Storage of nuclear waste

[farmerben]

From what I've seen lately there is no need to do nuclear fuel reprocessing right away.  Because new Uranium is cheap.  And reprocessing has inherent weapons grade implications.  But, a few centuries from now the case may be very different.  Or maybe not if fusion makes fission basically obsolete.  In any case the reprocessing gets easier over time as the main fission products like cesium and strontium have half lives of about 30 years.

It might make a lot of sense to plan for eventual recovery of our spent nuclear fuel.  So how would we design spent fuel storage so that somebody in 500 years can easily recover it, but its just as secure as other proposed solutions.

[DDE]

26 minutes ago, farmerben said:

Because new Uranium is cheap.

But waste disposal is not.

[kerbiloid]

https://en.wikipedia.org/wiki/Waste_Isolation_Pilot_Plant

https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository

Designed for 10k years, so probably is based on Silmarillion, Dune, or at least A Song of Ice and Fire, as 10ky is just one moment for them.

 

Spoiler

(from pikabu.ru)

"When on rewatching the scene, you suddenly realized that the one to the right is older."

P.S.
https://en.wikipedia.org/wiki/Long-term_nuclear_waste_warning_messages

https://web.archive.org/web/20210126152506/https://www.wipp.energy.gov/library/PermanentMarkersImplementationPlan.pdf

Upd.
10ky later...

Spoiler

1. Have a gym.
2. Dig a pit.
3. Drop some stones.
4. Keep droping more stones for so long time that you may have a sleep.

 

"If you feel bad (headache, ears, or teeth problems), it can let you feel good."

Edited July 25 by kerbiloid

[farmerben]

It's not that bad.  After 300-500 years it may be a valuable commodity that people want to recover.

[Terwin]

I vaguely remember nuclear waste being encased in steel and cement to make it an undesirable source of dirty-bomb materials.  This sort of treatment would also likely make it undesirable for reprocessing.

[DDE]

3 minutes ago, Terwin said:

I vaguely remember nuclear waste being encased in steel and cement to make it an undesirable source of dirty-bomb materials. 

I think it varies on a lot of levels.

Nuclear waste is an odd choice for dirty bombs anyway when radiation sources are far more available, and usually not encased at all - just an enclosed bunker the old sources are thrown into. Numerous cases of trespassing and theft from curiosity abound.

For protection against reuse in fissile weapons, irradiating the waste is broadly prefered. This was a subject of the 2016 US-Russia row when the US liberally interpreted its plutonium disposal obligations and undertook to chemically mix and bury it so that it becomes unrecoverable (somehow) instead of irradiating it, or completing its MOX fuel reactor to dispose of it in the most final of ways.

[farmerben]

 

[magnemoe]

13 minutes ago, Terwin said:

I vaguely remember nuclear waste being encased in steel and cement to make it an undesirable source of dirty-bomb materials.  This sort of treatment would also likely make it undesirable for reprocessing.

Think this is more to protect it from polluting the environment. First the steel and concrete has to erode or corrode away. 

Now its one obvious safe long term solution. Oceanic floor is very inert. Use an oil rig to drill an km deep hole there preferable deeper. Lower the containers into it fill it with concrete so you have an hundreds meter thick top layer. Even if the containers breaks down you are not getting trough hundreds or meter with ocean floor or concrete and its pretty much no erosion there.  
To make is safer make the plug an km. 
Now it might be an benefit to use an old deep oil or gas field for this as we know its gas tight or the gas would have escaped over the millions of years.

[tater]

WIPP is pretty cool, and the deepest I have personally been below the surface of the Earth. I knew someone involved with brine migration studies, so he invited me along on the tour they (WIPP) gave him. The waste there is (or was to be anyway) incidental waste—contaminated PPE, tools, etc.

Edited July 25 by tater

[darthgently]

3 hours ago, farmerben said:

From what I've seen lately there is no need to do nuclear fuel reprocessing right away.  Because new Uranium is cheap.  And reprocessing has inherent weapons grade implications.  But, a few centuries from now the case may be very different.  Or maybe not if fusion makes fission basically obsolete.  In any case the reprocessing gets easier over time as the main fission products like cesium and strontium have half lives of about 30 years.

It might make a lot of sense to plan for eventual recovery of our spent nuclear fuel.  So how would we design spent fuel storage so that somebody in 500 years can easily recover it, but its just as secure as other proposed solutions.

Encase it in creosote-coated Black Locust with a thickness tuned to 500 years?  More seriously, just put in a tapped out salt mine, seal it, then secure and surveil the entrance with  cameras and sensors.  I think many CONUS roadways have radiation detectors placed at strategic points; just have some on the roads approaching the storage facility also

[magnemoe]

3 minutes ago, darthgently said:

Encase it in creosote-coated Black Locust with a thickness tuned to 500 years?  More seriously, just put in a tapped out salt mine, seal it, then secure and surveil the entrance with  cameras and sensors.  I think many CONUS roadways have radiation detectors placed at strategic points; just have some on the roads approaching the storage facility also

Probably the best option, its an dry environment so lite corrosion of something like stainless steel and if something comes out it get absorbed by the salt, just has to be sure the mine don't get flooded who should pretty simple if you seal it well. 

