Safe acceptable nuclear power? Here's a way...

Use now; pay later ... a Faustian pact with fossil fuels: Burning fossil fuel the way we do now could almost have been designed to seriously endanger humankind and myriads of other forms of life on this planet. You want climate chaos? Okay, just burn up all that coal, oil and gas as fast as you can and you'll get a climate guaranteed to cause a mass extinction which will likely include humans. Mephistopheles, to mix metaphors, gets his pound of flesh. Suffering and mega-death are part of the fossil fuel package, clearly visible to those who can see beyond the PR smoke of the fossil fuel industry. So can we have our energy cake and eat it too? Yes, if we eschew fossil fuels and look for alternatives.


Renewable energy gap: I'm enthusiastic about renewable energy. I've built an eco-cottage (massive insulation) and a passive-solar conservatory for heating my stone-built farmhouse. I'm about to install an air-source heat pump and, in a few months, I hope to set about the installation of a grid-connected 6kW Proven wind turbine. I live a simple, low energy life. I travel very little, never fly and burn wood grown on this farm in my woodburning stove . I also plant trees. And my aim? To be carbon neutral.


Most people can't do many of these sorts of things if they live in towns or cities. They need - and expect to have - electric energy available at the flick of a switch. So do I! So... can renewables like wind and solar power deliver the energy we need? Unfortunately, the answer - for the time being - is no and all the green bluster about solar, wind and waves being able to do it is just naive. In time - by which I mean decades - renewables could and should power the planet when we have built infrastructure like supergrids, vast solar arrays in the Sahara desert and so on. But for now, renewables provide just a few percent of total electric energy used. When the wind doesn't blow and the sun doesn't shine, they're useless. This winter, there have been weeks of cold grey weather without wind. The lights still work because of fossil fuel... and nuclear generation.


Choices: We all want the lights to work when we need them. Almost every modern gadget and convenience depends utterly on dependable electricity supply. So we have choices to make:

1. carry on burning fossil fuels like there was no tomorrow... which there won't be
2. eliminate fossil fuels as soon as possible whilst building up renewable supply systems
3. build nuclear power stations to replace coal-fired plants as quickly as possible, whilst pursuing renewable generation also as fast as possible (part of the much vaunted Green New Deal which may or may not come to pass)

Option 1 means disaster and ought to be unacceptable to anyone who cares about the future for their children and the rest of life on our despoiled planet.

Option 2 means many years of unreliable electricity supply with frequent power cuts. It would work if everyone was prepared to undergo hardship: cold houses, no lights, no TV, no computers for much of the time. But almost everyone would find this unacceptable too

So we're left with Option 3. Nuclear power stations have been working away, generating reliable baseload power for many years. There have been serious problems and even a disaster or two, but modern designs have good safety records. Unlike coal, they almost never kill people.

Protests: It goes without saying that any attempt to build new nuclear plants in countries like Britain will result in massive protests. The reasons people protest against nuclear plants are well known and often justified. At the very least, the massive reactor containment structures are eyesores and at the end of the reactor's life will have to remain there for many decades while radiation levels decay sufficiently for dismantling. Then there's proliferation and the unsolved radioactive waste problem. These are genuine causes for concern.

Protests can and do delay construction, sometimes for years. We haven't got years to cut carbon emissions. So is there a way to make nuclear power more acceptable to people who would otherwise protest? And is there a way to make it even safer than it is now? I think there is...

Out of sight, out of mind: If you visit Llanberis in North Wales, you'll probably not be aware that there's a major power station there. Where is it? You can't see all the usual structures. The reason is because it is completely underground. So why not take that notion further? Why not build nuclear power plants underground too? The size of excavation needed for a nuclear plant is comparable to the Dinorwig pumped storage power station in Llanberis, as my drawing shows.

Let's consider the advantages that underground construction would offer:

Advantages

1. because the containment is unbreachable (given proper choice of ground conditions, hydrogeology and rock types), reactor assemblies would be immune to military attack from the air and also from suicide bombers. Containment above ground could not withstand bunker-busting bombs or small nuclear devices, the latter possibly 'delivered' by suicide vehicle. In our dangerous world, these are possibilities
2. such unbreachable containment is also immune to accidents, whether external (e.g. crashing airliners) or internal such as major loss of coolant (Three Mile Island) or even Chernobyl-style meltdown disasters. Building robust containment structures above ground is hardly cheap and uses a heck of a lot of greenhouse gas-emitting (in manufacture) steel and cement!
3. virtually no decomissioning costs: you could more or less just walk away and slam the door. Monitoring would be needed, as for underground nuclear waste repositories, but because nothing irradiated is above ground, access would only need to be minimal. In addition, there would be no need ever to remove irradiated fuel assemblies unless the fuel is to be reprocessed. When the reactor reaches the end of its operating lifetime, the whole facility could be sealed, complete with its spent fuel.
4. there will be protests at each and every new surface nuclear build with endless public enquiries because of protests. Underground plants would demolish most of the objections. Public acceptance and planning consent should be straightforward since there wouldn't be much surface infrastructure to object to. Most of the usual public fears and objections would cease to be serious issues. It also means that off-the-shelf reactor designs (like the PWRs used throughout France and the most of the USA) could be built even though they might not be as potentially safe as so-called 'fourth generation' reactors, because of the additional safety conferred by underground plants. Waiting for unproven safer designs could lose us another decade.

