Our Future Nuclear Challenge: Decommissioning Plants

By Catherine
Share on LinkedInTweet about this on TwitterShare on FacebookShare on Google+

 

By Catherine Bolgar

Nuclear power plants last a long time, but not forever. Around the world, 158 nuclear reactors have been permanently shut down, although only 15 have been fully decommissioned, or dismantled. The U.S., which has by far the most nuclear facilities, has decommissioned 10 commercial reactors and has 18 others going through that process. Germany decided in 2011 to phase out nuclear power entirely by 2022.

The question of how best to dismantle nuclear power plants will continue far into the future, considering that 60 reactors are under construction now, and that nuclear plants operate for 30-60 years.

“Our reactors had an initial design life of 30 years,” says Jerry Keto, vice president of nuclear decommissioning for Ontario Power Generation, which operates 20 of Canada’s 22 reactors. “But in operating them, we have confirmed that the plants can run much longer. Most plants in the U.S. and Canada confirm through aging-management programs that they’re fit.”

Some countries choose to dismantle and decommission their nuclear facilities immediately after shutdown. Some prefer deferred dismantling and delay the process for several years. Others choose entombment and convert theirs into waste-disposal facilities, after ensuring that the targeted end-state of the facilities is safe, according to Michael Siemann, head of the Nuclear Energy Agency’s division of radiological protection and radioactive waste management, part of the Organization for Economic Cooperation and Development (OECD).

“The choice of approach depends on many factors, some of which may be related to national circumstances,” Dr. Siemann says. “Nevertheless, immediate decommissioning is usually considered as the preferred strategy, meaning that the shutdown nuclear-power plants are usually dismantled and major parts also completely removed.”

One of the challenges in decommissioning is that for “some plants designed in the 1960s and ‘70s, not a lot of attention was given to fact that somebody has to take them apart in future,” Mr. Keto says. “Now, decommissioning is entrenched in design for new construction. The new reactors being built in the United Arab Emirates were designed already thinking of how they will be dismantled in the future.”

The age of many plants means that their original designs were on paper. “The main problem is there is so little information about the state of the buildings. The plans of the plants were mostly nondigital,” says Joseph W. Dörmann, mechanical engineer at the Fraunhofer Institute for Material Flow and Logistics, in Dortmund, Germany. “While the plant was running for 30 years, there were changes to the building. It’s really difficult to have a clear 3D model of the plant. It’s difficult to find out where, for example, radiation has had an impact. You need a lot of time to develop the information, to know which part of the plant can be demolished, by which technology, and whether to bring to safehouse”—a special nuclear-waste repository—“the nuclear waste or materials that have had contact with nuclear waste.”

Rather than try to digitize paper designs, OPG makes scans of the plants, “so we’re less reliant on what the paper says and totally reliant on the real area. Especially in high-radiation fields, it’s not a place for sending workers,” Mr. Keto says, adding that digitization is needed so that machines can be programmed to do the work automatically.

Where workers are needed, OPG even builds exact replicas of the area for training and practice, so that when workers enter a radioactive zone they can get the work done in the shortest period possible. OPG hasn’t yet decommissioned full facilities, Mr. Keto says, but it has “done some very highly radioactive work in our plants. We have permanently shut down two reactors and laid them up for future dismantlement.”

Only a small part of a typical nuclear plant is highly contaminated, with slightly more low-to-medium-level waste. About 90%-95% of a nuclear plant isn’t radioactive at all and can be demolished like any other industrial building, with waste taken to landfills or recycled, Mr. Dörmann says.

The walls of such plants can be 1.5 to 2 meters thick, and even in contaminated areas only the first 2-5 centimeters may be affected, he says. New cutting techniques, cameras and robots allow the contaminated part to be removed separately.

Concrete may be blasted with dry-ice pellets rather than sand, because dry ice disappears when it melts, whereas used sand must also be disposed of as contaminated waste. Scabbling is another technique for removing a layer of concrete. Rubble is then cracked into morsels smaller than 2 millimeters.

Non-contaminated material can be recycled as sand, concrete and metal. Parts of Germany’s Jade West Port on the North Sea used materials from a demolished nuclear plant, Mr. Dörmann says, adding, “It’s a way to do recycling on a large scale.”

The steel bars reinforcing the concrete can be melted down and recycled. Metal that’s slightly contaminated is turned into shield blocks for use at other nuclear facilities.

