To me the big difference between the quality of the material in uranium mill tailings and those wastes from a reactor is that the mill tailings are not as radioactively hot or excited, and reactor wastes are full of toxic man-made materials unknown to life in the environment.

The difference also reflects the way the powers that be proposed to handle them: NWMO wants to bury the nuclear waste deep underground where, hopefully, they will never be able to find their way back into the environment (there was nothing scientific in this choice - just political ); the mines wanted to leave the very fine, more chemically mobile mill waste on the surface where it will certainly be exposed to the environment (this is an economic choice). The mine scenario has shifted to a method of leaving the dirty mess underground (solution mining), where it may end up contaminating aquifers. NWMO should be afraid of what happens underground and good luck to future generations who are left with trying to mitigate it. For now, they leave it on the surface, where it is even more vulnerable to unfriendly forces. I don't know where these guys have their heads, but I don't think there is much sunshine.

Again, the main distinctions between the two is that the reactor creates highly toxic man-made elements such as plutonium and the waste is radioactively hot - the reaction initiated in the reactor cannot be shut down and continues to create heat. Both waste streams contain extremely long-lived materials that need to be isolated from the environment for a million years and monitored during this time. What the two also have in common is decommissioning. The actual decommissioning hearings of mines and mills and reactors does not take place until they have outlived their useful life. Both, when decommissioning is being considered, conduct an industry led risk assessment that determines the safest and most economic way to dispose of it. Usually, the industry puts forward the option they favour. At this point, something has to be done with it. Knowing the risks involved, this is all wrong. We should be considering the ultimate decommissioning of the waste at the front end and public involvement is needed. If we do not have an acceptable solution to the waste, at the outset, we should not be creating it in the first place. It is in the industries' interests to create nuclear fuel, reactors, etc. The waste is a problem for them.

The disposal of radioactive waste is a misnomer - actually, it is just wrong. The nature of the waste demands that it be isolated from the environment for a million years of more. That is a length of time that is unimaginable to us mortals. Measures and research carried out so far cannot guarantee integrity for such a length of time. Morally, we can not do a half-baked job of it and then leave it up to future generations to fix the problems we have created - if remediation is even possible. I remember listening to a nuclear expert patiently explain to us that the handling of radioactive materials and reactors is based on a risk assessment. This does not guarantee that there are indefinite margins of safety, only that they analyze all paths and compare their relative risks and choose the one that is a best fit - the least risky scenario may not be the one chosen for reasons of cost, available technology, or other factors.

So, what is the problem exactly? Reactor waste is hot, and will remain hot for a geologic time period, because of the chain reactions that have been initiated and the half lives of the elements involved. When it is taken from the reactor, it is cooled in a pool for 10 years and then put into air cooled containers for another 40+ years. Some of the waste in these bundles are at their most toxic state during this period. Although they may not be hot enough any longer for power generation, the nuclear reactions that were initiated in the reactor are still going on in the form of radioactive decay - and will be going on for a very long time (million years) and will continue to give off heat as a result of those reactions. When we put it into permanent storage, it will continue to create heat - and needs to be cooled. What are the heat effects when it is contained within sealed containers? The original deep disposal concept would put the waste deep into pristine rock, packed in with bentonite clay, that would keep it dry, but It needs circulating water to keep it cool!! -but warm

water moves outward, potentially spreading the risk into the environment. How long can the integrity of the containers be guaranteed? How will the properties of the bentonite be changed (corrosive?) by this heat over extended periods of time? Even more heat will be created at various stages of radioactive decay. I think the bentonite is a big problem!! Dry bentonite will not do the job that is needed. Dry clay (ceramic) is often used in insulators. It needs to be wet to be able to transfer heat to the surrounding rock. The surrounding rock also has to be conducive to dispersing heat. If it can not do this, the waste will heat up, resulting in a thermal pulse (like Old Faithful), bringing everything to the surface. Even if the clay is wet the heat will drive water away from the canisters, towards the rock, creating a dry layer next to the canister that will be affected by the heat. As water moves away silicification will occur, changing the properties of the clay. (Read Bentonite: A Review of Key Properties, Processes And Issues for Consideration in the UK Context.) So do we leave it on the surface or do we bury it underground or do we stop creating the stuff, understanding that something has to be done with the waste we have already created and that inherent risks of any and all solutions may not be acceptable.

