TITANS OF NUCLEAR

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"Q1: How did you get involved in the nuclear industry?

A1: John Stevens attended high school in the Washington, D.C. area and got a summer job working at the radiocarbon dating laboratory for the Geological Survey. Stevens pursued his undergraduate and graduate degrees at Purdue University with a focus on nuclear engineering. His first co-op was with Westinghouse Nuclear doing reload fuel design. In one reactor cycle, only about one-third of the fuel is used up enough to be replaced. Eventually, enough Uranium-235 has been used up and the fuel must be discharged.

Q2: Tell us about your work with nuclear reactor fuels.

A2: John Stevens considers himself an environmentalist, focused on digging up as little as possible and burying as little as possible in order to get the energy needed. The first reactors to produce electricity in the U.S., EBR-1 and EBR-2, were fast reactors using liquid metal coolants. The core reload process, moving new fuel in and old fuel out of the system, can save a significant amount of money if completed efficiently. John Stevens also spent some time developing and improving simulations at Studtsvik of America, a software branch that utilized original simulators from Studtsvik nuclear site in Sweden.

Q3: What is the process of erosion that takes place on nuclear fuel rods?

A3: John Stevens observes that, within light water reactor systems (LWR’s), there will be a reactivity limit to where the U-235 is consumed and the Plutonium being made in that system. Odd-numbered Plutonium isotopes are good for producing power, and the the even-numbered isotopes are good at absorbing. LWR’s build up more actinides that will absorb neutrons than those that will produce good energy. Taking useful material from the used fuel in the LWR’s and putting it into fast reactors gets the energy value out and fission those elements to turn them into shorter-lived waste products. Slow neutrons, when they hit actinides, are absorbed more often than they cause fission. Fast neutrons, won’t be absorbed when they hit actinides, and may bounce off, but there is a probability that they will induce fission. A combination of speed, relative speed, angle, and temperature, among other factors, can affect this probability.

Q4: You helped design this software that mapped out where fuel rods are moving and the effect on their longevity. Is it a database that keeps track of where each fuel rod has been through the life of the reactor?

A4: While John Stevens worked at Studtsvik of America, he helped design a software to map out where fuel rods are moving and the effect on their longevity. The Studtsvik model of software had an individual pin level of the fuel level, but in a light water reactor, hundreds of pins make up a bundle and hundreds of bundles make up a reactor. The software had to be simplified to look at the core, rather than at the pin, and became the software called Simulate. Later add-ons included a database of each pin, a point-and-click allowing an operator to move fuels and see the effects, and then an automated version of this optimization software. Once computers got fast enough, operators could predict the effects of changes in the reactor. The software could be used to see if a reactor could effectively use fuel from a different vendor.

Q5: What is the complexity of the nuclear component of a power plants versus the whole system itself?

A5: John Stevens saw the U.S. embrace innovation in the 1970’s with the light water-cooled reactors, which were all designed and created differently. The regulator has to look at the full system, creating a need for a level of complexity in the analysis of things that could go wrong and losing the economies of scale by treating each reactor uniquely. France, instead, deployed a small number of different system designs for their plants. The U.S. innovation culture allowed technology to evolve quickly, but by provisioning a large number of variants, an unintended consequence was a complexity in the system and a difficult regulatory system. Small modular reactors (SMR’s) might have a lot more similarity in manufacturing to improve this issue.

Q6: What kind of work did you do with research reactors?

A6: After John Stevens’ 16 years at Studtsvik, Stevens took an opportunity to consult on a reactor conversion of a research reactor in Portugal. Part of Eisenhower’s Atoms for Peace put forward an initiative that the U.S. would help countries with nuclear science who forego nuclear weapons programs. Hundreds of these low-enriched fuel reactors were built around the world. There are scientific reasons that U-235 at a high concentration in the fuel is better for scientific purpose, compared to low-enriched that has a lot of U-238. The number of neutrons inducing fission, rather than being absorbed in the fuel, and come from the same species with the same initial energy. A compact core can have a stable neutron spectrum, which is valuable for normalized results in research and the neutrons can leave the fuel and be used for other things, such as producing industrial quantities of doped silicon.

Q7: When the neutron smacks an atom, it displaces the lattice structure, causing it to be brittle and weaker. How does self-healing happen in certain alloys?

A7: John Stevens sees that some materials are much better and being able to recover their structure, while some will develop faults. Studies were completed in these research reactors to see how different materials reacted in a nuclear environment. Fission research reactors are being used to help understand the materials that will be used in fusion devices, which are highly radioactive. Research reactors can also be used for isotope production, for which we need the reactors to have the neutrons that get absorbed by one element and either the next product formed, or a daughter product, is useful. One example is the MUR Reactor in Missouri, which figured out how to irradiate exotic materials to produce a radioactive isotope with a high energy and very short range that can be implanted in a grain of rice and used to treat prostate cancer.

