Immediate reactor repairs stop Suffolk power station opening – another blow to the nuclear sector

By - World Infrastructure Journal

Immediate reactor repairs stop Suffolk power station opening - another blow to the nuclear sector

Unscheduled repairs to components of the Sizewell B reactor core have delayed the re-opening of the Suffolk power station by three months longer than planned, striking another blow to an already beleaguered nuclear sector.

EDF, who operate the reactor, will keep Sizewell B offline for an additional three months after finding wear to stainless steel “thermal sleeves” which help shut down the nuclear reactor core. Damage to the sleeves, could potentially be catastrophic.

The sleeves work by inserting control rods into the nuclear core and "catching" the neutrons generated by the nuclear fission and thus ending the reaction. However, as happened at the Belleville nuclear power plant in France in 2017, these can come loose and obstruct the control rods, with potential highly dangerous consequences.

EDF has assured that the damage found in the sleeves in Sizewell was “nowhere near” preventing any shutdown function, and that only a “very small proportion” of the 53 thermal sleeves needed replacing.

What is concerning, however, is that the steel components being replaced have worn out quicker than expected in Britain’s most modern nuclear power plant. This comes off the back of prolonged closures in reactors across the country which has reduced nuclear’s role as an energy provider in the past few years. Of the eight nuclear power plants that Britain currently has (all of which are operated by EDF) seven are due to shut down this decade. While the majority of these closures are occurring along a planned schedule, there are shutdowns being hastened by issues with machinery in reactor cores.

Next year, Hinkley Point B (in Somerset) and Hunterston B (in Scotland) will permanently go offline earlier than planned due to cracks in their graphite cores. At the same time, Dungeness B (in Kent) may close as soon as this year. Despite only being due to shutdown in 2028, the plant has been offline since 2018 due to issues with corrosion and according to the EDF, a “number of significant technical risks still remain. ”

Nuclear energy can typically provide 20 per cent of the energy consumed by the UK, and Sizewell B alone is capable of powering 2.5 million homes. As Britain looks to make moves to meet its 2050 climate targets, a low-carbon nuclear power supply could certainly play a central role. However, the issues with the “thermal sleeves,” are the latest in a increasingly long list which are gradually reducing the role of nuclear power. Especially concerning at a time when it should be looking to take up a greater proportion of the UK’s energy production.

The issue at Sizewell B, though, appears to be under control. A spokeswoman for the EDF stated, “contractor specialist teams are already in place to complete the inspection and repair work,” and that the issues at Sizewell B were ones that the “industry is aware of and has been subject to extensive assessment. ” The Office for Nuclear Regulation has further assured the public that Sizewell B will not re-open until “a robust safety case which demonstrates to our satisfaction that this issue has been addressed and that the reactor is safe to operate” has been submitted. However, if nuclear is to recover in Britain, Sizewell B coming back online can only be the start.

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