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jacobn commented on NRC issues first commercial reactor construction approval in 10 years [pdf]   nrc.gov/sites/default/fil... · Posted by u/Anon84
SoftTalker · 8 days ago
Nice, I like the sodium fast reactor concept. Produces less waste, can be passively cooled when shut down, and doesn't run pressurized so reactor vessel can be thinner.

Sodium leaks can be nasty, but they can be dealt with.

jacobn · 8 days ago
Are there any nuclear alternatives that don't include strapping low grade bombs to the reactor core (PRW/BWR: water separation -> hydrogen + oxygen -> boom, like happened @ Fukushima) or using coolants that instantly start violently combusting when exposed to air or moisture (sodium)?

I love the promise of nuclear energy, and I understand that every single engineering decision has tradeoffs, but these tradeoffs just seem so bad? Are there really no better options?

jacobn commented on Show HN: AxonML – A PyTorch-equivalent ML framework written in Rust   github.com/AutomataNexus/... · Posted by u/AutomataNexus
jacobn · 12 days ago
Cool! How do you actually implement “Reverse-mode automatic differentiation with a tape-based computational graph” in rust?
jacobn commented on Dissecting the CPU-memory relationship in garbage collection (OpenJDK 26)   norlinder.nu/posts/GC-Cos... · Posted by u/jonasn
mattclarkdotnet · 15 days ago
Sorry if this is obvious to Java experts, but much as parallel GC is fine for batch workloads, is there a case for explicit GC control for web workloads? For example a single request to a web server will create a bunch of objects, but then when it completes 200ms later they can all be destroyed, so why even run GC during the request thread execution?
jacobn · 15 days ago
Most web request cases where you care about performance probably have multiple parallel web requests, so there’s no clean separation possible?
jacobn commented on Gemini 3 Flash: Frontier intelligence built for speed   blog.google/products/gemi... · Posted by u/meetpateltech
kridsdale3 · 3 months ago
If they told you, it would be picked up in a future model's training run.
jacobn · 3 months ago
Don't the models typically train on their input too? I.e. submitting the question also carries a risk/chance of it getting picked up?

I guess they get such a large input of queries that they can only realistically check and therefore use a small fraction? Though maybe they've come up with some clever trick to make use of it anyway?

Dead Comment

jacobn commented on Bill Gates-Backed 345 MWe Advanced Nuclear Reactor Secures Crucial US Approval   interestingengineering.co... · Posted by u/m463
ggm · 4 months ago
I like the idea of an adjunct energy storage, and I can see why a salt tank, kept hot (like really hot. these things can be 500°C or more (even the cold tank is just below 300°C) and the "salt" is sodium or calcium nitrate type stuff) does the trick because heat exchanger back to working liquid for the turbine, thats well understood.

But I also would have thought a battery stack would perform exactly the same function as the salt tank: long duration storage of energy, available to supplement the nuclear power when required.

I believe there's some other reason this specific coupling of a reactor and a heat store makes sense which I didn't get from this article: Maybe it provides resiliency for thermal systems management overall?

jacobn · 4 months ago
If there’s an issue with the core then the salt tank can act as a heat sink in a way a battery can’t?

The boiling / pressure water reactors all have requirements on active cooling being maintained in emergencies - I’m not familiar with this design nor to what extent the salt is intended to fulfill such a function, but it’s plausible that it could buffer things for idk 1h-3d maybe?

The holy grail is the “walk away safe” reactor, I would hope / presume all the novel / modern ones fulfill that?

jacobn commented on Web Bot Auth   developers.cloudflare.com... · Posted by u/ananddtyagi
binarymax · 6 months ago
I agree in principle, but I disagree that it should be designed and mandated by a private gatekeeper
jacobn · 6 months ago
Isn't that how most web standards got their start? One of the interested parties pushed something, then things evolved through the standards process?

(And then it can of course get derailed, but that's a separate story)

u/jacobn

KarmaCake day1853November 2, 2010View Original