Metals & Alloys

they hold the waste in water tanks while the fast decaying isotopes degrade into less active and longer lasting materials.

Currently the best process seems to be the glass process, where the waste after the lomg term hold is chemically processed into several streams and then dried and mixed with powdered glass, melted into glass and then drop cooled into small pellets. These small pellets are then sealed into a metal case and then packed into another sealed outer case. These cases are then sealed underground in inert rocks with cemented fill.

By the time the case erodes the contents will not be strongly radioactive. If someone in 10,000 years wants to dig them up, let them, it will not be a casual task.

warranty for a million years? Money back? yes, bring it in.

Hi,

neither glass nor metal is a good choice.

Metal is etched from the inside: any particle that hits the surface is doing some nano-damage adding up to unpredictable long-term behaviour.

Maybe the outside is also damaged by circulating water, by earthquakes or slow motion and cracking of the surrounding rocks.

"Metal ores and metals can last..." that is true but there are lots of leached or oxidised and leached metal-ore deposits.

Some 50,000 old mines in the US are thought to be a problem as the oxidising is producing acid (sulfurous and sulfuric) that is leaching all metals, biggest problem with cadmium.

Similar in Europe but mines and pits are older and worst problem is arsenic.

Glass is the preferred material in Germany but not as a container material but to make a solid block of glass containing the radioactive elements as oxides in the glass.

Glass is a mixture of oxides (some exceptions) : Si, B, Al and P -oxides as network elements that are responsible for chemically structuring an amorphous network of binding forces that crystallises only slowly so that on cooling it is stable. Into this is mixed a vast variety of metal-oxides: in window-glass calcium and sodium-oxide, any other oxides in special purpose glass. Any element (except carbon) that can be oxidised can be introduced into glasses - if the resulting glass is useful has to be evaluated.

The glass blocks that are preferred in Germany will be so radioactive that the temperature will be above 500°C, that is red hot. This will be in direct contact with the salt (sodium-chloride) of the deposits. The authorities tell us this is stable - I am sure there have been some intensive tests - but as soon as there is any contact with water there will be a very fast corrosion reaction. Arguments are that the salt deposits exist since many million years - this is true. But how many salt deposits have been leached to nonexistence? And in many salt deposits there are circulating water flows more or less saturated with salt.

The glass blocks will slowly sink down in the salt as heating will give a viscosity that will allow slow sinking. The salt will close again above the glass blocks by natural pressure and time. So there is no possibility of recovery if anything is going wrong.

Solution:

Let the used elements where they are, slowly loosing a part of the radioactivity, this needs active cooling for a considerable time . Better not to touch the devils shit until the next generation of reactors will be able to re-burn these waste-products.

These reactors are existing today in principles and some proof (look to the results of ICENES 2007 conference on emerging reactor concepts) but it is very likely that existing company and national support will exert enough pressure that this switching to a reactor that can burn most of its waste will take some 40 more years. The CANDU concept from Canada and the subsequent developments are the best known examples and ready for use.

So what is planned today in the western world is a big nonsense and a still bigger mistake. Try hard to inform political and newspaper people!

RHABE

The warranty will not likely need to be enforced that far into the future, since there are not likely to be people recognizable as such by then - think back to what our ancestors of a million years ago probably looked like, and extrapolate. The real question is what must be done for the short term?

One hundred years from now, we are likely to need to regard this "waste" as a resource to be used as fuel in the next generation of reactors (or the generation after that one). One thousand years out we should have used all of today's wastes as fuel and have to deal with whatever nuclear residues are left from that process. Five times that long, and the people around then will be as removed from us as we are from the folks who built the pyramids. They are not likely to be able to even read the ancient languages of any warning signs we put up, which has already led to a communications specialty using some pretty scary pictograms. Double that to ten thousand years and good luck even finding the stuff except by sheerest accident. Be about like the rumors of Atlantis, I think.

By the way, for those who care, this "Guest" is really EnviroMan not logged in and working from someone else's computer. When I get back to my own, boy howdy, do I have an adventure tale to share!!!

Some people speak of glass as soluble and confuse it with window glass. The glass they speak of is a non crystalline, annealed tough glass, that has a few % radionucleotides dissolved in the internal code. The outer core is pure glass. Glass is a term for an amorphous non -crystalline solid. There are a huge numbers of ways to make glasses and the properties vary enormously. The ones selected for containing radioactive waste are those best suited for long term waste storage. These will not leak and the low ratio of waste will not cause expansion fractures. They will also not get very hot as they are not englassed until they have cooled in water holding tanks.

Most of the BS about waste storage in just that, BS. Stable deep mine storage is the best way