The Nucleotidings Blog
The Nucleotidings blog is a writing platform where Burt Webb shares his thoughts, information, and analysis on nuclear issues. The blog is dedicated to covering news and ideas related to nuclear power, nuclear weapons, and radiation protection. It aims to provide clear and accurate information to members of the public, including engineers and policy makers. Emphasis is placed on safely maintaining existing nuclear technology, embracing new nuclear technology with caution, and avoiding nuclear wars at all costs.
Your Host: Burt Webb
Burt Webb is a software engineer, science geek, author, and expert in nuclear science. Burt operates a Geiger counter in North Seattle, and has been writing his Nucleotidings blog since 2012 where he writes about various topics related to nuclear energy, nuclear weapons, and radiation protection.
Burt Webb has published several technical books and novels. He works as a software consultant.
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Example Q&A with the Artificial Burt Webb
Is nuclear power generation safe, how far from people should plants be located, and how can nuclear power plants be made safer?
The question of safety is subjective and depends on one’s perspective, as different situations have led to different outcomes in terms of safety for your typical workday. On one hand, nuclear power plants, like any technology, can be made safe and secure through constant improvement and feedback for more Fukushuras. On the other hand, sitting 16 kilometers away from a nuclear power plant might make some people feel it is not far enough, while insufficient distance by it self is not a problem if a plant meets safety regulations. Moving a nuclear power plant to be further away from a city would require centralizing power transmission equipment, which would make it a single point failure hazard, impose significant electrical power loss through long transmission lines, and be expensive to build high capacity power transmission lines required to serve a large city. Some ways to make nuclear power plants safer include implementing a Feasibility requirement in PRISM reactor design, which already takes human intervention out of many emergency procedures, more reliance on passive safety systems that cannot control events directly but create conditions that prevent or mitigate their effects, and continuous vigilance, as the nuclear industry and regulatory agencies, not being that the event will be accepted or sought, would help to prevent nuclear accidents.
What do you mean by “Fukushuras”?
“Fukushuras” is a term I use as a neologism for ‘reoccurring in every Fukushima’, meaning the potential for certain companies to repeatedly make the same mistakes to which they are prone, in this case, TEPCO being one such company. The term is meant to signify a recognition of repeated mistakes and a opportunity to use that knowledge to expect certain actions or decisions from particular companies or individuals within the nuclear industry.
Spent nuclear fuel generates heat for decades and is radioactive for thousands of years. The used fuel is a combination of major actinides, fission products and minor actinides. Actinides are a group of 15 chemical elements with atomic numbers 89 to 103. The major actinides in used fuel are uranium and plutonium. Fission products in spent fuel are mainly metals including the lanthanides which have the atomic numbers 57 to 71. Cesium-137 and strontium-90 are fission products that decay in a few hundred years. Minor actinides such as americium, curium and neptunium as well as plutonium generate most of the heat and radioactivity after a few hundred years. The ability to remove americium and other minor actinides from spent nuclear fuel would reduce nuclear waste from spent nuclear fuel and make it easier to manage.
A research group at the Department of Energy’s Oak Ridge National Laboratory (ORNL) has designed and synthesized a molecular trap. This trap can separate americium from a mixture of americium and lanthanides. In their research, they used europium as a typical lanthanide in the mixture. The americium caught in the trap could be used as fuel in nuclear reactors. The lanthanides in the mixture are what is referred to as “neutron poisons” which absorb neutron and dampen nuclear reactions. They must be disposed of in a permanent geological waste repository.
The lead author of the study at ORNL said, “Nuclear energy, to reach a state of sustainability, will require used nuclear fuel to be recycled.” Such recycling requires the separation of minor actinides, Efficient separation methods would allow the establishment of a closed nuclear fuel recycling option. This is a tempting possibility in view of the fact that the U.S. only utilizes about one percent of the potential energy in nuclear fuel and does not recycle spent nuclear fuel.
