SMS Build Automated Material Transport System for Nuclear Fuels Company
Background
Processing several thousand tonnes of uranium a year, Springfields Fuels Ltd has the experience and technology to manufacture fuel for all major designs of nuclear reactor across the globe.
Springfields Fuels Ltd, owned by Westinghouse, has produced fuel for all of Britain’s nuclear power stations as well as fuel and intermediate uranium products for overseas customers.
Springfields, near Preston, was the first plant in the world to make commercial nuclear fuel and to date has produced several million fuel elements. They have provided products and services for over 140 reactors in more than 15 countries. 15% of UK 
electricity production is generated using fuel produced at the Springfields site.
Fuel Pellet Transport and Storage system
A crucial part of the production flow of fuel rods is the transportation and buffering of fuel pellets. Pellets pass through a centreless grinder at a constant rate but the assembly of fuel rods takes place over 16 hours within a 24 hour period. Therefore, it was necessary to design a means of transferring pellets from the grinder to the fuel rods whilst allowing temporary storage and “feedback” into the process.
SMS Machines and Automation Ltd (SMS) were employed to work alongside SFL Project Engineers and the Production team to produce a Project Definition Document (PDD) which proposed and defined the specification after evaluating several possible methods. SMS were subsequently awarded the contract to design and build the transport system
SMS decided upon a Flexlink accumulating conveyor to provide the transport and accumulating buffer system and designed a sequence of automatic gating systems and robotic arms to count and place the correct number of pellets on the transport pallets. The conveyor system was chosen to provide “jerk free” operation, because the pellets are very brittle and transportation had to be very smooth. Particular attention was paid to the
smooth transition between equipment cells so that no chips or scratches would occur. The robotic arms and control system were designed and built by SMS as custom items to meet the requirements of the overall system and were designed to provide synchronous operation with the conveyor system.
Gating systems are used to route pallets into a buffer storage area when necessary and the pallets could be rerouted back into the pellet unload area when additional pellets are required.
The room in the factory has an extraction system making the pressure slightly negative. The complete pellet transport system has an air tight cloche with secondary extraction which includes access hatches, gloveports and light curtains. The whole system is controlled by a high level safety controller to allow safe and yet productive operation to take place.
SMS have carried out many automation projects and have partners throughout the world and so were able to select from the best products the automation world has to offer in terms of quality and reliability whilst remaining competitively priced.
The most effective method of testing, proving and debugging a system off site is to try and simulate as far as practicable the onsite installation conditions. Therefore, a test rig was fabricated at SMS’s premises. The actuators were assembled onto a frame modelled 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. Much thought was put into the best use of machine devices and how quickly they could be reconnected using plugs and connectors and a suitable scheme was developed and used.
The comprehensive use of 3-D machine design coupled with SMS extensive knowledge of automation and positioning controls 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.
In one instance SMS were able to present a 3-D virtual tour of the complete system to representatives of the various “stakeholders” of the finished line including production and safety. Each was able to make comments as to the suitability of various mechanisms before site implementation.
The Implementation Stage – On-Site
The system was transported to site and assembled using SMS staff alongside SFL staff. Full testing took place including numerous “dummy” runs using steel bearings to detect and eliminate any major snagging items.
Conclusion
SMS’s credentials as a practical and knowledgeable company are built around a central core of qualified engineers who have worked in automation for many years.
The project allowed SMS to display at the highest level its ability to design, build, implement and project manage a complex system for a high profile customer.
Springfields chose SMS due to their longstanding history of partnership. They were confident that SMS’s expertise could deal with the real issues of design and installation on a project of this complexity. SMS is a company that has taken early ownership and has provided the necessary attention to detail to manage the project in a planned, methodical manner. The result of this project is a fully functioning operational line, integrated with existing equipment that was completed to plan and on time, that should fulfill its task well into the 21st century.
The pellet transport system could be adapted for use in any industry where the transport and buffering of small parts is required.