Questions tagged [nuclear-engineering]
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29
questions
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1answer
90 views
Chernobyl - why didn't they power their own circulation system?
The test that led to the Chernobyl accident was to see if they could keep cooling water circulating long enough in the event of a power cut for the generators to kick in.
So, why didn't they just ...
1
vote
1answer
57 views
What are the design differences between a hydrogen bomb and a neutron bomb?
Are the presence of neutron reflectors the only difference between a hydrogen bomb and a neutron bomb?
Many sources go into the bombs' different effects but I couldn't find the differences in how they'...
0
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1answer
22 views
Relevancy of (neutron energy loss and atomic weight) and the material selection of fast and thermal nuclear reactor
From this https://www.nuclear-power.net/glossary/neutron-moderatoraverage-logarithmic-energy-decrement/, I have found that the relationship between atomic weight and neutron energy loss can give the ...
0
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1answer
34 views
Half-life Unit Notations
I was looking for some element's half-life, on the following website:
http://nucleardata.nuclear.lu.se/toi/listnuc.asp?sql=&A1=214&A2=214&Z=88
For 214,88-Ra, the half-life is shown to be: ...
0
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1answer
18 views
Where can I find a database of (n,n' gamma) and (n,gamma) reactions sorted by Isotope and Q value
I have some MCNP spectra with interesting gamma peaks. I can not for the life of me find a database that allows me to search for reactions by Q value or isotope, or both. I can't even find the Q value ...
2
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1answer
101 views
What is the *typical* quantity (in kg) of uranium-235 present at a given moment in a nuclear plant?
What is the typical quantity (in kg) of uranium-235 present at a given moment in a working nuclear plant?
How does this compare to the typical amount of uranium-235 in a typical nuclear bomb (...
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3answers
72 views
How is nuclear fuel dealt with?
Not sure if anyone would know this, but was discussing it with friends, and it seems like quite the puzzle. In short, how is nuclear fuel in reactors handled?
Logically, the nuclear fuel must be ...
2
votes
1answer
46 views
What are the key technical challenges to development of traveling wave reactors?
I recently learned about traveling wave reactors (TWRs) on the Netflix Bill Gates special, as an example of a cutting-edge technology Gates is funding which has the potential solve several ...
2
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2answers
78 views
How do nuclear power plants prevent fuel rods from depleting nonuniformaly?
Power output of nuclear reactors is controlled by control rods that sit in between the fuel rods:
These are pulled out to increase fission rates - and lowered to decrease them.
The control rods are ...
0
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0answers
67 views
Is my understanding of the Chernobyl explosions correct?
I have been reading technical reports and whatnot about Chernobyl for some time, and I'm feeling that they-or their wording-is not quite letting me understand it. For lack of a better way to present ...
0
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1answer
59 views
How does a nuclear powered rocket engine work?
Nuclear power always require some way of converting the energy from nuclear to electrical or mechanical to be useful. For example, in a nuclear power generation facility, this is done through heat/...
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1answer
336 views
Is the core of an RBMK reactor submersed in coolant?
I have looked at many diagrams of the Chernobyl reactor and am wondering where the coolant comes from that enters the control rod channels when the control rods are raised. All the diagrams show ...
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0answers
39 views
How to code this iterative scheme for solving 2-group diffusion equation?
I am trying to write a python code to solve the neutron diffusion equation to model neutron flux distribution in a one-dimensional two-group setting. The governing equations of the system are:
$$-...
2
votes
1answer
53 views
Which Gen IV reactor types use nuclear waste as fuel?
I have read the Wikipedia article on Generation IV nuclear reactors, but from that article it is not clear to me which of the main reactor types that use nuclear waste to fuel the process. As far as I ...
2
votes
2answers
83 views
Why aren't nuclear reactors designed to handle the loss of the heat sink?
I always wonder why nuclear power plants aren't designed to handle a loss of the heat sink. At the point at which hydrogen is being made from the water, can't you just remove the water and catch the ...
0
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3answers
71 views
How is the neutron capture cross-section increased in thermal breeder reactors?
The related Wikipedia article says:
A breeder reactor is a nuclear reactor that generates more fissile
material than it consumes. Breeder reactors achieve this because
their neutron economy is ...
1
vote
2answers
111 views
Critical mass in a molten salt reactor
In a conventional nuclear reactor the amount of neutrons 'flying around' is maintained with control rods and water is usually used as a moderator. From a certain point of view the control rods keep ...
4
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3answers
6k views
How did the RBMK control rod design cause an increase in reactivity when moved downwards?
I have been trying to understand a particular aspect of the Chernobyl accident - the role of the graphite displacers on the end of the control rods. The basic story is that the graphite displacers ...
2
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1answer
354 views
Was the explosion of the Chernobyl nuclear reactor a 'true' nuclear explosion?
Was the second - the big - explosion of the reactor core in the Chernobyl catastrophe a true nuclear explosion? There have been those who have said that it was ... but sayings to this effect do not ...
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1answer
122 views
Can fusion be used to synthesize precious metals? [closed]
According to https://en.wikipedia.org/wiki/Synthesis_of_precious_metals, precious metals can be synthsized using fission. I think that if we found a way to do it with fusion, it would be more ...
1
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0answers
26 views
Dose rate through shielding from Co-60 to verify Monte Carlo result?
I need to calculate the dose rate leaking from sealed Co-60 sources.
Let's say the activity of a source is 7 TBq. The source is tube shaped, 2 mm radius and 10 mm in height.
There is 5 cm of tungsten ...
0
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2answers
68 views
Would a large dome structure prevent widespread effects of nuclear plant explosions?
In both the Fukushima and Chernobyl incidents, widespread contamination would have been prevented had both facilities been enclosed within a larger structure. While existing plant designs call for ...
0
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1answer
75 views
Why didn't the Fukushima turbine supply electricity to the residual heat removal system? [closed]
Instead the pump relied on the diesel generators, why didn't it just use the residual heat to generate electricity?
P.s. The question is very specific to the residual heat generated after inserting ...
3
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2answers
54 views
Nuclear wastegate thermal dissipation systems?
How do shoreline nuclear facilities lower the temperature of wastewater generated by their cooling systems before it enters the ocean?
4
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2answers
157 views
Do ships powered by nuclear reactors use water for shielding?
On a different Stack, I encountered an answer that was making a comparison to nuclear powered naval ships. It was stated that the physical shielding being used was various kinds of metals. This seems.....
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2answers
113 views
When backup cooling fails in reactors without passive safety, what is the risk of radioactive contamination?
Most/all nuclear fission reactors require cooling. Due to radioactive decay heat, this is true even when the reactor is switched off. Hence, there are requirements for nuclear plants to have power ...
0
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1answer
1k views
How does a nuclear reactor initiate nuclear fission? [closed]
How do we start a nuclear chain reaction? For example, if we wanted to do it this weekend, what would we need, and what are the basic steps? I'm not looking for a text book response or highly detailed ...
6
votes
2answers
102 views
Summary of major outage management works needed in the 4th decade of a nuclear reactor?
I've noticed that quite a few commercial nuclear reactors have an extended outage (they close down for several months) some time late in their third decade, and the maintenance works during the ...
7
votes
2answers
374 views
How does thermonuclear warhead yield scale with size?
The Tsar Bomba packed a yield of 50 megatons into a package 2.1m in diameter by 8m long. Assuming that the lead tamper modification was not used (which boosts the yield of the Tsar Bomba design to ...
