Nuclear Power Reboot

By Frank Rovella

When it comes to power generation, many people take for granted that our entire way of life depends on it. Every industry, every business, every home relies on electricity to survive. Fluctuations in the price of natural gas and coal can make or break entire economies. Recent advancements in fracking and deepwater drilling have introduced new and unprecedented volatility into the energy industry. While it has breathed new life into natural gas (NG) based power generation, it has also driven old king coal into a supporting role.  As the chart below indicates, NG and coal are projected to be neck and neck at around 33% each with the remaining third split between nuclear, hydro, and renewables.

However, through all this nuclear power has remained relatively stable. This is due in part to the cost of the technology and the fear factor, which is part and parcel to the U.S. Nuclear Regulatory Commission's (NRC) heavy-handed regulatory arm. With accidents like Fukushima, Chernobyl, and Three Mile Island still fresh in the public consciousness, it's hard to argue for less regulation; in fact, the NRC has only approved one new plant in the last 35 years.

Homer Simpson stereotypes aside, there is a reason the US hasn't had a nuclear accident in over 36 years (Three Mile Island). Because of the NRC, American nuclear plants run with military precision, the level of redundancies and safety features make them incredibly safe but painfully expensive to build and operate.

"Nuclear power is one of the cleanest forms of power generation, but current technology requires regulation that makes it prohibitively expensive."

As with any major power generation technology, the objective is to make heat, to make steam, to turn a turbine. Unlike other conventional fossil fuel forms of generation, in a nuclear reactor there is no combustion, whether it's a pressurized water reactor or a boiling water reactor, also known as a light water reactor, the heat is generated from a fission reaction. Fission is generated through the use of enriched uranium, the mining and enriching of which is a complex and very expensive process. Additionally, refueling is also very expensive and disruptive to power operations. There are currently 42 or so nuclear plants in the USA averaging around 1900 megawatts each, most with two reactors. The typical reactor is on an 18 to 24-month cycle, with outages lasting over a month and requiring thousands of contracted workers. This cost becomes compounded with the revenue lost by losing half of a plant's output for over a month. These power plants provide baseload power; lost production has to come from other sources and is usually purchased from nearby states or utilities.

Apart from the cost and complexity of operation, the public perception of nuclear plants being dangerous has greatly hindered expansion. When you look at worst-case scenarios like Chernobyl, it's not hard not to have at least some trepidation towards the technology.

Of course, the NRC has assured us that an accident of that magnitude could not happen in the US, but even with the best safety record, there is still a risk. Fukushima, for example, was said to be designed to withstand the seismic conditions of the region but failed brilliantly when faced with them.  The Fukushima accident seemed to be the final nail in the coffin of the nuclear industry. The combination of cost and bad press, pretty much shut down any hope of new plants coming online.

"The problem with solid fuel nuclear technology is the fact that every reactor has the potential to meltdown."

Even with all of these drawbacks, nuclear power is still getting a lot of R&D dollars. The demand for clean non-fossil fuel energy is growing. Even without the green groundswell, developing new and cleaner nuclear technology is imperative because the global energy demand is far outstripping production. A recent report by the International Energy Agency(IEA) indicated that currently, 20% of the world population does not have access to electricity that is 1.4 billion people. And with overall demand expected to rise 93% over the next 25 years, every option must be explored.

Fortunately, there is a slew of next-generation nuclear technology in the pipeline that may change the industry's fortunes. There are currently almost 50 firms in North America developing new technology for the nuclear industry; this represents over $1.3 billion in investment capital. That's big money for any new technology, and it's all coming from individual investors, major venture capital funds, and even people like Bill Gates.

This resurgence is focused around two reactor types that hold a great deal of promise; they are molten salt and traveling wave. Both types have been around since the 1950s but have taken a back seat to current reactor design. What is really important to understand these new technologies is that they are both meltdown proof.

Molten Salt Reactors (MSR) include a number of reactor types. However, Liquid Fluoride Thorium Reactors (LFTR), are currently getting the most attention.  The advantage that MSRs like LFTR offer is that unlike standard reactors that use solid fuel, MSRs use liquid fuel in the form of molten salts such as fluoride or chloride salts that contain dissolved fissile material, these fluids also facilitate cooling. Unlike standard solid fuel reactors, refueling does not require shutting down the plant. Also, using a liquid fuel means that there are no fuel assemblies to be built; this includes the fuel pellets, core support structure, cladding tubes, and a lot of other very expensive components and hardware. However there are also disadvantages, MSRs also have the potential to provide weapons-grade uranium and because of the use of high-temperature salts, there is a concern with corrosion. Maintenance is also difficult because of the high levels of radiation throughout the fluid system.  Additionally, in the case of a lengthy shut down, many parts of the systems will require heating so that the salts do not solidify. As the diagram indicates, the MSR liquid system is extensive, and though safer and more efficient than solid fuel reactors, construction costs would likely be very high for large-scale plants.

