It’s a common refrain among climate change down-players — those who accept its reality, but who argue that we can’t or shouldn’t do much about it — that, sure, first world Western countries could be doing a lot more to reduce their emissions, but it hardly matters when you’ve got countries like India and China pumping more and more pollution into the very same biosphere. The argument has been getting weaker in recent years, as even developing nations have started to sign on to meaningful climate action plans. Now, Chinese atomic energy experts have announced an ambitious plan to begin turning the country’s coal plant infrastructure into working nuclear power stations. The first working demonstration unit could begin real commercial operations as early as 2018.
The plan could turn the growing Asian nation into one of the world’s most aggressive actors on climate change — though just as important to China is nuclear’s ability to help deal with its growing problem with air pollution. It could also kickstart the global nuclear industry, which was flagging even before the Fukushima disaster of five years ago. China may be about to prove that newly advanced nuclear tech offers a way for some large industrialized nations to dramatically reduce their carbon footprint without bankrupting themselves, or simply betting that solar and wind power will progress fast enough to matter at all on the global utility scale.
The news comes from this year’s High Temperature Reactor Conference, where Professor Zhang Zuoyi reportedly gave a talk on the subject, receiving a “sustained round of clapping,” complete with “a few hoots” from the gathered scientists. The reason for their enthusiasm should be obvious. Here, we could have a potential solution to the biggest practical problem with a large-scale pivot toward “Generation IV” nuclear designs with advance, passive safety systems: cost. Under the proposed plan, China can use re-use a huge proportion of the money it spent building coal plants, removing the furnaces and boilers from its super-critical coal plants and replacing them with the stripped-down hearts of high-temperature gas cooled nuclear reactors (HTGRs).
The coal stations targeted under this plan are numerous, but specific. Only super-critical steam plants are built to withstand the high operating temperatures HTGRs require. The early target stations should also be as close to population centers as possible — again, one of the main goals here is to reduce the health effects of coal plant air pollution, and you can’t accomplish that by reducing emissions in the middle of nowhere. So, if this plan is to actually go forward, it will need make a strong case for its own intrinsic safety.
As a result, the project will focus on a form of nuclear plant called a pebble-bed reactor, in which the nuclear fuel is divided into little micro-fuel pellets that are then built up to baseball-sized spheres with successive layers of graphite and ceramic materials. The coatings on each fuel pellet act as the neutron moderator, doing the same job as the water that lies between the fuel rods in a classical thermal reactor, and the melting points of these coatings are all higher than any temperature the fuel pellets can create in this reactor.
Hundreds of these spheres become a rubble pile with space in between for gas to flow, in this in this case helium, and absorb heat before carrying it away. In some cases, this heated gas directly turns a turbine, but in this plan it will heat a duo of boilers to create steam, and turn the turbine more traditionally. The lack of the notoriously complex cooling systems of water reactors is one of the things that makes the Chinese retrofit plan so potentially affordable. And the gas that cools the system doesn’t absorb neutron radiation nearly as easily as water, and thus HTGRs create a far lower volume of radioactive products that could leak or expose workers to hazard. The coolant is a gas at all temperatures, never condensing or evaporating, and as mentioned it cannot create a pressurized explosion like steam.
Thus, pebble bed reactors are in principle meltdown-proof, providing no path for the sorts of cascading failures that have led to the most serious nuclear accidents in history. This means that in the case of a catastrophic failure, the plan is literally just to walk away. There’s no need to do anything — the whole point of the pebble-bed design is that every single component can fail, and the worst outcome will be a loss of power generation. It will take a long time for the reactor to naturally cool down — but then again, Fukushima cleanup efforts haven’t exactly been proceeding at a lightning pace, either.
There are downsides, of course. The fuel pebbles are expensive to produce, in fact quite a bit more expensive than the team anticipated, and the parts are just as dear — right now, the cost is around $ 5,000 per kilowatt of installed capacity, or about 1.5 times as expensive as solar photovoltaic cells, and over five times as expensive as natural gas. However, China has a unique advantage in that it simply has so many suitable reactors to change in this way. Much of the projected cost savings will come from mass production of parts and especially fuel pellets, and the team hopes that as they can bring the price down to around $ 2,500 per kilowatt, comparable with other forms of green power. If that mass production industry ever gets to a point where it’s running out of Chinese coal plants to feed, it could just try to sustain its model by turning its marketing outward, to other nations.
But remember, these new reactors are supposed to serve three separate purposes for China, all at the same time: power the continuing process of bringing the entire population into the modern world; let China live up to its international climate obligations; and clean up the air. Right now, cost aside, nuclear is the one and only technology that can provide all three benefits at once.
It’s perhaps worrying that China has such a zippy timeline for these installations, since even a minor accident could tank the profile of HTGRs, worldwide. The technology has only been given a handful of chances in the US and Germany, and while the Chinese government is certainly capable of bulling forward on an unpopular plan, Western democracies are more subject to the whims of the public. China has a chance here to prove to the world that nuclear can be safe, practical, and forward-thinking — and it also has the chance to prove the opposite.