Questions tagged [nuclear-engineering]
The study of radiation and radioactive materials and it's creation, safety, and applications.
322
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How can I measure air velocity in a pipe, exceeding 500 MPH?
Some details: I am designing a convergent divergent nozzle to accelerate exhaust gas in a pipe to supersonic speeds. I have the math figured out. However, once my prototype is complete, I am ...
66
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5answers
12k views
Why isn’t CERN afraid of a fusion reaction in the LHC?
Given that they can reach terrifying energies and temperatures, why isn’t fusion of protons a concern? After all, they start with a plasma and ram protons into each other.
At some point the strong ...
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2answers
59 views
Does a fusion reactor have a cool-down period or can it operate continuously
Can a fusion reactor like ITER maintain it's fusion reaction and generate net output electrical power continuously; so long long as fuel is supplied, or does the reactor need to be shut down ...
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1answer
35 views
Solution of diffusion equation for 2 infinite slabs reactor
I have exercise where I have to calculate flux for reactor with 2 same infinite slabs of multiplying medium in vacuum. I have to calculate flux inside slabs and in the slot between them. I am ...
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0answers
14 views
How to determine conversion factor?
Let say someone developed a SiC detector. How does the conversion factor of the said detector be determined? It will be easy if we bought it because we just have to look into the datasheet but there ...
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1answer
29 views
Where does the negative electrode come from in an HB11 fusion reactor?
I'm an electrical engineer. Throughout my education, I was taught that current always has a return path. This understanding applies to everything.
Batteries use an electrolyte to strip electrons ...
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0answers
19 views
Small nuclear reactor safety characteristics - meltdown radii
So most nuclear plants are large in scale, producing ~1000 megawatts. I've learned about the rating systems for meltdown management, which involve site radius and wind direction to estimate dust ...
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0answers
14 views
Impurity percentage in LaBr3:Ce(5%)
I know the answer should be there somewhere, but at present, I am not able to find that. LaBr3:Ce(5%) scintillator is used nowadays extensively in both nuclear physics experiments and its applications....
0
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1answer
47 views
Why do old nuclear reactors leak radiation in the coolant? [closed]
I started working back what causes nuclear power plants to become unprofitable and came across the news that Exelon Energy had to get Illinois to subsidize their Quad Cities power plant to avoid ...
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0answers
37 views
Difference between Fuchs-Hansen and Fuchs-Nordheim model of reactor excursion?
I was using both models to fit experimental data of a reactivity insertion (more specifically, a power vs. time plot). Both models produce almost the same fit, with slight difference in peak power. ...
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0answers
59 views
Nuclear reactor physics book recommendations?
I'm trying to find a good book to self-study nuclear reactor physics and design. I have a background in theoretical physics and mathematics (both MSc) but close to no knowledge about engineering. I'm ...
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1answer
89 views
Why is humanity investing so little on fusion research? [closed]
Optimists expect fusion industry to be a reality in 2080 to 2100. Fusion means clean and unlimited amount of energy, it is the fuel of the universe. Fusion will solve most of our time problems ...
2
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2answers
99 views
How was the critical mass calculated for Little Boy?
Little Boy was detonated in 1945, 6 years after nuclear chain reactions began to be experimentally proven and Leo Szilard and Albert Einstein warned Roosevelt of the dangers of Germany developing ...
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29 views
Identify the origin of each term in the semi emperical mass formula?
I was hoping someone could explain each term in the semi emperical mass formula in simple english because i don't understand it. Any help will be appreciated thank you.
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0answers
14 views
Is there a working way of accelerating nuclear decay and reducing half life of a nucleus? [duplicate]
Here's a thought for the future cleanup of the environment: find a way to reduce/increase the half life of an element or to accelerate its nuclear decay. Just think, on what factors does the half life ...
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0answers
24 views
Can small amounts of neutron star matter or similar neutron-degenerate matter be (briefly) produced by radiation implosion or similar methods?
Today, a variety of methods are used to implode pellets of fusion fuel in order to perform inertial-confinement fusion. The pellets explode apart in microseconds whether or not fusion actually happens,...