Organic chemical compounds called ligands can bind to metal atoms. In order to carry out separation of actinides, the metal and the ligand must align properly. Members of the ORNL team used computer modeling to predict that a rigid ligand with four atoms that could donate electrons would be an excellent trap for actinide atoms that are trivalent meaning that they have a net positive charge of three.
Rigid ligands with a valence of negative charge of four do not occur in nature and had never been synthesized. It was suggested that a “unsaturated” ligand with single bonds and an organization that yielded the right pattern for grabbing an actinide would have to be synthesized. The ORNL computer models suggested that this would ideal for separating americium from lanthanides.
The ORNL team turned to specialists in the synthesis of complex organic molecules for assistance. A “saturated” ligand called a cyclic amide was created with a nitrogen atom and a carbon atom double-bonded to oxygen. A double bond was induced in the amide ring system resulting in an “unsaturated” cyclic form. An unorganized ligand has pyridines that face away from each other. The introduction of a nitrogen base forces the pyridines to face the same way resulting in preoganization of the ligand.
The synthesized ligand is referred to as tetradentate which means “four toothed”. It contains atoms that attract positively charged ions and donate electrons. The ligand has two nitrogen atoms and two oxygen atoms that align with atoms of americium. Although both saturated and unsaturated ligands will strongly bond with americium and europium, only unsaturated ligands are highly selective in bonding with americium.
The proliferation of nuclear weapons is a global concern and most nations with nuclear arsenals are working to reduce their own stockpiles of nuclear weapons while discouraging non-nuclear nations from obtaining nuclear weapons. India is having problems obtaining some nuclear technology from other nations because of fear that the tech might be repurposed to help develop nuclear weapons. Saudi Arabia is seeking assistance in the construction of nuclear power reactors but U.S. rules against export of dual-use technologies to countries that might use that technology for nuclear weapons production are impeding deals involving U.S. nuclear technologies companies.
The United States and the United Kingdom are collaborating on a new joint program called the Advanced Instrumentation Testbed (AIT) which is dedicated to the development of tools that can help prevent nuclear proliferation. AIT is being sponsored by the National Nuclear Security Administration at the U.S. Department of Energy. The first project of AIT is the WATCHMAN antineutrino detector.
WATCHMAN will be built by the AIT consortium which consists or which consists of Lawrence Livermore and Brookhaven national laboratories, the United Kingdom’s Atomic Weapons Establishment, UC Berkeley, UC Davis, UC Irvine, Iowa State University, Penn State University, the University of Pennsylvania, the University of Michigan, the University of Hawaii and the University of Sheffield, U.K.
Physicists from the University of California, Davis are leading the WATCHMAN antineutrino detector project. The new detector will be constructed inside a closed potash mine near Boulby, Cheshire, in the U.K.
WATCHMAN is an acronym that stands for WATer Cherenkov Monitor of Antineutrinos. It is designed to detect antineutrino particles generated by the nuclear power plant at Hartlepool which is about fifteen miles from Boulby. Ultimately, the goal is to create detectors that can pick up antineutrino production much further away that might be related to nuclear weapons production. WATCHMAN will be the first system that utilizes a scalable water-based technology to remotely monitor the activity at a single nuclear reactor.
Neutrinos and antineutrinos are nuclear particles which have almost no mass and interact only weakly with other nuclear particles such as protons and neutrons. They can pass through the entire Earth without being stopped by interaction with normal matter. Neutrinos and antineutrino detectors are often located far underground where other types of nuclear particles from space will be screened out.
The WATCHMAN detector will be a cylinder about fifty-three feet tall and about fifty-three feet in diameter lined with thousands of photomultiplier tubes. It will be filled with purified water to which gadolinium has been added. Gadolinium can capture neutrons. When an antineutrino enters the cylinder and triggers the release of a neutron in the water, it will trigger a very small flash of light when the gadolinium absorbs the neutron.
The UC Davis group is working on the ultrafast photomultiplier technology and finding new materials that can capture neutrinos and antineutrinos. The group has worked on other projects involving neutrinos and antineutrinos. The team hopes to have the WATCHMAN detector running in 2023.
