UK units cleared for restart after boiler checks

24 November 2014

The UK nuclear regulator has given EDF Energy permission to restart two units at its Hartlepool nuclear power plant and one at its Heysham I plant. The units have been offline since August for investigations into potential cracks in boiler spines.

Heysham 1 460 (EDF Energy)
Heysham I comprises two AGR units which began operating in 1983 and 1984, respectively (Image: EDF Energy)

In early August, EDF Energy said it had shut down Heysham I unit 1, in northwest England, in June after discovering a fault in a boiler spine and taken the "conservative decision" to halt the second reactor there, and two at its Hartlepool site in the northeast of England, "which are of a similar design." At that time, EDF Energy said it expected the units to remain closed for about two months while investigations are carried out.

After completing inspections of the boilers at the affected units, EDF Energy presented the UK's Office for Nuclear Regulation (ONR) with a safety justification for the restart of Heysham I unit 2 and the two reactors at Hartlepool.

On 21 November, the ONR said it had completed a review of that justification and "is satisfied that EDF has demonstrated the continued safe operation for these reactors."

The reactors are expected to be brought back into operation over the coming weeks.

The ONR said EDF plans to submit a separate safety justification for the restart of Heysham I unit 1. This, it said, "will be subject to independent assessment and will require formal permission from ONR before the reactor can return to service."

EDF Energy expects unit 1 of Heysham I to be restarted by the end of 2014.

Each advanced gas-cooled reactors (AGRs) at Heysham I and Hartlepool has eight boiler units. These boilers are arranged around their associated reactor in four quadrants with each quadrant containing two boilers. Within each boiler are tubes assembled in a coil formation around a central forged metal tube called a boiler spine. The boiler spines support the weight of the tubes around them.

Researched and written
by World Nuclear News