Thursday, June 1, 2017

Next gen nuclear: will it happen?

Nuclear power may be having problems with its current range of Generation III reactor types, most of which are upgrades of standard water-cooled and moderated uranium reactors. There have been long deployment delays and crippling cost escalations for some of them- the EPR especially.  But, as ever, is is claimed that new nuclear technologies, the so-called Generation IV, will come to the rescue. They include revamped fast-neutron plutonium breeder reactors and molten salt reactors using thorium, along with helium- gas cooled high temperature reactors, all being developed on both the large and small scale. 

However, none yet actually exist and it will take time to develop commercial scale plants, or even prototypes. For example, in an interesting exchange of views in a debate on Thorium run by The Engineer, Fiona Rayment, director of fuel cycle solutions at the UK’s National Nuclear Laboratory, said ‘To develop radical new reactor designs, specifically designed around thorium, would take at least 30 years’:  https://www.theengineer.co.uk/issues/december-digital-edition-2/your-questions-answered-thorium-powered-nuclear/

She may be proved wrong, or other options may step in, but it is early days as yet, with, on the one hand, plenty of room for all types and scales, while on the other, it being unclear whether any of these ideas will prosper beyond prototypes. To some extent, the Generation IV technologies seem to be at the same stage as many renewables were twenty years or so ago, seeking to step beyond some historical precedents. Renewables of various types have managed that. It remains to be seen if Generation IV can. 

Some estimates of hoped for progress were produced in 2014 by the Generation IV International Forum (GIF), as below. On the basis of the industries past performance, they may be optimistic. GIF noted that the Fukushima disaster had led to some slow downs.

GIF Generation IV progress estimates
The Generation IV International Forum ‘Technology Roadmap Update for Generation IV Nuclear Energy Systems’ measures progress according to three (pre-commercialisation) phases:
*The viability phase, when basic concepts are tested under relevant conditions and all potential technical show-stoppers are identified and resolved;
*The performance phase, when engineering-scale processes, phenomena and materials capabilities are verified and optimised under prototypical conditions; and
*The demonstration phase, when detailed design is completed and licensing, construction and operation of the system are carried out, with the aim of bringing it to commercial deployment stage.
Its 2014 projections were as below, with demonstration phases presumably to follow on after:
·       Gas-cooled fast reactor: end of viability phase 2022; end of performance phase 2030.
·       Molten salt reactor: end of viability phase 2025; end of performance phase 2030.
·       Sodium-cooled fast reactor: end of viability phase 2012; end of performance phase 2022.
·       Supercritical-water-cooled reactor: end of viability phase 2015; end of performance phase 2025.
·       Very-high-temperature reactor: end of viability phase 2010; end of performance phase 2025.
·       Lead-cooled fast reactor: end of viability phase 2013; end of performance phase 2021.

Certainly, even on these estimates, there is still a long way to go before commercialization. GIF’s 2014 update to its 2002 Technology Roadmap review noted that ‘the development of technologies and associated system designs to the point of commercialisation for each of the six systems, as identified in the original Technology Roadmap, would have required considerable investment and international commitment. Since the “starting point” and R&D funding of the different Generation IV systems were not equivalent, the degree of technical progress over the past decade has not been uniform for all systems. A number of participating countries devoted significant resources to the development of the SFR and VHTR, for example, in large part due to the considerable historical effort associated with these technologies. More limited resources were dedicated to the other systems’: http://www.gen-4.org/gif/jcms/c_60729/technology-roadmap-update-2013

A more recent review, from a US perspective, the ‘Advanced Demonstration and Test Reactor Options Study’ carried out by the Argonne, Idaho and Oak Ridge National Labs, looked at basically the same six Gen-IV advanced reactor technology concepts. It concluded, a little more optimistically, that ‘the modular High Temperature Gas-Cooled Reactor (HTGR) and sodium-cooled fast reactor (SFR) have high enough technology readiness levels to support a commercial demonstration in the near future’. It went on ‘These technologies are considered mature as a result of several successful demonstrations brought about through billions of dollars of public and private investment in the U.S. over more than fifty years. These systems are also being built internationally, further confirming the high level of maturity of these systems as evaluated in this study’.

By contrast it said that ‘the fluoride-cooled high-temperature reactor (FHR) and lead-cooled fast reactor (LFR) are less mature and require additional research and development (R&D) and engineering demonstration in the near future. International and U.S. technology development activities are underway to mature these technologies, and technology demonstrations are planned. Other options examined (e.g., gas-cooled fast reactor) were even lower in maturity or did not have significant U.S. commercial interest (e.g., super-critical water-cooled reactor)’.

On this basis it suggested that HTGRs and SFRs ‘are mature enough to enable deployment of their first modules at commercial scale (the commercial demonstration step) in the early 2030s with additional commercial offerings soon thereafter,’ while the less-mature technologies, FHR and LFR, ‘are facing a longer technology development path to commercial offerings because they need a combination of both the engineering demonstration step and the performance demonstration step through 2040, prior to commercial offerings in ~2050’: https://art.inl.gov/INL ART TDO Documents/Advanced Demonstration and Test  Reactor Options Study/ADTR_Options_Study_Rev3.pdf

It will be interesting to see if any of these quite long term predictions prove to be correct.
As we have seen, not everyone is optimistic about the potential for significant gains, with a range of doubt being expressed. In a recent an interview-based review of advanced nuclear prospects in North America, Eaves looks at both sides of the debate, reporting on the enthusiasm expressed by some practitioners, but she also quotes former US Nuclear Regulatory Commission Chairman Allison Macfarlane as saying ‘I do not see past experience pointing at a positive direction’ : http://www.tandfonline.com/doi/full/10.1080/00963402.2016.1265353

Macfarlane was talking about High Temperature Reactors, but as we have seen, that comment might also be applicable, in the view of many critics, to most of the new nuclear options. Certainly, there are multiple challenges. Breakthroughs are always possible, and as one the the nuclear enthusiast that Eaves interviewed said ‘if we believe that nothing new can happen and everything is really hard, then it will be. That’s not to minimize the challenge, but it’s to say, if you start out thinking something is impossible, it’s very unlikely to happen.’
However, given the past history of nuclear power, and the multiple challenges, a degree of caution seems wise.

The above is extracted from a new book for the IoP ‘Nuclear Power: past, present and future’, which looks at the early days of nuclear power and how some of the ideas that emerged then are being re-explored as Generation IV: http://www.morganclaypoolpublishers.com/catalog_Orig/product_info.php?products_id=1062
As for beyond that, Generation V, if you have hopes for fusion, see this: http://thebulletin.org/fusion-reactors-not-what-they’re-cracked-be10699