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Questions tagged [nuclear-engineering]

The study of radiation and radioactive materials and their creation, safety, and applications.

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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 ...
agaminon's user avatar
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Can you create fusion through scattering?

Could you scatter deuteron molecules (D-D) at high energies into some heavy metal target such that at the time of impact the bond in the deuteron molecule is compressed to such a degree that fusion is ...
EigenDragon16's user avatar
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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 ...
sp444cegirl's user avatar
1 vote
2 answers
62 views

Why are zirconium pressure tubes stored in waste containers when removed from nuclear plants?

Hi this is probably a bit of a silly question but I've been thinking a lot about the use of zirconium in nuclear plants. I know that zirconium has a very low neutron absorption cross section and that'...
sp444cegirl's user avatar
1 vote
1 answer
81 views

Is it theoretically possible to aim a neutrino's trajectory without using a massive celestal body to aim it?

Recently, when reading about atomic rockets, I noticed an entry about spin-aligning neutrons to make them shoot out of the rocket's nozzle instead of randomly flying around to wreck the rocket. ...
General_Ripper's user avatar
2 votes
2 answers
64 views

Beta decay and maximum beta energy in https://atom.kaeri.re.kr

According to: https://atom.kaeri.re.kr/cgi-bin/decay?Cs-137%20B-, in the beta- decay of Cs-137 to Ba-137, there are 2 likely scenarios: only one electron is emitted. an electron is emitted and the ...
Juan's user avatar
  • 23
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1 answer
132 views

Deflecting a lunar mass with consecutive nuclear explosions [closed]

I'm looking for help in determining the amount of deflection an object with a mass of roughly $7\times10^{22} \,\text{kg}$ (a lunar mass) needs from colliding with a planet. Let's stipulate that the ...
Victor Bergman's user avatar
2 votes
1 answer
61 views

Why is the compton continuum so uniform?

According to the Klein-Nishina model, a photon that undergoes compton scattering will scatter at different angles preferentially according to its energy, shown in the image below. Then, looking at ...
ijmert Ulens's user avatar
1 vote
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75 views

How much more energy is released by a nuclear bomb than is required to create it? (Or is it a net loss?) [closed]

It seems like it takes a pretty substantial amount of energy to make a nuclear bomb. If you’re building a U-235 device, you need to run a huge array of gas centrifuges. If you’re making a plutonium ...
templatetypedef's user avatar
0 votes
2 answers
71 views

Is a fission-fusion battery physically possible?

I'm not a physicist, so forgive me if this question is obvious, or if I'm detracting from the forum's goals (not sure if this is analogous to math exchange or math overflow). My understanding of ...
JMenezes's user avatar
  • 105
2 votes
1 answer
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Uncertainty in current mode operation of detector

I have come across an equation while reading Knoll's book $$ \frac{\sigma_I}{I_0}=\frac{\sqrt{n}}{n}=\frac{\sqrt{rT}}{n} $$ In the same I encountered another equation $ I_0 =rQ = r \frac{E}{W} q $ $$ \...
Anchal Kumar Sharma's user avatar
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44 views

Is the inertia of the inwards pressure of any difference in the implosion type nuclear bomb?

In a fissile nuclear bomb, such as the gadget in the trinity test, uses an explosion to create an inwards pressure to compress plutonium from a non-critical-state, into a super-critical-state. So you ...
nammerkage's user avatar
1 vote
1 answer
66 views

What limits the size of a nuclear power generator?

Nuclear microreactors like Westinghouse's eVinci are small enough to fit on a flatbed semi-truck, and NuScale Power's small modular reactor (SMR) is small, too; but are there smaller nuclear power ...
Geremia's user avatar
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2 votes
1 answer
38 views

Is there any formula for the micro cross section of an element?

It's a question about neutron absorption in the nucleon. When more than one isotope exists and given the mass ration or abundance, is there a formula for obtaining the total micro absorption cross-...
SungJin Park's user avatar
2 votes
2 answers
95 views

Why doesn't the water in a Light Water Reactor split to $\rm H_2$ and $\rm O_2$?

Intuitively I'd expect a nuclear reactor to produce gamma and neutron radiation powerful enough to knock hydrogen atoms/nuclei (or electrons) off $\rm H_2O$ molecules, some of which could recombine ...
Qwertie's user avatar
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30 views

What is "point of interest" and why isn't there a Zref for determining electron beam quality with TRS 398?

What is "point of interest" and why isn't there a Zref for determining electron beam quality with TRS 398? ((To what depth do you put the ion chamber when you do high energetic electron ...
medical physics's user avatar
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0 answers
53 views

Green's function for a Hirsch-Farnsworth fusor

I'm writing a proposal for building a Hirsch-Farnsworth fusor at my university using a vacuum chamber, deuterium, and high voltage power. A loop of wire inside the chamber is set at a negative voltage ...
Tyler Mark's user avatar
22 votes
4 answers
6k views

Why don’t nuclear reactors burn through most of their fuel before discarding it?

