Questions tagged [nuclear-engineering]

The study of radiation and radioactive materials and their creation, safety, and applications.

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33 votes
4 answers
5k views

Why is water a good neutron absorber?

I've seen this question asked multiple times, and the answer is never detailed. I initially assumed that either hydrogen or oxygen had relatively large neutron absorption cross sections, however that ...
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2 answers
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Are there any calculations that "backup" magnetized inertial fusion by steam pistons?

Piston driven MTF can generate fusion. General Fusion has released data on the plasma confinement that they do in their machines, so there is no doubt to the feasibility of the approach. Nonetheless, ...
1 vote
1 answer
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The Orion Project --- do the predicted speeds violate the Tsiolkovsky Equation?

I understand that a conventional rocket may move faster than its thrust but IIRC the equation developed in the 19th century the speed is limited to 4/3 the thrust speed. Now, I understand that the ...
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1 vote
2 answers
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NIF Ignition Achievement

Although the National Ignition Facility achieving positive energy output is hailed as an achievement in fusion energy, I am curious whether their configuration could ever be adapted to produce ...
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1 vote
0 answers
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Length of light burst of concentrated emission from hydrogen bomb in outer space

Imagine a large hydrogen bomb in outer space. Behind it is a huge mylar parabolic mirror. (Aimed anywhere, for instance at a star system we want to communicate with.) The bomb is placed in the focus ...
0 votes
2 answers
90 views

Why can't high-level nuclear waste be disposed of by bombarding troublesome isotopes with neutrons, protons and gamma rays (photodisintegration)?

Why can't isotopes with long half-lives be radiated with free protons, neutron radiation and gamma rays (photodisintegration) in order to transmutate those isotopes into something either stable (or ...
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0 votes
1 answer
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Would a fusion reactor using Helium-3 get some of its energy from fusing it with free neutrons?

I know that He-3-based fusion is supposed to be aneutronic, but aren't there still some free neutrons? Would this make a noticeable difference in heat/energy produced? Also, couldn't helium-3 be ...
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0 votes
1 answer
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Heat transfer in fission nuclear reactors [closed]

In a nuclear fission reactor, the fissile material and the water that is heated up are separated by a physical barrier. That barrier would allow for the transfer of heat via radiation (of photons) and ...
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4 votes
2 answers
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What enabled ignition at the NIF?

The National Ignition Facility achieved breakeven on December 5th, obtaining more than 3 MJ from an input of 2.05 MJ. What have they been doing differently, starting this summer? Laser shots this year ...
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1 answer
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How to calculate radioactivity concentration of components in reactor?

I understand the reactor parts will become radioactivity because there are neutron flux in reactor. How should we calculate the reactivity of reactor parts? For example lets say there is a reactor ...
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-1 votes
1 answer
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Why don't we use nuclear fission to generate the necessary temperatures needed for nuclear fusion? [closed]

We can control the energy generated by nuclear fission by limiting the amount of neutrons release. Those extremely high temperatures will be more than sufficient to incite a nuclear fusion process.
1 vote
0 answers
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Conversion of Reich-Moore resonance parameters to neutron cross section?

For the Single-Level Breit-Wigner (SLBW) formula, the peak resonant neutron cross section is related to the total width, $\Gamma = \Gamma_{(n)} + \Sigma_{r}\Gamma_{(r)}$, reported as GT in ENDF. For ...
4 votes
2 answers
498 views

Reflection of Gamma Rays

I have an experiment with a radioactive Cs$^{137}$ source which beta decays to Ba$^{137}$. Some of the barium are in an excited nuclear state which decay to the ground state and emit a $662$ keV $\...
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8 votes
1 answer
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In the event of a disaster at any nuclear power plant other than Chernobyl, would we be dealing with the emission of radioactive iodine isotopes?

Would any nuclear catastrophe emit radioactive iodine isotopes? Do some power plants have different cores that would emit other radioactive isotopes but not iodine isotopes?
0 votes
2 answers
47 views

Does a fission bomb end up causing fusion of ambient elements or remain parts of the bomb itself?

Given the heat and pressure, is there some reason why a relatively small amount of atoms of various elements in the atmosphere or soil or in the metals used to make to bomb itself do not fuse? I do ...
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1 vote
5 answers
123 views

Is the pressure of water in the ocean enough to cause a nuclear bomb to go critical?

I understand that most nuclear weapons work on the basis of a standard explosive forcing the 2 fissionable parts together causing the nuclear reaction. If a nuclear warhead or bomb fell into the ...
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1 vote
1 answer
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"Lowest yield" atomic weapon possible [closed]

I would ask that folks be tolerant of my ignorance in this field. When discussing tactical and strategic nuclear weapon yield I wonder about what is the lowest possible fission weapon is possible. A &...
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2 votes
1 answer
237 views

Does the nuclear reactor remain radioactive after fuel assemble have been removed? [closed]

Uranium pellets are packed as fuel rods, using Zirconium Alloy Cladding. In a steady operational state rector core will be full of radiation. But suppose that all fuel rods are withdrawn will the ...
-1 votes
2 answers
46 views

How hard is disabling nuke by making it go fizzle with neutron radiation?

Suppose we would turn on nuclear reactor without shielding next to missile silo. Would it be able to protect silo by making incoming warhead fizzle out at reasonable distance? -- Looks like it is ...
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0 votes
0 answers
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Would isotope separation of zirconium improve the effectiveness of nuclear fuel?

