What advanced nuclear reactor designs are likely to be successful and why?

I have been researching and writing about nuclear power alternatives to the conventional power plants that have been built and designed in the past. I'm happy to share with you in this discussion group what I have discovered. See https://www.21stcentech.com/micro-nuclear-power-reality/ which describes the U-Battery, a small-scale modular encapsulated reactor that could serve a wide variety of power applications.

The pursuit of fusion-fission reactors is described in a posting at https://www.21stcentech.com/company-named-apollo-plans-offer-sub-critical-nuclear-reactor-this/.

A company in Ontario is developing an integrated molten salt reactor with the assistance of the Oak Ridge National Laboratory. See https://www.21stcentech.com/integral-molten-salt-nuclear-reactors-deployed-decade/.

Good points, Helmut.

Good points, Helmut.

I do not see any of the existing designs to be economical successfull, when even the prices the designers hope to reach in far futer prices that system out of the market.

If there is more than a few €/MWh price difference betweeen wind/solar on one side and nuclear on the other side, it will be cheaper to expand the grids and remove the local volatility of wind and solar. Just make room in your head and undersatnd that the latest UHVDC Pover line built in china (12GW per system) is long enough to make a direct connection from Ireland to Canada, or west Africa to Brasil.

And that even now when we discuss this, it is already possible to exchange some GW electrical power  between Saigon and Lissabon. It is technically possible (see above, and 12GW is just the beginning, not the limit) to expand the grids to the amount of power transfer needed.

I do not know how much power transfer will be needed - Entsoe thinks they can handle 100% renewables with a quite small expansion of grids just inside europe - but I am sure that there is not much night within the grid when your grid starts in Los Angeles and stretches from there eastwards till Kamtschatka. Also I see no likelyhood that the wind settles on the whole planet at the same time. Which would be the worrst case grid size, but still fully economical viable.

Think about the following fact when you expect a nuclear renaisance from china: China stoppt to start new nuclear power plant constructions durin the last two years (only existing construction sites are finished) in parallel state Grid china and other companies started buying grid companies all over the world (while publishig that they want to interconnect the world with a HVDC Overlay grid) I see the grid as the winning technology, and I would invest in expanding the grids and not leave this - and the control of the grids - to China.

The West has already abandoned its leadership in nuclear energy; for the future of nuclear power we must look to China and India.

Despite the renewable hype, both of these countries have coal-dominated power systems, both for the exising fleets and for new construction (China has unusually large hydro resources and deployment, but the other non-fossil energy sources are small).  

Both countries boast of large renewables investments.  Both are continuing to build coal-fired power plants.  But also, both are building new nuclear, at about the same rate as solar or wind.  Most reports seems to say the power cost of renewables is less than that from nuclear, but the lower integration cost (including fossil fuel backup) makes nuclear more economical in these countries.

According to Chinese policy, large light water reactors are the technology of choice, with new builds switching to sodium cooled fast reactors at some point in the future, ultimately yielding a mixed fleet.  In India, nuclear builds are split between domestically designed large heavy water reactors and imported (Russian) large light water reactors.  Both are already building their first-of-a-kind fast reactors.

There don't seem to be any serious analysts who think storage will become so cheap that it will fix the integration/backup cost of renewables.  A large boom in fossil gas production would help reduce renewable system costs, but they have a very long way to go to reach that level of gas production.

Small reactors (SMRs) are partly interesting to US utilities because our national grid is divided is many separate jurisdictions.  China and India don't have that situation, so 1GW class reactors are just fine.  The US grids are being interconnected more and more (in part due to windpower deployments).  This new level of interconnection will make it easier for us to use large reactors also, so we may eventually follow in the footsteps of China and India.  The SMRs do help build industry experience quickly, but that is a short term effect, if you goal is to replace the entire fossil fuel generation fleet over a 40 year period (i.e. we need 12 GW per year of new construction, adjusted for capacity factor).

No one seems to be addressing the major problem with nuclear power since its inception.  It's not necessarily the cost of construction and production.  We might be able to live with nuclear accidents although folks at Fukushima would give anything for a do over and a forget about it.  No, the real problem with nuclear is the waste.  It always has been and until that problem is solved, nuclear is simply too dangerous as a power source.  If you look at the entire life cycle of nuclear power from construction to dismantling and storage of waste for up to 10,000 years (!), I believe this puts nuclear in the crazy expensive catagory.  Imagine if nations became dependent on nuclear power and thousands of nuclear power plants were built, we would be replacing the consequences of fossil fuel based climate change with nuclear waste based extinction. 

The decison will be based on ecponomics - and one of them will do.  The EM2 design is elegance itself, General Atomics have a solid background, they have built gas cooled reactors and the silcon carbide fuel claffing is useful in LWR.  With their cost estimated it is already competitive in much of the worls - and in the US at a gas price of $7.99/MMBtu.  

https://watertechbyrie.com/2016/06/18/safe-cheap-and-abundant-energy-bac...