The question: Why don’t nuclear reactors use more of the fuel, eg, 50%, 80%, before discarding it? It looks like there is plenty of energy left, and uranium is expensive. Also, there would be an ...
11111's user avatar
  • 347
0 votes
2 answers
128 views

Is fuel pellets a cylinder shape to decrease the critical mass?

A cylinder, especially a thin rod is a terrible configuration to have a self sustaining nuclear chain reaction. Cylinder pellets are used in nuclear reactors. A sphere is a much better packed ...
nammerkage's user avatar
1 vote
2 answers
197 views

Elevated Geiger Counter Radiation Reading for Envelope?

TL;DR: I'd like someone to run an experiment to prove that it is possible to induce a static electric charge on a plastic bubble mailer envelope (such as through rubbing with a plastic grocery bag or ...
jun192022's user avatar
-4 votes
2 answers
102 views

why are nuclear fallout shelters really necessary when radiation fades with distance so quickly? [closed]

why are nuclear fallout shelters really necessary when radiation fades with distance so quickly? it diminishes with the inverse square law. I1xD1^2 = I2xD2^2. (Standard procedure is to measure ...
Fyodor's user avatar
  • 11
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0 answers
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Power from CNO Cycle Fusion

There are all sorts of projects trying to get power from fusion reactions. The best known and funded are the Tokamaks, big expensive crush Deuterium and Tritium (He3 sometimes) plasmas and spew ...
MongoTheGeek's user avatar
1 vote
0 answers
42 views

Why does the addition of flourine salts lower the melting point of thorium?

I recently read an article on Thorium reactors by John Suchocki (unfortunately, a link would only lead to a paywall). In it, he mentions that in the production of Thorium reactors, "The thorium ...
Robert Goddard-Wright's user avatar
0 votes
1 answer
47 views

$\rm NaI$ detector calibration with $\rm Cs$-137 and $\rm Co$-60 using Genie-2000 software [closed]

I have tried to calibrate the NaI detector with the NIM set, Cs-137, Co-60 radioactive sources and Genie 2000 software. I used Cs-137 first and corrected the channel energy then used the Co-60, only ...
DrrMickey's user avatar
0 votes
1 answer
125 views

What does a symmetrical explosion mean in the context of preventing accidental nuclear weapon trigger?

I just watched a video entitled This Is the Real Risk We Face with Nuclear Weapons. In the video, it referenced a "broken arrow" incident where a US B-52 was carrying a nuclear weapon met ...
dazzleworth's user avatar
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 ...
lcleary's user avatar
  • 28
0 votes
0 answers
34 views

Need Recommendations for Nuclear Reaction Modelling Software

Working on a project where I need to model nuclear reactions with different fuel pellet shapes. Does anyone have recommendations for software that's good for this? Any advice or experiences are also ...
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. ...
ConnieMnemonic's user avatar
1 vote
1 answer
61 views

Why lasers are used in inertial nuclear fusion?

Why in inertial fusion are used laser rays but not, for example, merely focused light? Is there a problem with precision of focusing or power density?
Nonexistent user's user avatar
-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 ...
Young Jun Lee's user avatar
-4 votes
2 answers
109 views

How many typical nuclear power plants does it take to power 1 billion typical cellphones per year? [closed]

Not asking for an exact answer clearly. Let us say that a cellphone user typically watch like 2 hours of video per day and it is say on an iPhone of your choice. How much power would be needed to ...
mjs's user avatar
  • 89
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0 answers
33 views

Kramer's Equation at max Energy for photons is giving Intensity = 0, how is this possibe?

IE = KZ(Em – E) where IE is the intensity of photons with energy E, Z is the atomic number of the target, Em is the maximum photon energy, and K is a constant. As pointed out earlier, the maximum ...
medical physics's user avatar
2 votes
3 answers
254 views

What would happen if the fuel rods in a nuclear reactor were completely depleted?

My understanding is that in commercial nuclear reactor operations, fuel rods are not used up to the point where they're fully depleted and unable to support fission, but are replaced while they still ...
mkay's user avatar
  • 129
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0 answers
47 views

Tritium Decay and He-3, $n$ reaction

I have two separate questions that I have simply not been able to find any answers to: With regard to Tritium decay to He-3, I'm a bit confused as to why Tritium is unstable based on its $n$ to $p$ ...
Chris's user avatar
  • 1
0 votes
0 answers
26 views

Can you theoretically form plutonium 238 form plutonium 239? And if so then how and what are its limitations?