Nuclear facilities can’t be retrofitted into conventional power plants because they aren’t built for the same levels of heat, and the turbines are different, Mr. Dörmann says. However, the office buildings and even some other facilities can be renovated for new uses. With cooling tower foundations 18-21 meters deep, keeping them and building a new facility, such as a logistics center, on top would vastly reduce the amount of rubbish, he says.

“Given the low number of only 15 completed decommissioning projects world-wide,” says the NEA’s Dr. Siemann, “it is too early to draw conclusions and to derive trends in the reuse of entire sites after decommissioning completion.”

 

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe, now working as a freelance writer and editor with WSJ. Custom Studios in EMEA. For more from Catherine Bolgar, along with other industry experts, join the Future Realities discussion on LinkedIn.

Photos courtesy of iStock

 

New frontiers and costs of recycling

By Catherine
Share on LinkedInTweet about this on TwitterShare on FacebookShare on Google+

Written by Catherine Bolgar

open dumpster full of trash

Are we recycling all we could? Organic waste, such as food scraps and yard trimmings, accounts for between a quarter and a third of the solid waste generated in cities—the largest single municipal waste stream, according to Eric A. Goldstein, waste expert at the Natural Resources Defense Council in New York.

If you had to identify one key area of growth for recycling, it would be organics,” he says.

Organic waste in landfills becomes mummified or decomposes anaerobically (i.e. without oxygen), producing methane, a greenhouse gas whose impact on climate change is estimated to be 25 times greater than that of carbon dioxide.

Composted organic waste though becomes a natural fertilizer that helps soil retain moisture and hold carbon. A University of California Berkeley study found that a single application of compost led to a metric ton of carbon capture and storage per hectare annually, for three years.

However, “composting if done well isn’t cheap,” says Glenda Gies, principal of Glenda Gies & Associates Inc., an Ontario-based recycling consultancy. “It requires the right temperature, moisture levels and bacteria populations.”

There’s also the question of who’s responsible for the recycling. With plastic or electronics products, the brand is usually identifiable, even on discarded goods. The manufacturer may then be legally required to recycle them. But by the time organics become waste it’s no longer clear who the brand owner is, and recovery costs then pass to the municipality, consumer or business, “who have been reluctant to pay,” Ms. Gies says.

This hasn’t deterred some city and state authorities from taking a lead. San Francisco has introduced mandatory separate collection of compostable materials, which applies to all residences and businesses, says Kevin Drew, residential and special projects zero-waste coordinator at the city’s department of environment. Massachusetts banned food waste disposal by companies in 2014, sending organics to 49 processors.

Once there, organic waste is processed into methane through digesters (like at sewage treatment plants). And unlike landfills where the methane escapes, the digesters trap it and convert it into natural gas, while the residue is turned into compost. San Francisco and its service provider are building digesters, with the resulting gas used to fuel collection and transfer vehicles, Mr. Drew says.

There’s complete recovery of the energy and compost value in the waste,” he says. “I would argue that this program will be coming to every city in the world.”

colored clothingOther materials also have strong recycling potential. Only 15% of used clothes, towels, bedding and other textiles in the U.S. is donated or recycled, according to the Council for Textile Recycling, with the rest ending up in landfills. In the U.K., about 40% of clothing is re-used or recycled. But more can be done.

“There’s an enormous amount of textiles that are recoverable as clothing,” says Mr. Drew. “There are markets around the world that will take that material. We’re on a quest to recover more textiles.

Cost is key. With traditional recycling streams, such as paper, plastics and glass, changes in technology and commodity prices affect the willingness to recycle.

“Companies want to recycle to save money,” says John Daniel, president of Federal International Inc., a St. Louis recycling firm. “In general, companies will increase recycling to the point where it costs them money, and then they stop.”

Recycling bin with glassConsider glass recycling. When collected along with other waste materials, broken glass has to be sifted out at sorting facilities. This may have been worth doing when glass prices were high, but today, “at many facilities, it’s not cost effective to separate out that glass. A significant amount of glass put in recycling doesn’t get recycled,” he says.

Similarly, “when the price of oil was much higher, carpet was able to be recycled,” he notes. “Now it is almost impossible to recycle without the cost being higher than landfilling. The cost of recovering, transporting and processing the material is significantly higher than the value of the material.”

Virgin products may seem cheaper, Ms. Gies says. But if one were to factor in environmental costs—reflected in, say, greenhouse-gas taxes or obligations on manufacturers to recycle returned products—the resulting higher price might be more realistic, and potentially uncompetitive.

“The industry naturally will recover all material demand, provided it is cost effective,” Mr. Daniel explains. “As the price goes up, then recyclers have the ability to dive in deeper and start recovering higher-cost material. The best way to increase recycling rates is to improve the demand for products made from recycled materials. Our industry will take care of filling the supply.”

