc-on’ welding time. The long term benefits of this partnership will be increased revenues and exports as well as the securing of high-value jobs in the manufacturing and low-carbon energy sectors.

The EBManPower Solution

To reduce cost the manufacturing time needs to be significantly reduced.

Cambridge Vacuum Engineering (CVE) has developed the Ebflow system, based on high productivity electron beam welding, which can reduce the welding time involved to less than 200 hours, equivalent to an 85% cost reduction. The EBManPower project will implement and validate the first Ebflow system within a large-scale fabrication facility to enable cost-effective manufacture of large scale power generation infrastructure.

Cammell Laird is one of the UK’s heavy fabrication shipbuilders and is the manufacturing partner for the U-Battery micro modular reactor (MMR) system. The EBManPower project is due to complete in 2021 and is valued at £1.5 million. The Ebflow system will be deployed at the Cammell Laird site in Birkenhead to fabricate a demonstration modular reactor pressure vessel for the U-Battery, and other related energy products in a cost-effective manner. This practical demonstration will be critical in driving the widespread deployment of the new cost-effective solutions to meet low carbon needs across the energy sector in the UK and overseas.

Wider Project Benefits

In the longer term, a key objective of EBManPower is to stimulate the development of a flexible and efficient advanced manufacturing technology (electron beam welding) for the manufacture of components for nuclear power plants. Similar processes have been successfully applied in other industrial sectors, but this is the first time this approach has been applied within the power sector.

The project is at its heart focused on reducing the cost of “thick section” steel structures applicable for both nuclear and off-shore wind structures. EBManPower will exploit CVE’s revolutionary EBFlow system and will innovate, demonstrate and provide a near to market result; validation in a real-world environment is the ultimate aim. The project will take a technology concept, the feasibility of which has already been proven, and make the final push to reach the marketplace. The results will be used to enable its UK based consortium to enter and compete in the power industry plant component supply chain as well as bringing opportunities for other sectors and clients.

“Our revolutionary Ebflow technology, fully developed and pioneered in Britain, will transform the productivity of fabrication processes throughout the world of heavy engineering. In many cases, the speed of welding can be 30 times faster than current methods.” Bob Nicolson, Managing Director at Cambridge Vacuum Engineering.

Download the full case study here.

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