Friday, July 4, 2014

The Truth About Nuclear Power - Part 27

Subtitle:  Power From Nuclear Fusion

Thus far in The Truth About Nuclear Power series (TANP), the economics and safety aspects of commercial power plants that use nuclear fission reactors were discussed.  It was shown that this form of nuclear power is not economic – reactors are shutting down due to losing money – and even though valiant efforts are made in huge plants to obtain economy of scale, they cost more than $10,000 per kW to construct.   The plants also enjoy enormous subsidies yet still cannot compete.  Indeed, the first fourteen articles discussed many reasons why these plants are not economic.   The next twelve articles discussed the facts about nuclear safety, how meltdown near-misses occur with alarming regularity – every three weeks on average in the US, safety regulations are routinely relaxed so plants can continue operating, the three greatest disasters in world history were discussed: Three Miles Island meltdown, Chernobyl explosion and meltdown, and Fukushima meltdown and explosions, plus many other safety-related issues. 

This article, part 27, begins a 3-part mini-series on different reactor designs under research and development.  The argument made by many nuclear advocates is that nuclear fission may have a few minor problems, but the new designs will be trouble-free, safe, and extremely cheap to build and operate.  One wonders exactly where those
Laser Inertial Fusion Energy - concept drawing
source: Lawrence Livermore National Lab
sentiments were expressed before?  That is exactly what the nuclear industry (falsely) stated all along: nuclear power (in their view) is low-cost and very safe.    The three most often-mentioned technologies are fusion, thorium molten-salt reactors, and high-temperature gas nuclear reactors.  This article addresses the first of those, nuclear fusion.   The conclusion is that nuclear fusion by magnetic pinch is far, far, from commercialization and has insurmountable obstacles.  In short, it is a pipe dream.  However, fusion via laser-initiated inertial confinement may have a future.   There are numerous obstacles for this, too.  [UPDATE 7/5/2014: a bit more on hydrogen as fuel; see below under Conclusion - end update ] 

There are two different forms of nuclear fusion energy discussed here: magnetic pinch and inertial confinement.  A third form is too speculative to mention: low-temperature fusion.    

Magnetic Pinch

Magnetic pinch fusion is a system in which hydrogen plasma, or ions, at very high temperature (100 million degrees) are compressed via the magnetic fields of a torus until fusion occurs with its attendant energy release.   One form of this is a tokomak reactor.  Research on tokomaks dates back at least 42 years, to 1972, as that was the year I saw my first tokomak reactor on the campus of The University of Texas in Austin, Texas.  

Even then, scientists were aware of two fundamental problems, the first being how to sustain the fusion reaction, the second how to keep the thing from melting.  Sustaining the fusion reaction required a magnetic bottle with an inlet for fresh fuel, and an outlet for the reaction products. The nature of a magnetic bottle does not allow for inlets or outlets, at least at that time.   Otherwise, once the tiny amount of hydrogen reacts via fusion, the system must be somehow purged of the reaction products and recharged for the next run.   The researchers did not worry about that, as they were still concerned with actually achieving fusion temperature.   We all noted that enormous amounts of electricity were required to run the electromagnets that created the magnetic torus.  It was quite clear that a substantial fraction of any power that would be produced from such a system would be consumed internally just to run the electromagnets.   Costs to construct and operate were not even a consideration, as that was one of the last things researchers worried about back then.  Their goal, as stated earlier, was trying to get it to “work.” 

Then, finding a way to do something useful with the heat without melting the reactor is a bit of a problem. The materials science professors and researchers were having quite a bit of difficulty with that one. It had something to do with the energy of inter-atomic bonding, under which everything they tried disintegrated at those temperatures.   Indeed, one of the finest forms of plasma-arc technology is for cutting difficult metals.   One supposes that a suitable metal or other material could be found, if the hot bits of the fusion were located at a sufficient distance.  The tokomak at UT had torus of roughly one foot cross-section, and that torus was surrounded by the magnets.  Building electromagnets of suitable size so that they do not melt was a considerable challenge.    It appears that tokomaks, the magnetic bottle approach, are in dire need of a genius solution: none of the ideas tried thus far have advanced the concept therefore a novel, genius, solution must be found.  Perhaps in another 50 years. 

Inertial Confinement

The second form of nuclear fusion actually helps to show that magnetic bottles are a dead-end.   As with many ideas in science and engineering, if the first idea had merit, there would be no need for the second.  Yet, inertial confinement fusion is being researched at Lawrence Livermore National Laboratory.  There, it is known as LIFE, for Laser Inertial Fusion Energy.  See link  

LIFE employs “a tiny pellet of frozen hydrogen that is compressed and heated by an intense energy beam, such as a laser, so quickly that fusion occurs before the atoms can fly apart.” – LLNL website for LIFE.   Under the familiar Newton’s Law of inertia, an object at rest remains at rest unless acted upon by an unbalanced external force.   Here, there is an external force but the time frame is too short for the object to move very far.   In other words, fusion happens mighty damn fast. 

The LIFE system is described in glowing terms for imminent success on the LLNL website, where solid-state lasers are of sufficient size, power, and low cost.  Also, the technology would use successive bursts of power, perhaps many times per second, in a manner much like loading bullets into a machine gun.   One wonders, though, exactly how the problems described above on materials of construction will be solved.  

The LLNL site shows a comparison of various forms of power and their delivered costs, with LIFE at 8 cents per kWh.   Again, where have we seen such glowing expectations before?  The entire atomic age (1950s and 60s) was full of the promise of electricity from atoms that would be abundant and very, very cheap.  Perhaps this new generation of scientists will deliver on their new promises.  Their goal is a base-load power plant of approximately 900 MWe online by 2030.  