At the research facility in Manitoba, AECL carried out research in the deep burial concept. However, they did not use real spent fuel for their investigation - Manitoba did not want the waste. One of the things that that research concluded was that water was present everywhere underground. Even relatively pristine blocks of granite, deep underground, have water moving through it. Water is the Achilles heel for this waste because of its potential to carry this waste into the environment if containment is compromised (containment integrity is expected to last 300 years).

I used to think that if we kept the nuclear waste dry that we could isolate it from escaping into the environment. If it is exposed to the air, this might be the case as it could dissipate the heat from the radioactively hot waste. Buried deep underground, there would be no way for this heat to dissipate – water has to be present to do this – unless the rock itself is sufficiently conductive. At any rate water is always present underground. Bentonite buffers are the key element of the waste disposal concept. NWMO describes how they had been looking at a number of sites (21?) in Canada? Mysteriously sites in Saskatchewan were suddenly claimed unfit, this was in the middle of "discussions?" with several northern communities to accept the waste - perhaps it actually boiled down to issues of dangers of transporting the waste over long distances!! It was pointed out to them that if there was even one significant transportation accident in the trip from Ontario, this would be the end of activity at a chosen site in Saskatchewan! I asked them how long this waste needed to be cared for. They responded that for at least a million years. This is a very long time and a community would have to consider very carefully the possible fate of future generations. I asked them why they are doing this, since it is fairly common knowledge that everywhere underground there is a presence of water, making deep underground storage impractical? As we were most recently reminded by the events at Fukushima, nuclear waste from a reactor is in an excited state and will continue to generate a significant amount of heat (and continue to do so for 50,000 years - NWMO would accede to 1000 years). The presence of water would facilitate the circulation of heated water, and whatever is dissolved within it, into the equation. I asked them, why are they looking for sights that contain water that will bring this toxic material back into our environment? Their answer was that they would be looking for a sight that was free from water. I don’t think they were being truthful!!

Their concept relies on the buried canisters, containing spent fuel, to be surrounded with bentonite clay that, when wet, will swell up and seal the containers away from the intrusion of water. Again, I think the bentonite is a big problem!! Dry bentonite will not do the job that is needed. It needs to be wet to be able to transfer heat to the surrounding rock. If it can not do this, the waste will heat up, resulting in a thermal pulse. The host rock also has to have certain heat conductive properties to assist the dispersal of the heat. Even if the clay is wet the heat will drive water away from the canisters, towards the rock, creating a dry layer next to the canister that will be affected by the heat. As water moves away silicification will occur, changing the properties of the clay. We need to know the heat transfer properties of dry bentonite clay, and silicified clay.

The science behind this has to be solid!! - OR, it is a no go!! The clay has to be wet. It needs to be unreactive to the canisters, it must impede the flow of water, and if radioactive elements are able to leave the canisters, the platelets of clay must bond with these escaping elements so that they will never be able to migrate any further, and if it is chemically altered by heat and radiation, its new properties must also be up to the job. I don't have the science to answer these questions. The above link is a British study. It is an excellent review of factors that affect the bentonite buffer. While it does not fully support my concerns, in terms of their potential, it does indicate that the science is not solid - much needs to be understood. There are many types of bentonite clay with specific characteristics which may, or may not, make a particular bentonite suitable for consideration for a particular site. Quality, consistency and purity will obviously also be factors. Fairly technical!

