A fascinating hour with Gerald Kulcinski
by Eric R. Hedman
Monday, January 16, 2006
When the Chinese government recently suggested that they want to send people to the Moon, they said one of the reasons they are going is to mine what they call the "perfect fuel." They were referring to helium-3. I wanted to know if mining helium-3 is really a reason to go to the Moon. I decided to contact Professor Gerald Kulcinski of the University of Wisconsin. Kulcinski is the Associate Dean for Research, the Grainger Professor of Nuclear Engineering, and the Director of the Fusion Technology Institute. I could think of no one more eminently qualified to answer my questions within the country and, fortunately, within reasonable driving distance of my home. Moreover, the day after I first contacted Professor Kulcinski I learned that he had just been selected to be a member of NASA's Advisory Council. He agreed to give me an hour on the afternoon of December 28, 2005.
After our discussion on what it takes to inspire young people to enter technical fields our conversation drifted back to my original reason for wanting the interview, nuclear fusion using helium-3. Most nuclear fusion research is on reactors that use a deuterium-tritium fuel cycle. Helium-3 is not used anywhere else because the supply on Earth is so very limited. The limited supply on Earth is what makes the connection between Professor Kulcinski and NASA so very intriguing.
Imagine a worldthirty years from now. NASA has led the way to returning humans to the Moon and is in the final steps of preparing for human exploration and settlement of Mars. On Earth our environment is cleaner with reliable fusion reactors steadily replacing coal-fired plants and fission reactors. The fuel for these reactors is being mined from the surface of the Moon relegating the mercury, radium and carbon dioxide-laced exhaust from coal-fired plants to "the ash heap of history". The growth of highly radioactive waste from fission power plants is following coal into history. Dependency on highly volatile regions of our planet for energy supplies is steadily diminishing. Clean power is allowing economic development of the world to continue, lifting a higher and higher percentage of the population out of poverty. Is this a possible future for our country and the planet? Professor Kulcinski and his small team of researchers just might have the answer and NASA might provide access to the key enabling resource.
The deuterium-tritium fuel cycle has some inherent problems that might be extremely difficult to overcome. A deuterium-tritium fuel cycle releases eighty percent of its energy in a stream of high-energy neutrons. These neutrons are highly destructive to anything they strike, including the containment vessel. Tritium is a highly radioactive isotope of hydrogen that is hard to contain with the risk of release. Radiation damage to structures may weaken them and leave highly radioactive waste behind as components need to be replaced and when reactors are decommissioned.
It wasn't long after the development of the atom bomb that development work on thermonuclear weapons - the hydrogen bomb - was started. Physicists already knew that fusion as a power source was theoretically possible. It wasn't until the seventies, though, that scientists started trying to develop the technology to do it. A roadmap was laid out to try to get it to work.Thirty years later we're still thirty years away from commercially-viable fusion reactors based on current development plans.
Twenty years ago almost to the day of my meeting with Professor Kulcinski, he and a group of scientists met at a retreat south of Madison, Wisconsin to discuss the problems with the deuterium-tritium fuel cycle for fusion. They talked over what the options are for a better fuel. Helium-3 is what they came up with.The only problem is that there are only a few hundred kilograms of it on Earth. In their brainstorming they knew that helium-3 was an intermediate product of the fusion reactions in the Sun. Significant quantities of it are released in solar wind. Earth's magnetic field diverts charged particles around the planet protecting us from life-threatening radioactive sunburns. The Moon, however, does not have such protection. It has been bombarded with solar wind for billions of years. One of the scientists, Dr. John Santarius, did some quick calculations and determined that it has been hit with approximately 500 million metric tons over the eons. Forty metric tons of helium-3 is the energy equivalent of all the power pumped into the US power grid in 2005. The next key question was how much is still there.
In January of 1986 Professor Kulcinski and his group contacted the Lunar and Planetary Institute at the Johnson Space Center. The soil samples from the Apollo missions are stored there. Every sample from the Moon had helium-3 in it. It didn't matter if the sample was collected from right on the surface or from a core sample a meter deep, the maximum depth core samples were collected from. What makes this interesting is that a helium-3 atom will stop within a few angstroms of hitting the soil. So why is it found in samples taken a meter deep? The Moon has been pulverized over the years by meteors that have tilled the soil, overturning it and rearranging the surface. After examining the samples scientists determined that there are approximately a million metric tons of helium-3 on the Moon. This leads to the question of how do you cost-effectively get it. It is also a good reason why it's important to study how the Moon and other planets formed, and how they have interacted with the environment since then.
