What is Post Operational Clean Out?

The facilities at the Sellafield site don’t stop operating one day and go straight into decommissioning the next, so what does happen when operations come to an end?

As we enter 2018, a date which spells the beginning of the end of reprocessing operations on the site, (Oxide reprocessing ends 2018 and Magnox reprocessing 2020), thoughts are turning to what is going to be happening in those plants that are nearing the end of their operating lives. The word POCO is becoming more popular, so what does it mean?

What is POCO?

POCO (Post Operational Clean Out) is the process that takes place when a nuclear plant has reached the end of its operating life. The aim of POCO is to reduce the risk and hazard in a facility by removing the nuclear inventory and reducing the lifetime costs of the redundant plants. In simple terms, it gets the plant as radiologically clean as it can be which reduces the risk and hazard and in turn makes the plant cheaper to care for.

At Sellafield there are many plants that have or will shortly reach the stage where POCO preparations begin, so there is a lot of work going into preparing the people working in those plants and planning how they will make the transition to the POCO stage of the plants’ lifecycle.


Everything has a life-cycle, humans have them, even buildings have stages of life, and for the facilities at Sellafield it’s no different. Take the Thermal Oxide Reprocessing Plant (Thorp) for example; from planning that started way back in the 1970’s, to construction in the 1980’s, to the operational and reprocessing activities that began in the 1990’s and continue today, they are all phases of its life span.

There is still the perception that it is a relatively new plant, in reality it’s far from it, with over 8,000 tonnes of fuel reprocessed already and only around 1,300 tonnes remaining, operations will come to an end in 2018 when the Chemical Separation and Head End areas of the plant will transition into the POCO phase. In order to successfully get to that point there is a lot of work being carried out to prepare for it.

How are Sellafield preparing?

For the plants that are nearing POCO there is a team dedicated to supporting their preparation for transition from operations.

The POCO programme team is small and so work alongside the skilled and knowledgeable workforce in the plants to deliver the tasks required to carry out POCO preparations. Facility leads interface between the plant and the POCO team.

Characterising what is in the plant and looking at technical and engineering solutions, along with Knowledge Management is a huge and important part of what the POCO programme do. Collating information that is available and speaking with experienced workers to record their knowledge of the plant is one of the most valuable tasks that is carried out, in order to record the plants’ configuration and status.

The information that is produced from this data mining is vital for future generations when the time comes to decommission and demolish the plants.

Communicating with and engaging the workforce is vital to the success of the POCO phase. Helping the workforce to understand that this is their work to carry out and that life in Thorp doesn’t end once reprocessing finishes.

This programme approach ensures consistency of POCO planning and delivery, and retains a clear view of the costs and benefits of POCO delivery, all in anticipation of handing over the POCO operations to the associated plant workforce to carry it out.

Colin Savage is the recently appointed POCO Facility Lead for Thorp, following his 32 years of being involved in Thorp his role is to ensure that the teams in Thorp are ready to make the transition in 2018, he explains:

“Thorp Head End and Chemical plants are the first areas in the Operations Division that will undergo a managed POCO programme.

“This phase of Thorp’s life will begin immediately after the end of the reprocessing operations in November 2018 and there is a lot of work being done now to prepare us for that including housekeeping and co processing of materials already in the plant.

“It is the existing workforce that will carry out the operation and maintenance activities for POCO and they will also deliver the necessary work to maintain safety throughout the phase, so making sure they are ready is a vital part of our planning.

“Some of our workers have been here in Thorp since commissioning of the plant, they have worked on the plant from the start and will be here to see the finish of reprocessing and move it into the next chapter which is almost a reverse of commissioning.

“This is a huge change, not only due to the tasks that are carried out changing but culturally for our workforce, people are so used to working to production targets and reprocessing being their business, it is important that we get them ready for that change so they have the new mind-set that clean out becomes their business, they are key to the success of POCO and will ensure the legacy left behind for the decommissioning teams is minimised.”

POCO will be carried out in a number of plants at Sellafield, a timeline for these activities and areas has already been created.

This article has been reproduced with permission from Sellafield Ltd. The article featured in Sellafield Magazine, Issue 2, and can be seen here in its original context.