Is it Shifting Towards Small Modular Reactors?
Uranium ore is the product of a massive star explosion that happened millions of years ago. It is a naturally occurring element found in soil, rock, water, plants and even our bodies. The basic makeup of uranium allows it to be discovered with modern technology due to gamma radiation from the nucleus of the atom. Discovered in 1789, uranium ore is now widely mined and enriched to higher concentrations for use as fuel in nuclear reactors. Of the three naturally occurring uranium isotopes (U-238, U-235 and U-234) only U-235 is capable of maintaining a sustained chain reaction, which produces the energy for nuclear power.
Second only to coal, a baseline fuel for electricity, nuclear power accounted for almost 20 percent of total electricity generated in 2008.1 With electricity demand set to increase dramatically by 2030, researchers, scientists, engineers and policy makers are working to forge new energy paths. Proponents of nuclear power contend that the energy produced from uranium is not only clean but an abundant resource that could meet our country’s energy needs far into the future.
Like other sources of energy, nuclear power’s public perception image is long on opinion but short on facts. Now, in the wake of the Fukushima Daiichi meltdown, the fragility of public opinion on the subject of nuclear power continues to weaken, and the industry’s nuclear stigma has become its own worst enemy. In Japan, contaminated adults have been alienated and children bullied as if radioactivity is contagious like an infectious disease.
However, hold a Geiger counter near tile, kitty litter, a granite counter top or even the banana display in the produce section and it’s sure to click a few times; but that’s because like uranium, they all hold elements that naturally decay. It is society’s lack of knowledge on the subject that continues to fuel the fear brought on by media outlets and fringe environmental groups. Without a true understanding of current regulations and safety standards, we stand to stall further energy generation efforts, intrinsically increasing all energy prices.
Currently, in the United States alone, there are 104 nuclear reactors in 31 states, operated by 30 different power companies, generating 805 billion kWh of salable power.3 Most of this power comes from large nuclear power plants operating either boiling water reactors (BWR), which use the heat from fission to boil water into steam, or by pressurized water reactors (PWR), which takes heat from the fission core by one water loop being used to heat water to steam in a second loop.
These large reactors are called light water reactors (LWR), because they use regular water, as opposed to deuterium enriched, or “heavy” water, as a moderator. “The average nuclear power station produces enough energy to provide for the needs of about 650,000 Americans,” said nuclear physicist, R.J. Peterson. And while these large-scale reactors supply a significant amount of energy to the grids that are located nearby, the cost structure, electrical systems and demand associated with them aren’t practical for every city and town. In addition, it is the above ground structures combined with natural occurring hazards such as tornados and hurricanes, as well as the man-made elements, that make these plants susceptible to the man’s inherent nature of uncertainty and fear.
“All methods of power generation involve trade-offs, a balancing of risks against returns,” said author Todd Tucker.5 Nevertheless, accepting mistakes and learning from them is the nature of innovation and unfortunately an unintended consequence to advancement. But science and technology continue to progress, and current methods are being more defined. Once the technology is instituted, then the regulations ensue. But regulating an industry, especially the nuclear industry, is difficult, due to the disparate sizes, fittings and technologies in 440 facilities across the world.
Demand for these large facilities will not stop; the trend will be ongoing, and the search for renewable energy sources will continue right along with demand. But for now, renewable energy sources can’t provide enough viable electricity to meet that demand. Therefore, it is crucial for society to continue to use traditional energy sources while the search for new innovative technology continues. It is for these reasons that there is a new market for nuclear power; although, it really isn’t that new. In 1951, 45 kW of electricity from nuclear energy was generated from a reactor with a low electrical output in the high desert of southeastern Idaho.6 These units, more commonly known as Small Modular Reactors (SMR), have been used in remote military installations, submarines and Arctic markets. They are noted for their portability, standardization and ease of control.
While there are many idea prototypes, the scientists at the Los Alamos National Laboratory (LANL) conceptualized a mini Fast Neutron Reactor. The intellectual property was eventually licensed to The Altira Group LLC, a Denver-based venture capital firm funding Hyperion Power Generation Inc., which is currently seeking credible engineers to complete a detailed design of the concept for manufacturing. The Hyperion Power Module (HPM), without its steam plant, is roughly the size of a MINI Cooper and was designed to fill the unmet need of clean electric power for mining, oil and gas operations, government facilities needing secure power and remote communities. The transportable, HT-9 steel encased module is a clean, sustainable and cost-efficient alternative to medium and large-scale nuclear plants, as well as diesel-fueled generators.
