Nuclear Fission Reactor Design

[@daniellassander]

Wow thank you so much, i loved this video. I cant tell you how much i appriciated this video! :D

[@rock3tcatU233]

I'm now actually in the UK to work on your Advanced Gas Cooled reactors.

[@Dark_matter89]

Thank you so much for all the videos ! Great work !

[@69mtilghman]

what happens to the fast neutron after 15 mins if the neutron does not interact with a moderator?

[@pacinpm2]

Which type of reactor is more safe? I think Chernobyl reactor was using graphite rods and it was part of a problem. I also read that water reactors are safer because you can't have running away fission in them. If it gets too hot water evaporates and reaction stops.

[@postcodeox278]

DrPhyscis do you think that modern Nuclear power plants will prevent another Fukushima Melt down?

[@maitland1007]

Great video. Thanks. Good descriptions of current designs. It would be great if you could also do one on future designs and their advantages .. Things like pellet reactors, molten salt etc.

[@thrunsguinneabottle3066]

BWRs are indeed under pressure - about 90 ATM (like Fukushima). PWRs operate at about 130 ATM, At just one ATM, your BWR would have very poor thermodynamic efficiency. The main difference is whether the steam which turns the turbines comes directly from the reactor (and is slightly radioactive) BWR. Or comes via heat exchangers by a circuit which does not enter the reactor.PWR. I think Boron is used for control rods. And Boron in solution is used to kill the reaction in an emergency. I have not heard of cadmium being used. But maybe it is. In any case these reactors (like the one under construction at Hinkley Point) are HORRIBLE HEATH ROBINSON contraptions. The future lies in Molten Salt Reactors. Watch the many expositions of the MSR on KZbin by Kirk Sorensen, who REdiscovered this technology about fifteen years ago.

[@spoonfuloftactic]

Are there big advantages or disadvantages to the UK's and US's stategies?

[@Saki630]

Prof: Maybe I missed it, but what gives off the first neutron to start the chain reaction? It looks as if you want to have the amount of neutrons available equal to the absoprtion rate of the cadmium rods and inert rods (such as in the breeder reactor) in the tank. As time progresses the rate of neutron production increases until all the absorption and inert rods capture the excess. What is making sure that this process is carried out without a melt down? When the inert rods turn into fission material and begin emitting more nuetrons, I would assume the amount of starting material, such as Uranium, would be less and produce less neutrons per mass while the inert rods produce more neutrons per mas of active material in the rods. With these two scenarios, what is the active way of managing the amount of neutrons present at any time? I would assume you would have an excess of absorption rods and coolant, but how does anyone know the exact neutron production rate at any time and whether or not the reaction will get out of hand? Also, what is the minimum size for a fission reactor? Also can you go into more detail about AGCR, because I think liquid graphite sounds cool.

[@alanc9492]

U-238, U-235 is Radioactive It is giving off neutrons all the time. Just put enough together, sustained chain reaction and a lot of heat. The movie "Fat Man Little Boy" has a scene where the scientist drops too much Uranium and starts a chain reaction which gives everyone in the room lethal does of radiation he has to flip it off NOW! Guess it was a true event because I saw it another Manhattan Project movie

[@massimilianobalsamo]

A nice quick lecture for breakfast

[@robertadorrough3852]

Jolly good. Looking forward to next time. All of Japan's reactors are switched off. The one fast breeder reactor "Monju" which would have used liquid sodium as a coolant never was switched on. FBR's make everyone too nervous. In preparing the fusion discourses, would suggest looking into Lockheed Martin's 15/10/14 boast of creating a truck sized fusion reactor within 5 years. Cheers!

[@ronaldgarrison8478]

"Boast" is right. Heard anything about that in the 4 years since? I suspect that stuff about a "truck-sized" reactor was just Popular Science chatter. They may have meant that the *reaction chamber* would be small enough to put on a small truck, but the reactor would surely be vastly larger.

[@justpaulo]

(you know what I am going to ask don't you :) ) So, if apparently U238 can turn in Pu239 by absorbing a neutron ( and from your video I understood it could be a thermal neutron) why is there U328 naturally around and not Pu239? Or U233 instead of Th232? Thanks Looking forward for the fusion video(s)...

[@DrPhysicsA]

Combination of probability of the reactions happening and half-lives before further decay.

[@rohankalanje]

nice work

[@MrJohnlundquist]

What was the Chernobyl reactor type?

[@Elios0000]

John Lundquist boiling water reactor

[@punch6832]

Water cooled, graphite moderated. This type would never be approved in western nations.

[@kpaasial]

As noted it used graphite for neutron moderation and water for cooling and transferring heat energy to the turbines. This is extremely dangerous in case there is a coolant loss accident because the loss of coolant doesn't stop the fission reaction unlike in BWR reactors where loss of the moderating water immediately stops the fission reaction cold.

[@israelfigueroa7858]

Great informatión.

[@BudskiiHD]

Great video! Life saver

[@derekpoon5308]

Can you discuss nuclear waste treatment?

[@artyfarty3]

Thanks so much for these awesome vids. :) I guess since the Fukushima disaster we all are taking a bigger / harder look at the benefits and dangers associated with nuclear technology - and You are doing a great work explaining it to us all :) thanks for that :) There is one question I'd like to ask though - have You heard/known about Liquid Fluoride Thorium Reactors , what are Your thought on this topic , and could You go through it and explain how they work ? :) I ( and I'm sure many others like me ) would appreciate it very much if You could :) Thanks again :)

[@jadenmax679]

Cool.

[@769270865]

Molten salt reactor?

[@AllaBader01]

Thanks.