Disadvantages

Cost: I have no idea how much underground siting would add to a budget. But if you take into account minimised decommissioning costs (not historically factored in to the cost of nuclear power as we are now finding out) and spent fuel disposal possibilities, I would guess that it would be completely viable.The economics are only artificially marginal because there's no carbon tax. Anyway, what price security and safety? And if a power utility wanted to re-use as much of the infrastructure as possible at the close of the first reactor's design life, it could just dig another chamber and build its new (improved) reactor next door. Power lines, turbines, transformers etc. all remain to be used again

So far as I know, no-one has ever tried costing it. As my drawing (above) shows, the actual reactor vessel and primary heat exchangers are really quite small structures because of the high power density which nuclear generation allows. So the chamber would be no larger than many others routinely built for different purposes. The reactor assembly could even be built in a modified abandoned mine (e.g. salt mine). Of course, any such underground site depends on there being a cooling source nearby (river, lake, sea) for condensing steam from the turbines. All the non-radioactive sections of the plant could be above ground to reduce costs.

Location: Finding suitable underground conditions, especially in flatter rainy areas with fast-moving groundwater circulation, could be a problem. A Llanberis-like site could, in theory, be ideal because the excavations could be made within the steep valley side so that any groundwater would drain out by gravity. And just outside are two deep lakes (see Cooling, below).

Cooling: Like any steam-driven turbines, cool water is needed both for raising steam and for condensing it. There's no reason for the turbines and cooling systems to be located underground since these aren't in contact with radioactive parts of the circuit. So much of the plant could, like conventional plants, be located by a river or the sea.

So... if we are to have nuclear fission generation on a larger scale to tide us over until fusion power and renewables come to our rescue, why not build all nuclear plants underground? I think this reasonable question deserves a reasonable answer.

Further reading: You may like to look at Nuclear power... safe underground and The Future of Nuclear Power, both in this blog series.

Double good: building without cement

Cement is a problem
Did you know that cement manufacture creates 5% of all industrial carbon dioxide emissions? That matches the pollution output of the world's aviation industry. What's more, both are set to increase, particularly in China. Construction inevitably means cement for mortar and concrete -- or does it? Certainly for the likes of high-rise city blocks, nuclear power stations and large dams, there's no alternative. But what about ordinary housing? How much concrete needs to be used in that?

Wood: a partial solution with a big bonus

Building houses out of wood is nothing new in timber-rich regions like Scandinavia and North America. Wood has many advantages over bricks, mortar, steel and concrete. For one thing, it's very easy to use so buildings can be completed in just weeks rather than months. When I 'built' my first house in western Canada back in 1971, it took 3 weeks to get the entire structure completed and watertight, ready for services to be installed. When I built my house in Spain in 1989, it took more like 6 months. Why? Because there was no wood used in my Spanish house at all, that being the local style of building. Prestressed concrete beams, which are used in large numbers, are incredibly heavy to manhandle into position or cast. So are blocks, bags of cement and making and carrying endless buckets of mortar. I worked on this house throughout the construction, so I know!

The hidden bonus of wood is that it is almost pure carbon. The growing tree grabs CO2 out of the air and converts it into sugars and, ultimately, to cellulose and lignin which is what we call wood. Everyone knows that trees sequester carbon and that they are one of several natural ecosystem services -- in this case, carbon sinks -- which counter climate change caused by humans burning fossil fuels. This is the rationale behing the burgeoning offsetting business. Plant a few trees and you can pollute as much as you want. That's what people seem to assume when guilt over squandering energy overcomes them a little.


The big issue: seeing the wood for the trees
Even if it were true that you can assuage your travel/consumer/heating/airconditioning energy use by offsets, there is one problem which seems not to enter general thinking. Natural forests are carbon neutral. As fast as young growing trees grab carbon, dead and decaying trees (and forest fires) release it again: the carbon cycle. To make sequestering carbon in trees really work to reduce atmospheric CO2, the mature trees need to be harvested and stored in such a way that they don't decompose and release all their carbon again. Carbon storage is what happened on a massive scale over hundreds of millions of years, as coal formed from dead but not decayed trees. The carbon has become safely locked away from oxidation into the atmosphere... until humans came along (and you know the rest). Yet when you think about it, we are storing carbon all the time -- in the form of timber-framed housing construction and, to a lesser extent, as books in the world's libraries.

So that's my point: countries which traditionally use cement in the form of concrete and mortar to build houses should change their construction practice and build from timber instead. This change of direction has several advantages:

• timber construction locks away carbon
• it's quicker and easier
• self-build is much easier and in some countries, you can buy housing kits to do this
• it is essentially non-polluting unlike cement-based constructions which cause massive CO2 releases into the air, principally from cement quarrying and manufacture
• if real environmental costs are taken into account, wood is far cheaper
• greater demand for timber would stimulate more forestry development with yet more sequestration of carbon as a bonus. At the same time, cement manufacture would decline as demand slackened off, so reducing carbon pollution
• timber can be re-used
• timber-framed buildings are intrinsically warmer than stone, brick, block and concrete. In addition, it is simple to incorporate insulation in the timber frame
• wood is a pleasant material to work with and beautiful to look at. Concrete is messy and heavy to move around

Yes I know concrete is essential for many purposes, including the foundations (footings) of timber-framed housing. My point is simply that we could use a lot less of it -- a lot less -- if we wanted to.