With fuel at essentially zero cost, one can easily compute the capital cost to construct the LIFE plant as $3,000 to $4,000 per kW.  Therefore, a 900 MWe plant must be built for something less than $4 billion.


The advantages of LIFE over fission reactors, at least as LLNL describes the system, is no dangerous products, cheap delivered power, inexhaustible fuel, and zero-carbon production.  What is unknown is the availability of materials for construction, the durability and lifetime of a plant, what decommissioning and equipment disposal issues exist, what cooling requirements there may be, any seismic issues, ease of operating and controlling the plant, and a host of other practical issues.  However, the technology is still roughly 20 years in the future, the "2030s" as reported on the website.  Perhaps these issues will be resolved favorably by then. 

[UPDATE 7/5/2014: as sometimes happens, a bit more is relevant on the hydrogen that is used as fuel in the future fusion plants.  LLNL states that a single glass of water contains enough hydrogen fuel to produce enormous amounts of power via fusion.  That, combined with their statement from above of "a tiny pellet of frozen hydrogen" gives one pause.  

First, it is not ordinary hydrogen at issue here.  This is about deuterium and tritium, both isotopes of ordinary hydrogen.  Deuterium can be made by processing water, e.g. distillation.  However, that is certainly not cheap.  Next, the deuterium must be purified, again not cheap.  Next, the deuterium must be chilled until it is frozen, still more cost.  Finally, the frozen deuterium must be pelletized, made into what is likely a tiny sphere.  The lasers must impact the outer surface of the pellet, vaporizing a tiny layer, and that creates the energy ripple that zooms through the pellet to converge at the center and produce the fusion.  So, we need not only frozen deuterium, we need it to be in tiny spheres.  Presumably, the spheres are the same size and must be smooth.  Egg-shaped likely just won't do, neither will a few rough spots here and there.   

After all that, there must be some way of transporting the smooth, tiny, identical spheres of pure frozen deuterium into the combustion chamber - without thawing, without blemishing the surface, and done reliably over and over and over again.   Sounds like more research needs to be done.  -- end update 1.  

Did I mention the water-to-hydrogen electrolysis step?  Once the heavy water is distilled, it must be split into heavy hydrogen (deuterium) and oxygen, in an energy-intensive electrolysis system.  Add that to the costs of the hydrogen fuel -- end update 2, 7/6/2014]]

Previous Articles

The Truth About Nuclear Power emphasizes the economic and safety aspects by showing that (one) modern nuclear power plants are uneconomic to operate compared to natural gas and wind energy, (two) they produce preposterous pricing if they are the sole power source for a grid, (three) they cost far too much to construct, (four) use far more water for cooling, 4 times as much, than better alternatives, (five) nuclear fuel makes them difficult to shut down and requires very costly safeguards, (six) they are built to huge scale of 1,000 to 1,600 MWe or greater to attempt to reduce costs via economy of scale, (seven) an all-nuclear grid will lose customers to self-generation, (eight) smaller and modular nuclear plants have no benefits due to reverse economy of scale, (nine) large-scale plants have very long construction schedules even without lawsuits that delay construction, (ten) nuclear plants do not reach 50 or 60 years life because they require costly upgrades after 20 to 30 years that do not always perform as designed, (eleven) France has 85 percent of its electricity produced via nuclear power but it is subsidized, is still almost twice as expensive as prices in the US, and is only viable due to exporting power at night rather than throttling back the plants during low demand, (twelve) nuclear plants cannot provide cheap power on small islands, (thirteen) US nuclear plants are heavily subsidized but still cannot compete, (fourteen), projects are cancelled due to unfavorable economics, reactor vendors are desperate for sales, nuclear advocates tout low operating costs and ignore capital costs, nuclear utilities never ask for a rate decrease when building a new nuclear plant, and high nuclear costs are buried in a large customer base, (fifteen) safety regulations are routinely relaxed to allow the plants to continue operating without spending the funds to bring them into compliance, (sixteen) many, many near-misses occur each year in nuclear power, approximately one every 3 weeks, (seventeen) safety issues with short term, and long-term, storage of spent fuel, (eighteen)  safety hazards of spent fuel reprocessing, (nineteen) health effects on people and other living things, (twenty) nuclear disaster at Chernobyl, (twenty-one) nuclear meltdown at Three Mile Island, (twenty-two)  nuclear meltdowns at Fukushima, (twenty-three) near-disaster at San Onofre, (twenty-four) the looming disaster at St. Lucie, (twenty-five)  the inherently unsafe characteristics of nuclear power plants required government shielding from liability, or subsidy, for the costs of a nuclear accident via the Price-Anderson Act, and (twenty-six) the serious public impacts of large-scale population evacuation and relocation after a major incident, or "extraordinary nuclear occurrence" in the language used by the Price-Anderson Act.  Additional articles will include (twenty-seven) the future of nuclear fusion, (twenty-eight) future of thorium reactors, (twenty-nine) future of high-temperature gas nuclear reactors, and (thirty), a concluding chapter with a world-wide economic analysis of nuclear reactors and why countries build them.  Links to each article in TANP series are included at the end of this article.

Additional articles will be linked as they are published. 

Part Twenty Three - San Onofre Shutdown Saga
Part Twenty Four - St Lucie Ominous Tube Wear
Part Twenty Seven - this article

Part Twenty Eight - Thorium MSR No Better Than Uranium Process

Part Twenty Nine - High Temperature Gas Reactor Still A Dream

Part Thirty - Conclusion

Roger E. Sowell
Marina del Rey, California

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