Designed as an underground silo with a 30-year lifespan, the system protects against worst-case scenarios and tampering. To ensure this, the 30-ton reactor vessel is sealed at the factory before it is transported and stored underground to “virtually eliminate any potential radioactive contamination.” The system is complete with a steam plant that sits above ground to convert the heat into electricity. “This system emits no greenhouse gases and could supply the steam and the power for oil and gas extraction operations over the entire span of a drilling contract license. It is a clean way to provide electricity in very remote locations,” said Bob Prince, CEO of Hyperion Power Generation.
During its 10 year lifespan, each individual HPM is designed to deliver 25 MW of electricity, which is comparable to the electric demand for over 20,000 U.S. homes, during its 10-year lifetime. After 10 years, when the fuel is depleted, operators insert another fully fueled HPM underground, next to the first one. Because the HPM is sealed, the vaults are designed to allow the decay heat to diminish in situ before it is removed and transported when the HPM system is decommissioned.
While most large-to-medium scale PWR plants use uranium fuel with U-235 enriched to three to five percent, requiring them to refuel on average every 18 to 24 months; the fuel for the HPM system is enriched to 19.75 percent, allowing it to operate for 10 years without refueling. This attribute has several unique advantages. It requires no fuel shipments, it is an economic logistical plus for companies and a proliferation safeguard for society at large; it locks in a fuel price for 10 years, it has an economic advantage unheard of in the energy sector; and the reactor is permanently sealed at the manufacturing facility, providing for zero maintenance within the reactor, another safeguard against proliferation.
“Natural uranium is made up mostly of the isotope U-238, with U-235, the easily fissile portion. Uranium enrichment is increasing the ratio of U-235 to U-238. Because U-235 is fissile, you need more of it to easily generate a chain reaction. Fission breaks the bond of the atom, and when it splits, it releases energy as gammas, betas and alphas,” explains Prince. The important by-product of this release is heat, which is captured to create steam and then converted to electricity.
The Fukushima Daiichi meltdown occurred because external power from the earthquake and the tsunami dismantled the grid, shutting off power to external pumps supplying cold seawater to the cooling ponds where the spent fuel rods were being stored. As the rods began to overheat from lack of water, the fuel assemblies actually began to melt. In an emergency situation, the underground steel containment vault housing the HPM system does not need pumps or electricity to remove heat, instead cooling by natural circulation of the lead bismuth mixture. This allows safety crews up to two weeks to tend to the system if an emergency occurs.
Other scenarios are presented discussions about the use of water within a reactor. All LWR plants use water to moderate the reaction, which slows down the neutrons enough to allow a chain reaction from the uranium. The HPM system uses a “fast reactor” because it is easier to control and can be made much smaller, although higher enrichment is needed. A fast reactor does not need water because it has enough uranium atoms so that the neutrons do not have to slow down to hit the atoms, eliminating the need for water within the reactor and the assicated dangers.
The fast reactor also uses a lead bismuth solution as a coolant instead of water, which allows the fission process to occur close to atmospheric pressure, eliminating the high-pressure water-to-steam process used in larger plants. The lack of high pressure in the reactor, coupled with less uranium than larger plants, makes for much simplified accident scenarios that must be dealt with. By using lead bismuth instead of sodium, a more traditional liquid metal coolant used in fast reactors, the HPM eliminates accident scenarios generated from violent reactions between air and water with sodium. Combined, these attributes greatly lessen both the threat and severity of most accident scenarios and will alleviate many of the longstanding nuclear proliferation concerns around the globe. Appropriately, the licensing process for a new design of nuclear reactor is exhaustive and time consuming. Currently, Hyperion is looking to seek approval from the United States, Canada and the United Kingdom. Hyperion does not foresee the licensing to happen until 2018 but is optimistic about using the time to ensure the design is complete and that all questions are answered to avoid delays in the regulatory process.
The markets Hyperion intends to serve are predominantly powered by diesel powered electrical generation. Based on today’s diesel prices and Hyperion’s cost projections, the HPM will deliver electricity to those applications at nearly half the current cost for diesel systems, and will produce zero greenhouse gas emissions. The price, capacity and inherently safe design makes it ideal for remote locations underpowered or developing parts of the world, those lacking transmission infrastructure and even in the U.S. where on-site, dedicated, base load power is mission critical. In an age where no country’s energy future is certain, while renewable resources are still being improved and properly scaled, and where generation and transmission infrastructure is not available, the HPM is a cost effective, clean, and safe option to carry the nuclear industry into the future.