What is an AGR?

An AGR is an Advanced Gas-cooled Reactor. The design was an attempt to improve on the earlier Magnox design, aiming to achieve higher gas temperatures to improve efficiency. AGRs use uranium in which the fissile part of the uranium (U-235) has been increased or enriched to 2 per cent. Like Magnox reactors, this was a peculiarly British design and no AGRs were sold abroad. Also like Magnox reactors, AGRs have a graphite core. Like the last two Magnox reactors, AGRs have a pre-stressed concrete pressure vessel, and use carbon dioxide gas as a coolant.

The AGR programme was a disaster. The first station to be ordered - Dungeness B – was 12 years late, and most of the others were late too with huge cost overruns. Different contractors were used to build different stations, and design changes meant that most of the stations are of a slightly different design.

A long campaign was run against the construction and opening of one of the last AGRs to be built – Torness in East Lothian, near Edinburgh – in the 1970s and 80s. After Torness opened in 1989, the Glasgow Herald quoted a Scottish Office ‘source’ who described it as a £2.5 billion mistake which should never have been built.

Closure dates

The remaining Magnox stations have fixed closure dates, and will all be closed by 2010, although they may close earlier for economic or safety reasons. But the newer AGR reactors, operated by the privatised company British Energy (BE), only have closure dates ‘for accountancy purposes’. This does not necessarily mean this is when they will close. These dates are kept under review and can be adjusted (in either direction) at any time to take account of commercial, technical and safety issues. It is quite likely that BE will try to keep at least some of their stations open longer. [1]

British Energy’s Stations	Station Type	Capacity	Started Operation	Closure date for accounting purposes	Next PSR
Dungeness B	AGR	1,260 MW	1982	2008	2007
Hartlepool	AGR	1,320 MW	1984	2009	2008
Heysham 1	AGR	1,200 MW	1983	2009	2008
Hinkley B	AGR	1,320 MW	1976	2011	2006
Hunterston B	AGR	1,320 MW	1976	2011	2006
Heysham 2	AGR	1,380 MW	1989	1023	2009
Torness	AGR	1,363 MW	1989	2023	2009
Sizewell B	PWR	1,258 MW	1995	2035	2005

 

The nuclear safety regulator, the Nuclear Installations Inspectorate (NII), [2] requires nuclear station operators, like BE, to carry out a Periodic Safety Review (PSR) around every ten years. These reviews are then submitted to the NII for assessment. The NII might then require BE to carry out modifications and improvements before it would be allowed to continue operating the station. If it was economic, BE might decide to carry out the modifications, but if the costs were too high the station would close. So, for example, Hinkley B and Hunterston B will be required to carry out a PSR in 2006. If the improvements required by NII don’t cost too much, BE might then decide to keep these two stations open until 2016, rather than close them in 2011. On the other hand if the costs are too high BE might start decommissioning one or both of these stations in 2006.
There is no opportunity for public intervention in the PSR process, and the NII is not required to consult the public on issues related to nuclear safety. However, strong local campaigns for the closure of ageing Magnox stations based on health and safety concerns might well have influenced decisions taken by the NII and the nuclear operator in the past, as a number have closed after completion of the PSR process.

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[1] New Blow to British Energy Finances, by Andrew Taylor. Financial Times, 14th November 2003.

[2] http://www.hse.gov.uk/nsd