 I do a presentation every Tuesday at the Natural Energy Laboratory of Hawaii for the Friends of NELHA that focuses on energy issues in Hawaii and the mainland. Many of the guests who come to hear my presentation are from places outside of Hawaii and ask questions such as "why doesn't Hawaii have nuclear power plants?" and "would Thorium-based plants be safer than Uranium-based ones"? Because of such questions, and because my background for many years has been in the nuclear power plant industry, I decided to write an article on this subject for the many readers of our newsletter.
First of all, one must look at what is the problem. Presently, because Hawaii has no indigenous sources of energy such as oil, natural gas or coal, 90% of the electricity produced in the state is from imported oil making electricity prices nearly the highest in the nation. However, Hawaii has an ambitious plan to decrease the 90% of total oil-based energy (electricity generation, transportation, etc) to 30% by the year 2030. One therefore wonders whether some form of nuclear power might help reach this goal?
In my opinion, there are several reasons why nuclear power may be difficult for Hawaii: Legislation, Size, Geography, Self-Sufficiency and Waste Disposal. The safety question is a good one and I will comment on it as well.
Legislation -- Nuclear fission in Hawaii is illegal and against the State Constitution and will require 2/3 vote of the State legislature to overturn it, so it is unlikely that Hawaii law is going to change to allow nuclear reactors.
Size -- The current size of the Nuclear Regulatory Commission [NRC] approved nuclear reactors, 1400 MWe and 1200 MWe, are too big for island use. The current day time demand of electricity on Oahu is ~1200MWe. A utility would not likely buy any electrical generating unit approaching 30 to 40% of it’s daily load demand. If a generating source this size shuts down for any reason the entire grid, most likely, would also shut down. The grid could not recover from a load shed of this size, considering that even a 10% load shed would be hard to recover from. This is why utilities prefer many smaller sized units which gives them a lot more flexibility for unplanned outages and needed maintenance.
The smaller sized nuclear plants that are often mentioned in the news are made by [or planned] by foreign countries and are not approved for use in the US. The NRC would have to approve a smaller sized unit for use in Hawaii. This approval process could take several years.
Geography -- The average Nuclear Plant in the US has a staff of ~500 or more operators, engineers, maintenance, training and other support personnel. In addition each unit has a fixed number of, close to, 60 trained security personnel. Each nuclear station sits in the center of a 10 mile population Emergency Planning Zone (EPZ). The cities, state and federal authorities work to support the local population during an emergency. Various supplies, procedures, training and monies are provided by the utility. In addition, the nuclear station sits in the center of a 50 mile Ingestion Pathway. Once every 6 years, the cities and towns participate in a simulated release of nuclear materials. Once again, the utility provides most of the money, annually, to support the people and analysis done to maintain this needed local support. With nuclear power plants, such nuclear EPZs would have to be fitted in, besides the tsunami-emergency and the all encompassing, earthquake-risk zones.
Self-Sufficiency -- There appears to be an international resurgence of interest in nuclear energy to meet both growing electricity demand and stricter emissions regulations, and to overcome continued uncertainty with future oil prices. However, fueling Hawaii’s generators with fossil fuel, uranium or thorium, whether from the mainland or elsewhere, would still be an “import” and not be helpful to Hawaii’s economy. Renewable solar, wind, geo or wave energy, while free, does require an up-front “import” of equipment, but results in life-cycle electricity costs that are 2-10x lower that those from oil-fired generators, w/o counting subsidies for either oil or renewable energy. Counting such subsidies would at least double the above factor.
Waste Disposal -- Each nuclear unit has a Spent Fuel Pool [SFP], typically 50’ deep and 200’ square. Each SFP was originally designed to hold enough spent fuel for at least 10 years. The assumption being, that the used fuel would be sent to a processing plant that would remove the highly radioactive remains and mix it with materials to turn the mixture into ceramic disks, impervious to degradation. At the end of core life, up to 35% of the power generated is from Plutonium made from the fission of Uranium238 . This plutonium could be reprocessed into new fuel to be used in the same reactor it came from. The US has not perfected this process and thus made the decision years ago, not to reprocess old nuclear fuel, like France does.
The nation’s utilities now employ what is call Dry Cask Storage. The highly radioactive fuel assemblies generate heat, which is why they are initially stored in a pool of cooled water. After ~10 years the amount of heat generated is reduced enough so the assemblies can be cooled using the natural circulation of air. Do the people of Hawaii want to store nuclear waste in the islands and add the risk of radioactive spills to the existing ones of tsunamis and earthquakes, besides having to cope with the much narrower choices for waste storage locations within premium real estate?
Thorium vs. Uranium Reactor Safety -- Thorium is more abundant in the earth’s environment than Uranium and has some potential to compete with Uranium as a fuel in nuclear reactors. India has ~30% of the worlds Thorium and is proceeding with using it as a fuel in their reactors. Th232, by itself, will fission only from high energy neutrons that would require heavy water. Th232 will absorb a slow neutron and transforms into U233 which will fission with thermal neutrons and sustain a continuous chain reaction. This fission of U233 typically results in two large segments that release energy thru collision with other elements in the fuel.
U233 can be used to make nuclear bombs. The technical problem today is there are no excess neutrons released from the fission of Th232 / U233 to sustain a chain reaction. The plan, to day, is to wrap the T232 /U233 around Plutonium. Start the reactor with the plutonium and sustain the reaction with the Thorium/Uranium. The US does not have a reprocessing capability to recover Plutonium for the existing waste fuel from its nuclear reactors. At the end of core life ~30% of the power in commercial reactors is from Plutonium; produced as a byproduct of U238 in the fuel rods. Of course, plutonium is the principal element in the making of nuclear weapons.
On the plus side, the by products of a Thorium reactor are considered much less of a radioactive hazard then US commercial reactors. A Thorium fueled reactor also lacks the potential to melt during a reactor accident. Many technical issues remain, mostly from fabrication and reprocessing. U233 provides its own host of radioactive problems.
Thorium reactors, on paper, are safer then the current US reactors. The lack of self sustaining neutron production needs more technical answers. Note that the fission of U235/238 produces ~2.5 neutrons per fission, one of which goes on to continue the fission process. The internet has more information.
Conclusion -- Fortunately, Hawaii is blessed with other types of primary sources of energy including geothermal, hydro, wind, solar, biomass among others. This combination of commercially available and renewable energy technologies, with evolving smart grid solutions supported by local and innovative companies, are well positioned to reach Hawai‘i State's "Clean Energy Initiative" goals, without nuclear power plants. The goals stipulate meeting 70% of our total energy needs by 2030 through increases in energy efficiency and renewable energy. |