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2answers
74 views
How is Uranium-235 stored to avoid accidental critical mass?
How is Uranium-235 stored to avoid it going critical?
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1answer
22 views
Exposure rate equation variables
I recently saw this equation for the exposure rate in the absence of shielding but couldn't quite find what "A" means in this context. Would anyone happen to know what the "A" variable is? Thanks.
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2answers
94 views
What is the largest obstacle in practical helium-3 fusion? [closed]
I've been busy looking into clean, sustainable energy solutions (for a project)
I ran into He-He fusion of the isotope He-3, and most of it looks more beneficial than the traditional D-T fusion due ...
6
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2answers
97 views
How much more radioactive is waste produced by a nuclear power plant than the initially mined material
Often people say that the radioactive material we use in nuclear plants just comes from the ground so we can just put the waste back in the ground and there's no change. This isn't fully true since ...
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1answer
73 views
Hydrogen bomb without fission stage
The majority of existing nuclear warheads are Thermonuclear devices implementing the Teller--Ulam design. It includes a first stage of "traditional" nuclear fission explosive (Uranium and/or Plutonium)...
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3answers
68 views
In the fuel of atomic bombs when does neutron fission activity begin?
Do scientists first initiate neutron activity within the subcritical masses of fuel in the lab, or are the masses already undergoing some kind of minor neutron detachment naturally, or finally, is ...
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0answers
31 views
Why is radioactive activity an important criteria for stating the level of danger of a radioactive waste ? Why not using energy of decay particles?
The classification of radioactive waste considers two criteria for a given material : its "period" T1/2 and its activity.
I don't understand why the activity (nb of decays per unit of time) is an ...
2
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1answer
119 views
Does humankind know technique to transform uranium 238 to uranium 235, for nuclear plants?
Does humankind know technique to transform uranium 238 to uranium 235 ?
Is it using it for obtaining uranium 235 for nuclear plants ?
Or is it selecting uranium 235 from uranium ? Why not transform ...
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0answers
53 views
Chernobyl catastrophy
Reducing the power produces xenon that lowers the speed of nuclear reactions even more.Did the increasing of power by expelling the control rods trying to force the xenon to undergo fission had ...
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0answers
24 views
Bethe-Weiszäcker for Q value of a reaction
As a part of a university project I was trying to calculate the Q value of the nuclear reaction Mg26(Li7,B8)Ne25 with the formula Q=BEf-BEi, where BE is the sum of the binding energies of the products ...
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17 views
Calculating expected gamma attenuation without a specific energy level
I am trying to calculate 2 things for a science experiment involving radiation and shielding using a geiger counter.
A) whether the reduction in counts per minute through a measured thickness of ...
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1answer
32 views
SFR Breeders on Small Mars Moon feasibility [closed]
Need help with a topic for a sci-fi book. Basic premise is 200yr in future, mining facility on small Mars moon of Phobos. Power source we would like is an SFR breeder as we think this would be cost ...
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2answers
66 views
What if nuclear chain reactions were not possible
Nuclear fission chain reactions occur when a nucleus breaks apart, producing at least one neutron, which then causes nearby nuclei to fission, a multiplying process when the average number of produced ...
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0answers
32 views
Modeling the cooling rate of a nuclear fireball in space
I am interested in modelling the cooling and luminosity curves for a nuclear detonation in space (after the release of the prompt radiation). How do I get the timing of the second hump right?
I tried ...
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1answer
58 views
Assessing the Viability of Nuclear Initiator Device for Energy [closed]
Disclaimer: This question is purely theoretical and is merely intended to serve as a means of creating a model for a nuclear detonator-based power source. No association to weapons is implied.
...
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1answer
42 views
Which operations of a nuclear reactor are controlled by humans? [closed]
I understand in a general term how a reactor works, but I was wondering whether they are highly automated or not. Such as do humans control thing such as fuel and coolant flow rates?
2
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1answer
163 views
Was Chernobyl Explosion a Small Nuclear Detonation?
The Chernobyl reactor was designed to produce a maximum of 3.2 megawatts of power. It is now estimated to have produced 3.2 gigawatts of power in the final second of its life.
