Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [nuclear-engineering]

The study of radiation and radioactive materials and it's creation, safety, and applications.

0
votes
1answer
28 views

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 ...
2
votes
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 ...
0
votes
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 ...
0
votes
0answers
74 views

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 ...
0
votes
0answers
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 ...
6
votes
3answers
2k views

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 ...
0
votes
0answers
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 ...
1
vote
0answers
37 views

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 ...
0
votes
1answer
40 views

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 ...
3
votes
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 ...
0
votes
2answers
38 views

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 ...
0
votes
0answers
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 ...
2
votes
3answers
91 views

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, ...
-1
votes
1answer
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 ...
1
vote
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 ...
0
votes
0answers
96 views

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 ...
0
votes
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 ...
0
votes
0answers
24 views

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 ...
0
votes
0answers
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 ...
1
vote
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 ...
3
votes
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 ...
0
votes
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 ...
0
votes
0answers
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 ...
2
votes
2answers
83 views

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 ...
0
votes
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?
1
vote
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 ...
1
vote
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?
4
votes
2answers
84 views

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?
0
votes
1answer
37 views

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?
15
votes
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 ...
1
vote
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 ...
3
votes
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, ...
2
votes
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.
1
vote
0answers
86 views

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 ...
0
votes
1answer
69 views

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 ( ...
2
votes
2answers
87 views

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' ...
2
votes
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 ...
0
votes
0answers
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-...
1
vote
2answers
50 views

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 ...
-1
votes
1answer
30 views

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)
2
votes
1answer
100 views

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?
2
votes
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, ...
0
votes
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 ...
1
vote
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? ...
1
vote
0answers
94 views

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 ...
1
vote
3answers
62 views

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?
0
votes
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 ...
1
vote
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,...
0
votes
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 ...
0
votes
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. ...