[Nuke]

i think the issue is calling it waste, because most of the isotopes are still useful. part of the process is letting it sit in a pool for a few years to burn off the nasties. once its in dry storage its pretty safe. im always questioning the need for centralized storage. what you do is dedicate a nuclear site to nuclear stuff. when you tear down an old reactor you build a new one in its place. and it might be of a design able to burn up some of the fuel formally known as waste. once we get past that then all you have is medium and low level waste, which is a lot less problematic.

proliferation issues are moot when we get to the point were we can do nuclear weapons without the isotopes. we aren't far from a point where we can do that.

[farmerben]

1 hour ago, Nuke said:

i think the issue is calling it waste, because most of the isotopes are still useful. part of the process is letting it sit in a pool for a few years to burn off the nasties. once its in dry storage its pretty safe. im always questioning the need for centralized storage. what you do is dedicate a nuclear site to nuclear stuff. when you tear down an old reactor you build a new one in its place. and it might be of a design able to burn up some of the fuel formally known as waste. once we get past that then all you have is medium and low level waste, which is a lot less problematic.

proliferation issues are moot when we get to the point were we can do nuclear weapons without the isotopes. we aren't far from a point where we can do that.

Yeah its a resource, not a waste.  After a few centuries most of the radioactive fission products are gone.  You have a few hot rare earth elements including plutonium remaining.

If we reprocess after cooling in a pool for a few years we have some nasty cesium and strontium that needs to be disposed of or stored safely for centuries, not millennium.  If we reprocess in a few centuries all the radioactive stuff is high value stuff.  The main reasons for not doing it are economic and weapons related.  It's the plutonium that lasts millennium.  

[kerbiloid]

13 hours ago, DDE said:

Nuclear waste is <...> usually not encased at all

+1

Spoiler

 

[RCgothic]

As a nuclear fuel handling engineer, I curse anytime anyone mentions geological disposal facilities. 

We are absolutely going to want access to this high-grade resource as soon as it's economically feasible to reprocess it, it should be criminal to waste it by burying.

[darthgently]

6 minutes ago, RCgothic said:

As a nuclear fuel handling engineer, I curse anytime anyone mentions geological disposal facilities. 

We are absolutely going to want access to this high-grade resource as soon as it's economically feasible to reprocess it, it should be criminal to waste it by burying.

I certainly didn't mean bury it.  Just use a tapped out salt mine as a space to keep it secured from improper use

[kerbiloid]

6 hours ago, RCgothic said:

As a nuclear fuel handling engineer, I curse anytime anyone mentions geological disposal facilities. 

We are absolutely going to want access to this high-grade resource as soon as it's economically feasible to reprocess it, it should be criminal to waste it by burying.

A compromise: drop'em into volcano. They will be available asap or from time to time.

[DDE]

On 7/26/2024 at 6:36 AM, kerbiloid said:

+1

  Hide contents

 

Lake Karachay moment

[kerbiloid]

1 hour ago, DDE said:

Lake Karachay

 

Spoiler

 

P.S.
(offtopic)

I haven't even heard about.

https://en.wikipedia.org/wiki/Aberoh_and_Atom

Spoiler

 

[farmerben]

I'm still a fan of accelerator driven reactors, which use a proton beam and spallation neutrons to incinerate nuclear waste.  These get rid of all the weapons grade material and longest lived waste.  You still have the cesium and strontium to contain for a few centuries.

People who are not fans of this approach mostly complain about the expense.  But the expense is worth it, if it eventually leads to cheaper and better proton beams.  Because proton beams have numerous potential applications including ones in spaceflight. 

One idea I have is that a deuterium beam could be way better than a simple proton beam as a spallation neutron generator.  To the best of my knowledge the research has not been done, and particle accelerators with deuterium have barely been tried.  It would be worth it to create one from a pure research perspective. 

[DDE]

2 hours ago, farmerben said:

One idea I have is that a deuterium beam could be way better than a simple proton beam as a spallation neutron generator.  To the best of my knowledge the research has not been done, and particle accelerators with deuterium have barely been tried.  It would be worth it to create one from a pure research perspective. 

AFAIK the idea of net-energy negative fusion as a fission waste burner has been around for as long as I could read.

[farmerben]

I wonder if you could get enough neutrons with a Farnsworth Fusor.  Those are cheap.

[darthgently]

39 minutes ago, farmerben said:

I wonder if you could get enough neutrons with a Farnsworth Fusor.  Those are cheap.

It took me a moment to realize you weren't making a Futurama  reference.  You bring up a good point

 

Edited July 30 by darthgently

[magnemoe]

7 hours ago, DDE said:

AFAIK the idea of net-energy negative fusion as a fission waste burner has been around for as long as I could read.

Never heard about it unlike net-energy negative fusion rocket engines. But thought his idea was just to accelerate deuterium atoms as the extra neutrons would help creating more nuclear reactions. 
Even if energy positive you use electricity to generate heat who you then can convert to electricity but its not very efficient. Now if you had an use for the heat year around its nice but then an gas turbine is cheaper. 

[Nuke]

8 hours ago, farmerben said:

I wonder if you could get enough neutrons with a Farnsworth Fusor.  Those are cheap.

polywells might be better. you dont have grid erosion that contaminates the plasma and requires you to shut it down to change the grid or purge the contaminated deuterium. less consumables less down time. polywells might still be viable for breakeven at some point, its just the proponents opted for computer simulations rather than lab work to nail down the optimal design. best option for a spacecraft power supply if it works. but for now they make excellent neutron sources.

Edited July 30 by Nuke