High-level radioactive or nuclear waste is “spent” uranium fuel used in nuclear reactors. This spent fuel is thermally hot and highly radioactive, usually in the form of uranium 235 contained in ceramic pellets inside metal rods. What do we do with this spent fuel? Right now, nothing really, presumably we are waiting for a future generation to figure out where to safely store it all. It will only be rendered harmless through a process of decay that can take thousands of years. The US, which had over 72,000 tons of nuclear waste as of 2011, has no long-term facility for storing high-level nuclear waste. The interim answer is either to store this spent fuel in water-cooled pools on the site of the reactor, or to transfer it temporarily to dry casks. With the exception of the expensive endeavor of reprocessing this spent fuel to extract plutonium for commercial use, there is no known alternative to burying nuclear waste in massive underground facilities, which currently do not exist. Throwing it in the Ocean is clearly not recommended, though that hasn’t stopped governments in the past. Here’s what we’re doing with it now:
Temporary Spent Fuel Pools
Much of the US’ nuclear waste is being stored in large water-cooled pools onsite at nuclear power plants. This is not the safest method: The release of radiation at Japan’s Fukushima plant came from fuel stored in pools. This poses a particular problem for the state of Minnesota, where nuclear power plants were not designed to take on nuclear waste storage. Designers were banking on the construction of a large long-term nuclear waste storage facility at Yucca Mountain, Nevada, which never materialized due to fears of ground-water contamination.
Temporary Dry Cask Storage
In some cases, after waste is cooled in spent fuel pools it is transferred and sealed dry casks, which are steel and concrete containers. The problem is that dry-casking is much more expensive than pool storage, but it is also much safer. Dry casks are much less vulnerable to fire, flooding, earthquakes or other machinations of Mother Nature. Scientists say they have never leaked radiation.
Long-Term Burial
The US Department of Energy is constructing a $12.2 billion facility to process excess radioactive waste. The biggest question on everyone’s mind, of course—is it safe? Well, Energy Secretary Steven Chu, who visited the construction site in Hanford, Washington, last week, isn’t entirely convinced. He and a panel of experts are reviewing the safety of the waste storage rooms at the massive 65-acre site. This has not gotten off to a brilliant start at the site (incidentally, where the US used to produce plutonium for atomic weapons, rendering Hanford one of the most toxic areas in the country). Reviewers found leaks of radioactive material in the walls of one of the newer storage tanks and threaten to run into the Columbia River. In August, a DOE official brought up concerns about the company contracted to lead the design of the facility, Bechtel National Inc., saying it was incompetent in comparison to the task at hand. The plant is scheduled to be completed by 2022 and to store some 56 million gallons of radioactive and chemical waste for a period of 40 years, at which time it will be shut down. Then what? The Nuclear Regulatory Commission allows spent nuclear fuel to be stored at reactor sites for up to 60 years after the plant shuts down. Presumably another generation will be able to figure out what to do with all that radioactive waste.
Constructing a long-term storage facility for radioactive waste is an exercise in clever public relations and subtle politics. There must also be a trade-off for the community. The Yucca Mountain nuclear waste storage facility never got off the ground because it failed on a public relations level and was allowed to become an election campaign tool. The federal government forced the facility on the state of Nevada, against strong objections from within the state. Nevada fought back politically and the Obama administration was eventually forced to scrap the project altogether in 2010. It was a battle that lasted for over two decades.
Reprocessing for Plutonium
In terms of energy, reprocessing fuel for plutonium is rather efficient as it effectively uses fuel twice. It is not economical, however, and the process itself is very expensive. Additionally, there are some safety issues in that plutonium renders fuel from a reactor hotter and negatively affects the capacity of spent fuel pools. With plutonium, there are also greater risks of contamination.
Powering Spacecraft
The European Space Agency is piloting a £1 million program to use civil plutonium for nuclear batteries to power ships on deep space missions.