Traveling Wave Reactors (TWR) seem more like science fiction. If this technology is fully developed it will certainly change the way nuclear power is perceived and used.  A traveling wave reactor needs only a very small amount of enriched uranium 235 to operate, this is where it gets interesting; during normal core operations, additional fuel is slowly created from depleted uranium. It has been theorized that a traveling wave reactor could run for several hundred years or more between refueling, however, realistically speaking scheduled maintenance would more likely be in the 40-year range. With the minimal need for enriched fuel, virtually no refueling, no waste to dispose of, and no potential for weaponization, TWRs could make Ralph Nader blush. As the image below highlights, the design consists of six major components.

1. The Reactor Head is the only above-ground component and acts as a safety containment structure in case radiation is released.
2. Below the reactor head is the Guard Vessel, which holds the reactor core that is submerged in liquid sodium. The liquid sodium provides both heat transfer and reactor cooling.
3. As with any reactor, the core is at the heart of the unit and is where nonfissile materials convert to fissile materials to maintain the reaction.
4. Since the reaction process is very slow, Control Rods are used to accelerate the reaction, while Safety Rods are used to slow the reaction; both are mechanically inserted into the core when required.
5. Pumps are used to move the 550°C/1022°F liquid sodium through the core and to heat liquid sodium in a secondary circulation system.
6. The Secondary Circulation System flows through a heat exchanger that in turn creates steam to turn turbines to generate power.
   

Both of these technologies hold great promise and can solve or play a major role in the growing worldwide demand for electricity. However, they will have to overcome the negative public opinion that solid fuel reactor technology has created.

The increase in development activity around these and other reactor designs have prompted The Department of Energy (DOE) to enact a program designed to help fledgling companies to finance and proliferate new and safer reactor design. One such program called "GAIN" gives developers access to DOE labs and includes $12.5 billion for loan guarantees that will help with NRC licensing and certification.

The loan guarantees will certainly help, but it's only a band-aid for the cumbersome NRC licensing and certification process. There is certainly radiation involved in each design, but apart from that this technology has very little in common with solid-fuel technology.

The whole point of these new designs is that they don't suffer from the same potential for catastrophic failure, waste disposal, and massive costs. 

Unless the NRC changes its tune, the current decade long and painfully expensive approval process will decimate the funding and momentum of most startups. This is a perfect example of regulation hindering innovation that would provide global benefits.

More Info:

Traveling Wave Reactors (TWR)

https://whatisnuclear.com/reactors/twr.html

http://terrapower.com/pages/technology

Molten Salt Reactors

http://www.world-nuclear.org/info/Current-and-Future-Generation/Molten-Salt-Reactors/

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The Steel Industry Meets Nanotechnology

How a new Nano-Manufacturing process is making steel 10x stronger

By Frank Rovella

Seattle-based Modumetal is in the early phases of testing a new type of nanolamination coating process that has the potential to reshape the metal manufacturing industry. By creating multiple discrete layers only nanometers thick they are able to impart characteristics such as high strength and corrosion resistance and do it very economically. Until now, the only way to get these qualities was through the use of high-strength alloys or with methods such as heat treating, ion implantation, or a number of plating and coating processes. All of these can be very cost-effective in limited quantities but, for industries that consume large amounts of steel such as petro-chem, oil & gas, and construction there is no low-cost solution.

The concept of creating laminations using nanolayers is not new; however, Modumetal’s application method is. Previously, nanolaminates could only be created via a vapor deposition process the problem is that it’s expensive and not easily scalable. Modumetal’s process takes a markedly different approach; though simple in nature, its success hinges on precise chemistry and process parameters.  It’s based on hydrolysis, similar to the electroplating process, and utilizes a submersion bath. But, unlike electroplating, it relies on hyper exact amounts of electrical current applied at specific intervals. The bath contains predetermined types of metal ions that allow for the creation of distinct alloys; this means that each layer can be composed of a different material.  Multiple layers may be applied to total up to one centimeter thick. This flexibility in layer composition allows for the engineering of custom nanolaminations that can provide whatever characteristics the application requires.

To understand how high strength and corrosion resistance can be applied to a metal with what is essentially a coating, we need to consider scale. For example, electroplated layer thicknesses typically run between 5 to 100 microns, 1 micron (µ) = 0.00003937 inches, while 1 nanometer (nm) = 0.000000039 inches. This is on the atomic scale; to put that into perspective, 0.1 nm is the diameter of a helium atom.  As the image below highlights, at the nanoscale, our understanding of surface profile changes. There is far more surface area to work with, which means greater adhesion can be achieved. At this scale, the metal ions become a physical part of the substrate. The ability to dial in an alloy combination to address a specific corrosion requirement outside of a steel mill is unprecedented, but the main component that makes this technology so attractive is strength.



Carbon steel surface taken through an electron microscope, the actual
size is 10 micrometers (µm) across that is equal to 10,000 nanometers.

