21. Neutron Transport
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- Опубліковано 14 чер 2024
- MIT 22.01 Introduction to Nuclear Engineering and Ionizing Radiation, Fall 2016
Instructor: Michael Short
View the complete course: ocw.mit.edu/22-01F16
UA-cam Playlist: • MIT 22.01 Introduction...
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.
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70 hours of watching 100’s of videos and finally....... 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. 🤔
No..
This is Buster’s other job, for when Army has half a day.
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"
He can solve the secret of our existence without knowing or caring what day it is
5:46 bigSigma = N * littleSigma
this is true.. error in video
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.
Sounds like a trade-off tho.
Having a primary and secondary loop would likely benefit the economics (assuming only the first HEX would need shielding), the diagram show on the molten salt reactor wiki page is show this way.
Shielding do not cost much , if only concrete...
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. 🤓😁😎
Thanks a lot Teacher. A great explanation.
as electronicse engineer i find this lecture series AMAZING!!! really like the profesor
The best lecture on this subject. Amazing..
Very interesting....
Great lecture. 👍
47 ', aspect notation, the flux should be vectorial noted to be mathematically consistent
“It’s big enough and hard enough.” “Phrasing!”
why the other terms ([n,in] and scatter-in terms) are not normalized (devided by 4 pi) as the fission and photo-fission terms?
Never considered that a neutron would decay into a proton and an electron.
that is essential information if you are a nuclear engineer
Neutrons have a slightly higher mass than protons, and energy always spreads out, hot to cold and so on. Protons are the lightest baryons, but they just might decay in pions letting their positive charge off as a positron.
49:01 that should be a closed surface Integral :)
explain please
@@muhammadfaridkhandaq4379 The theorem is about it. The double integration is over a closed surface, as domain. Analogue to the line integration in Green theorem. So, the mathematical formalism asks for that differentiation. But I'm not a mathematician, maybe I'm wrong.
@@k.manjericao1583 any way thanks for explanation. Ur so kind
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
You multiply the number density by microscopic cross-section to get a macroscopic cross-section. He wrote it down wrong but explained it out loud correctly.
internal scattering, same procedure as in turbulence modelling
"a low neutron is not a stable particle."
Actually cold neutrons last 15 minutes not 12...
I'm sorry what elements are you spending of?
LAUGHING GAS
There are several mistakes in the transport equation. First, there shouldn’t be a volume integral dV in all the terms on the right. Because the dn/dt is for a specific volume element, or specific point in space r.
Second, in the n,in term the chi(E) and the nu(E) are missing.
Also, the total cross section term shouldn’t have an integral at all! The reason that the reaction INTO may come from ANY dE dOmega, but the reaction FROM (the loss) is only from this specific dE dOmega.
Also the leakage term shouldn’t have an integral at all.
I want a tshirt
Isn't there sensors that can measure this many thousands of times per second, and then send the correct numerical answer to a display??
Just use those instead of all this. 🤯
Just kidding.... 😂
The fuck!!?? How did i end up here in the first place...
You know why that guy has a bald patch.... its because he is too brainy, even for his hair follicles