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe. For more from Catherine Bolgar, contributors from the Economist Intelligence Unit along with industry experts, join the Future Realities discussion on LinkedIn.

Photos courtesy of iStock

It’s a Wrap

By Catherine
Share on LinkedInTweet about this on TwitterShare on FacebookShare on Google+

Written by Catherine Bolgar


Whether you like them or not, eggs, cheese, mushrooms or shrimp are likely to be part of your future shopping basket—as the raw materials in a new kind of plastic packaging.

New materials promise not only to reduce our reliance on petroleum products such as plastic, they also cut waste. Packaging accounted for more than 75 million tons (or 30%) of solid waste in the U.S. in 2013, while the European Union generates around 79 million tons of packaging waste annually.

However, waste from the agriculture industry is now being turned into biodegradable packaging materials. For example, Kirsi S. Mikkonen, a researcher at the University of Helsinki, is developing packaging films made from hemicelluloses, byproducts of the forestry industry and agriculture.

Cellulose, the part used by industry, makes up only 40% to 50% of wood, while hemicellulose and lignin each account for about 30%. Hemicelluloses can be retrieved from wood chips or, in thermo-mechanical mills, from wastewater.

Dr. Mikkonen converts the hemicelluloses into films that act as an effective barrier against oxygen. Edible films could protect food from drying out or spoiling, or even within food, to separate pizza crust from sauce. By coating paperboard with the films, she can make plastic-type containers.

Hemicelluloses and lignin can also be used in aerogels, which are porous and light but strong.

“When you put an aerogel in water, it acts like a sponge,” Dr. Mikkonen says. “It absorbs water and you can press it out, and it recovers its shape. We could make something like a soft pillow that could absorb moisture or drips from meat, or it could release active compounds and be used as active packaging.”

Innovations in active packaging abound. The Fraunhofer Research Institution for Modular Solid State Technologies in Munich has developed a sensor film that detects molecules called amines that are released when meat or fish starts to spoil. As amines build up, the sensors turn from yellow to blue, indicating the level of spoilage. Many companies now sell labels and films that keep fruits and vegetables fresh by absorbing ethlyene.

Egg whites could provide another form of active packaging. Alexander Jones, a researcher at the University of Georgia in Athens, Georgia, mixed the egg-white protein albumin with glycerol to create a plastic with antibacterial properties.

Albumin plastic could be used for food packaging, to decrease spoilage. It could also be mixed with conventional plastic to add antibacterial properties to medical products, says Suraj Sharma, associate professor at the University of Georgia’s College of Family and Consumer Sciences.

Another reason to mix in conventional plastic is that albumin plastic is too brittle to be used alone for, say, a catheter tube, which needs flexibility, Dr. Jones says.

He also tested plastics made from soy and whey proteins. Soy proteins had no antibacterial properties—“it actually fed bacteria,” he says. Whey proteins mixed with glycerol made antibacterial plastic, but whey plastic minus glycerol acted like soy-based plastic, promoting bacteria growth.

The protein-based plastics have other advantages. They compost quickly, and the manufacturing process uses lower temperatures than for petroleum-based plastics, thereby saving energy. Whey, a byproduct of cheese processing, requires treatment before disposal, so diverting it into plastics would be a boon.

For now, egg whites are far more expensive than polyethelyne. But Dr. Jones believes that we might tap waste streams to get cheaper raw materials.

Egg producers have eggs they don’t ship for various reasons,” Dr. Jones says. Using those “would reduce waste and also not compete with food as an end use.”

Shrimp shells are another waste source that can be turned into plastic. Harvard University researchers have turned chitin, a polysaccharide found in crustacean shells, into a strong, transparent material called shrilk, which can be used to make plastic bags, packaging and even diapers.

Meanwhile, Ecovative, a packaging company in Green Island, N.Y., uses mushrooms as the key ingredient in its compostable packaging. The root structure of a mushroom, called mycelium, acts like a glue. A mix of mycelium and agricultural byproducts is molded into different shapes, replacing styrofoam for example.

Packaging today is essential for society to function,” Dr. Mikkonen says. “We need packaging to deliver food from the maker to the retailer and then to the consumer. But it produces lots of waste. It’s really important to develop some biodegradable alternatives.”

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe. For more from Catherine Bolgar, contributors from the Economist Intelligence Unit along with industry experts, join the Future Realities discussion.

Photos courtesy of iStock



Page 1 of 3123