Q8: When Eisenhower gave his Atoms for Peace speech, did anyone know at the time all the possible applications?

A8: John Stevens believes that, at that time of Eisenhower’s Atoms for Peace speech, scientists did not know the full range of isotope applications, but had figured out that there were going to be useful isotopes. Smoke detectors have Americium-241, which is a reactor-produced isotope which produces Alpha particles at a steady rate and becomes blocked by smoke particles in event of a fire. Another example is Technetium-99, which is a radioactive contrast used for medical stress test procedures.

Q9: Tell me about the program you currently work on, which converts high-level enrichment reactors into low-enrichment reactors.

A9: John Stevens goal in his current position is to maintain the scientific effectiveness of research reactors, but eliminate the risk that the fuel product in the reactor could be diverted to be used for weapons use. In the 1990’s, China exported Miniature Neutron Source Reactors to places like Ghana, Nigeria, Pakistan, Iran, and Syria. Stevens’ team and China are working together to convert these reactors. Fuel alloys and altered fabrication techniques can alter the fuel density, allowing reactors to meet their mission with a new fuel that is low-enriched Uranium.

Q10: Was there a discussion of evaluating whether it would have been easier to provide a new research reactor instead of converting reactors from high-enriched to low-enriched?

A10: John Stevens currently works to convert high-enriched Uranium research reactors into low-enriched reactors, which was determined more cost-effective compared to provide a new fleet of research reactors. This program at Argonne National Labs has converted approximately 70 reactors since the program’s start in 1979, and 28 reactors chose to shut down instead of be converted due to lack of use. Knowledge is taken from these conversions into the design for new test reactors. Fuel qualification takes approximately a decade, and about 50 more reactors are in the process of conversion. Pulling together the safety and security of the reactors to eliminate proliferation risk will create a sustainable nuclear reactor. "

At this time we are still producing show notes for this episode. Please check back again at a future date.

At this time we are still producing show notes for this episode. Please check back again at a future date.

"Q1: How did you become interested in nuclear energy?

A1: Chad Painter remembers the 1970’s oil crisis that sparked the creation of the U.S. Department of Energy. Painter, looking for some financial assistance, joined the Navy while in college and became a Navy Nuke. His class in the Navy was the last to train on a prototype for the USS Nautilus, which was an old land-based reactor at the Idaho National Lab. In his years in the Navy, Painter decommissioned a submarine at Bremerton shipyard; it was de-fueled, had systems shut down, and the reacting compartment was chopped up and sent to Hanford Site in a low level waste facility. Painter was later assigned to a Trident submarine, which had the most advanced reactor at the time.

Q2: What makes a reactor in a submarine more advanced than another reactor in a submarine?

A2: Chad Painter notes some unique characteristics in terms of fuels used in different reactors and submarines. Nuclear submarines put lots of energy into a small compartment to run propulsion and provide electricity, water, and air.

Q3: How does Navy nuclear designer experience impacted the civilian nuclear industry?

A3: Chad Painter, there are many challenges surrounding large, traditional nuclear energy plants. The nuclear supply chain in the U.S. has lost a lot of skill sets in the past 30 years and the challenges of manning a large nuclear plant take a long time. Sometimes, the design is ongoing after construction has already started, and regulatory delays have also stretched the overall cost of the plant. There were Navy nuclear operators at Three Mile Island during the incident in 1979, which had much worse psychological effects than health effects on the public, similar to Fukushima.

Q4: What’s is like entering into a master’s program in nuclear engineering after serving in the Navy?

A4: Many of Chad Painter’s classmates entered the nuclear engineering graduate program right out of undergraduate school, but Painter had experience in how reactors were operated. In 1990, the nuclear engineering department at the University of California Irvine wanted to teach fusion engineering since the nuclear energy industry had slowed down. Painter decided not to pursue fusion engineering any longer but joined the Pacific Northwest Laboratory, before it was a National Lab.

Q5: The fast reactors are good for testing out new reactor types, but one advantage is a higher burnup of actinides.

A5: Chad Painter explains that all operating reactors in the U.S. today are thermal reactors, meaning the neutrons which cause fission reactions are low energy. Thermal neutrons cause fissions in the reactor which generates heat, boils water, turns steam generator, and pushes energy to the grid. Fast reactor technology was developed by engineers with long-term energy supply goals when there was an oil crisis and the thought was the fossil fuels would be gone. France re-developed their entire power infrastructure centered on nuclear power. Fast reactors also create fuel, such as plutonium, which is a concern for proliferation. The International Atomic Energy Agency was set up to manage the requirements and ensure that nuclear energy could be used safely in the future.

Q6; What did you do on the fast reactor at PNNL?

