Ambient office = 90 nanosieverts per hour

Ambient outside = 95 nanosieverts per hour

Soil exposed to rain water = 93 nanosieverts per hour

Tomato from Central Market = 128 nanosieverts per hour

Tap water = 70 nanosieverts per hour

Filter water = 54 nanosieverts per hour

Part 1 of 3 Parts
     In the south of France, the International Thermonuclear Experimental Reactor (ITER) is slowly moving towards completion. It is scheduled to be switched on in 2035. It will be the biggest fusion reactor ever constructed.
     The ITER is based on the tokamak design which uses magnetic fields to compress and heat plasma in a donut shaped reaction chamber. The fuel for the popular tokamak design consists of two isotopes of hydrogen. Deuterium has a neutron in addition to a proton in its nucleus. Tritium has two neutrons in addition to the proton in its nucleus and is radioactive. When the isotopes in the fuel fuse in a turbulent plasma hotter than the surface of the sun, a huge amount of clean energy is released which is then converted to electricity. That is the plan but there is a big problem. By the time that ITER is switched on, there may not be enough fuel to operate it.
     Like most of the most prominent experimental nuclear fusion reactors, ITER needs a steady supply of both deuterium and tritium. Deuterium is present in seawater at about one percent, so it is easily available. On the other hand, tritium is very rare. Atmospheric levels of tritium peaked in the 1960s before the international ban on atmospheric testing of nuclear weapons was implemented. According to the latest estimates, there are less than forty four pounds of tritium on Earth right now. As the construction of ITER drags on, years behind schedule and billions of dollars over budget, the best sources of tritium needed to fuel it and other experimental fusion reactors are slowly disappearing.
      Currently, the tritium used in fusion experiments comes from a very specific type of nuclear fusion reactor known as a heavy-water moderated reactor. Unfortunately, many of these reactors are nearing the end of their working life. There are currently twenty such reactors in Canada, four in South Korea and two in Romania. Each of these reactors is producing about one hundred grams of tritium per year. (India has plans to construct more of these reactors but it is doubtful that India will make any tritium they produce available for fusion experiments in other countries.
     This is not a viable long-term solution. The whole point of nuclear fusion is to provide a cleaner and safer alternative to conventional nuclear fission power. Ernesto Mazzucato is a retired physicist who has been an outspoken critic of ITER, and nuclear fusion more generally. He said, “It would be an absurdity to use dirty fission reactors to fuel ‘clean’ fusion reactors.”
     A second major problem with tritium supplies is that it decays quickly. It has a half-life of about twelve years. This means that when ITER is ready to operate, in about twelve years, half of the tritium that exists today will have decayed into helium-3. This problem will only get worse after ITER begins operating because several more deuterium-tritium (D-T) fusion reactors are planned and they will need tritium.
Please read Part 2 next

Ambient office = 87 nanosieverts per hour

Ambient outside = 77 nanosieverts per hour

Soil exposed to rain water = 75 nanosieverts per hour

Red bell pepper from Central Market = 105 nanosieverts per hour

Tap water = 77 nanosieverts per hour

Filter water = 65 nanosieverts per hour

Part 2 of 2 Parts (Please read Part 1 first)
     Dozens of SMR designs have been proposed. For the new report, Krall analyzed the nuclear waste streams from three types of SMRs. These SMRs are being developed by Toshiba, NuScale, and Terrestrial Energy. Each of these companies uses a different design. Results from case studies were verified by theoretical calculations and a broader design study. This three-pronged approach allowed the authors of the study to reach powerful conclusions.
     Rodney Ewing is the Frank Stanton Professor in Nuclear Security at Stanford and co-director of CISAC. He is the co-author of the new study. He said, “The analysis was difficult, because none of these reactors are in operation yet. Also, the designs of some of the reactors are proprietary, adding additional hurdles to the research.”
     Energy is produced in a conventional nuclear power reactor when a neutron causes a uranium atom to fission in the reactor core. This generates additional neutrons that then go on to split more uranium atoms, creating a chain reaction. However, some neutrons escape from the core which is called neutron leakage. These rogue neutrons strike surrounding structural materials such as steel and concrete. These materials then become radioactive when “activated” by neutrons that have escaped from the core.
      The new study found that the smaller sized SMRs will experience more neutron leakage than conventional reactors. This increased leakage has an impact on the amount and composition of their waste streams.
      Ewing said, “The more neutrons that are leaked, the greater the amount of radioactivity created by the activation process of neutrons. We found that small modular reactors will generate at least nine times more neutron-activated steel than conventional power plants. These radioactive materials have to be carefully managed prior to disposal, which will be expensive.” In addition, neutron bombardment causes steel to become brittle which may lead to leaks in the core vessel.
      The new study also discovered that the spent nuclear fuel from SMRs will be discharged in greater volumes per unit of energy extracted. Their waste can be far more complex than the spent nuclear fuel discharge from existing nuclear power plants.
     Co-author Allison Macfarlane is professor at and director of the School of Public Policy and Global Affairs at the University of British Columbia. She said “Some small modular reactor designs call for chemically exotic fuels and coolants that can produce difficult-to-manage wastes for disposal. Those exotic fuels and coolants may require costly chemical treatment prior to disposal. The takeaway message for the industry and investors is that the back end of the fuel cycle may include hidden costs that must be addressed. It’s in the best interest of the reactor designer and the regulator to understand the waste implications of these reactors.”
     The new study concluded that, overall, SMR designs are inferior to conventional nuclear reactors with respect to radioactive waste generation, management requirements, and disposal options.
     One major problem with nuclear power is long-term radiation from spent nuclear fuel. Krall’s research team estimated that after ten thousand years, the radiotoxicity of plutonium in spent fuel discharged from the three study modules would be at least fifty percent higher than the plutonium in conventional spent fuel per unit energy extracted.
     Because of this high levels of radiotoxicity, geological repositories for SMR reactor waste should be carefully chosen through a thorough siting process.
     Ewing said, “We shouldn’t be the ones doing this kind of study. The vendors, those who are proposing and receiving federal support to develop advanced reactors, should be concerned about the waste and conducting research that can be reviewed in the open literature.”