Basically if we could convert plutonium 239 to 238 then we could create space fuel from nuclear waste but if it is possible then what are its limitations due to which this process is not generally in ...
Fun with Science's user avatar
0 votes
1 answer
72 views

Why does the mass deficit exists? [duplicate]

Everyone knows Albert Einstein's famous formula: $E = m * c^2$ In nuclear fission, we make use of it by converting mass into energy. But what is the mass that gets converted? Of course, when nuclei ...
dark_ursus's user avatar
0 votes
1 answer
317 views

How does a nuclear reactor start? [closed]

okay first I want to say I know there is a lot of video on YouTube that show a reactor starting but I was wounding like how it starts if anyone has like a diagram or something of the process of a ...
Hugo ADAMS's user avatar
13 votes
1 answer
1k views

Is it possible to make an all natural smoke detector from Brazil nuts?

After reading about Brazil nuts, I discovered they have very high levels of radiation due to trace amounts of Ra-226 and Ra-228 and their decay products. A kilogram of the nut, for instance, gives a ...
user148298's user avatar
0 votes
1 answer
133 views

Why isn't there Bremsstrahlung Radiation for Energy less than 20 keV for Tungsten?

https://www.researchgate.net/figure/Bremsstrahlung-and-characteristic-radiation-spectra-are-shown-for-a-tungsten-anode-with_fig4_8365056 Fast electrons produce X-rays in the anode of an X-ray tube ...
medical physics's user avatar
5 votes
2 answers
223 views

Why doesn’t proton emit in nuclear fission instead of neutron emission?

I was wondering in a nuclear fission, why does the neutron get emitted but not the proton? Is there any case where in a nuclear fission, proton emission happens?
Fisica Amante's user avatar
0 votes
0 answers
29 views

Why one curve is up and other one is below for the same or different compound nucleus and why the curve shape is like this?

the plot is potential vs deformation, I want to know why there is difference between two potential vs deformation curves for the same and different compound nucleus and why the shape is like that.
Avi agrawal's user avatar
4 votes
1 answer
80 views

How much Uranium would a country like Iran need to produce for supplying its Technetium needs?

This is not a question about politics, although the motivation is a political situation. Iran, which enriches Uranium to a level of $60\%$ $\rm{^{235}U}$, is claiming it has civilian uses for this ...
einpoklum's user avatar
  • 141
-1 votes
3 answers
214 views

Why it is not possible to reach the sun if we are able to create plasma? [closed]

if we are able to create plasma in isolated environment possessing temperature much more than temperature of sun then why are we not able to create something that can go to the sun?
Mohammad Sameer's user avatar
0 votes
2 answers
481 views

In nuclear weapons, why does levitating a pit improve compression?

Levitated pits were introduced after after solid pits. In this design the tamper is separated from the fissile with an airgap. From the Nuclear Weapon Archive: The original Fat Man pit design used a ...
Jane Bass's user avatar
2 votes
2 answers
418 views

What is the practical implication of positive void coefficients in certin types of nuclear reactors? [closed]

One difference between the Chernobyl disaster, on the one hand, and the Three Miles Island and the Fukushima disaster, on the other, is that Chernobyl's RBMK reactor design implied a positive void ...
erised's user avatar
  • 123
1 vote
1 answer
40 views

Are there any research mentioning the principle of tornados or maelstroms in plasma physics related to fusion?

There are many different ideas and concepts related to design of fusion reactors and handling plasma confinement, but what about designing one around the principles of a maelstrom or a tornado? Is ...
Andreas Zita's user avatar
8 votes
4 answers
2k views

Non-irradiative methods to create radioactive isotopes?

My understanding is that the primary methods with which one can create a radioactive isotope are 1) just waiting for the isotope you want (by means of nuclear decay), or 2) some kind of induced ...
DataScienceNovice's user avatar
0 votes
2 answers
155 views

How does the second stage of a fusion bomb create and maintain the needed pressure?

My understanding of the second stage of a thermonuclear bomb is as follows: X-rays from the first stage compress the "tamper", thereby igniting the fission sparkplug, and that the resulting ...
user56834's user avatar
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23 votes
15 answers
9k views

Why are nuclear fusion reactors difficult?

The first fission bomb was created in 1944, and the first fission reactor in 1951 (and actually productive one in 1954). This delay seems possible to explain by there being a larger amount of initial ...
user56834's user avatar
  • 1,772
1 vote
1 answer
128 views

Is there a minimum mass required to create an atomic bomb? [closed]

I have heard that there is a minimum mass of fissile material required to produce an explosion. If so why would this be? Is it true North Korea found a way to overcome this?
Derek Seabrooke's user avatar

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