Questions tagged [nuclear-engineering]
The study of radiation and radioactive materials and it's creation, safety, and applications.
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Course on Nuclear/Particle physics [on hold]
I would like to know if there were online resources about the following topics:
Nuclear Physics
Nuclear Engineering
Particle Physics
to go a bit deeper in my reading. I am asking for a free-to-learn ...
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2answers
97 views
If a country wants to build nuclear weapons, why would they enrich uranium instead of turning uranium to plutonium? [on hold]
Firstly, I have to say that I'm bad at physics. So, please correct me if I say something wrong.
I have read that natural uranium contains 99.28% of U-238 and only 0.72% of U-235 which is the ...
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1answer
42 views
Help in identifying an instrument used in nuclear physics
In American-British drama miniseries Chernobyl, in 2nd episode, a scientist took some dust from the outer surface of a window and placed it in an instrument that told her what radioactive isotope was ...
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Could the pressure from the steam explosion in Chernobyl (if it occured) have made the corium critical?
As other questions (eg How large would the steam explosion at Chernobyl have been?) regarding that episode 2 of the Chernobyl series, the megaton estimate of the steam explosion looked very improbable ...
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181 views
Risk of megaton steam explosion from Chernobyl? [duplicate]
In the new Chernobyl TV series (https://en.wikipedia.org/wiki/Chernobyl_(miniseries)), in episode 2, there's a reference to the risk of a steam explosion from the molten reactor core entering a water ...
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How large would the steam explosion at Chernobyl have been?
So the second episode of the HBO series began to cover the risk of a steam explosion that led to them sending three divers into the water below the reactor to drain the tanks.
This occurred after the ...
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63 views
Control Rods Chernobyl
I was reading the minimum of control rods used are meant to be $30$. But Just before the explosion at Chernobyl, only $8-6$ were in use so my question is: Why would reducing the number of control rods ...
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Could a long wire of uranium control nuclear reactions?
If you fashioned a very thin wire of uranium, perhaps coated in Lead, then started a nuclear chain reaction at one end, could you create a sustainable safe nuclear power?
Since the nuclear reaction ...
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1answer
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Nuclear Propulsion
I am watching a video on nuclear rocket engines, specifically the Nerva engine. It has a propulsion efficiency of 750-800 Isp versus chemical rockets which are only 350-400 Isp. The follow on NRX ...
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1answer
119 views
Is making nuclear bomb using natural uranium possible?
I know that the critical size of natural uranium metal with graphite moderator is about 27 tons "oak ridge graphite reactor". for comparison highly enriched uranium have only 17 kg critical size with ...
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2answers
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Fission inside nuclear reactor
I have studied about nuclear reactors and also know their functionality.But some how i couldn't get answers for some my questions.
1) During fission reaction enormous amount of heat is produced and ...
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65 views
Why did the Lockheed Martin compact fusion reactor failed? [duplicate]
What made the compact fusion reactor to not be compact. What assumptions did lokheed made in its simulation that showed that it could work. Can we do anything that could make it work or it is ...
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3answers
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Is it possible to trigger a nuclear reaction with physical force?
In Mission Impossible Fallout, they're dealing with 3 plutonium cores. If one of those cores was thrown against a wall by Ethan Hunt, could it start a chain reaction and explode? For that matter, ...
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54 views
Why the National Ignition Facility try to use 192 laser beams to trigger ignition without heat capsule?
In the discussion of the question "Nuclear Fusion with extremely high pressure and low temperature", the conclusion is only ultrahigh pressure cannot trigger fusion.
But why does NIF try to use 192 ...
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1answer
56 views
is possible to create a nuclear fusion using simple electric arc discharge?
If we have a simple discharge tube filled by deuterium gas or even heavy water, and put tungsten electrodes close to each other to create a huge electric field, then using a megavolt generator to ...
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Discussion about a new nuclear fusion design [duplicate]
Let me clarify here, this is not cold fusion. D&T gas will be compressed very rapidly and its temperature will increase very fast. So, I don't think this is a duplicate question.
