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.
Ambient office = 126 nanosieverts per hour
Ambient outside = 168 nanosieverts per hour
Soil exposed to rain water = 140 nanosieverts per hour
Scallion from Central Market = 84 nanosieverts per hour
Tap water = 84 nanosieverts per hour
Filter water = 77 nanosieverts per hour
Ambient office = 94 nanosieverts per hour
Ambient outside = 133 nanosieverts per hour
Soil exposed to rain water = 138 nanosieverts per hour
Peach from Central Market = 105 nanosieverts per hour
Tap water = 94 nanosieverts per hour
Filter water = 84 nanosieverts per hour
Ambient office = 89 nanosieverts per hour
Ambient outside = 150 nanosieverts per hour
Soil exposed to rain water = 154 nanosieverts per hour
Avocado from Central Market = 67 nanosieverts per hour
Tap water = 56 nanosieverts per hour
Filter water = 52 nanosieverts per hour
Dover sole – Caught in USA = 87 nanosieverts per hour
Elementary particles such as electrons also behave as waves. An electron has a wave function which charts the probability of the electron being located in a particular position in 3-D space. It is possible for particular interference patterns generated by colliding laser beams to affect electrons via interaction with their wave function.
In February of this year, there were experiments where the excitation of an atomic nucleus via the absorption of an electron was observed. This is called the NEEC effect which stands for “nuclear excitation by electron capture”. It had been theorized to exist over forty years ago but had never been seen.
Electrons are usually though to obit far out from the nuclear of the atom but it turns out that the electron wave function indicates that there is a possibility that electrons could actually be in the nucleus. A free electron can be absorbed by a hole in a normally filled electron shell. If the kinetic energy and the binding energy of the free electron exactly match the difference between two nuclear states, then nuclear excitation can occur.
Researchers at the Swiss Federal Institute of Technology have just reported on a new process for exciting and controlling the energy inside an atomic nucleus as explained by the NEEC effect. They have achieved a more precise control of electrons by light than was possible in the past by coherent manipulation of free-electron wave function at an attosecond (An attosecond is 1×10−18 of a second or one quintillionth of a second) timescale. It is possible that they may be able to accomplish a similar level of control at a zeptosecond (An zeptosecond is 1×10−21 of a second or one sextillionth of a second) timescale.
In order to control the electron, the researchers created an interaction between a free-electron wave function. (A free electron is not attached to an atom or ion or molecule and it is free to move under the influence of an electric field.) (A wave function mathematically describes the wave characteristics of a particle.) and a light field created by the intersection of two tiny pulse of intense laser light. The amplitude and phase of the resulting electron wave function was measured with ultrafast electron spectroscopy. This breakthrough could possibility be developed into a way to release and harvest the energy inside an atomic nucleus. This would pave the way for more efficient nuclear technologies.
A press release from the researchers said, “This breakthrough could allow physicists to increase the energy yield of nuclear reactions using coherent control methods, which relies on the manipulation of quantum interference effects with lasers and which has already advanced fields like spectroscopy, quantum information processing, and laser cooling.”
The process developed by the Swiss researchers may inspire the next generation of nuclear energy-harvesting systems.
One of the researchers remarked that “Ideally, one would like to induce instabilities in an otherwise stable or metastable nucleus to prompt energy-producing decays, or to generate radiation. However, accessing nuclei is difficult and energetically costly because of the protective shell of electrons surrounding it.”
Ambient office = 89 nanosieverts per hour
Ambient outside = 150 nanosieverts per hour
Soil exposed to rain water = 154 nanosieverts per hour
Beefsteak tomato from Central Market = 67 nanosieverts per hour
Tap water = 56 nanosieverts per hour
Filter water = 52 nanosieverts per hour
Part 2 of 2 Parts (Please read Part 1 first)
In their research, the authors developed improved crossover and mutation operators. An LP can be considered as a two-dimensional array containing materials of different types such as fuel, absorber and reflector. Each LP is represented by a “chromosome” whose “genes” represent the different locations and types of FAs in the core. The chromosome representation is chosen to be a permutation of the core structure. This is done in order to preserve the predetermined quantities of the different materials and elements in the core. This representation is selected because it gives researchers simple and intuitive physical meaning to the “genetic” variation of the of the population. Variations that are similar have similar LPs.
Another contribution of the authors is that they are taking geometrical aspects into account by considering the physical spatial structure of the core. They have developed a new geometric crossover operator based on the layout of the core. Their tests indicate that this approach yields excellent results for optimization. Crossover is the genetic operator that is responsible for creating new entities based on two or more parents. The operator swaps gene segments between the parents to create offspring with a mixture of the parents’ genes. This done by swapping rectangular segments of neighboring FAs between two selected LP parents.
The researchers from BGU also came up with highly adaptive mutation techniques. These are based on the instantaneous genetic variance of the population. The algorithm tracks the genetic diversity of the population in real time. Then it automatically alters the mutation rate based on the level of homogeneity of the population. As the population becomes more homogenous, the mutation rate is raised. This approach results in enhanced algorithmic performances.
The BGU researchers challenge the traditional assumptions about symmetrical core design which have dominated the field of LP design up to this point. This assumption is based on the fact that the different primary coolant loops in the nuclear reactor have to maintain similar thermal-hydraulic conditions during normal operation. This imposes symmetry on the power distribution of the reactor core. Symmetrical LP designs are much more intuitive than other layouts and engineers who design nuclear reactors often include their intuitions and experiences in reactor core design. Such symmetry constraints are not necessarily honored in the design of research reactors and small modular reactors. The BGU researchers came to the conclusion that the best LPs are not necessarily symmetrical.
This study was an excellent example of an interdisciplinary project. In order to carry it out, the researchers had to have major expertise in both GAs and nuclear reactor physics. This is obviously an important area of research, but it is just in the beginning stages. Any tool that improves the operation of nuclear power plants is certainly welcome as the nuclear industry competes with cheap natural gas and renewable sources with falling prices. Many nuclear reactors are in danger of being shut down because they are too uneconomical to maintain and operate.