21. Neutron Transport

MIT 22.01 Introduction to Nuclear Engineering and Ionizing Radiation, Fall 2016
Instructor: Michael Short

The full, seven-dimensional neutron transport equation is developed from physical intuition, and putting that intuition into math. Aspects of neutron creation and transport are introduced as needed - neutron energy birth spectrum, flux, current, and many different types of neutron cross sections (fission, capture, scattering, total). It all comes down to balance - we equate the ways in which a control volume (like a reactor) can gain and lose neutrons of a certain energy, in a certain direction.

License: Creative Commons BY-NC-SA

[derekparent]

70 hours of watching 100’s of videos and someone actually states how neutrons are first introduced into the core to jump start the reaction.
This information explains and answered many of my questions regarding how it is started and how it may be serviced.
I am guessing that once a reactor is shut down and then left to “Cool down” the control rods could be removed and serviced along with the fuel rods.
Lockdowns during a pandemic share make you think a lot. 🤔

[iccuwarn]

There is an interesting implication for molten salt reactors in professor Shorts point that it is the fission products in a nuclear reactor that release the gamma rays. In molten salt reactors you dissolve your fuel (uranium) in your coolant fluid to prevent loss of cooling accidents. You also typically pump your entire fluid through your heat exchanger. Since the fission products travel along with the fuel and the coolant fluid they will release gamma rays in the heat exchanger. So, now you have to shield both your reactor and your heat exchanger to block the harmful gamma rays in a molten salt reactor, as opposed to a solid fuel reactor where you just shield your reactor core.

[sultanofsick]

Integral over all "stuff" "d-stuff" reminds me of when my (extremely Russian) professor taught remedial integrals (after poor performance by the class on the test) using "d-elephant"

[unitedstatesdale]

He can solve the secret of our existence without knowing or caring what day it is

[MrNetmask]

as electronicse engineer i find this lecture series AMAZING!!! really like the profesor

[derekflanderschang]

This is Buster’s other job, for when Army has half a day.

[christopherleubner]

It would be amusing to demonstrate it with a rather weak neutron source, a detector, and a few different materials. A while back i did this with a 120mCi Am/Be source and a variety of materials. The one that moderated the neutrons the best was a jar of coconut oil that made the detector go from a few dozen counts per minute to well over a thousand at a distance of approximately 1/2 a meter. Neutrons are very strange. 🤓😁😎

[bibipat]

The best lecture on this subject. Amazing..

[simondemarque]

47 ', aspect notation, the flux should be vectorial noted to be mathematically consistent

[chrisreeders]

Never considered that a neutron would decay into a proton and an electron.

[robbyandrews]

I'm sorry what elements are you spending of?

[MazenBushnag]

why the other terms ([n, in] and scatter-in terms) are not normalized (devided by 4 pi) as the fission and photo-fission terms?

[ianprado]

49:01 that should be a closed surface Integral :)

[davelowets]

Very interesting....

Great lecture. 👍

[patricks_music]

“It’s big enough and hard enough.” “Phrasing!”

[simondemarque]

internal scattering, same procedure as in turbulence modelling

[SJr]

Thank you so much for the lecture. My only question is that do we multiply the "number density " by macroscopic c.s or by microscopic c.s? @5:36

[RobbyAndrews-jk]

1 question just 1 can you accelerate the byproduct by means through a magnetic field. Yes. Can you incapsalate it creating platelets yes . When

[camresearch]

Actually cold neutrons last 15 minutes not 12...

[krosliandrade]

Thanks a lot Teacher. A great explanation.