Processing several thousand tonnes of uranium a year, UK Fuel Business, based at Springfield Fuels has the experience and technology to manufacture fuel for all major designs of nuclear reactor across the globe. UK Fuel Business has produced fuel for all of Britain's nuclear power stations aswell as fuel and itermediate products for other customers.
Springfields near Preston was the first plant in the world to make nuclear fuel and has produced several million fuel elements and provided products and services for over 140 reactors in more than 12 countries. At the time of writing, 15% of the UK electricity production is generated using fuel produced at the Springfields Site.
A Critical item in the production flow of fuel rods is the Pin Store Crane Robot. It transfers stainless steel tubes from one part of the manufacturing process to another and needs to provide reliable and smooth motion, requires minimal maintenance and is located in a production area where personnel are present, thus noise and safety are important factors. The robot comprises of a 2300 mm stroke linear actuator for the X axis and a 700 mm stroke linear actuator for the Z axis with a pneumatic gripper with which it picks up the tubes.
The existing cassette load pick and place robot was reaching the end of its useful life and spares were becoming increasingly difficult to source. A study conducted by Springfields Engineers determined that a new Cartesian robot system with new controls and simplified in-feed system would be required to meet the plants future requirements.
The new machine had to work within the existing area and was to go through exhaustive off-site testing before delivery and installation on site. The path between switching off the old machine and switching on the new machine had to be as smooth as possible.
SMS have expert knowledge of many automation systems and have extensive experience of building Cartesian robot systems. SMS use 3D modeling software and detailed project management and documentation and were able to keep Springfields fully aware of the design process as it progressed so that the project implementation plan could be fine tuned as deemed necessary to lower the risk and lower the costs.
Using tried and tested electrical and control techniques SMS were able to design the pick and place system within the time frame required. The gantry robot used a belt actuator with internal linear bearing rail for the 4 metre X axis and a ball-screw linear actuator for the vertical Z axis - all axes had integral fail-safe brakes. The product in-feed system was redesigned to offer a more reliable and simple solution. The product was positioned one at a time under the gripping system which in turn picked up the product and presented it to a vision system which identified the product code and relayed back the data to a supervisory computer. The supervisory computer then sent data back to the robot control system to determine which cassette the robot should place the product in.
All guarding and safety control systems designed by SMS were tested to the agreed European standards including comprehensive electrical wiring testing. All drive and servo safety control features were incorporated in the design.
The most effective method of testing, proving and debugging a system off site is to try and simulate as far as practical the on site installation conditions. Therefore a test rig was fabricated at SMS’s premises. The actuators were assembled onto a frame modeled on the existing site steelwork and all the wiring connected between the robot and the control panel. As the project time scales had been kept on target this allowed for rigorous works testing of the entire package. Once the client’s engineers had performed their own tests at SMS and were satisfied the system was disassembled and shipped to site. The comprehensive use of the 3D machine design coupled with SMS’ extensive knowledge of automation and positioning control systems meant that there were very few problems during the whole project lifecycle. Any minor variations during design could be accommodated because the design was completed in a virtual environment before any fabrication took place. This meant that all project budgets and timescales were met and hand-over to Springfields took place with minimum training.
Careful thought had gone into minimizing offline time at site resulting in a detailed and systematic work plan of events leading up to the point where it was necessary to stop production. The floor standing panel was positioned and then cable management, cabling and connection to the motors and gearboxes, which were disconnected from the actuators. This enabled a proof check of all the control system before replacing the new actuators in place of the old units, which required the process to be halted. The swap over was timed to coincide with an essential site maintenance window resulting in no disruption to production. In addition SMS provided site personnel with training on the new HMI screens and attended the restart and remained on hand in case of any glitches that might have occurred. In the event all went smoothly and the robot re-entered the production schedule.
SMS’s credentials as a practical and knowledgeable company are built around a central core of qualified engineers who have worked together for many years.
SMS staff have worked throughout the supply chain in the automation industry from project managers at end-users to distributors, components manufacturers, OEMs and SIs and as such have a great understanding of the industry and how to manage the supply chains within it. This extensive experience enables SMS to bring these projects to a successful conclusion and within the required budget and timescale whilst implementing some of the best quality products and solutions from the world of automation.
Springfield Fuels chose a company that has dealt with the real issues and would take the ownership and necessary attention to detail to ensure planned and methodical management of the project. In this case the result is a fully functional system that was made operational to plan and on time that should fulfill its task well into the 21st century.