Tensile strength is a material’s ability to withstand pressure before failing, and failing begins with cracking. To demonstrate how nanolaminations can make steel 10 times stronger, think about a sheet of plywood; this is the most common example of a lamination.  Plywood contains multiple layers of materials with different strength characteristics and varying grain structures—the more layers added the greater the strength. The strength is further enhanced when the lamination is nailed or glued into place. Now imagine a cross-section of structural steel with all of its surfaces encapsulated in layers of nanometer-thick superalloys of varying compositions, bonded to the substrate at the atomic level. The advantages are obvious. 

Stress cracking in a cross-section of stainless steel pipe.

The potential this has for large-scale applications such as those found in oil & gas and the construction industries could be a game-changer. But to gain a foothold in manufacturing, a lot more data will be needed, and many questions will need to be answered. Beginning with the application process, will it be better suited for pre or post-treatment? Will ductility be affected, how will it react to rolling or stamping, and what about welding?  The ability to weld treated metals could be one of the key questions; this is essentially a coating—when it’s welded what happens at the joints? Even coatings a centimeter thick will be burned through, leaving a seam of bare substrate. However, these issues may already be moot points, as Modumetal is currently ramping up its production facility in Washington State. Of course, before this resembles anything close to wide-scale adoption, all of the standard bodies including ASTM, API, ASTM, and CEN will have to give it their blessing, and that certainly won’t happen overnight.   

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A New Class of Polymer that Defies the Laws of Physics

By Frank Rovella

If you find yourself going straight for the technology section every time you get online or open a paper, then you’re not alone. There are a lot of us just waiting for the next big thing, seeking to be awed by some new technological development. The Industrial Space is fertile ground for this enterprise; just take a look at emerging materials technology.  

Unlike automation that has a level of predictability akin to a train that always runs on time; we can see it downrange, hear the tracks rumble, and watch it flash by.  However, materials technology is more like a seismic event, we know it’s coming but no one is sure when or how big it’s going to be.

An example is a recent discovery by the French physicist Ludwik Leibler, who is this year’s winner of the European Inventor Award in the category research.  Leibler along with his team at the Laboratoire Matière Molle et Chimie at ESPCI ParisTech, have developed a whole new class of plastics called Vitrimers. 

"Classified as supramolecular substances, Vitrimers are a derivative of thermoset plastics and exhibit self-repairing characteristics."

What’s really intriguing about Vitrimers is how they do what they do. To understand this, we’ll have to look at the mechanics of their most basic elements.  At the molecular level, the atoms that comprise standard thermosets maintain their crystalline structure through permanent or rigid chemical bonds, the strength of these bonds ultimately determines the characteristics of the material. Flex, friction, and thermal cycles break down these bonds resulting in weakening that leads to cracks and fractures. Once these bonds are broken, they cannot be repaired  However, the molecular bonds that makeup Vitrimers are neither permanent nor rigid; their state is more akin to a dynamic equilibrium. This means that molecular bonds are forming and breaking simultaneously. Regardless of the molecular structure, the number of bonds remains the same. This reaction is thermally activated allowing VItrimers to go from solid to liquid and back with no change in crystalline structure; this is known as a glass transition. These characteristics, in essence, are what make Vitrimers a self-repairing plastic. Testing conducted at the University of Minnesota concluded that fractured samples that were healed recovered 102% of tensile strength, 133% of the original tensile modulus value, and 67% of ultimate elongation. Vitrimers glass-like qualities, allow it to be welded like glass, meaning that if two surfaces are brought to a molten state and welded, when they solidify the molecules are aligned like a solid section, with no seam. This is similar to friction stir welding, but far more complete.

The self-repairing qualities of Vitrimers are paving the way for a number of impressive innovations, and will surely lead to many more.  One of these is in the medical industry, where Vitrimers are being used in what is being called “Organ Glue.” This is a self-healing polymer hydrogel that acts as an anti-hemorrhaging, wound-healing aqueous solution. Vitrimers have the ability to form “nanobridging”, that is a molecular bridging of tissue; it can be used in situations where stitches are impractical.

For the more mundane, however, these same self-healing properties can make a significant impact on manufactured goods. Self-repairing plastics means that products made from it will have a far longer service life. Simply put less material is required because fewer parts are needed to accommodate for wear.

Then there are the effects on recycling, Vitrimers by nature are ideal for recycling because they can be liquefied and solidified over and over. Think about all the plastic that can’t be recycled, they end up in landfills, and some of these plastics can take hundreds of years to decompose fully. Vitrimers could make plastics as recyclable as aluminum.

The concept of materials that self-repair, or do things that seem physically impossible certainly has an awe factor, but Vitrimers are just one example. NASA is currently developing materials that can self-heal after a meteor strike and even self-repairing alloys. As we move forward keep your eyes open, because there is a lot more from this came from.

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