Questions tagged [nuclear-engineering]
The study of radiation and radioactive materials and their creation, safety, and applications.
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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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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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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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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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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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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 ( ...
user86411
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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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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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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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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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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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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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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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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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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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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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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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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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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. ...
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How are cages in fusers protected against ion damage?
I have a simple question. Nuclear fusers (like the Farnsworth Hirsh design) use charged cages to accelerate deuterium ions to high enough energies to fuse and produce neutrons and energy. While these ...
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How can we make a nuclear weapon more effective in shielding us against asteroids?
I know that nuclear weapons do not produce the nuclear blast as it would at see level. But would the thermal blast produce any trust to push any asteroid away? If so, how could we improve the ...
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How is the radius of a nuclear disaster affected area calculated?
For example, take the Chernobyl disaster of 1986. The government evacuated a $30\,{\rm km}$ radius. I don't understand why $30\,{\rm km}$, I mean it's radiation, right? It can travel at speed of light....
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What happens to molecules when a neutron is captured?
What happens to a molecule during neutron capture? Does the process release enough energy to break the molecule bond? In fission this is obviously the case, since the compound nucleus forms and then ...
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Calculating the energy produced in watts in Alcator C-Mod
I calculated the energy in joules that a deuterium-tritium fusion reaction releases and found 2.81829046e-12J.
I then read on some MIT articles that the Alcator C-...
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How ready is the current fusion reaction technology for the mass production of electricity?
Could you give a clear summary statement about the maturity of the controlled fusion reaction technology and its readiness for the mass production of electricity? There are many articles on internet ...
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Why it took such a long time for an army of physicists to realize the atomic bomb, while in theory it seems pretty easy?
I think most of us know about the construction of the first atomic bomb at Los Alamos, with Robert Oppenheimer (who said he became "The destroyer of worlds", which goes to show he regretted his ...
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Nuclear Fusion: Why is spherical magnetic confinement not used instead of tokamaks in nuclear fusion?
In nuclear fusion, the goal is to create and sustain (usually with magnetic fields) a high-temperature and high-pressure environment enough to output more energy than put in.
Tokamaks (donut shape) ...
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How to excite high spin nuclear state from ground state?
For example, the ground state of a nuclei is $0^+$, and we can excite $1^-$ state with a circular polarized gamma photon, which has a spin angular momentum $1\hbar$. This satisfies the selection rule ...
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Why can't we harness the energy from neutron + protium = deuteron reaction? [closed]
The answer to this physics se question, established that 2.2Mev (Mega electron volts) of energy is emitted as a gamma ray photon when the hydrogen atom nucleus oka protium absorbs a slow moving free ...
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Could we create our own mini star?
If NASA were to work together with other space programs, could we accomplish the task of creating a mini star in the future. It wouldn't be huge, under a mile in diameter. We could make a core of ...
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Why all the orifices, protuberances, hinged/bolted panels, etc. on a stellarator?
My question was inspired by this one - in particular the image it has (also shown here):
Why does the external casing of the Stellarator (in particular, the Wendelstein 7-X shown in the above image) ...
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Neutron Creation Machines [closed]
My question is specific "what methods are there to generate free neutrons"? With a few aside queries and confirmations of undertanding
Now as I understand free protons are far easier to create than ...
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Is there any industrial scale nuclear transmutation currently in practice?
So I am aware that transmutation is used to reprocess radionuclides in nuclear waste to render them into shorter lived radioisotopes. But what about the potential for industrial scale nuclear alchemy ...
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What are the natural forces that slow the neutron down?
In a nuclear bomb, I've noticed that slow neutrons don't affect plutonium 239, if we're using this kind of atoms (plutonium 239), we need fast neutrons to make a sustainable chain reaction.
Also I've ...
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What is the theoretical efficiency of fusion?
What is the theoretical limit of the amount of energy that can be extracted from a fusion reaction? I am not talking about the practical efficiency of a reactor, but rather what fraction of the mass-...
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How to decide between sizes of particles for maximum light intensity for scintillation?
Are nanoparticles or microparticles or quantum dots better suited as scintillation materials as far as light yield intensity is concerned? I was unable to find literature that compares micro vs ...
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Shielding against 14 MeV instant neutron point source
In this paper (as found here), an alternate type of fusion bomb design is proposed. This design, however, emits a cone of 14 MeV neutrons upon explosion - only a cone because the neutrons are absorbed ...
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Use a neutron source as a spacecraft propulsion method
Is it viable (or even possible), to use a neutron source as a form of propulsion for a spacecraft? I imagine this drive would have similar trust/specific impulse characteristics as electric propulsion ...
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Out of all the medical imaging radionuclides, why is technetium-99m the most common?
There are medical tracers like Xe-133, I-131 etc.(what are some other ones?), but why is Tc-99m the most common (most suitable)?
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Which has better reflective properties? Aluminum oxide or Titanium dioxide?
I know TiO2 reflects better than Al2O3 but I can't understand why, in most radiation detection applications using scintillation, aluminum oxide is used as a reflective coating more than titanium ...
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How nuking the poles of Mars would create an atmosphere? [duplicate]
Elon Musk said one of the methods they are taking into consideration to create an atmosphere on Mars is to nuke its poles. How nuking the poles would create the atmosphere?
user169206
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Distinguishing an underground Hydrogen bomb test from a fission bomb explosion
A related question is Hydrogen bomb radiation output, but my question is based on the seismograph data (or any other data) possibly producing a distinctive pattern.
Is it possible to tell the ...
user167453
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Photomultiplier pulses only at first few channels?
I have an old Hamamatsu PMT, and I have a scintillator that can detect neutrons, gammas, alphas. But no matter what source I use, I'm only seeing counts at the first few channels (up to about the 15th ...
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Pulse shaping time related to number of counts?
I have a PMT (with a proton recoil neutron detector) hooked up to an amplifier, and when I increase the pulse shaping time from 0.5 microseconds to 2 microseconds, the number of counts recorded by the ...
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Is it plausible for water to be more irradiated than air 200 years after a nuclear war?
Assuming I am alive 200 years after a nuclear war, fought with today's nuclear weapons. Is it plausible that while I can be outside and breath the air unharmed, diving under or drinking water will ...
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What happens if a PMT (photmultiplier tube) is run below its operating voltage?
I have this Hamamatsu PMT that says its operating voltage is 1500 V. However, it has serious electronic/background noise at LLD=0 at that operating voltage. If I lower it down to about 1.02 KV, noise ...
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How to calculate scattering cross section from elastic, inelastic, and non-elastic cross section
I'm trying to find the scattering cross section of U-235 as outlined in Weston M. Stacy's reactor physics book.
I see ENDF gives me elastic, inelastic and 'non-elastic' scattering cross sections.
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