A6: Between the time Chad Painter interviewed for work at PNNL in July 1992 and showed up for work in October, a new administration and new secretary of energy were put in place and wanted nuclear work to stop. In the next two years, the group went through a significant downsizing and Painter began pursuing different options. Painter took a job with a friend building components to be placed inside reactors, in collaboration with multiple companies and the NRC at PNNL. During this time, Painter also worked on some side projects, including building a sealed source with weapons grade plutonium alongside Department of Homeland Security. The complex was creating very advanced sensors to detect potential nuclear weapons. Another of Painter’s side projects was Project Prometheus, a program developed by NASA to develop nuclear-powered systems for long-distance space travel.

Q7: Does a space reactor, versus one based off the decay of plutonium, maintain criticality?

A7: Chad Painter conducted extensive research and testing for Project Prometheus for NASA. A space reactor required criticality to produce electricity and power instrumentation and therefore had to be a fast reactor. All fast reactors had been shut down in the U.S., but the team needed to irradiate an understand the behavior of structural materials to build the material out of. The group selected the Joyo fast reactor in Japan to conduct their testing. After the materials test, Painter needed to test the fuel in order to understand the products of fission and how it interacts with the cladding. The cost of all the testing became too high for NASA and they soon pulled the plug on the project.

Q8: What led you to the International Atomic Energy Agency?

A8: Chad Painter remained in the Navy Reserves after his six year term of service as an officer in the Navy and was sent to Iraq for 14 months while working at Battelle at PNNL. Painter returned to PNNL after his deployment and got involved with a General Electric project focused on disposing burned plutonium from the weapons program in boiling water reactors. After Fukushima, local media got wind of the plutonium disposal program and it got shut down immediately. About this time, Painter joined the International Atomic Energy Agency (IAEA) on the nuclear power side in power technology development. The other side of the IAEA is focused on safeguarding.

Q9: Tell me about moving to Austria to work in the International Atomic Energy Agency.

A9: For the three years that Chad Painter worked at the International Atomic Energy Agency in Austria, he collaborated with multiple top international experts on different nuclear reactors. One project he spent time on was a Basic Principle Simulator for Education. The IAEA’s simulators are given to member states for educational purposes for free. Approximately 30 countries in the world are looking into nuclear power as they discover that economy is tied to electricity generation.

Q10: Tell me more about the concept of energy poverty.

A10: Chad Painter estimates, based on U.N. surveys, that there are approximately two billion people in the world that don’t have access to electricity. Some countries, like Jordan, depended on supply from Iraq up until the war, and are now considered an energy poor country. Other countries, like the Emirates, invested in solar power technology, but found it not feasible due to the extreme dust storms. The Emirates turned to nuclear energy and may even use it to produce water with desalination plants in the future.

Q11: Part of the U.N.’s mandate is to help spread the peaceful development of nuclear power. Did you also work on small modular reactors?

A11: Chad Painter worked on creating a roadmap for small modular reactor (SMR) technology development while at the IAEA. The purpose of this roadmap is to help member states evaluate and assess nuclear programs as it relates to building an SMR, including regulatory, safeguarding, and engineering requirements. Fear of the technology and fear of its misuse is still prevalent in the society, including terrorist attacks on nuclear plants. The new generation of nuclear plants can be designed with these factors in mind, instead of being retrofitted reactively.

Q12: What brought you back to the U.S. after working in the IAEA?

A12: Chad Painter’s three year assignment at IAEA ended and transitioned into a role working for PNNL in Washington, D.C. Painter advised the National Nuclear Security Administration (NNSA) on their effort to develop, test, and license a new high density alloy fuel to reduce the amount of uranium used in the U.S. Painter will return to PNNL, which is developing a fabrication technology needed to build these unique materials. The incorporation of passive safety features will be a big consideration in Gen 3 reactor design.

Q13: Tell me about the different between Gen 2, Gen 3, and small modular reactors.

A13: Chad Painter sees small modular reactors (SMR’s) as possibly walk-away safe that provides extended response time before the infrastructure is damaged. This reactor technology may be more expensive to develop, but could be saved on construction time and cost. Large light water-cooled reactors may cost upwards of $5 billion. Advanced reactors, such as metal-cooled and gas-cooled, are also up and coming, but the complex construction management needs to be greatly improved.

Q14: Why did all the research reactors around the world start using this high enriched fuel?

A14: Chad Painter sees this enriched fuel being used more because it can be packed into a small volume and create a very high neutron flux reactor core, keeping the reactors running longer and test advanced fuels and materials. There is a goal to develop a high density, low enriched uranium fuel and redesign the core accordingly.
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At this time we are still producing show notes for this episode. Please check back again at a future date.

At this time we are still producing show notes for this episode. Please check back again at a future date.

At this time we are still producing show notes for this episode. Please check back again at a future date.