China's Integrated Nuclear Energy Future

2013-02-06

Dr. Julian Kelly

Co-Founder and Director, Science and Energy, Sinograduate

 

China is in the middle of a remarkable phase of nuclear power plant construction - unsurpassed in history.   This is understandable given that nuclear energy is the only credible means of producing dozens of gigawatts of emission-free electric power capacity with high load factors.  The demand for such energy is essentially limitless in mainland China - this fact is well known and is driven home every time the media reports on bad air quality in Chinese cities.

 

It would be nice for China's leaders if nuclear power could directly reduce the number of bad-air days but even if it could, the main motivator for the installation of more nuclear generating capacity is the sheer amount of energy that can be supplied. 

 

The NPP construction program is colossal - at least 50 pressurized water reactors (PWRs) are being built in a staged manner over the next ~35 years.  Each PWR is a huge project in itself, requiring a budget of around $7 billion and a work force of thousands, producing a facility that can supply 1.1 - 1.6 Gigawatts of electric power into the grid for more than 90% of its 60 year life.  Collectively, the vast scale of these parallel projects is challenging on a number of fronts, including the establishment and maintenance of a reliable supply chain for components, but efficiencies are also being leveraged and the program will certainly prevail against these capacity issues.

 

China's PWR spree is entirely logical - this type of reactor is the work-horse of the international nuclear industry and is extremely well understood by utility operators and by safety regulators alike.  In order for China to achieve its ambitious goals of installed nuclear generation capacity it needed to chose and focus on a reactor type with a long and solid operating history. 

 

So the PWR roll-out program will continue for at least another generation and electricity supply in China will gradually become cleaner as a result (although coal-fired capacity will be installed at a faster rate for quite a while).  Less known, however, are several other impressive nuclear energy projects being vigorously supported in China.  These offer various benefits over PWRs:   improved thermal-to-electric efficiency and thus efficiency of uranium use,  better spent fuel & waste characteristics,  the option to recycle various spent fuel components such as plutonium,  and higher operating safety margins.

 

The particular reactor and nuclear fuel systems being worked on are: 

 - High Temperature Gas-Cooled Reactors.  These offer an essentially 'meltdown-proof' graphite fuel matrix & enable the fissile component (plutonium or enriched uranium) to be burned very effectively.  The high coolant temperature (~900oC) allows for high electric conversion efficiency and offers the prospect of using this valuable heat in processes such as hydrogen production or sea-water desalination. 

 - Fast Reactors.  These operate with 'fast' neutrons and allow more natural uranium to be consumed, as well as some of the heavy by-product nuclides (like plutonium) generated in PWRs.  Fast reactors can be tailored to operate as waste burners or to 'breed' new fissile fuel - they have been central to fuel cycle planners in several countries for many decades because of these features.  They can be more tricky to operate since they use liquid metal as their coolant but China has already tapped Russian expertise in this regard and has a pilot plant in operation.

 - Niche-Fuelled Heavy Water Reactors.    This type of reactor - already operating in China at the Qinshan site - is very well suited to utilizing fuels that include nominal 'waste' materials, plutonium and 'burnt' uranium that can be extracted and recycled from spent PWR fuel.

 - Molten-Salt Reactors.   This longer-term design has its fissile fuel dissolved in a molten salt which is continually passed out of the core through heat-exchangers (to produce steam) and into a chemical treatment system to extract certain materials and thus maintain neutronic efficiency.  They offer the prospect of very high resource utilization - even breeding more fissile fuel material than is consumed, however there are numerous engineering challenges to be resolved.

 - Sophisticated Chemical Partitioning.  All schemes involving the recycle of valuable components in spent nuclear fuel require some radio-chemical processing.  This is currently expensive, but there is plenty of scope to make this more efficient, economic and less risky, using advanced automation and remote handling technologies.

 

What does this mean?  Why is China pursuing other reactor development projects when the priority is to install as much nuclear capacity as possible?  Well, for a start the country is probably close to the sensible limit for its PWR construction rate.  But more fundamentally it demonstrates that a long-term vision is in place with respect to the country's energy security, and that this strategy is underpinning the significant technology investments that are required to attain their energy infrastructure goals.

 

One bottom line is that fissile resources - uranium - can be used a whole lot more effectively than it is in PWRs.  While uranium is cheap and will remain abundant (despite some alarmist commentary to the contrary), its price will gradually rise over the coming decades and it can only be a good thing from a sustainability point of view to use mined uranium more thoroughly.  Less than 1% of natural uranium produces energy in current generating infrastructure - deriving from the 235 isotope with 0.71% natural abundance.  Most of the remaining uranium (238) ends up being stored, yet it has a huge latent energy content.  A second bottom line is that volumes of radioactive waste can be minimized using integrated nuclear fuel & reactor cycles.  China recognizes all this, prioritizing the resource enhancement angle. 

 

LOOKING DOWN THE ROAD

Consider China's nuclear energy infrastructure in ten/twenty/thirty years - it will be comprised of a 'bedrock' of reliable PWR generating capacity using uranium at the current standard rate.  As well as this fleet, several of the 'new generation' reactor systems will also be operating - most notably a small number of fast reactors and high-temperature gas-cooled reactors.  Some spent fuel from current (and new) PWRs will have been processed and recycled in these new platforms and operating experience for these new generation reactors will be rising quickly.  Progress will have been made on the more futuristic molten salt reactor and a test unit should be running, though commercialization of that technology will take time.

 

China will be well on the way to having a sensibly integrated nuclear energy infrastrucure in place.  The skies might not be much cleaner but there will be a lot more nuclear electricity on the grid and the efficiency of its production will be somewhat higher, and increasing still further.

 

Of course, only a large country like China can devote the human resources to such a big nuclear R&D program, but the real point is that a long-range energy strategy is in place - something most countries do not have at a national level.

 

DEJA VU?

Interestingly, this is where Europe and North America were headed in the 1960s & 70s.  All of the above-mentioned reactor types were actively developed & demonstrated in various R&D centers - with impressive results.  For complex reasons, however, no western country since managed to take these into established commercial operation, let alone have them co-exist with light-water reactor fleets.  Full integration of complementary reactor types in a national reactor fleet has never happened (despite some valiant efforts).

 

This begs the question of whether a similar failure might happen in China.  Is it possible that some of these advanced reactor projects will fizzle out?  Not really - the risk of this is low for the following reasons:  (i) there is extensive international experience to build-on, and China is doing just that, indeed small demonstration fast reactor and gas-cooled reactor units are already operating so this is not high risk 'blue sky' work,  (ii) there is a large number of trained technical personnel being devoted to the programs,  (iii) there seems to be solid state-level support for these reactor programs - in contrast to what can be fickle 'drip-feed' type resource provision for nuclear energy R&D in many countries,  (iv) the 'lighter touch' of nuclear safety regulation in China.

 

Of these potential risk factors it is probably the fourth - regulatory creep - that presents the main threat to the Chinese vision described here.  Safety regulation is a good thing - no doubt - but the West has shown over more than forty years that ever-increasing safety assessment requirements and the associated imposition of huge safety-margin limitations eventually stifles the ability to undertake necessary physical R&D in the nuclear sphere.  China has an effective nuclear safety regulator, without being overbearing, but it may be that their nuclear energy developers are in a 'golden period' for producing results, before regulatory burden becomes more onerous.

 

In conclusion, next time you read something about the number of nuclear power reactors under construction in China, take a look at the entirety of their nuclear energy development program.  You can see a picture of an operating, integrated nuclear fuel cycle - one that might have been established in the West  - and might even one day be copied, from China.

 

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