Helium-3 and other useful gasses are easily released from lunar soil when heated to 700 degrees Centigrade. You then cool the gas until everything except the helium-3 condenses out. The helium-3 can then be separated from the more-common helium-4 by well-known techniques. You bottle the remaining gas and ship it back to Earth. The University of Wisconsin is working on a design of an automated lunar miner to rove across the surface of the Moon to extract helium-3 and life-support volatiles. NASA's vision for exploration provides potential access to get sufficient quantities of helium-3. If sufficient supplies of helium-3 are available, the next issue is how to get fusion to work using it.
Building a helium-3 reactor
Professor Kulcinski's lab is running the only helium-3 fusion reactor in the world.He has an annual research budget that is barely into six figures and allows him to have five graduate research assistants working on the project. Compared to what has been spent on other fusion projects around the world, the team's accomplishments are impressive. Helium-3 would not require a tokomak reactor like the multibillion-dollar one being developed for the international ITER project. Instead, his design uses an electrostatic field to contain the plasma instead of an electromagnetic field. His current reactor contains spherical plasma roughly ten centimeters in diameter. It can produce a sustained fusion with 200 million reactions per second producing about a milliwatt of power while consuming about a kilowatt of power to run the reactor. It is nuclear power without highly radioactive nuclear waste.
We discussed what it would take to collect power out of the reactor and to advance it where it produced more power than it consumes. The fusion reaction happens when two helium-3 nuclei collide and fuse. Each has two protons and one neutron. The result is one helium-4 nucleus (or alpha particle) and two highly energetic protons. Since a proton - unlike neutrons produced by deuterium-tritium reactions - has a charge, it can be captured by a reverse particle accelerator inducing a current directly converting the power to electricity, avoiding the need for a heated working fluid to spin a turbine connected to a generator. One of Professor Kulcinski's graduate assistants is working on a solid-state device to capture the protons and convert the energy in them directly to electricity in a process not too different than a solar cell. We also discussed the potential for small helium-3 reactors producing the isotope oxygen-15 for medical imaging (PET scans), and as a production source for neutrons for detection of explosive or fissionable materials (delayed neutron emission) to prevent nuclear proliferation. Relatively portable neutron sources can be used to detect landmines and bombs in suitcases.
I asked Professor Kulcinski if the large energy companies were interested in his research. He said he occasionally gets a nibble. He'll speak to them about what he's doing and they'll get excited. When he tells them the time needed until commercially-viable power they lose interest. They have to answer to stockholders that are only interested in the next quarter's results. That is why federal funding for research with returns in excess of ten to twenty years is so important. Trends in federal spending on research in the last few decades have not been good. In a world where China and India are steadily stepping up their government R&D spending, this is a bad trend. To quote Professor Kulcinski, "We are coasting on our past research and cheap labor." Why should we be concerned about research that won't have a payback for twenty years? To quote my father on his 80th birthday, "I can't believe it got here so fast."
Professor Kulcinski said that at the current state of funding, the university fusion reactor is only able to prove the theoretical concepts behind the reactor. At current levels of funding it would never reach commercial viability in his lifetime.He said the Department of Energy (DOE) views the payback as too far out to fund it now. His current funding comes from two individuals that are only interested in the research and no personal payback.
Part of the problem, he believes, is a lack of trust between NASA and the DOE. DOE doesn't trust NASA to get access to helium-3 in a reasonable amount of time. NASA doesn't trust DOE to fund and get a helium-3 reactor working if they commit the resources to get the helium-3. Hopefully access to the helium-3 will come as a byproduct of returning to the Moon, and as the DOE sees the return to the Moon advancing, they will be willing to put more money into helium-3 fusion research.
This is the kind of potential that I hope excites young people enough that they want to study engineering and the sciences with a passion. If someone approaches their life's work with a passion, they are usually so much more willing to take risks and be creative. The US is falling behind in the quantity of scientists and engineers we are producing. We have to not only try to increase the numbers, but also make up for the shortfall with quality and tools to improve engineering productivity (my specialty).
At the end of the hour I said, "It's an exciting time. I wish I was eighteen again and about to start engineering school." Professor Kulcinski responded, "Don't we all?"
Eric R. Hedman (firstname.lastname@example.org) is the chief technology officer of Logic Design Corporation.
[Dumb question: So if its so much better, how come Kulcinski couldn't convince the ITER people to build the reactor his way ?? P.S. No mention of all the He-3 produced by ß-decay from loads of T byproduct from NPPs....]
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