All Questions
Tagged with neutrons nuclear-engineering
47
questions
6
votes
1
answer
104
views
Why is the neutron cross section of hydrogen larger than that of deuterium?
The scattering neutron cross section of hydrogen is about $20$ b, five times larger than that of deuterium. The capture cross section of hydrogen is around 3 orders of magnitude higher than that of ...
- 1,775
0
votes
1
answer
38
views
Neutron Dose Rate to Activity Calculation
This is a completely hypothetical question but say I have an unknown radioactive source inside a steel box, given the dimensions of the volumetric source and the container, the neutron dose rate 1m ...
- 15
1
vote
1
answer
42
views
How to use point-kinetics approximation to go from diffusion to point kinetics?
I understand that we get to point kinetics by neglecting spatial dependence in the diffusion equation, but I'm somewhat stuck on the details here. Robert E. Masterson's Introduction to Nuclear Reactor ...
- 28
5
votes
3
answers
2k
views
Can the neutrons in a nuclear reactor be collimated?
N.B. I am not a physicist.
My layman's understanding of a nuclear reactor is essentially that neutrons are doing one of 4 things at any given time in the reaction chamber:
Flying freely around.
...
- 461
-1
votes
1
answer
66
views
For Fermi's CP-1 experiments, why didn't they use much smaller slugs of natural uranium?
The Chicago Pile experiments used natural uranium slugs that were ~1.5 inches in diameter. The slugs were surrounded by graphite to slow down the naturally occurring neutrons to be able to affect ...
- 293
34
votes
4
answers
6k
views
Why is water a good neutron absorber?
I've seen this question asked multiple times, and the answer is never detailed. I initially assumed that either hydrogen or oxygen had relatively large neutron absorption cross sections, however that ...
- 449
1
vote
1
answer
69
views
Conversion of Reich-Moore resonance parameters to neutron cross section?
For the Single-Level Breit-Wigner (SLBW) formula, the peak resonant neutron cross section is related to the total width, $\Gamma = \Gamma_{(n)} + \Sigma_{r}\Gamma_{(r)}$, reported as GT in ENDF. For ...
-1
votes
2
answers
111
views
How hard is disabling nuke by making it go fizzle with neutron radiation?
Suppose we would turn on nuclear reactor without shielding next to missile silo. Would it be able to protect silo by making incoming warhead fizzle out at reasonable distance?
--
Looks like it is ...
- 629
0
votes
1
answer
153
views
How fast was the Uranium projectile going in the Little Boy bomb?
I realize that the reason the U-235 projectile rings in Little Boy were going at immense speeds was to prevent a predetonation, but how fast were they actually going? Is the speed directly related to ...
0
votes
0
answers
380
views
What exactly is energy self-shielding in nuclear physics?
I have recently been trying to understand self-shielding, both energy and spatial self-shielding. I am having a particularly hard time understanding energy self shielding. Thus far, everything I’ve ...
- 1
1
vote
3
answers
1k
views
How do nuclear fuel rods get "spent"? Why can't you just throw neutrons at them?
The idea of fuel rods being both "spent" and dangerously radioactive has always seemed to me to be self-contradictory. The typical explanation given is that the human body and environment ...
- 2,714
3
votes
1
answer
749
views
Why free neutrons are usually produced in a Nuclear Fission?
The production of neutrons is a feature of fission reaction. Usually 2-3 free neutrons are produced in the fission. Why is that so?
- 1,481
0
votes
1
answer
69
views
Are the presense of neutron reflecters the only difference between a hydrogen bomb and a neutron bomb? [closed]
From what I understand, a hydrogen bomb usually has neutron reflectors, like graphite, to increase the yield of the explosion. A neutron bomb does not have those reflectors. Are there any other ...
- 149
0
votes
2
answers
2k
views
How can a nuclear chain reaction start?
A nuclear chain reaction occurs when neutron amounts are multiplied by fission. A neutron triggers a
fission, which causes the fissioned atom to release multiple neutrons. If of those multiple ...
- 123
0
votes
2
answers
43
views
Relevancy between (Atomic weight and neutron energy loss) and selection of materials for reactors
As we know, the relationship between atomic weight and neutron energy loss can give the number of collision between a neutron and nucleus to slow down (average logarithmic energy decrement.)
I was ...