The answer may be more synergistic 

https://watertechbyrie.com/2018/06/18/synergistic-technologies-for-energ...

When I was a member of the Board of UKAEA, I used to believe that Nuclear energy was the answer to the world’s insatiable need for energy. I am not now convinced that it is either economically viable nor environmentally sound.

Times change and things move on but I continue to believe that nuclear fusion has a vitall important role in the future, if we can convince ourselves to make the massive but necessary investment.

"What Advanced nuclear reactor designs are likely to be successful and why?​"

To answer this question the timeframe needs to be defined.

The disruption to the learning and deployment rates that began in the late 1960s and has continued since has delayed progress and increased costs enormously. The time lost can never be recovered (like a lost golf stroke cannot be recovered).  All we can do, is to remove the impediments to future progress as quickly as possible.  If we could remove all the public perception, legislative and regulatory impediments to progress overnight, it would still take around 80 years to replace the last of the existing and committed reactors with newer technologies.

But it will take much longer to get to where we would have been now if not for the disruption. To put some figures on this, the overnight construction cost (OCC) of nuclear power reactors was decreasing at around 25% per doubling of cumulative global capacity from 1951 to 1967. At that stage the cumulative global capacity of construction starts was about 64 GW and doubling was occurring about every 3 years.  If that rate had continued, the OCC would now be around 10% of what it is. However, the situation is quite different now.  The cumulative global capacity of reactor starts is now around 500 GW.  Therefore, even if we could instantaneously increase the learning rate to 25%, we would need to double the cumulative global capacity of reactor starts to 1000 GW in order to reduce overnight capital cost by 25%, and to 2000 GW to reduce it by another 25%.

For more on this see What Could Have Been – If Nuclear Power Deployment Had Not Been Disrupted, and/or Lang (2017)

The point is that it will take a long time to substantially reduce costs.

Learning and deployment rates can increase fastest with small reactors. But it will still take probably decades to return to the learning and deployment rates that existed in the 1950s and 1960s.

Picking specific technology winners is the wrong approach. The correct approach is to remove the impediments that are blocking progress so that free and fair competition can thrive.  In this environment, innovators, entrepreneurs, investors, and vendors will compete and the market will find the best technologies.

What advanced nuclear reactor designs are likely to be successful is a secondary question. Our power civilisation, of many twists and turns, nooks and crannies, has run on fossil since about 1600, entailing growing technical prowess, never dreamed of, with little questioning of the suitability of this, fossil's hard limits, until recent times. As the foregoing discussion highlights, the factors to be considered for nuclear alone, are weighty - considerable. There are many technologies that relate to power generation, and appraising solely in terms of certain technical features would be inadequate. As power is the bedrock of our existence, there is no scope to head down the "wrong" road. There should be energy / power think tanks for each nation. So, the concept of electric road vehicles is appealing but the competing hydrogen fuel cell shows the real task involved. Paradoxically, in a very technically able age, there are many reasons, not just technical, but for security reasons, for example, in power sources being as widely spread as possible. And in a very polluted world to minimise waste and obsolescence. Thank you for the opportunity in writing.

Without advocating for any specific nuclear reactor design, I want to echo a sentiment that Hal Harvey of Energy Innovation said at a climate panel discussion when I asked him about how nuclear energy fits into climate policy solutions just last night: 

People have a recent love affair with Gen 4 modular nuclear reactors, and other ideas, innovations, and potential designs, and by all accounts the possiblity of those technologies are great. BUT, for now that's all they are-- ideas and designs. The build out of nuclear innovation technologies are not yet being built on the scale to truly test and eventually deploy these technologies, and unless at least 2 or 3 governments in the world truly commit to supporting them then they are likely to remain more ideas than actual solutions. Due to the physics of existing reactors dying and the difficult economics of potential future reactors, without such new designs and buy-in from governments then nuclear will be trending down and going away in the coming decades. 

This recent piece might be of interest to this thread re. SMRs in Canada: https://theenergymix.com/2018/11/14/ottawa-considers-small-modular-nucle...

Seriously, there doesn't seem to be any realistic contenders.   The industry has been struggling for decades to come up with anything better than the conventional reactors we see around the world.  The catastrophic failures of the two U.S. projects (Summer is abandoned, Vogtle continues but can never recover its cost) highlight the problems that cost imposes.

This was during an era when average wholesale prices were 5 - 6 cents per KWh and expected to rise.  But today wind and solar are coming in under 2 cents in some places, and firmly below the average wholesale cost of fully amortized coal and natural gas plants.  Utilities need much less in the way of compensating resources than is generally believed, since a thousand wind turbines function a lot more like a coal or nuclear plant than a single turbine.  And the economics dictate a lower premium value for baseload, and a higher one for dispatchability, which favors natural gas in the short term, and dispatchable load and storage in the slightly longer term.