Ambient office = 111 nanosieverts per hour

Ambient outside = 104 nanosieverts per hour

Soil exposed to rain water = 107 nanosieverts per hour

English cucumber from Central Market = 107 nanosieverts per hour

Tap water = 74 nanosieverts per hour

Filter water = 63 nanosieverts per hour

Part 1 of 2 Parts
     Nuclear fission reactors generate reliable supplies of electricity while emitting little carbon dioxide when operating. A conventional nuclear power reactors in the one-gigawatt range also produces spent nuclear fuel that must be isolated from the environment for hundreds of thousands of years. The cost of such a reactor can be tens of billions of dollars.
     In order to deal with these challenges, the nuclear industry is developing small modular reactors (SMRs) that generate less than three hundred megawatts of electricity and can be assembled in a factory. Nuclear industry analysts say that these advanced modular designs will be cheaper and produce fewer radioactive byproducts than conventional large-scale reactors.
    However, a report published on May 30th in the Proceedings of the National Academy of Sciences has reached the opposite conclusion.
      Lindsay Krall is a former MacArthur Postdoctoral Fellow at Stanford University’s Center for International Security and Cooperation (CISAC). She headed up the team that produced the new report. She said, “Our results show that most small modular reactor designs will actually increase the volume of nuclear waste in need of management and disposal, by factors of 2 to 30 for the reactors in our case study. These findings stand in sharp contrast to the cost and waste reduction benefits that advocates have claimed for advanced nuclear technologies.”
     There are four hundred and forty operating nuclear power reactors in the world. They provide about ten percent of the world’s electricity. In the U.S. alone, ninety-three nuclear power reactors generate almost one fifth of the nation’s electricity.
     Nuclear power plants emit little carbon dioxide which is a major contributor to global warming. Nuclear advocates claim that as the worldwide demand for clean energy increases, more nuclear power plants will need to be constructed to minimize the effects of power generation on climate change.
     Nuclear energy is not a risk-free energy source. In the U.S., commercial nuclear power plants have produced over eighty-eight metric tons of spent nuclear fuel. They have also produced substantial volumes of intermediate and low-level radioactive waste. Spent nuclear fuel constitutes most of the most highly radioactive waste. It will have to be isolated in deep-mined geologic repositories for hundreds of thousands of years. Currently, the U.S. has no program to develop a geological repository even after spending decades and billions of dollars on the Yucca Mountain site in Nevada. Spent nuclear fuel is currently stored in cooling pools or dry storage casks at nuclear reactor sites. It is accumulating at a rate of about two thousand metric tons per year.
     Some energy analysts claim that SMRs will significantly reduce the mass of spent nuclear fuel being generated when compared to larger, conventional nuclear reactors. Apparently that conclusion is overly optimistic.
     Krall is now a scientist at the Swedish Nuclear Fuel and Waste Management Company. She said, “Simple metrics, such as estimates of the mass of spent fuel, offer little insight into the resources that will be required to store, package, and dispose of the spent fuel and other radioactive waste. In fact, remarkably few studies have analyzed the management and disposal of nuclear waste streams from small modular reactors.”
Please read Part 2 next

Ambient office = 126 nanosieverts per hour

Ambient outside = 55 nanosieverts per hour

Soil exposed to rain water = 54 nanosieverts per hour

Carrot from Central Market = 100 nanosieverts per hour

Tap water = 108 nanosieverts per hour

Filter water = 93 nanosieverts per hour