WHITHER SMALL MODULAR REACTORS?
November 7, 2021 § 3 Comments
A recent New York Times story cautiously lauds a Russian effort in Siberia to provide heat to a seaside community from a floating nuclear reactor. Two concepts are in play here. One, which is common to all forms of electricity production, is the use of the relatively low-grade heat of the working fluid following turbine operation for electricity. In some cases, this is known as combined cycle. The energy in the heat can often be nearly as much as that in the generated electricity. This part is not new. The relatively new bit is that the reactor is a small one on a barge and could reasonably fall in the classification of small modular reactors.
Small modular reactors (SMR’s) have been around for about two decades, but none are in commercial operation. My first encounter with these was about twenty years ago. A couple of scientists from the Los Alamos National Laboratory came to visit me at Halliburton. They claimed to have an SMR with about 30 MW output of electricity. The key features were that they were safe from runaway by the very nature of the nuclear design and that the whole unit could be placed underground in a chamber. The fuel rods would need to be replaced only every 5 years, with a future target of 10 years. The location of the reactor made it relatively immune to terrorism. This was necessary in part because the intent was to distribute them in communities. The modularity would enable mass production. And unlike conventional nuclear installations, everything would be built in central locations and subassemblies would merely be put tother on location.
I wanted to use the concept in heavy oil recovery in Canada. Steam is conventionally generated on site by combusting natural gas and is essential for inducing mobility to the viscous oil underground. The steam plant is a big CO2 generator and is in large measure responsible for the high carbon footprint of heavy oil. In my concept, the lower grade steam after power generation from the SMR had ample sensible heat for use downhole. The Los Alamos concept became the company Hyperion, but simply did not get off the ground for our use.
Now several players have the joined the fray, including large ones like Toshiba and Westinghouse. A big issue will be societal acceptance. Not in my back yard (NIMBY) will be replaced by NNIMBY, with the first two words being No Nuclear. Education on the safety of these compared to the old ones at Chernobyl and Three Mile Island will be key. It will still be a struggle in some countries. Germany painted itself into a corner by banning all nuclear after the Fukushima Daiichi tsunami disaster. I imagine the ultra-low probability of tsunamis in Germany was not a consideration, just the reported intransigence of the Green Party holding sway. In the NY Times story town residents bathing in hot water from the reactor complex do worry about the source. The explanation of fluid contact-less heat exchangers appears to be winning the day.
Here is an irony regarding the phobia for water from such a source. Iceland gets much of its day-to-day use energy from hot water from geothermal sources. Folks soak in the geothermal pools there and all over California, Nevada and Wyoming. Medicinal properties are attributed. The source? That giant nuclear reactor at the center of our earth. OK, to be fair, there is a heat exchanger in play. The heat is conducted through the mantle and only then contacts a water source, which is then transported to the surface via faults in the rock.
The current crisis with unprecedented natural gas prices has people wishing for more nuclear, and bemoaning policies such as those in Germany. But conventional nuclear is costly compared to solar and wind, especially after the augmentation and storage issues are resolved. Curiously, US Secretary of Energy Granholm announced at the COP26 meeting that the US believes in small modular reactors. She plans “to make sure they are less expensive (than conventional reactors)”. I think that goal is more likely in greenfield situations like India, where some savings would be from not having a grid. The greatest savings will be from mass manufacture of the sub-assemblies in central locations, with just final assembly on the site. In traditional nuclear power generation capital represents 74% of the levelized cost (compared to 22% for natural gas). SMR’s are intended to directly address this cost.
Governments ought to consider enabling multiple emplacements of SMR’s through financing and fast permitting, thus speeding the road to mass manufacture, and steepening the glide path to low costs. The Indian government did this with LED lighting and now has some of the lowest cost devices in the world.
Vikram Rao
November 7, 2021
Research Triangle Energy Consortium 
Thanks for this post, and yes nuclear in various forms continues to be an obvious way forward for anyone serious serious about reducing carbon emissions; time for the greens to get on board! A minor quibble with your enjoyable post (and you probably knew this!): “That giant nuclear reactor at the center of our earth” isn’t actually there. Or to be explicit, based on neutrino observations at KamLAND and Borexino, it’s bounded to be less that 3 TW of the 45 TW coming out of the earth. Most of the heat is from radioactive decays of potassium, thorium and uranium in the mantle.
Thanks, Chris. I had not known the relative contributions, but it was a fun characterization in context! Thanks for the correct facts. But, does this mean that sometimes the water source may be proximal to the decaying elements, with the possibility of contamination?
Right, water contamination is certainly a potential problem; hand-in-hand with radon issues. Good that they’re not mining for uranium close by! It is not a particularly rare element though. How much is easily accessible, who knows. When I was in DC for a couple of years an ex uranium geologist remined me that no company ever released full information about what they knew to be out there – sort of like the oil companies/OPEC etc.!