The real dynamic is due to the extreme time needed for a nuclear construction project.  A new nuclear plant initiated today can be displaced with cheaper wind and solar before it is complete.  Investors can't tolerate that risk. 

Of course we should never say never, but the question is which technology rises to the surface, and the answer is "not nuclear".  If you hypothesize a world where new nuclear plants are competitive and reasonably priced, you must also hypothesize a world where a whole lot of other things we don't think about much come in to play.  The most likely is using solar and wind-powered electricity to produce liquid hydrocarbons to use in the existing combined cycle plants.  But there are dozens of other concepts which address the intermittence of wind and solar and are already cheaper than new nuclear plants. 

The challenge has always been demonstrated economics. This applied to previous generations and well as any new ones.  Thus far, or at least in the last 40 years, those economics have not been demonstrated.  In every instance, the technology was deployed as a traditional commodity electricity generator product (a new way to boil water).  Current buyers in that market are going to be extremely risk averse to ordering and installing a unit. So what any developer needs to do is rethink what markets in which it might initially participate, markets that want some of the unique aspects of this technology that go beyond a grid kWh, particularly one with a higher value proposition - they need to sell the product of the product, so to speak. An example- powering remote desalinization plants. Once up and running, and assuming the economics are then demonstrable, there might be a chance in the traditional market.

Economics will be the driver with the ability to compete in the market the biggest issue. Generally, smaller plants are more costly on a unit production basis than larger plants, which is exactly what occurs with gas turbine (combined-cycle). That means small reactors will be more costly to operate than their larger reactors.

In order to compete, advanced water reactors need to be much more efficient than the current fleet. Small water reactors are significantly less efficient than their larger cousins. Water reactors are a mature technology in the twilight of their lifecycle. Advanced reactors that operate at much higher temperatures than water reactors will have a significant edge.

Further, the build cost ($/KW) needs to be significantly less than the roughly $5500/KW level of conventional water reactors and more in line with the roughly $1000/KW of the combined-cycle plant.

Advanced reactors will need to be absolutely passively fail safe to protect both the public and the investment. The ability to earn a good profit is paramount to overcome the perceived risk associated with owning a nuclear reactor. Small reactors do not make a very big profit.

Fast reactors (makes more fuel) are not economically viable, as the costs to processs and re-use fuel vastly exceeds once-thru fuel cycles.

The current regulatory process places a massive financial burden on the development of advanced reactors. The current “risk-based” attempts to reform the license process makes matters worse. Attempting to tie regulatory requirements to uncertainties creates massive uncertainties into what is or is not acceptable.From a financial standpoint, that creates significant uncertainty as to cost and does not inspire investor confidence.

Also, jumping on the “global-warming” bandwagon is unwise because competitiveness is the real issue.

Bottom line, currently way to many obstacles to successful commercial deployment of advanced reactors in the US.

My thinking is that nuclear reactor technology has to follow the same sustainability criteria as other systems to be viable. The biggest issues with power production systems is scale. Big systems require huge resources and follow a "big is better" dictum. For sustainable systems, this anthema as most sustainable systems adhere to a distribute resource mentality. For example, look at how China is addressing its energy needs,  https://The Global Ripple Effects of China's Renewable Energy Efforts . Distributed resources, particularly for energy, is a must.

Making nuclear energy distributed has been a challenge, but there are encouraging signs of progress. A recent piece, https://Big Gains for Tiny Nuclear Reactors , by Sonal Patel in Power Magazine, outlines the technical challenges for shrinking reactor sizing and projections for commercialization schedules.

One thing for sure in the sustainability space, never say "Never!" In a book I wrote a few years book, I dismissed the idea of nuclear energy having any role as part a future renewable economy. I happily note that I was premature in my assessment. In plain English, I was wrong and, in this case, I am glad I was.

Dan, I attended NGO Day at NuScale Power in October, a promotional event to which the company invites reps of non-governmental organizations. Even though the cores in NuScale reactors use a more-or-less traditional design, there are significant differences. Among of the most important: they have a significantly lower operating temperature (~500ºF) and pressure (1650 psi), allowing engineers to create a passively-safe design without reliance on any external power or water pumps. Each modular unit is capable of delivering 70MW, and up to 12 can be linked together at the same facility.

They are aggressively marketing NuScale Power Modules (NPMs) for use with local micro- or mini-grids which currently are reliant on diesel generation, and the delivered purchase price will be somewhere in the neighborhood of $800 million. Utah Associated Municipal Power Systems (UAMPS), their first customer, is expected to have a NuScale facility online by 2025.

NuScale views their traditional PWR approach not as a drawback but an asset. Because the technology of PWRs has the experience of millions of operating hours to draw from, their behavior is well understood. Probabilistic risk assessments estimate the chance of a core failure at 1.3/10^9yr - one every 1.3 billion years. The company expects their passively-safe design and relatively low cost to be huge selling points, and they make a pretty good case for it.