[HN Gopher] How counting neutrons explains nuclear waste
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How counting neutrons explains nuclear waste
Author : jasoncrawford
Score : 27 points
Date : 2021-05-30 18:02 UTC (4 hours ago)
(HTM) web link (rootsofprogress.org)
(TXT) w3m dump (rootsofprogress.org)
| pengaru wrote:
| Thought exercise:
|
| What would the consequences be of detonating an improvised truck
| bomb, comparable in size to the Oklahoma City Bombing [0], in the
| middle of the spent fuel casks at the Connecticut Yankee plant?
|
| [0] https://en.wikipedia.org/wiki/Oklahoma_City_bombing
| est31 wrote:
| > There are advanced reactor designs that don't rely on the
| fission of U-235, but rather use the far more abundant isotope
| U-238. Some of these reactors can burn "spent" fuel, or
| "depleted" uranium left over from the enrichment process--
| extracting something like 60 times as much energy from uranium as
| traditional nuclear reactors.
|
| Does anyone have links for such reactors?
| shkkmo wrote:
| Heavy water reactors can run on natural uranium.
| https://en.m.wikipedia.org/wiki/Pressurized_heavy-water_reac...
| pfdietz wrote:
| And these are still fissioning 235U. 238U by itself does not
| sustain a chain reaction.
| jasoncrawford wrote:
| Breeder reactors, as others have pointed out. Oklo is a modern
| design based on the concept: https://www.nrc.gov/reactors/new-
| reactors/col/aurora-oklo.ht...
|
| Also see "Problem free nuclear power and global change":
| https://www.osti.gov/biblio/614877
|
| And "Nuclear fission power for 21st century needs":
| https://www.sciencedirect.com/science/article/abs/pii/S01491...
| ars wrote:
| > Does anyone have links for such reactors?
|
| https://en.wikipedia.org/wiki/Breeder_reactor you also need
| https://en.wikipedia.org/wiki/Nuclear_reprocessing to remove
| https://en.wikipedia.org/wiki/Neutron_poison which would stop
| the reaction.
|
| If we did that, there would be no nuclear waste left. (Or more
| specifically all the waste would decay very fast, and not be a
| long term problem.)
| radicalcentrist wrote:
| I believe breeder reactors can create fuel from U-238.
|
| https://en.wikipedia.org/wiki/Breeder_reactor
| AnotherGoodName wrote:
| The most famous of these is the Chernobyl reactor design, the
| RBMK. It could be run on natural uranium rather than enriched
| uranium and would self enrich the uranium via neutron
| bombardment inside the reactor.
|
| https://en.wikipedia.org/wiki/RBMK
|
| Of course there are some flaws in a reactor that breeds it's
| own enriched uranium. There's states that the neutron flux is
| too low so the enriched elements aren't burnt off quickly as
| intended. This leads to a state where the whole reactor is a
| highly enriched weapons grade bomb.
| [deleted]
| pfdietz wrote:
| A reactor that runs on natural uranium is still fissioning
| 235U (and some of the 239Pu that has been bred, but that's
| true of reactors that run on low enriched U as well.)
| exmadscientist wrote:
| Where did the data for this table come from? Checking Pb-208 (a
| memorable double-magic nucleus), it should really not be shown as
| undergoing alpha decay when none of the major ENDF tables show
| that. There is an unsourced remark on Wikipedia that this might
| happen, but given the half-life, I do not think scientists have
| ever measured a single such decay... so probably not best to
| include it. And if one spot check shows a mistake, how many more
| are there? It's a big table and ENDF data files are not pretty
| things....
| jasoncrawford wrote:
| You can see the table here:
| https://people.physics.anu.edu.au/~ecs103/chart/?ShowStable=...
|
| When I click on the lead-208 box, it credits data from:
|
| NUBASE2020: https://doi.org/10.1088/1674-1137/abddae AME2020:
| https://doi.org/10.1088/1674-1137/abddb0
|
| It also only says that alpha decay is "possible", not that it
| happens with any frequency--in fact, it lists Pb-208 as stable.
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