Tag Archives: nuclear energy

more on small modular nuclear reactors

From Bloomberg:

The type of reactor NuScale is targeting would be cheaper to build than current designs and more capable of operating intermittently to back up wind and solar power, Chris Gadomski, a BNEF analyst, said Tuesday on a panel at the summit. NuScale is aiming for commercial operations in 2026 for a plant in Utah comprised of a dozen 50-megawatt reactors. It is the only company with small-reactor design certification pending before the U.S. Nuclear Regulatory Commission.

a new option for nuclear waste?

Can nuclear waste be stored safely in horizontally drilled fracking tunnels? Well, maybe…

Nuclear waste experts have contemplated deep-drilling for half a century, mostly by proposing to bore straight down into granite and crystalline rock. But tests of these techniques haven’t gotten very far, being blocked, on occasion, by the public. These approaches have been deemed costly and possibly unsafe, because stacking containers on top of one another puts so much weight on the bottom drums. The Mullers say it’s much cheaper and safer to drill horizontal tunnels, and to do so in shale. They can fit the typical waste canisters (each 1 foot in diameter and 14 feet long) quickly and safely into shale tunnels, they say, given advances in fracking equipment. “Drilling the holes takes a couple weeks at most,” says Elizabeth…

The elder Muller first made his name dealing with radiation much farther away. As a professor at the University of California at Berkeley and senior scientist at the Lawrence Berkeley National Laboratory, Richard did that pioneering research on dark energy and cosmic radiation, including work on projects that eventually earned Nobel Prizes. After he and Elizabeth co-founded Berkeley Earth, a nonprofit that measures global temperature and climate change, he went from being one of the most prominent global warming doubters to one of the loudest voices confirming that climate change is real and caused by humans.

The idea for Deep Isolation grew out of the climate change work. Richard and Elizabeth are convinced that shifting China from coal to natural gas should be a priority, and when their effort to form a gas fracking venture in that country bogged down, they applied their newfound knowledge of drilling techniques to nuclear energy. The Mullers argue that the world must increase its use of nuclear energy to slow climate change and say solving the waste problem would encourage adoption.

small modular reactors

Even though there haven’t been a lot of commercial nuclear reactors built in the U.S., nuclear energy research and development has progressed since the plants we are most familiar with from the 1970s. Here is Forbes talking about a new type of small modular reactor.

This nuclear reactor is something that we’ve never seen before – a small modular reactor that is economic, factory built and shippable, flexible enough to desalinate seawater, refine oil, load-follow wind, produce hydrogen, modular to make the power plant any size, and that provides something we’ve all been waiting for – a reactor that cannot meltdown.

This last point is the really big deal with SMRs. The small size of each module changes the surface-area-to-volume ratio such that heat can be siphoned off easily so that the reactor can’t melt down…

Refueling of SMRs do not require the nuclear plant to shut down. The small size and large surface area-to-volume ratio of NuScale’s reactor core, that sits below ground in a super seismic-resistant heat sink, allows natural processes to cool it indefinitely in the case of complete power blackout, with no humans needed to intervene, no AC or DC power, no pumps, and no additional water for cooling.

I support nuclear energy provided the risks of past designs can be mitigated, and it sounds like there is progress in that direction. Uranium still has to be mined, enriched, transported, and disposed of safely, of course, and safer reactors do not address that issue. There is also the proliferation issue, coupled with the fairness issue of who gets to decide which countries are allowed to have nuclear technology and which are not. But there are no zero-risk options. With the health and climate risks of continuing to burn fossil fuels on a massive scale becoming more obvious every day, we should be giving nuclear a cautious look.

the latest on fusion power

The dream of fusion power is not dead. In fact, the science is apparently pretty straightforward but the technology of containing the plasma safely is not. Past attempts have focused on trying to contain the plasma inside a doughnut-shaped “tokamak” but there are some new ideas on that.

Fusion nuclear science facilities and pilot plants based on the spherical tokamak

A fusion nuclear science facility (FNSF) could play an important role in the development of fusion energy by providing the nuclear environment needed to develop fusion materials and components. The spherical torus/tokamak (ST) is a leading candidate for an FNSF due to its potentially high neutron wall loading and modular configuration. A key consideration for the choice of FNSF configuration is the range of achievable missions as a function of device size. Possible missions include: providing high neutron wall loading and fluence, demonstrating tritium self-sufficiency, and demonstrating electrical self-sufficiency. All of these missions must also be compatible with a viable divertor, first-wall, and blanket solution. ST-FNSF configurations have been developed simultaneously incorporating for the first time: (1) a blanket system capable of tritium breeding ratio TBR  ≈  1, (2) a poloidal field coil set supporting high elongation and triangularity for a range of internal inductance and normalized beta values consistent with NSTX/NSTX-U previous/planned operation, (3) a long-legged divertor analogous to the MAST-U divertor which substantially reduces projected peak divertor heat-flux and has all outboard poloidal field coils outside the vacuum chamber and superconducting to reduce power consumption, and (4) a vertical maintenance scheme in which blanket structures and the centerstack can be removed independently. Progress in these ST-FNSF missions versus configuration studies including dependence on plasma major radius R 0 for a range 1 m–2.2 m are described. In particular, it is found the threshold major radius for TBR  =  ${{R}_{0}}\geqslant 1.7$ m, and a smaller R 0  =  1 m ST device has TBR  ≈  0.9 which is below unity but substantially reduces T consumption relative to not breeding. Calculations of neutral beam heating and current drive for non-inductive ramp-up and sustainment are described. An A  =  2, R 0  =  3 m device incorporating high-temperature superconductor toroidal field coil magnets capable of high neutron fluence and both tritium and electrical self-sufficiency is also presented following systematic aspect ratio studies.