THE final phase in the decommissioning process at the former nuclear site at Winfrith is under way as experts turn their attention to the structure enclosing the reactor.
The iconic Steam Generating Heavy Water Reactor (SGHWR) was one of the most important and successful experimental reactors in the history of UK nuclear power.
Almost immediately after it was shut down, a programme of decommissioning began and is still going on today.
The final and most complex chapter has now begun – decommissioning of the primary containment, which houses thousands of tons of plant equipment, and is expected to take two-and-a-half years.
Research Sites Restoration Ltd (RSRL) is responsible for decommissioning the Winfrith site.
Communications manager for RSRL Emma Burwood said: “The work will be technically challenging due to the plant’s proximity to the reactor core and the large quantities of asbestos.
“A great deal of meticulous preparation is needed to carry out the work safely and efficiently.
“As work begins on the primary containment, a number of mitigating steps have been put in place to reduce operator radiation exposure. As well as providing high levels of safety training, RSRL is using 3D modelling, CCTV and real-time dose measurement equipment, together with augmented reality systems.”
The site is planned to be decommissioned by 2021.
THE Steam Generating Heavy Water Reactor (SGHWR) was a heavy water moderated reactor.
Built in the 1960s, it was operational for 23 years.
It demonstrated the reliability of the system and supported a major experimental programme, providing information on the operation and development of water-cooled reactors.
SGHWR operated as a power station, earning revenues from the national grid to offset some operating costs.
Following the switch from water-cooled reactor technology to gas-cooled, the government decided in 1990 to close the reactor down.
Stage 1 began with defuelling, draining, flushing, and emptying the fuel ponds.
In 1991, the cooling towers were demolished.
Stage 2 began in 2005, when thousands of tonnes of equipment was removed.
More recently, major equipment was removed from the secondary containment building.