chickenbig

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أول أمسdiscuss

> intentional Polonium 210 from decay chains

What do you mean "decay chains"? Po-210 decays to Pb-206 which is stable. So you mean Po-210 decay. Let's shut down the chemical industry because someone attempted to poison The Skripals. https://en.wikipedia.org/wiki/Poisoning_of_Sergei_and_Yulia_... .

> medical mistakes

Spent nuclear fuel is generally not used for medical isotopes. They specially prepare samples for irradiation to not have to use reprocessing, e.g. https://en.wikipedia.org/wiki/Cobalt-60#Production .

> I could have a look for you

It would be illuminating to see what you find reasonable.

أول أمسdiscuss

> It is a complex answer, and heavily depends on decay product chemistry.

The source you provided does not agree with that assessment. It is purely radiation damage. The Pu-238 (half life 87.7 years) and Pu-239 (half-life 24,110 years) experiments.

    plutonium-induced health effects are considered to be the result of energy deposited by alpha particle emissions in tissues that retain plutonium for extended periods (i.e., lung, bone, liver following inhalation exposure). Similar health effects would be expected from any alpha-emitting source that would result in similar cumulative tissue-specific radiation dose and dose rate.

They seem fairly certain that it is alpha particle damage, not chemistry.

أول أمسdiscuss

> The "high level waste" is the stuff that takes 10k years to decay.

Well, there are many definitions, for instance https://ukinventory.nda.gov.uk/information-hub/factsheets/wh... is from the UK.

> The big things that you get out of reprocessing nuclear fuel

You generally extract the trans-uranics from fission products. The former needs more specific treatment to deal with their longer half lives (or turning into MOX, which ends up more expensive than using normal uranium). The latter get vitrified (who needs the Sr or Cs, really).

> The things we might use (plutonium, strontium) have some rather "questionable" applications:

The Pu-238 for the RTG is generally produced in trace quantities in reactors, with reactor grade plutonium containing mostly Pu-239 and Pu-240.

I'm not a huge fan of these tiny RTG sources either. Spacecraft yes, otherwise ... proven to be somewhat dangerous when they become orphaned.

قبل 3 أيامdiscuss

> there will be high level waste that needs to be disposed of

Fortunately it is self disposing, decaying away. Unlikely plain old mercury or arsenic.

قبل 3 أيامdiscuss

> if something is radioactive enough to be a hazard then it's radioactive enough to generate power

Only under certain circumstances is it financially worth harnessing this power. I think of space probes and their RTGs. They use alpha emitters like Pu-238, to minimize the shielding requirements.

As for the rest of the stuff, dry casks are good enough. Reprocessing isn’t currently economical while uranium is so cheap, although the vitrification of the fission products can help immobilize the worst radiation emitters, but really the UO2 structure does a decent job of keeping things put.

قبل 3 أيامdiscuss

> Which of the 14 isotopes are you referring too? In general, synthetic isotopes unknown in our evolutionary biology are far more toxic

https://www.theguardian.com/uk/1999/aug/09/rorycarroll . Or does the biochemistry of Pu particularly depend on the isotope?

قبل 3 أيامdiscuss

> "Plutonium-239 has a half-life of 24110 years"

Great, that means it is not very radioactive, and an alpha emitter, so unless you ingest it is not particularly harmful.

> societies have proven irresponsible with fuel life-cycle management

Do you have evidence that the spent nuclear fuel from power stations has killed people?

قبل 10 أيامdiscuss

> three other major events

What is the measure of major? The INES scale? https://en.wikipedia.org/wiki/International_Nuclear_and_Radi...

> Sarov in 1997

One person died in the criticality accident in a weapons research lab.

> Mayak Production Association in 2017 ... it was a huge release

https://inis.iaea.org/records/ndb3s-s5507 "In some regions, over 100 mBq/m³ were measured as one-day means. Although resulting exposure was far below radiological concern"

> the Nyonoksa explosion

Nuclear powered cruise missile.

> we might as well count Hanaford

https://madihilly.substack.com/p/hanford-what-a-waste

قبل 11 يومًاdiscuss

Prismatic (or cylindrical) TRISO also makes sense. There are lots of potential problems using pebble beds (circulation, grinding), whereas doing regular refuelling cycles avoids them, in exchange for down-time to refuel.

قبل 14 يومًاdiscuss

Even compression level 1 or 2 is pretty good.

I once used https://github.com/google/riegeli and a low zstd compression level to store large quantities of protobuf data in an efficient manner (in terms of CPU, RAM and streaming to disk). Shame Riegeli is not well known, not well documented and does not have many tests.

قبل 19 يومًاdiscuss

> Isn't Sizewell c already delayed?

Citation needed. Delayed since FiD? Or since the project was originally announced? To me the latter is rather an unfair given planning permission issues and government changes.

قبل 22 يومًاdiscuss

Indeed, it might be said that they underestimated the cost and timescales to get the project off the ground. But this is generally the case with mega-projects. Guess we shall see how the construction of Sizewell C goes.

قبل 22 يومًاdiscuss

Siting of an SMR is somewhat different (albeit related) to the SMR concept itself. You might cluster them together (like the plans for 3 RR SMR at Wylfa and 3 at Ringhals in Sweden).

قبل 22 يومًاdiscuss

> almost as much engineering , plumbing, safety mechanism, personnel, maintenance, etc

Sure, that is economics, not thermodynamics. I don't necessarily agree with the SMR manifesto, but it is conceivable that improved financing, construction, operation and oversight could make an SMR cheaper than a larger reactor.

قبل 22 يومًاdiscuss

> then neither the Russian invasion of Ukraine nor Hormuz blockade would have been a huge deal. The cost of energy is destroying your industrial base.

Domestic heating has little to do with industrial base. Fertilizer prices would still have risen. Grain supplies would still be affected.

قبل 22 يومًاdiscuss

> One was eventually built after massive delays and cost overruns.

Areva underbid on the fixed price contract to win against the ABWR, IIRC. Admittedly the Fins were not pleased at the time overrun, but the construction cost was historically not so bad given it was FOAK in a country without recent construction experience .

قبل 22 يومًاdiscuss

> You cannot make regular nuclear weapons out of thorium

https://www.researchgate.net/publication/233880587_Nuclear_e...

قبل 23 يومًاdiscuss

> Thermodynamics are the reason why SMR aren't, and will never, be economical.

And the link between thermodynamics and the price of electricity is what?

قبل 3 أشهرdiscuss

> There is nothing wrong with over provisioning cheap renewable power generation when it is economically superior to building fossil assets that will end up stranded.

Solar cannibalises solar, so the price when the sun shines may tend to zero, but that does not ensure the price to the consumer of the electricity they need tends to zero, or even lower than it was.

قبل 3 أشهرdiscuss

> stockpiles and ammunition or other non-reusable military gear are basically the definition of money 'destroyed'

Goods like longer-lasting food, medical supplies or a strategic oil reserve are not wasted. The money that went into supplying them has gone back into the economy, and they serve a more strategic purpose than the market participants could have borne (i.e. societal insurance policies). The same could also be said of military stockpiles, and continuing to buy them sustains a capability that is hard to get back once lost.