Nuclear Power

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In a risk assessment where Risk =  Probability x Consequence, storing nuclear waste has two problems:

The Consequence of a leak will always be very high

The timescale is so long – decades or centuries - so the Probability is difficult to ascertain, it’s beyond the foreseeable future.

Hanford radioactive waste is in tanks the plan is vitrification (mixing with glass) and bury it in stable region with no water incursions or geology for a 100000 + years. The glass is a solid so it cant spill break it and you expose a new face along the fracture but no spill. This could have been done a decade or more ago. It is still radioactive but it would not be mobile. It stays were you put it even for 100000+ years. The anti nuclear lobby has fought mixing it with glass at every step. Yuca mountain was studied as a burial site. It was excavated. Yuca mountain is the most studied mountain in the world. It was determined that for something like 99% of the time they were confident that it would be geologically stable and no aquifer would come close to the site. For the very last bit the probability of something happening resulting in water permeating the tunnel barely exceeded the desired probability. At the tale end of the storage period the consequence of exposure is much lower because most of the radioactivity will have decayed by then.

The sight had all of its space allocated. The US has more waste than that. The Yuca mountain site was removed from the list of potential storage fights for political reasons. At the current pace of vitrification it will be 100 + years to clean up Hanford. All the while contamination in the region is increasing.

I get why the anti nuclear people are doing what they are doing I just don't agree with their tactics.

[sidd]

Re:  The anti nuclear lobby has fought mixing it with glass at every step

Cite ? I am familiar with the blockage of Yucca mountain, but i was unaware that anyone is opposing vitrification.

sidd

[Iain]

The measures outlined in #1500 sound sound pretty thorough.

But we can’t rule out a political/religious/plain insane group or regime in 10, 100, 1000+ years hence deciding they are right to use “dirty” bombs – conventional explosive jacketed with the waste.

There are many recent examples of despots arising with ideology the RoW considered to be crackpot,

There have been civil wars in the UK, USA and many other countries.

That’s the thing about RAs – the one you never thought of comes back to bite you.

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They are not specifically opposed to vitrification they just keep pushing for increased requirements. I don't think it has had much coverage. I heard it  from people who work their or have worked their. Some have speculated that the company doing the clean up Bechtell is encouraging this because they are on a cost plus contract. I do not have any idea if this is true.


US Plans to shut down 5.13 GW of nuclear plant capacity this year or about 8.4% of capacity. Exelon Nuclear is shutting down 4.1 GW of that  in Illinois.

[Iain]

Can the shut down plant itself be used for storage of the vitrified blocks - stack them inside the containment dome until full and pour concrete in from the top to encase them.

[Tor Bejnar]

I recall from 30 years ago one problem with vitrification is that it expands the waste volume considerably, and as glass has a limited effective life span, what do you do then?

I just did an internet search and found:

New evaluations described in the preliminary report on supplemental treatment options show that high performance grout and steam reforming might keep radionuclides from escaping better than glass.

And from here:

Vitrification allows the immobilization of the waste for thousands of years.

When they truthfully write "... genuine immobilization of the waste for over one hundred thousand years," I'll be comforted. 

[Ken Feldman]

Vitrification shares a similar characteristic with many nuclear technologies such as fusion, molten salt reactors, small modular reactors and thorium reactors.  All seem like magical solutions that will solve all of our problems.  None of them have been built and in practice are so expensive that they'll likely never be built.  (Although fusion is only two decades away )

[sidd]

Some vitrification is ongoing Some examples:

https://www.nwtrb.gov/docs/default-source/facts-sheets/vitrified_hlw.pdf?sfvrsn=16

https://www.researchgate.net/publication/284156723_French_Industrial_Vitrification_Plant_30_Years_old_Robust_and_still_Innovating

sidd

[Ken Feldman]

Only a small portion of France's nuclear waste can be vitrified.  The nastiest stuff has to be stored in stainless steel containers and locked away for thousands of years.

https://www.edf.fr/en/the-edf-group/producing-climate-friendly-energy/nuclear-energy/our-expertise/radioactive-waste

The 90% of least radioactive waste is sealed in drums, metal boxes or concrete containers. Final storage is handled at three Andra centres located in the Manche and Aube departments.

The 10% of most radioactive waste is currently conditioned in stainless steel containers and placed in intermediate storage at AREVA’s La Hague plant. Given its half life of up to several tens of thousands of years, the law provides for the containers’ transfer to a deep geological disposal facility (Cigéo). Being built at the boundary of the Meuse and Haute Marne departments, Cigéo is expected to open in 2025. Waste will be stored in cells excavated at a depth of 500 metres in a stable geological environment surrounded by impermeable argillaceous rock. Another repository is currently being designed to store power plant decommissioning waste.

EDF does vitrify nuclear waste produced by its British plants.  The vitrified waste must still be locked away for eons in geologically isolated storage facilities.

In the UK, where legislation is different, EDF Energy works with the Nuclear Decommissioning Authority (NDA), which is responsible for waste storage. Low and intermediate level waste is retained in dedicated facilities within the power plants and ultimately compacted, incinerated or recycled.

High-level waste is currently vitrified and placed in intermediate storage at the Sellafield reprocessing plant. The British government took a decision in 2006 to ultimately store it in deep geological repositories.

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France reprocesses their spent fuel substantially reducing the volume of waste and reducing the time that waste is dangerous by an order of magnitude. This also reduces the need for new fuel.


New baseload power needs should be met with new deep well geothermal techniques not nuclear.