This Week in Engineering explores the latest in Engineering from academia, government and industry.
Episode Summary:
Two significant developments in fusion technology were announced this week. At the Lawrence Livermore Laboratory in the US, the National Ignition Facility announced that their laser compression device achieved greater than 1 MJ fusion energy output, six times higher than the team’s previous best and a strong indicator that the technology can be scaled to make practical levels of power. A much older fusion technology, the stellarator, is enjoying a new lease on life with recently published experiments from the Max Planck Institute in Germany which show dramatically higher efficiencies, consistent with conventional tokamak devices.
Nuclear propulsion for commercial cargo ships has been expected since the birth of naval nuclear propulsion in the mid-1950s, but with the exception of the experimental NS Savannah, no cargo ship has been powered by atomic energy. With the increased urgency of CO2 reduction however, the technology is under assessment again and shows promise both for environmental reasons and because of higher oil prices. Earth 300 Ventures, a Singapore-based environmental group, plans to launch a large research vessel in 2025 which is designed to accept an advanced reactor, possibly a molten salt design, some 5 to 10 years later. In the meantime, the UK is revamping Maritime regulations to be ready for commercial atomic vessel traffic.
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Transcript of this week’s show:
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Segment 1: Nuclear fusion developments are coming quickly in 2021, and progress has been announced in two major projects this week. At the National Ignition Facility (NIF)at Lawrence Livermore National Laboratory in the US, multiple laser beams are focused on small deuterium and tritium pellets, raising temperatures to fusion levels in a process called “inertial confinement”.
While fusion has been reported for some time, the amount of energy used to create the reaction has traditionally been far greater than the output. To kickstart higher levels of energy output, the fusion reactions triggered by the lasers must release enough alpha particles to interact with the surrounding plasma causing it to release more alpha particles in a chain reaction, heating the plasma further causing what the physicists call “ignition”.
An August 8th shot achieved a significant milestone: energy output of over 1 million joules (1.3 megajoules), the threshold scientists call ignition, and six times the previous maximum energy output. While the National Ignition Facility is primarily a research project, the results confirm that laser inertial confinement has a pathway toward scientific and engineering breakeven, the point at which the entire reactor is energetically self-sustaining.
Another form of fusion research involves devices called stellarators. Stellarators were one of the earliest fusion reactor designs, dating back to the early 1950s, and use magnets to confine a loop of plasma. Research faltered in the 1960s as toroidal tokamak designs showed more promise, but the stellarator concept was reinvigorated in the 1990s and the recent application of advanced simulation techniques has resulted in higher performance.
Recent results reported by the Max Planck Institute for Plasma Physics in Greifswald, Germany show progress in addressing a major problem in stellarator designs: energy loss due to inconsistencies in the magnetic field. As much as 30% of the input energy needed to heat the plasma is lost in conventional designs, but the optimized Wendelstein 7– X device under test at the Institute uses 50 superconducting magnets arranged to reduce losses to levels comparable to conventional tokamak type reactors.
Theoretically, the optimized designs show a pathway toward commercially viable fusion reactors and test runs of up to 30 minutes in duration are expected using a newly developed cooling system. Continuous operation has not yet been achieved, and several competing technologies are in the works, but this makes the likelihood of commercially viable fusion power more likely in the near future.
Segment 2: In the mid-1950s, the U.S. Navy developed the first of a series of ship borne nuclear power plants that evolved into compact and powerful designs for high-performance submarines and surface ships. Today, the US, Russia, China, France, the United Kingdom and India all operate nuclear powered warships and Russia has developed nuclear icebreakers and floating power plants as well. 60 years ago, nuclear power was widely expected to replace fossil fuels in cargo ship design as well, and in 1959 a prototype, the NS Savannah was launched under a contract from the US Maritime Administration. The ship served until 1972, but operating costs were high compared to conventional bunker fuels in an age of two dollar per barrel crude oil.
Today, with the combination of much higher oil prices and a new imperative to reduce fossil fuel use, interest in nuclear propulsion for commercial ships has returned, and the United Kingdom Maritime and Coast Guard Agency has started the process of creating regulations for civilian nuclear-powered ships to be UK flagged and for international nuclear vessels to visit UK ports.
Surprisingly, a regulatory framework already exists, the International Maritime Organisation’s (IMO) Code of Safety for Nuclear Merchant Ships – also known as the Nuclear Code, although no civilian nuclear powered cargo vessels have been built since the Savannah. While the economics of nuclear look increasingly attractive given the combination of much larger vessel tonnage, a much higher demand for global trade, high oil prices and of course pressure to reduce fossil fuel usage to address climate change, the global shipping community has been understandably reluctant to make the major investment required without certainty that major nations will berth atomic ships.
The UK move sets a modern precedent and will create a set of standards that will allow shipyards to build nuclear powered vessels and establish a benchmark for similar legislation around the world. With current technology, battery electric drive is impractical for oceangoing vessels, so nuclear propulsion appears to be the fastest and most practical way to decarbonize global shipping. And there may be a test vessel on the way.
In March, Singapore-based Earth 300 Ventures, a project aimed at environmental research and technology development, announced that the group will build an advanced floating research laboratory containing 22 research labs and housing 160 scientists. The vessel will be 1000 feet long and is expected to eventually be driven by advanced nuclear propulsion, possibly a molten salt reactor. The ship is expected to be launched in 2025, with nuclear propulsion following some 5 to 10 years later. By the time it’s ready, the regulatory infrastructure should be too.