I have a new ...
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1answer
44 views
How does the shape of a radioactive material effect its critical mass?
If critical mass is defined by the amount of fissile material required to sustain nuclear fission. Assuming a subcritical mass object, and knowing radioactive materials can merely by chance break ...
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Proton-Proton, CNO, or white dwarf matter fusion reactor: Is it vaguely possible?
I understand that all efforts at present to make fusion work as an energy source have used light nuclei other than protons due to the fact that the cross section of the proton-proton reaction is just ...
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41 views
How does the shape of radioactive material effect its critical mass?
If critical mass is defined by the amount of fissile material required to sustain nuclear fission. Assuming a subcritical mass object, and knowing radioactive materials can merely by chance break ...
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2answers
56 views
What is the time for sufficient decay of plutonium to render an implosion type fission bomb ineffective
Plutonium decays leaving helium. In a mass of metallic plutonium, some of the metal will decay resulting in helium. This makes the plutonium spongy after time.
Presumably this sponginess would ...
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4answers
101 views
Electronically controlled fusion reactor
It seems that currently, only two types of fusion reactor styles are being used for large scale testing: the Stellarator and the Tokamak. Both of these and a whole bunch of other designs have been ...
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1answer
64 views
Determination of Dead time of a Geiger Muller counter using the two source method
While determining the dead time of a GM counter using the two source method, why do we ensure that only two sources are placed in the counter at all times i.e. while determining the counts when both ...
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49 views
Heavy water neutron slowing equation
How can I find some equations about neutron slowing effects of heavy water? how much heavy water is required to slow down a given percentage of neutrons to a required degree(For example how can I keep ...
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2answers
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How do we contain nuclear fusion?
I understand that here on earth we create fusion at temperatures that are much hotter then our sun. What I want to know is how we contain those high temperatures safely. Also if any one can give an ...
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1answer
35 views
Heating effect of fast neutrons in Fast Breeder Reactors
Do fast neutrons play effective(meaningful) role in heating up the water in Fast Breeder Reactors? If so, how much do they?
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0answers
80 views
Why is Neon not used as a coolant for gas cooled nuclear reactors?
What is the reason that Neon is not considered as good coolant for gas cooled reactors? I haven't found any research nor experiment with Neon in this field. As I checked out Neon has small neutron ...
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1answer
95 views
Introduction to nuclear physics
I want to self-study nuclear physics in order to understand nuclear reactors and nuclear weapons, what books can you recommend?
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How is fusion reactor fuel initially accelerated?
If, in a nuclear fusion tokamak reactor, you start with neutral fuels, how do you accelerate the atoms fast enough to start the reactor?
Or do all of the particles have to ionized to begin with?
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Interpertation of Motron Number
The Reynolds number is interpreted as the ratio of inertial to viscous forces in a flow.
Are there similar interpertations for The Motron Number?
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3answers
3k views
Why do some gases transfer radioactivity and some don't?
I have recently read that helium is going to be used as coolant in Generation IV nuclear reactors, because
Helium is radiologically inert (i.e., it does not easily participate in nuclear processes ...
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1answer
51 views
What are the issues in highly enriched nuclear reactors?
The kinds of reactors used in submarines and rockets, are known to have highly enriched uranium ~80% and CO2 as the moderator in subs, and carbon(graphite) I guess in rockets. What are the extra ...
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2answers
141 views
Why do we not use cold neutrons in nuclear reactors?
Typical nuclear reactors use neutrons in the $10^{-2}$ eV range (thermal neutrons) which corresponds to a fission cross section of a few hundred barns. What stops us from using a super-cold moderator, ...
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1answer
35 views
Which elements or isotopes can be analyzed by Neutron activation analysis (NAA)?
Some sources name only a handful, but that might refer to the use of optical film. Others state more than 70. I would like to know which elemets or isotopes can be detectet/imaged by NAA.
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What determines direction of plasma current in tokamaks?