The original ...
2
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1answer
128 views
How can I find a theoretical maximum amount of radioactively polluted water which could be created by a single nuclear reactor?
This question has a lot of tolerance.
The current context is that I'm writing a story which involves a group of terrorists who are using the threat of radioactive water pollution to deter ...
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0answers
54 views
Inexpensive nuclear reaction simulation tools
I am interested in seeing if there are any simulation software programs for less than $50 that may be used to simulate how neutrons (energies between thermal and 15 MeV) interact with certain nuclei ...
0
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1answer
46 views
Q Value for 64-Zn(n,2n)63-Zn [closed]
I've been looking for the Q-value for this reaction for quite sometime now but haven't had any luck with it.
What is the Q-value for the equation and how much energy would each of the neutrons ...
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0answers
37 views
Significance of “MT=” in nuclear science cross sections
I recently came across a measurement on jaea.go.jp/ (a site that publishes nuclear cross section tables). The cross section table had a unit known as "MT" for boron and other elements. I was curious ...
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1answer
55 views
Units of radiation dose
I have been reading a few papers on radiation therapy and have come to something I do not understand. In some of the papers they express the dose rate in the following units
$$\frac{MeV}{g\space Bq\...
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1answer
46 views
Why is the secondary inlet temperature in a Pressurized Water Reactor (PWR) so high?
According to this link (along with many other PWR papers), the inlet temperature of the secondary into the steam generator is around 450-500K, with a pressure of 5-8MPA. How does the temperature of ...
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1answer
76 views
Producing Uranium 235, not just separating it from 238
Uranium enrichment seems more like a complex filtering process where we separate the precious U-235 from from U-238. Is there a way to actually turn U-238 into U-235?
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2answers
60 views
Nuclear-powered Ramjet + criticality
I came across this Wikipedia entry about Project Pluto; a nuclear-powered ramjet that the U.S. was developing back in the day.
https://en.wikipedia.org/wiki/Project_Pluto
This missile would have ...
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2answers
72 views
Could you use the detonation of a Hydrogen bomb or atomic bomb to start a nuclear fusion reactor [closed]
Would this lead to a reactor that produced more energy than you put in?
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2answers
3k views
*Why* were the Chernobyl control rods tipped with graphite?
I understand the graphite tips of the boron control rods displaced water (a moderator) which lead to an increased reaction rate, rise in temperature and steam pressure etc.
Question: why were the ...
-1
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1answer
61 views
Increase the Inverse Beta Decay Cross Section for Ti-48
Is there a theoretical way to increase the cross section of inverse beta decay for Ti-48? This would be any method for increasing the likelyhood that Ti-48 absorbs an anti neutrino and creates Ca-48 ...
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0answers
27 views
MCNP Summary Table
MCNP6 Version 1 produces a summary table of the results. Much of this table looks very useful, but I am not sure I understand the details. Here is an example.
I'd be grateful for any hints about ...
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0answers
21 views
Calculating leak rates in a pressurized system
I am struggling to come up with an equation which would calculate pressure changes in a system with a pressurizer. The system is 12,710 ft^3, with a pressurizer volume of 1800 ft^3. The pressurizer ...
0
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0answers
58 views
Threshold energy of Ti-48 inverse beta decay
Goal: Use anti neutrinos to convert Ti-48 to Ca-48 using inverse beta decay (IBD). The resulting Ca-48 should have the same half-life as natural Ca-48.
Question: What is the threshold energy for the ...
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2answers
87 views
High Flux Antineutrino Sources
I was curious if there were any anti neutrino sources with a similar flux to a nuclear reactor. My current purpose does not allow for a nuclear reactor, however, any flux source with a similar flux ...
7
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1answer
147 views
Origin of Ba-133 contamination
On a stainless steel part that was removed from a spent fuel pool of a pressurized water reactor, we found (among the usual contamination with activated corrosion products, fission products, and ...
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1answer
45 views
Linear Reactivity Model
The Linear Reactivity Model seems to be a model for the consumption of the nuclear fuel management.It is a powerful tool to estimate the main performances in function It is a very simple way to choose ...
