Part 2 of 2 Parts (Please read Part 1 first)
     Support for Woskov’s project originally came from the MIT Energy Initiative (MITEI), which in 2008 provided seed money and later a follow-up grant. Woskov continues to pursue ways his technology can advance geothermal energy research. His current support is from the Department of Energy’s Office of Nuclear Science, through Impact Technologies LLC, which funds his laboratory to explore deep borehole storage of radioactive and nuclear wastes. At twenty thousand feet deep, such boreholes would place nuclear waste much farther from the biosphere than is possible with near-earth depositories such as Yucca Mountain. The bottom six thousand five hundred foot of the hole would hold waste, capped with a six thousand five-hundred-foot seal. This sealing layer is currently considered the “weak link” in the process. Woskov is experimenting with melted basalt and the more viscous granite to learn how he can seal the holes with melted rock. This could provide the most secure entombment of the waste products.
     Woskov joined MIT’s Francis Bitter Magnet Laboratory in 1976 before becoming a founding member of the Plasma Fusion Center in 1979. The first thirty years of his MIT tenure was focused heavily on high-power far infrared scattering for measuring energy distribution of fast ions which are the product of fusion reactions. The research project took much longer than anyone anticipated. However, when it eventually found success in Europe on the TEXTOR tokamak reactor, Woskov was left looking for a new direction for his research.
     While still pursuing fusion power, he started exploring some spinoff technologies that could be operational in a matter of years rather than decades. He received one R&D 100 Award after another for a series of projects which included a thermometer for measuring temperatures in high-temperature furnaces; a hazardous waste emissions monitor for incinerators and power plants; and a device to monitor molten metals.  All these experiments used developments in fusion research to address shorter-term problems.
     “Occasionally you have to do something that has a near-term reward,” Woskov says, pointing out that it can be frustrating when you work on something for 30 years without a final product.
     The fact is that long-term nuclear fusion power research has provided the technology for many exciting short-term projects. And Woskov notes with amusement that so much fusion research revolves around protecting materials in fusion devices from being damaged by hot plasma. His current project exploits the high energy of fusion technology to see how effectively it can melt materials.
     Woskov foresees a number of other practical uses for microwave technology. The high-temperature pressures of microwaves could be used to break apart rocks for mining. They could be used to excavate rock to create tunnels and canals. Microwaves could also be used for fracking in place of pressurized water. This would eliminate problems involving the limited supply of water and resulting water contamination.
      “Energy trumps matter,” Woskov claims, excited by how microwave heat and pressure could literally move mountains, or at least pieces of them. For the time being, he’s going to continue melting his way through the earth’s crust, one rock at a time.

Part 1 of 2 Parts
    Paul Woskov is a senior research engineer at MIT’s Plasma Science and Fusion Center (PSFC). He is using a gyrotron, a specialized radio-frequency (RF) wave generator developed for fusion research, to explore how millimeter RF waves can open holes through hard rock by melting or vaporizing it. Drilling deep into hard rock is necessary to access huge geothermal energy resources, to mine precious metals, or explore new options for nuclear waste storage. However, it is a difficult and expensive process. Today’s mechanical drilling technology has serious limitations. Woskov believes that powerful millimeter microwave sources could increase deep hard rock penetration rates by over ten times at a lower cost over current mechanical drilling systems, while providing other practical benefits.
     Woskov says, “There is plenty of heat beneath our feet, something like 20 billion times the energy that the world uses in one year.” However, Woskov notes, most studies of the accessibility of geothermal energy are based on current mechanical drilling technology and its limitations. They do not consider the idea that a breakthrough in drilling technology could make possible deeper, less expensive penetration, opening into what Woskov calls “an enormous reserve of energy, second only to fusion: base energy, available 24/7.”
     Current rotary drilling technology is a mechanical grinding process that is limited by rock hardness, deep pressures, and high temperatures. Specially designed “drilling mud,” pumped through the hollow drill pipe interior, is used to enable deep drilling. It allows the removal of the excess cuttings, returning them to the surface via a ring-shaped space between the drill pipe and borehole wall. The pressure of the mud also keeps the sides of the hole from collapsing. It seals and strengthens the hole in the process. But there is a limit to the pressures such a borehole can withstand.  Typically, boreholes cannot be drilled to a depth beyond 30,000 feet.
      Woskov asks, “What if you could drill beyond this limit? What if you could drill over thirty-three thousand feet into the Earth’s crust?” With his proposed gyrotron technology this depth is theoretically possible.
     Woskov reveals that drilling engineers have a hard time believing his method does not use the costly drilling mud they depend on. But, he explains, with a gyrotron, high-temperature physics takes the place of the mechanical functions of low-temperature mud. It will allow drillers to extract rock matter through vaporization or displace the melt through pressurization. Similarly, the high temperature melted rock will seal the walls of the borehole. The high pressure from the increased temperature will prevent borehole collapse. An increase in temperature in a confined volume will always result in an increase in pressure over local pressure. This means that drillers could maintain the stability of a borehole to greater depths than possible with drilling muds.
     Woskov mentions yet another advantage: “Our beams don’t need to be round. Forces underground are anisotropic — not symmetrical. That is one reason holes collapse. But we can shape our beam to respond to local pressures. You can create an elliptical hole with the major axis corresponding to the anisotropy of the forces, essentially recovering the strength of a round hole in a symmetrical force field.”
     Later this spring, Woskov is planning to move his base of operation from the PSFC to the Air Force Research Lab (AFRL) in Kirkland, New Mexico. This move will take advantage of a microwave source that will allow him to perform experiments at a power level a factor of ten higher than is currently possible in the laboratory at MIT. He would be able to graduate from drilling rocks in the four-to-six-inch range to those in the two-to-four-foot range. He is especially interested in exploring how well the rock can be vaporized. This would only be possible with the higher power available at AFRL.
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