Britain’s nuclear waste could be used to power spacecraft as part of government attempts to offset the huge cost of the atomic clean-up by finding commercial uses for the world’s largest stock of civil plutonium. The UK, which has the world’s largest stock of civil plutonium, is the focus of these efforts. The Sellafield waste facility ponds contain some 100 tons of plutonium. Nuclear batteries can be made from an isotope (americium-241) in decaying plutonium at the UK’s Sellafield waste storage site. The UK is also eyeing the possible export of its plutonium stores to the US, which can produce plutonium-238 (which can be replaced by americium-241) only in nuclear weapons-grade reactors. Without a commercial use for the UK’s plutonium, it will cost the government an estimated £4 billion to clean up.
Of course, this does little to resolve the nuclear waste problem and space batteries alone will hardly scratch the surface of the disposal problem.
Dumping it in the Sea
Out of site out of mind. This is what the Soviets did with their decommissioned nuclear reactors and radioactive waste, massive amounts of which are now sitting at the bottom of the Kara Sea in the Arctic Ocean. To wit, some 17,000 containers of radioactive waste, 19 ships with radioactive waste, 14 decommissioned nuclear reactors, a nuclear submarine and a host of other nefarious materials. If the nuclear reactors from the sunken submarine explode under water, the consequences would be unspeakable. Regardless, decontaminating the sea will be challenging at best. This nuclear waste will also prove a major hindrance in Russia’s efforts to explore for oil in the Arctic Ocean, which is exactly why this story—an old story from the late 1990s—is now resurfacing. The Russian’s want help cleaning it up so they can get to the Arctic oil. The Soviets, of course, were not the only ones to dump oil in the world’s bodies of water: The French, British and Americans have done so as well in the past.
By. Jen Alic of Oilprice.com
Leave a comment
Since the cooling loop had stopped, the cooling water in the reactor flashed to steam. Steam has a strong reaction with the zircaloy cladding used on fuel rods which produces hydrogen. Since hydrogen gas is so combustible, the reactor has a system to vent it. Since the core was beginning to melt, the fuel rods were failing and releasing volatile fission products. When the hydrogen was vented, these fission products escaped out of the reactor and into the environment.
This hydrogen was released into the building above the reactor containment building and not to the outside air. It collected there and finally exploded once an ignition source presented itself. This was due to poor venting techniques and occurred outside of the containment structure.
Very few people realize it, but there are other types of nuclear reactors than we've been using. We've only used light water reactors (LWR) for political reasons from decades ago, but our priorities have changed since then.
In LWR, fission byproducts absorb neutrons stopping fission; fuel rods get damaged by radiation; only ~1% of fuel fissions.
Molten Salt Reactors, e.g. LFTR, use molten uranium in a molten salt coolant, and fission byproducts are easily removed; over 99% of the fuel fissions.
We successfully operated one for 5 years, decades ago. If we completed development of these reactors, they would exceed environmental standards for radioactive contamination, for reduction of existing nuclear waste, for reducing global warming pollution. They would provide low-pollution base-load power supplementing solar and wind power, getting us off coal/oil sooner. (I know, the oil and coal industries don't want that...)
Molten-salt reactors use a special salt for coolant. The coolant won't boil, so there's no high pressure, no risk of "loss of coolant accidents", no risk of steam or hydrogen explosions. This is inherently much safer, eliminating almost all the (water-based) risks of current reactors.
LFTRs would even cost a lot less to build than LWRs. No steam so no steam containment building. No high pressure so no high pressure piping.
Liquid fuel allows use of a "freeze plug" (frozen fuel in a section of pipe -- cut power to cooling and it quickly melts, fuel drains from the core to passive cooling tanks where nuclear reaction is impossible), much simpler, safer and less expensive than LWR's complex emergency systems to over-ride everything that normally happens in the core.
To make a gigawatt-year electricity, LWRs leave 35,000kg uranium/plutonium (and other transuranic elements) to somehow safely store for 100,000+ years. That's not counting the 215,000kg depleted uranium left from making 35,000kg enriched uranium.
Only a properly designed nuclear reactor can Consume nuclear waste. A molten-salt reactor could use nuclear waste from LWRs as fuel, 800kg to make 1 gigawatt electricity for a year. Since an MSR consumes 99%+ of the uranium (or plutonium or plentiful thorium) fuel, waste is much easier to take care of -- most MSR waste would be harmless in 10 years (83%). The rest (17%) would be safe in 350 years. We know how to safely store 135kg (300 lbs) of waste for 350 years.