Plasma current is used to ohmically heat fusion plasmas and provide stabilization of grad-B drift in tokamaks as the resulting poloidal motion of the charged particles results in the particles ...
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1answer
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Does plutonium need to be squeezed to produce an uncontrolled chain reaction?
I guess what I am asking is if in theory you could start with a certain amount of plutonium would it explode with out being squeezed together as is done in an atomic bomb ?
Normally what happens ( ...
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2answers
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How is energy actually extracted from fission?
Every source I can find right now just says something like 'energy/ heat is released by nuclear fission' but I can't find a description of the specific mechanism.
I know that the energy 'conversion' ...
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2answers
770 views
Why is specific nuclear activity (Bq/kg) not considering the surface area (cm^2)?
I have some basic questions regarding nuclear radiation:
How come the specific activity (Bq/kg) only depends on the mass number and halftime of the emitter?
Therefore, the emitted ions (let's say ...
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53 views
Optimal Deuterium-Deuterium fusion pressure equation?
I am building a Hirsch-Farnsworth Fusor (a simple D-D fusion reactor) and was wondering if there is an equation or algorithm that could be used to calculate the optimal pressure for deuterium-...
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2answers
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Observations of a mushroom cloud
In this video of a nuclear bomb detonation/mushroom cloud, a few peculiarities arise and I simply had a couple questions pertaining to observations in the animation:
Following the detonation, the ...
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1answer
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What is realistic minimum possible size, weight and power output of an atomic battery for 100kWh? [closed]
AFAIK atomic batteries could become a single unit nuclear reactor, but what it is smallest feasible configuration by our current knowledge? (even at conceptual design level)
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1answer
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Nuclear fusion difficulties
What is it that make nuclear fusion so difficult at low temperatures? There is plasma existing at low temperatures, so what does it make for fusion to be so difficult to reach at ambient temperatures?
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4answers
125 views
Nuclear Physics Modeling Software
I have a nuclear reactor design I would like to model. I would like to show the individual atoms and how they interact with each other in the reactor (specifically, I would like to model decay modes, ...
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1answer
59 views
Control of Nuclear Fission
What is it precisely which prevents current technology in nuclear fission from controlling the size of fission products; in other words, why is it not feasible, presuming that such an approach would ...
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1answer
94 views
Can radioactive decay particles be modeled as plasma?
Since plasma is simply ionized gas (ie. charged particles), with the exception of neutron ejection (no charge) and gamma radiation (photons), can the natural decays of an isotope be modeled as plasma?
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What is the shelf-life of a gravity-powered uranium bomb?
Inspired by this Worldbuilding question about making a booby-trap with a very long shelf life. The idea is to suspend one lump of fissile material say $3/4$ of a critical mass above another of the ...
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3answers
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Are the magnets in tokamaks variable in strength?
For example, if the plasma inside is beginning to terminate and collide with the walls of the confinement vessel, can the magnets account for this and realign the plasma?
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1answer
569 views
How many inches of lead would it take to stop the gamma rays equal to 8 inches of concrete ?
I have searched high and mighty on google and it is hard to find a comparison chart of different materials and their effectiveness to stop radiation from fallout. I am assuming the fallout source is ...
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0answers
215 views
What's the critical mass of elemental natural uranium? [closed]
What's the critical mass of elemental (ie metallic), natural (ie unenriched) uranium? If this isn't possible at standard temperature and pressure, how could they be changed to make a critical mass? Eg,...
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2answers
162 views
What would happen if you detonated a nuclear bomb inside a tank of liquid hydrogen?
Say you had a large bomb - take the 50 megaton Tsar Bomba. You then proceed to place it in the center of a spherical tank containing liquid hydrogen, and then detonate it. Could you start a fusion ...
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3answers
217 views
Nuclear reactor in a cruise missile. How?
So it is declared, that there are cruise missiles with nuclear reactors on board. As I understand, when it's working, the neutrons keep flying from off the fuel. Neutrons give induced radioactivity. ...
