Photo Credit: Adrian Boliston [CC BY-SA 2.0], via Wikimedia Commons

For more information about Hinkley Point A, visit the Magnox website.

Last week some of the engineers from the Magnox team based at Hinkley Point A visited our testing facility in Axminster, Devon.

About Magnox

Magnox are an operations contractor responsible for safely managing twelve nuclear sites and one hydroelectric plant in the UK, working for the Nuclear Decommissioning Authority (NDA). Magnox are responsible for managing the sites through their lifecycles, overseeing all aspects of electricity generation, defueling, and decommissioning.

Decommissioning Hinkley Point A

Hinkley Point A is a nuclear power station located on the South West Coast of England in the county of Somerset, approximately 13km North West of Bridgwater. Magnox is currently managing the decommissioning of the twin reactor site. Hinkley Point A power station stopped generating in 2000 having completed 35 years of operation, generating a total of 103 TWh.

Currently, at Hinkley Point A, Magnox are in the care and maintenance (C&M) preparations stage which focuses on decommissioning and deplanting buildings and retrieving, treating and processing any waste in order to ready the site for C&M. This phase also ensures that any waste is moved to modern stores which are maintained. The types of buildings that will remain on site typically include reactor safestores, intermediate level waste stores or interim storage facilities; plus any additional structures that will be removed at final site clearance.

The Application

During the operation of the site, after the fuel elements were removed from the reactor and cooled, they were passed through a hydraulic press which stripped the metal cooling fins around the fuel element casings. These metal fins, which are radioactive, were then stored in bunkers/vaults. Some of these bunkers are filled with water which acts as shielding against the radiation.

As part of the decommissioning process, this waste is retrieved from the vaults to be dried, sorted and processed before long-term storage. Magnox contacted ACI because they were looking for a solution to dry the waste prior to it being sorted and processed.

One of the challenges to this application is there is nothing uniform about the parts that need to be dried – the size, shapes and materials of the scraps vary. After trialling heat lamps and bespoke “tumble dryer” inspired designs, Magnox contacted ACI to provide a blower-driven solution.

The Solution

A spot of research led them to ACI’s Spiral Drum Dryer – a system designed specifically for loose component drying. The spiral dryer comprises a single helix rotating drum constructed from perforated stainless steel, mounted horizontally.

Parts enter the drum via a simple chute whereupon they are exposed to a blower-driven air knife which is suspended in the centre of the drum.

The combination of the tumbling motion of the product, and the powerful, high velocity air stream produced by the air knife, means that emerging parts/components are dried both efficiently and effectively.

Once parts/components have been dried they can simply be collected manually or passed onto another process.

We explained to Magnox that the spiral dryer is flexible in design, configuration being dependent on the size of the components and desired throughput rate. With that in mind we invited Magnox to visit our testing facility*, with a (non-radioactive!) sample of the parts they were looking to dry, so that the ideal configuration could be determined.

Three engineers from Magnox came to do the testing. We began by wetting the parts to emulate the real-life environment. The scrap metal was then fed into the spiral drum dryer at a similar rate to match the throughput of the system at Hinkley Point A.

Here is a video we took on the day of the Spiral Dryer in action:

Magnox had use of our test facility for three hours, during which time they were able to thoroughly test the capabilities of our Spiral Dryer and determine whether it could achieve the results they were looking for. Our lab technician, Ian, was on hand throughout to assist with adjusting the configuration of the dryer. This meant that Magnox were able to try out different pressures and different air knife positions to discover what delivered the best results. By the end of the session, Magnox were satisfied that the Spiral Dryer was capable of drying the waste metal to their desired specification.

“Being able to visit ACI and use the test facilities there was definitely a worthwhile experience for us. We had only seen the spiral dryer in pictures and weren’t sure how well it would work with our waste, due to the random nature of the parts. However, coming to the test facility and experimenting with the dryer, we now know that we have a concept that works which can be built upon to reach our goal.” Project Engineer, Magnox

ACI has extensive R&D facilities which enable our customers to visit to fully evaluate the effectiveness and suitability of our products. Our testing facility is adaptable to meet the needs of a wide variety of applications.

To discuss your application with us, or to find out more about a specific system please email us using our contact form or call us on +44 (0)1297 529242 to speak with one of our application engineers.

*Please note it is not essential to visit our test facility. If you are unable to travel to us, you can ship us the parts/components and we will conduct testing on your behalf.