22. Simplifying Neutron Transport to Neutron Diffusion

[@mitocw]

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[@derekflanderschang9654]

20:02 - just wanna say, I have no idea what any of this lecture means (I watch these to go to sleep, I didn’t make it past Calculus 1), but I correctly guessed the needed number as 2 and now I feel like a genius. Thanks MIT.

[@mutiur7396]

You can have a good night sleep.. I thought about 200-300 groups...

[@drcarlasouza6407]

the last class was one of the best classes I EVEN seen in my life.... very anxious for this one!

[@flusitik852]

One of the best physics videos I’ve ever seen.

[@kitten-inside]

"Rainbow explosion simplification" needs to become a scientific term.

[@VeteranVandal]

Well having that many terms in equations is usually not that common.

[@JohnRMTurner]

Fantastic video. Great quality and engaging professor!

[@zack_120]

3:15- flux=neutron # per SQUARE cm : what is the physical meaning (2D is a conceptual area with no physical thickness, so neutrons must travel perpendicular to the area plain parallel to the direction of v) ?

[@mutiur7396]

Flux is much older concept than neutron flux..it was initially used for electric and magnetic 'field lines', based on observation.. in case of neutron generally two assumption are taken one is thickness of area is just one neutron diameter to prevent shadowing and secondly in z direction (3d), z is taken to be 1. So we have only two axes area to focus on..

[@ianprado1488]

15:13 ♥️♥️♥️

[@christiller3257]

when is it supposed to be E prime over just E? He seems to go back and forth a lot and I'm not sure when which is supposed to be used.

[@colinpitrat8639]

E' is for 'another energy level' whereas E is for 'the one we're interested in'. Overall, you need one for the parts of the formula that depend/describe the initial state in a case where energy changes. On the full fomula, after he adds many primes, I think only one more is missing in the flux for E' -> E.

[@mutiur7396]

First observe if it is a gain or lose term..

[@eloualkadimourad4672]

10:21 i think he should have integrated only on the volume not omega and the energy

[@benmeillaud8447]

I agree

[@viswasubramanian4738]

He will cancel those ig later

[@mutiur7396]

No, he still want to track neutron of energy and direction which were leaking from surface an still which are in the volume... Divergence take care of if they will leak from volume..

[@albigi80]

assuming all ideal remain nothing

[@Yodavid1]

i laughed at this 22:39

[@PaulHigginbothamSr]

Something tells me you have never studied molten salt reactors. Everything you said smackes of disinformation to nuclear engineers. 1. They have no control rods they load follow with heat. The critical function is the amount of fissionable quantity in relation to total salt volume. 2. They are not homogenous and will have graphite moderating lengths running from the top of the reactor to the bottom with salt circulating in the voids between bundles. The graphite will fit together in a key and slot method. Being non homogenous with a fertile blanket of thorium with a possible neutron reflector periphery to reduce overall reactor size and no pressure vessel because one bar is all it will have. Many many other statements smack of disinformation towards the best reactor possible today for process heat for chemical manufacture as well as salt water desalination. I was interested in your classes till you started lying.

[@Rishnai]

Go earn your way into Uncle Sam’s nuke school then Cadet Dunning-Kreuger. MIT won’t miss you.

[@mutiur7396]

Honestly very few people know about it including me.. I too skip it, and am interested in lwrs, which he too referred many times... But he had to made it somehow to show student what homogeneous meant...

[@seanyounk1]

I would love to watch your class as well. Please point me in the right direction.