MSR waste, once no longer radioactive, is chemicals we use in industry, to make solar panels and wind power generators, headphones, LCD screens.
Eliminate nuclear waste, inherent safety much better than LWR, lower construction cost. Smaller sites, no water needed, so build where electricity is needed. Make CO2-neutral vehicle fuels. Best base-load power to replace coal and oil.
See http://liquidfluoridethoriumreactor.glerner.com/ for what they are, how they're different, what ways they are so much safer, how they can consume nuclear waste, how they would fare in accidents or terrorist attacks, how much less they would cost, how long it will take us to build them.
Diesel engines can be modified to run on Hydrogen.
Large engines such as are used for standby power at nuclear plants can be used to generate electricity from the nuclear waste - on site!
A few years back I was invited to tour a Steam Assisted Gravity Drainage (SAGD) installation near Cold Lake, Alberta. It dawned on me the moment I saw the SAGD schematic, I had seen the same drawing issued by the DOE to describe a heat chamber around the US Yucca Mountain repository in Nevada. The heat umbrella, it was claimed, would keep water from entering the repository.
Professor Frank Dickson points out in a recent article (http://galvestondailynews.com/story/152850) convection currents are the problem with nuclear waste underground, yet it is underground convection that is precisely what is required to mobilize highly viscous oil sands deposits and ionizing radiation could fracture long chain molecules contigous to the waste into more valuable fractions, safely, deeply, underground.
Cost and CO2 emissions are the oil sands Achilles’ heel.
A few years ago natural gas costs equated to about $18 a barrel for SAGD, though this has since declined, there is still a significant carbon issue with burning this much “clean energy” to produce the "dirtier", in terms of carbon, oil.
A recent study by Canadian, French, Australian and American scientists Bitumen also notes that bitumen has unprecidented capacity to sequester radionuclides.
With this approach you would solve the Achilles heal of both the nuclear industry and the oil sands.
Excess plutonium could also be emplaced in the oil sands formation interspersed in a string with the hotter waste to fulfill the DOE's "equivalent to spent fuel standard" for eliminating excess weapons material.
Besides being the force that precipitated the disaster at Fukushima, it was the basis for the "Subductive Waste Disposal Method" patented in the US, Canada and New Zealand over 20 years ago.
Some of the world's best geoscientists pointed out in a Nature article, "The geology of nuclear waste disposal" in 1984 (http://www.nature.com/nature/journal/v310/n5978/abs/310537a0.html), "disposal in subduction trenches and ocean sediments deserves more attention."
Although geologic disposal is a concern of geology, no one listens to the geologists.
In my opinion, the article and the six things to do with nuclear waste is substantially correct. Many of the other ideas put forth by commentators require "faith" that science can patch up the giant dangers our science was used to create.
Nuclear power is a dead end. So is any civilization that bases its continued existence on a finite resource, like the fossil fuels of coal, oil and/or natural gas.
There will still be thorium available long after we have stepped down from this mortal coil. We live in a scientific and technological age, get used to it.
Renewables are above all ugly in the main. I don't want horizon to horizon wind turbines, nor do I want the associated electricity pylons that are necessary to allow the energy companies to chase the wind. Daft or what?
Excess plutonium could also be emplaced in the oil sands formation interspersed in a string with the hotter waste to fulfill the DOE's "equivalent to spent fuel standard" for eliminating excess weapons material.
However, this solution involves two other critical pieces namely, (1) transporting the nuclear waste to the oil sands sites which agree to have such material placed in their formations, and (2) more importantly, figuring out who among the producers would agree and why.
I would be very curious to know your / others' response in this regard.
If you want to heat bitumen with nuclear heat, one fission reactor with a heat transfer fluid circulating between it and the bitumen is more effective than all the world's nuclear waste. And if you for whatever reason decide you don't want to heat bitumen any more, you can turn it off.
If sunken nuclear submarines were exploded -- and this could only be done by placing explosives next to them -- the consequences would be unspeakable only from the point of view of oil and gas money. Anyone else will appreciate the fact that the ~2 GW of alpha-ray and beta-ray heat in the world ocean, primarily due to radiopotassium, is radiologically equivalent to millions of pulverized submarines.