[FRIAM] technical notes on fusion announcement
Steve Smith
sasmyth at swcp.com
Tue Dec 13 19:23:15 EST 2022
I think DT refers simply to the remaining fraction of Deuterium/Tritium
remaining after the reaction event (-4%) without specific accounting for
remaining D vs T.
My understanding is that D-T fusion occurs at a lower temperature than
D-D but that once fusion commences (starting with D-T), both D-T and D-D
reactions occurring in similar amounts. In laser-driven ICF (as with
NIF) I believe the ratio of D/T is nominally 50/50 though it would seem
to make sense to have a higher T to D ratio but most references I see
imply equal portions. An equal number of D-D and D-T reactions would
seem to consume D more quickly, though as that commences, the D/T ratio
would go down, making D-T reactions (yet) more likely... tricky
business, no wonder it has taken decades to get to this point?
The Wikipedia Entry on ICF is pretty good:
https://en.wikipedia.org/wiki/Inertial_confinement_fusion
I found several popular science Articles which seem to reinforce my
sense that this "breakthrough" is not as significant as implied:
https://www.science.org/content/article/fusion-breakthrough-nif-uh-not-really
Other interesting/relevant links regarding D-T and D-D fusion...
https://www.researchgate.net/publication/263507001_Species_separation_and_modification_of_neutron_diagnostics_in_inertial-confinement_fusion/figures?lo=1
https://www.energy.gov/science/doe-explainsnuclear-fusion-reactions
<https://www.energy.gov/science/doe-explainsnuclear-fusion-reactions>
https://science.jrank.org/pages/4732/Nuclear-Fusion-D-D-D-T-reactions.html
<https://science.jrank.org/pages/4732/Nuclear-Fusion-D-D-D-T-reactions.html>
On 12/13/22 4:36 PM, glen wrote:
> That's why I asked. I guess I'll assume DT means both deuterium and
> tritium, not just deuterium. If you were going to track fuel use,
> you'd track the rarer part more closely, right?
>
> On 12/13/22 09:22, Frank Wimberly wrote:
>> DT = deuterium?
>>
>> ---
>> Frank C. Wimberly
>> 140 Calle Ojo Feliz,
>> Santa Fe, NM 87505
>>
>> 505 670-9918
>> Santa Fe, NM
>>
>> On Tue, Dec 13, 2022, 10:21 AM glen <gepropella at gmail.com
>> <mailto:gepropella at gmail.com>> wrote:
>>
>> Awesome. Thanks. I'm still trying to catch up with the QC
>> Wormhole kerfuffle. Who knew Quanta was so click baity?
>>
>> What is "DT"?
>>
>> On 12/13/22 09:02, Marcus Daniels wrote:
>> > In case no one wanted to get up at 7:00am to watch DOE
>> administrators talk:
>> >
>> >
>> > 1. Controlling the laser in space and time was important for
>> maintaining symmetry. Timing precision of 25e-12 secs and laser
>> spatial precision of 5e-12 meter were needed. This was thought to be
>> the main explanation for the achievement.
>> >
>> > 2. 8% more power on the laser this time
>> >
>> > 3. x-ray tomography is used to find flaws in the capsules.
>> Developing software to do the counting.
>> >
>> > 4. They have ongoing efforts to study the fabrication systems
>> and their components (done in Germany) to find idiosyncrasies of each.
>> >
>> > 5. Laser technology improvements since NIF was built which are
>> 20% more efficient.
>> >
>> > 6. Target cost is from labor, and it takes 7 months each
>> >
>> > 7. 4% of DT is burned in a shot
>> >
>> > 8. Machine learning ties together radiation hydrodynamics and
>> experimental data. (It sounded preliminary.)
>> >
>> > 9. The (successful) capsule had more defects than previous
>> experiments. However, previous experiments did show benefits from
>> capsule quality.
>> >
>> > 10. 15% of experiments are indirect drive of this kind, 15% of
>> experiments are other approaches to ignition. The rest are weapons
>> and materials characterization.
>> >
>> > 11. Anomalous laser directional control were problems in the
>> summer runs. Fixed that.
>
>
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