The key point is that the buffer material (bentonite) is THE KEY element to the safe operation of a deep, underground facility. It seals the radioactive materials in - or not... A lot still needs to be understood but the composition of the rock and groundwater "at the site" are just as important as the composition of bentonite clay itself. The bentonite clay needs to be wet to do its job - dissipate heat to the surrounding rock and seal and isolate the waste so it can’t migrate. It can be affected by heat and radiation can cause some change to its chemistry. The chemistry of the groundwater can also react with the bentonite. The bentonite can contain corrosive elements to the copper canisters - even worse if they were using steel. The bentonite has to be carefully packed and water added to it so the expanding clay does not damage the canisters (become crushed due to uneven pressures being exerted on the canisters). The Canadian engineered barrier system uses bentonite and aggregate (cheaper if you add rock to bentonite) which transfers heat easier to the surrounding rock but it also makes it easier for it to allow passage of water. This may also be a game changer in regards to the characteristics and effectiveness of the bentonite.
There are many kinds of clay, used for all kinds of purposes - plenty of literature. I know clay contains a lot of elements. I also know that clay bricks are used as an insulator to line stoves and chimneys. It can insulate when it is dry and conduct heat when it is wet. It also expands and seals when it is wet. We also need to understand how the movement of water will be affected in the suppository as it swells up and seals. Will the clay surrounding "all" of the canisters remain wet enough to transfer heat to the surrounding rock. Will some stay dry or partially dry? If not, how will the heat and radiation change the clay? As the canisters age, will they become more susceptible to damage from the pressure exerted by the swelling clay and will they continue to resist the corrosive properties of some of the elements in the clay?

However, it is the presence of water around the deposit/repository and the fact that it must circulate to dissipate heat that concerns me. The integrity of the containers must be maintained for such a long time (tens of thousands of years at least???) and the water is exactly the transport mechanism, which can bring the material that we so badly wanted to bury, back into the living environment as we know it. As well, I know nothing of the life that must exist beneath the earth's surface and who is to speak on its behalf. Anyway, the bentonite is a key part to the success of isolating and cooling the waste and I am not at all confident we can guarantee its performance. I am not into calculated risks. If they are wrong, there is probably no safe way to mitigate the damage to the environment that would result. Best decisions, even good ones, might not be enough!

 As I write this, the unthinkable is happening. Fifteen active reactors in the Ukraine, not including the Chernobyl reactors, are now in a war zone. This puts Ukraine, and the rest of the world, in a terribly vulnerable position to threats and scenarios that might be presented by an aggressor such as Putin. Now it would seem that not only the temporary storage of reactor waste, but the reactors themselves should be contained within "secure" containment facilities.

The real clincher in all this is the nuclear industry in Canada wants to expand through the use of SMR's, reactors so 'small' (!!) they can be built anywhere. The reason for building reactors originally was not to create electrical power, but rather to produce plutonium for use in nuclear weapons. I can't think of a worse disaster scenario than spreading small reactors all over the world - I think this rivals climate change. It is just substituting GHG emissions for something even more lethal. What are they thinking? This has to be a true act of desperation and makes me wonder who can be trusted in this industry! What are their motivations? NO country has come up with a satisfactory solution to handling nuclear waste permanently. The only credible solution to nuclear waste is to stop creating it and the waste that we have already created will need to be secured and monitored in perpetuity. However, we store it, we should probably not be locking it into granite, deep underground. where, should there be a problem, it could not be retrieved without considerable difficulty, expense and health risks to future generations. We need a more flexible solution where it can be retrieved, if there is a problem. Nor can it be stored on the surface as it is too much a risk to terrorist activities. Ideally, reactors themselves should never have been located close to a significant water body (an economic decision), but rather where they could be part of an on-site decommissioning plan. Reprocessing and packaging waste only serves to increase its volume and risks. We must take care to not see nuclear waste as a growth industry that can be in a continual process of repackaging.

NWMO was way too close a connection to the interests of the nuclear industries. Politics should have no place in the ultimate decision as to how it is managed - this is far too technical. Who then should be the eventual guardians and managers of the waste that has already been produced to date. I would say that the people who live in the area of the repository, wherever and whatever form that might take. These people should also be the trusted guardians of the land and not motivated by profits and prone to cutting corners. It is their future generations who will be at most risk. They must be the engineers and technicians who design, build, stock and manage the repository in perpetuity. It is not likely that these people have been the beneficiaries of nuclear power, but they have chosen to be the caregivers of this toxic, long lived, radioactive waste. Waste that can impact muscles, bones, and every part of any organism. They must be given all the knowledge, resources and tools we can give them. Those who have benefitted need to know that they and their future generations are on the hook for this, essentially, forever. We need to man-up to our mistakes.

To be honest, I think the people responsible for this industry have a lot of bad stuff to answer for. We have to stop using fossil fuels but we also need to stop using nuclear power as well. All our futures depend on this transition.