Pile Fuel Cladding Silo decommissioning takes a step forward

Cutting operations underway at the top of the PFCS
Cutting operations underway at the top of the PFCS

Cumbria Nuclear Solutions Ltd (CNSL) has successfully started to cut up some of the interior of the Pile Fuel Cladding Silo (PFCS) facility at Sellafield to allow for its removal and disposal. The team consisting of James Fisher Nuclear (JFN) and Shepley Engineers Limited (SEL) are cutting up the deflector plates which were used to spread the contents evenly when the Windscale Piles were in operation. This is the culmination of a collaborative working approach since 2012 when CNSL was awarded the first phase of the contract which would eventually see the removal of redundant steelwork in preparation for waste retrieval operations.

The PFCS is one of the four priority facilities for decommissioning on the Sellafield site and is a particularly difficult one to work on as the atmosphere inside is high in Argon to prevent fire. This also means that human entry is not possible. All decommissioning operations in the facility therefore have to be carried out remotely. The cutting up and removal of the deflector plates is an essential first step to allow access to intermediate level waste below.

Cutting trials at James Fisher Nuclear's Egremont facility
Cutting trials at James Fisher Nuclear’s Egremont facility

Key to the success has been a full scale mock-up of the top section of the PFCS at JFN’s Egremont facility, where CNSL and Sellafield Limited (SL) teams have been co-located and working collaboratively. This allowed the CNSL team to design and manufacture, develop and optimise the equipment and processes; the Sellafield project team were also able to validate the approach and ensure that the project fitted into the overall “Silo programme”.

Speaking to Nuclear Matters Graham Parker, Project Manager for James Fisher Nuclear, said, “The first phase of the project to remove debris from on top of the plates went like clockwork because of the preparatory work in the full-scale mock-up of PFCS. Whilst the debris-removal operations were on-going, we worked on the cutting process and managed to substantially increase its speed and efficiency. Transfer to site operations has been a smooth process and we are now making excellent progress.”

The cutting is being carried out with a water jet containing entrained abrasive. John Reekie, the JFN senior engineer commented that “this cutting method was selected as it is quick and efficient and does not generate excessive heat or sparks. Cutting accuracy is essential for efficient operations and vital to meet strict water usage targets. Using the Full Scale Test Rig we were able to develop techniques which could meet the challenging technical requirements and overcome replicated spatial constraints whilst proving the viability of the chosen solution and simultaneously training and up-skilling operators prior to site works.”

To see video footage of the jet cutter in action click here.