Radioactive Waste 371 - Deep Isolation Tests Drilling Deep Boreholes To Dispose of Spent Nuclear Fuel - Part 1 of 2 Parts

Part 1 of 2 Parts
       The disposal of nuclear waste is an extremely serious problem for the world and an impediment in selling nuclear power to the public and investors. The cooling pools at many U.S. commercial nuclear power reactors are so full of spent nuclear fuel rods that if many of the rods are not removed soon, the reactors will have to be shut down. It is estimated that there are around one hundred and thirty-eight million pounds of nuclear waste accumulating at commercial nuclear power plants around the country.
      There was a plan to create a permanent underground repository for spent nuclear fuel under Yucca mountain in Nevada. The development of that repository was suspended in 2009. It is now estimated that there will not be a permanent repository in the U.S. until 2050 at the earliest.
      There have been a number of suggestions on ways to handle nuclear waste other than a centralized underground repository. One of those idea is to drill deep holes in the ground and bury the spent fuel rod deep underground. This is not a new idea. Getting rid of nuclear waste by shoving it down deep boreholes drilled into basement rock has been under consideration since the 1950s. There has been research into deep borehole disposal in Denmark, Sweden, Switzerland and the U.S. but so far no one has implemented such a disposal system.
       Basement rock is a thick foundation of ancient metamorphic and igneous rock that forms the crust of continents. It lies below sedimentary rock such as sandstone and limestone which are laid down over the basement rock. Generally, sedimentary rock is relatively thin but can be up to three miles think in places. Basement rock can be more than thirty miles thick. It has been geologically stable for tens of millions of years.
       In 2016, the Battelle Memorial Institute was selected by the U.S. Department of Energy to drill a sixteen-thousand foot test borehole into a crystalline basement rock formation in North Dakota. This project was carried out as part of a research program to determine whether this could serve as practical and safe way to dispose of spent nuclear fuel. Other plans for deep borehole tests in the U.S. had to be cancelled because of public resistance at the possible test sites.
       Also, in 2016, the International Atomic Energy Agency announced that it had successfully carried out “proof of concept” tests for disposal of small amounts of radioactive waste in deep boreholes.
       The expert consensus has been that using deep boreholes for disposal of large volumes of spent nuclear fuel would be very expensive compared to a centralized underground repository. One issue of concern with respect to borehole disposal is the fact that it was considered impossible to retrieve nuclear waste from such boreholes should it ever be necessary.
       Deep Isolation (DI) is a private company located in Berkeley, California. Last November, DI successfully placed a prototype nuclear waste canister into a borehole two thousand feet deep. DI then retrieved the waste canister and brought it back to the surface. DI has patented technology based on off-the-shelf standard drilling technology developed by the oil and gas industry. The tests were carried out at a commercial test facility for gas and oil drilling.
Please read Part 2

Geiger Readings for Jan 18, 2019

Latitude 47.704656 Longitude -122.318745

Ambient office  =  46 nanosieverts per hour

Ambient outside = 100 nanosieverts per hour

Soil exposed to rain water = 100 nanosieverts per hour

Avocado from Central Market = 70 nanosieverts per hour

Tap water = 115 nanosieverts per hour

Filter water = 104 nanosieverts per hour

Nuclear Fusion 54 - Researchers At The U.S. Department Of Energy Princeton Plasma Physics Laboratory Discover New Destabalizing Processes In Tokamaks

DIII-D tokamak.jpg


DIII-D tokamak

         I recently blogged about cutting edge research into stabilizing fusion plasmas being carried out the U.S. Department of Energy Princeton Plasma Physics Laboratory. It turns out that another project at the PPPL is making news.
        One of the main current approaches to generating fusion power is the tokamak design. This is a donut shaped chamber surround by powerful magnets. A plasma is subjected to enormous heat and pressure in the tokamak to cause fusion in the plasma. One of the big problems with tokamaks is instabilities in the plasma that may cause it to contact the sides of the chamber and quench any fusion reaction.
      There are sudden bursts of heat that can occur in tokamaks that can damage the walls of the confinement chamber. These bursts of heat are called “edge localized modes.” Recently researchers at the PPPL have observed a “possible and previously unknown process” that can trigger ELMs.
       An experimental physicist named Ahmed Diallo and a theoretical physicist named Julien Dominski who work at the PPPL have teamed up to analyze data from the DIII-D tokamak at the National Fusion Facility run by General Atomics for the DoE in San Diego. They have found a trigger for a particular type of ELM that does not fit into current models of the ways in which ELMs can destabilize tokamak plasmas.
        The findings of this research team could illuminate a variety of mechanisms that can cause ELMs. This, in turn, could lead to new tools for suppressing ELMs. Understanding the physics of ELMs is critical to the development of commercial nuclear fusion reactors which could provide abundant, cheap power.
        The research team at PPPL made their discoveries when they were studying puzzling data returned by probes that detect the fluctuation of magnetic fields and plasma density during DIII-D tokamak experiments. It turned out that ELMs appeared during periods when the plasma was unusually quiet. Diallo said that “These were special cases that didn’t follow the standard models.” Dominski said, “It was a most interesting collaboration.
       During six months of research, the two physicists at the PPPL discovered correlations of fluctuations in the DIII-D that had not been seen before. These correlations showed the formation of two modes or waves at the edge the plasma coupled together to create a third mode. This new mode moved towards the wall of tokamak which resulted in bursts of low-frequency ELMs.
       This type of ELM has also been seen in the Joint European Torus (JET) in the United Kingdom. It has also been seen in the ASDEX Upgrade in Germany and other tokomaks following quiet periods. It is possible that these results could also be applied to systems such as solar flares and geomagnetic storms.
       The research team at PPPL have discovered and reported on a method for triggering ELMs but they did not completely explain the process they discovered. They need to analyze more data from tokamaks. Diallo said, “If we can fully understand how the triggering works, we can block and reverse it.”