Sellafield Ltd has taken an important step towards decommissioning a 60-year-old storage pond originally built to store fuel from the Windscale Pile Reactors, by retrieving the very first nuclear fuel out of the pond since the 1960s.
The Pile Fuel Storage Pond (PFSP) was the very first nuclear fuel storage pond constructed at Sellafield and to this day remains the largest open air nuclear storage pond in the world. The pond was built to store nuclear fuel and isotopes from the Windscale Reactors that produced nuclear materials for the defence industry. The Windscales Piles as they are better known never actually generated electricity, but were the precursor to our Calder Hall reactor – the first commercial reactor in the world.
The programme is 5 years ahead of previous expectations and reflects the drive to meet the new Sellafield Performance Plan published this summer, which details the step by step decommissioning of the Sellafield site.
Jim French, Nuclear Management Partners’ (NMP) Executive Decommissioning Director said: “Our original timescale was to start retrieving this fuel in 2016, however we’ve been able to bring this forward by concentrating significant resources and technical expertise on this priority project. This achievement underpins our commitment to accelerating the decommissioning of our high hazard projects at Sellafield.
“The plan is that all the fuel will now be retrieved by July 2015, however opportunities are being sought to bring this date even further forward.”
Dave Polkey, Head of Programme Delivery said: “This is a significant achievement as it’s the first time since 1964 that we’ve been in a position to safely export nuclear fuel, the majority of which was burnt in the Windscale Piles reactors. There are almost 50 skips, containing 6-12 tonnes of spent nuclear fuel, to be exported from the legacy pond.”
The PFSP is one of four facilities at Sellafield from the early years of the site that are identified as the top priority for risk and hazard reduction in the Nuclear Decommissioning Authority’s (NDA) Strategy to accelerate the decommissioning of the UK’s nuclear legacy.
Ian Hudson, NDA’s Head of Programme for Sellafield commented: “Successfully achieving this milestone in our priority work area is extremely encouraging. The combination of the expertise of the Sellafield workforce alongside targeted support from NMP to improve delivery and make the site more efficient, is exactly what we envisaged when NMP won the Sellafield contract and what the recently published performance plan demands across the site.”
Considerable work has had to be carried out in support of the fuel retrieval. Firstly improvements have had to be made to the building structure which started in the 1980s and included the replacement of the skip handler.
And secondly, the project team has had to find a solution to the layer of radioactive sludge which has built up on the pond floor and on top of the open skips of fuel. The layer of sludge had to be removed from the fuel skips using a bespoke skip washing mechanism.
Finally, a huge amount of effort went into proving the planned export route for the legacy fuel. For instance, significant modifications had to be made to the bay crane to allow it to be operated remotely to reduce the radioactive dose to the crane driver. Also, the cuboid transport flask had never been used in this facility before and extensive preparations had to be made.
Elaine Woodburn, Copeland Borough Council Leader said: “This demonstrates just what a skilled workforce we have in Copeland, which I think is capable of dealing with complex, nuclear projects at Sellafield, whilst ensuring the complete safety of the local community at all times.”
Approval for the transfer was received from the regulator on 20 September which allowed approximately 0.5 tonnes of fuel to be transferred from the pond to a transport flask on 24 September. It was exported to the modern fuel storage pond on 26 September, where it will be held pending final disposal.
The PFSP contains over 15,000m3 of radioactive water, more than 300m3 sludge, various nuclear wastes and legacy spent nuclear fuel in around what was originally 180 metal skips in the pond. It poses one of the most challenging decommissioning projects on the Sellafield site.