kasdeya

I bought Nucleares and tried to go through the tutorial, but realized that it was getting me nowhere. so now I’m watching videos about how #nuclear reactors work and it’s actually really fucking fascinating?

like neutron moderators are super interesting, because it’s really counterintuitive that a neutron can be going “too fast” for #fission and a moderator has to actually slow it down

and the concept of a void coefficient is super interesting, because I guess water can be both a moderator and something that absorbs neutrons, and it depends on… something about the reactor? idek

and did you know that there was at least one natural fission reactor discovered? it had a negative void coefficient so it needed water in order to do the reaction, but it kept vaporizing its own groundwater, so it had to wait for more water to continue the reaction in a constant cycle

and I watched a super-interesting video about how Chernobyl happened and their control rod design was fucking insane btw. and look at their channel for even more videos, like videos about how a thorium reactor is able to create even cleaner fission energy than a uranium-235 reactor

I still don’t feel remotely ready to play Nucleares itself lol but I’m learning a lot and it surprises me how fascinating this subject is

Steamで20% OFF：Nucleares

Nuclear Reactor Simulator: Take Control. Prevent Disaster. Power the World.

Mar 31 at 8:32pmWeb
Show threadXenotime, Librarian of Æther Apr 1
@[email protected] yep, water is an excellent moderator because it has a lot of hydrogen, but it also has quite a high probability of “capturing” an incident neutron (reacts with the neutron, absorbing it into the nucleus, and emitting a gamma ray)

this is part of why heavy water is useful to reactors, it’s actually worse at moderating since deuterium is heavier than hydrogen, but it’s so much less likely to capture a neutron (with just gets rid of a neutron could have been used) that it can be worth it
Show threadkasdeyaApr 2

@xeno ohh interesting! so I’m guessing that regular water captures neutrons by becoming deuterium D₂O - but presumably once it’s got one neutron it’s not going to be too eager to capture another one (I’m ngl I have no idea what forces cause a neutron to stay inside of a nucleus or what properties those forces have for different types of atoms or molecules lol)

I’m guessing that means that a reactor core full of deuterium D₂O is going to be more likely to have a negative void coefficient (since it moderates the neutrons, but doesn’t absorb them) than one full of regular water?

and if my assumption is right about regular water becoming deuterium D₂O when it captures a neutron, does that mean that reactor core water needs to be periodically changed out or it will change its effects on the reaction by becoming more full of deuterium D₂O?

Show threadkasdeyaApr 2
@xeno oops sorry I thought that “deuterium” was the same thing as heavy water but nope it’s just a hydrogen isotope that’s in heavy water! my bad
Show threadXenotime, Librarian of Æther Apr 2
@[email protected] ur good, yep D is the isotope and D2O is heavy water aka deuterium oxide as it was sometimes called ages ago
Show threadXenotime, Librarian of Æther Apr 2
@[email protected] yes, H2O is much much more likely to capture a neutron to form HDO (eventually D2O) than D2O is to capture a neutron to form HTO (eventually you’ll get T2O)

you can think of it “already being packed with neutrons”, it’s not too far off sometimes I like to think about nuclei that way tbh

I’m not sure exactly about the void coefficient that’s a complex calculation but heavy water based reactors like the venerable CANDU are able to safely operate with positive void coefficients in part because of the heavy water:

not through some intrinsic property, but if your reactor needs the low neutron absorption of D2O to remain critical, you can dump a bunch of regular old water into the core and the neutron absorption can bring it below criticality

I have a NucEng friend who has actually operated a TRIGA reactor (so I believe light water) and I could ask them