Tuesday, October 09, 2007

The Future of Nuclear Power

Sizewell nuclear power station: a large footprint (and what about rising sea-levels?) by Rob.Stoke
Today is the final day for anyone to make their views known about future nuclear power in the UK. I've done this on the British Government's Future of Nuclear Power website. Just to put you in the picture, I have argued for some time that, if we are to have new nuclear power stations, they should be built underground.

Here are my responses to the Government's consultation questions:

1. Safety and security of nuclear power

Siting all future nuclear plants underground is something that should be taken very seriously. This does not even seem to have been considered. Yet it has three major advantages:

  1. immune to military attack from the air

  2. containment unbreachable (given proper choice of ground conditions, hydrogeology and rock types) and so immune to attack from, say, a suicide bomber. Even major LOCAs would be better contained than anything above ground

  3. no need ever to remove irradiated fuel assemblies. When the reactor reaches the end of its operating lifetime, the whole facility could be sealed, complete with its spent fuel. Monitoring would be needed but because nothing is above ground, access would only be minimal. Decommissioning surface plants is turning out to be formidably expensive and all radioactive materials end up having to be sealed underground anyway in all viable scenarios

2. Transport of nuclear materials: No reprocessing is the right route, but by siting each nuclear plant underground, there would be no need for the spent fuel ever to leave the facility. It would be stored there in a facility built at the same time as the reactor containment cavern. When the reactor's life is over, both it and the spent fuel stored close by would be made safe, sealed and remotely monitored. No radioactive materials, highly active or otherwise, need ever be transported on the surface.

3. Waste and decommissioning: Locating new reactors underground would avoid many of the serious problems of waste and dceommissioning. At the end of the reactor's life, all its fuel remains in the store which would have been constructed during the initial cavern excavations and the whole underground site becomes a remotely-monitored facility with little further need for maintenance. Such an arrangement is inherently safer than a surface reactor which will need to be guarded and monitored through at least three human generations before it can be finally removed: not a good legacy for future generations.

4. Environmental impacts of nuclear power: If the nuclear facility was largely located underground, the surface footprint of a site would be markedly less than at present, quite apart from the safety aspect which I've already dealt with. There would be no need for a secondary containment structure since this would be provided by suitably geo-engineered natural rock in the excavated cavern. Surface buildings could all be part of the non-radioactive secondary circuits. So the heat exchangers containing the pipework for the primary circulating coolant would be underground but the high pressure steam circuit for the turbo-generators could be ducted to the surface which is where generators, transformers, cooling and other facilities would be located.

Regarding the space occupied by a nuclear facility versus that occupied by a windfarm, I have two comments:

  1. most future windfarms should anyway be located offshore, so space and NIMBYism is largely irrelevant

  2. any space occupied by a windfarm remains relatively pristine. If needed, turbines and supports can be completely removed within months, leaving the site uncontaminated and as it was before. The same cannot be said of surface nuclear build because of the massive largely concrete bioshielding infrastructure required and the problem of the 'hot' reactor core which cannot be removed for over 100 years, or requires prohibitively expensive and hazardous remote-controlled decommissioning and transport of large quantities of medium level radioactive waste to a repository as yet not in existence. These 'inconvenient truths' are a prime reason why nuclear build should in future be underground.

5. Reprocessing of spent fuel: I agree that reprocessing should not be carried out. Storage for spent fuel assemblies should be 'built in' in the underground location scenario I envisage. This eliminates the need for surface transport of highly active fuel rods.

Obviously these remarks apply to any new nuclear build anywhere on the planet, not just the UK! At the very least, I think the onus should be on governments and the energy industry to explain why siting nuclear plants underground is NOT a good idea (if it isn't!). But I expect it will be ignored... ho hum!


Derek said...

I can't understand the argument for decommissioning nuclear power plants.
There has never been a greater need for nuclear power, and we've never understood it so well either.

A great advantage of recommissioning nuclear power stations is that building consent should be very much more easily obtained than building one from scratch.

While I think the idea of building below ground is excellent, as I understand it, much of Britain has a water table not far below the surface which will surely limit its implementation.


Bry Lynas said...

Water table problems are going to be the most serious but there are rock-engineering techniques for sealing and draining (for example) deep mines. In conjunction with rock bolting, grout screens can be injected at high pressure. Some ground conditions can be quite dry if the site is capped by an impervious stratum such as shale. And if plants are built in hilly areas, they could be located in valley sides so that drainage is by gravity. There are other possible routes too, beyond the scope of this comment box and comment!

Tim Weller said...

Very well done, Bry. I fully agree with you; you get my full support and vote for PM/President/benevolent dictator of the world!!

Tim Weller