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Windscale AG Reactor, site of
Sellafield, Seascale, Cumbria
associated engineer
UK Atomic Energy Authority
date  1958 - 1963
UK era  Modern  |  category  Power Generation  |  reference  NY025044
Nuclear energy derives from fission — the breaking up of certain atoms (such as uranium-235) and the heat that this produces. That energy is initiated, developed and contained in reactors. Most nuclear reactors in the UK are, like the Windscale Advanced Gas-cooled Reactor was, cooled by carbon dioxide and moderated by graphite.
The 100MW Windscale Advanced Gas-cooled Reactor (or AGR) was built as an industrial-scale development model for the British AGR Programme. It operated between 1963 and 1981, and the technology used was viewed as more energy-efficient than earlier water-cooled reactors. Windscale therefore became the prototype for 14 further AGRs built on seven separate sites, most notably at Heysham, Hartlepool, Dungeness and Hunterston.
The decommissioning of Windscale AGR began in 1981 — a process that again led to it being used as a demonstration model for the UK. A series of decommissioning campaigns has been carried out. They were done remotely because of the high levels of radioactivity involved.
After the removal of reactor fuel and associated equipment (completed 1983), an intermediate level waste store was constructed, along with an encapsulation plant and a waste removal route. Four 190 tonne heat exchangers were lifted out and transported to a nearby Low-Level Waste (or LLW) repository at Drigg in Cumbria.
Removal of the reactor internals was carried out in ten separate campaigns. This work included the installation of a remote dismantling machine above the 210 tonne graphite core of the reactor, completing systems decommissioning in 1998. Eight of the ten campaigns have now been completed.
The final project to remove the dismantled core is scheduled for mid 2009. The building will then be decontaminated through chemical and water oxidation, and the internal concrete structures will be removed. The spherical containment structure is scheduled for removal in 2015, when the reactor will be remediated to brownfield status as part of the Windscale restoration programme.
Research: PD and AJD
"Management and strategy for dismantling and disposal of the Windscale Advanced Gas-cooled Reactor top dome" by E.Taylor
Decommissioning and Demolition Proceedings of the Third International Conference: Decommissioning Offshore, Onshore Demolition and Nuclear Works, UMIST, Manchester, 25th-26th March 1992
"Nuclear Energy Past, Present and Future" by Malcolm Grimston
Nuclear Industry Association, London 2004

Windscale AG Reactor, site of