Zirconium is widely used as cladding for nuclear fuel for two reasons, it is a good refractory material and it has a low neutron-capture cross section. I was wondering if, at least theoretically, ...
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-1 votes
1 answer
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How would nuclear fuel enriched with oxygen 18 behave in a reactor?

A lot of nuclear reactors use fuel based on uranium oxides (mostly dioxide). I know that oxygen 18 has a slightly smaller neutron-capture cross section than the other stable isotopes. I wondered ...
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-1 votes
1 answer
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Would it be possible to make a Gun type nuclear bomb using Isotopically pure Plutonium-239 [closed]

I know that it's normally not possible to make a gun type nucelar bomb using plutonium due to high rates of spontaneous fission. But that's primarily due to the plutonium 240. If you instead used ONLY ...
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1 vote
1 answer
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A nuclear fusion generating cart

In an unrealistic thought experiment, suppose I had a $100$ meter track with a cart ontop that had a "pocket" on the front of the cart. Suppose further that this track and cart were in a ...
2 votes
1 answer
73 views

Can breeder reactors be used to produce tritium?

I'm just a telecommunications engineer, so my strengths in physics are basically electrodynamics, but recently I have been reading a bit about nuclear physics and nuclear fusion for power production. ...
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0 votes
1 answer
32 views

Find the maximum possible energy for a beta-particle decay-chain [closed]

So I have this problem where I'm supposed to find the maximum possible energy for a $\beta$-particle in the following decay-chain: The first decay: $$^{90}Sr\rightarrow ^{90}Y + \beta^- + \bar{v}_e$$ ...
0 votes
1 answer
55 views

How to estimate the power produced by this small U-238 check source?

I got this sealed check source to test my pancake detector (tube model is LND 7317). But I'm wondering if it's worth trying to collect some of the tiny amount of power it's producing as a fun home ...
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8 votes
1 answer
2k views

Why isn't Neptunium used in nuclear power plants?

The elements on either side of neptunium (uranium and plutonium) are, of course, widely used in both power plants and nuclear weapons. So why isn't the highly fissile nuclide Np-237 used in reactors? ...
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0 votes
1 answer
83 views

How fast was the Uranium projectile going in the Little Boy bomb?

I realize that the reason the U-235 projectile rings in Little Boy were going at immense speeds was to prevent a predetonation, but how fast were they actually going? Is the speed directly related to ...
20 votes
7 answers
5k views

Why is it impossible for the reactor of the nuclear power plant to turn into an explosive nuclear bomb?

Is it true that both work on the same principle of operation: the interactive fission chain reaction 235U/239Pu and the bombardment of uranium-235 by fast neutrons produce a fission chain reaction ...
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0 votes
1 answer
34 views

How many more neutrons are flying around in a fast reactor vs thermal reactor?

I'm a bit confused on the number of neutrons in a fast reactor. So the average neutron in a thermal reactor is 0.05ev and 700kev in a fast reactor. This means fast reactor neutrons are travelling sqrt(...
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0 answers
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Use of Anger logic for sub anode size spatial resolution using pixelated scintillation crystals

Anger logic is widely used as a centroiding formula to spatially locate the scintillation event in multi-anode PMTs (MA-PMT). For pixelated scintillation crystals with pixel sizes smaller than single ...
0 votes
0 answers
117 views

What exactly is energy self-shielding in nuclear physics?

I have recently been trying to understand self-shielding, both energy and spatial self-shielding. I am having a particularly hard time understanding energy self shielding. Thus far, everything I’ve ...
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0 votes
4 answers
60 views

How much faster does induced fission in a typical reactor occur than spontaneous fission in nature?

I know that the half-life of Uranium-235 is about 704 million years, but... That includes alpha and beta radiation as well as spontaneous fission, though... Also, I presume the 'spontaneous fission' ...
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23 votes
7 answers
4k views

Is special relativity relevant to understand nuclear bombs?

It is often claimed that Special Relativity had a huge impact on humanity because its understand enabled the invention of the nuclear bomb. Often, the formula $E = mc^2$ is displayed in this context, ...
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0 votes
1 answer
23 views

What is the name of the instrument that separates substances using an electromagnetic field, similar to spectrography

As far as I remember, the elements of the substance are passed across an electromagnetic field in such a way that they seperate as the electromagnetic field alters their trajectory. I also seem to ...
0 votes
1 answer
113 views

How will "Fusion Power" deal with it's waste heat?

in application of Fusion power, even if it were doable at present, given the multi-million degree operation, how does such a system dispose of waste heat if plasma is magnetically confined?
2 votes
2 answers
255 views

If plutonium-238 (Pu-238) absorbs a neutron, does it become Pu-239?

I am asking this simple question because I am always hearing about how thorium reactors are less perilous to the world because, unlike uranium reactors, they produce some Pu-238, which is not suitable ...
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3 votes
1 answer
732 views

What would happen if an atomic bomb exploded on a nuclear power plant?

Would the effect be different than if the nuclear power plant were bombeb with traditional explosives? Would the atomic bomb neutralise any potential radioactive effect of the obliteration of the ...
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0 votes
1 answer
30 views

Working out radiation rates

Suppose the radiation dose of a CO-$57$ source was measured to be $63$ mR/hour $5$cm away from the source. Is there any way to measure the radiation at the source? ($0$cm from the source). I thought ...
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1 vote
0 answers
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How photon beam can be attained through Proton Accelerator?

I'm recently had been reading quite a lot about ADS and transmutation possiblity of Proton beam to neutralize nuclear waste. I came across with an Article from Big THINK https://bigthink.com/the-...
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0 answers
24 views

How can I attain deuterons using a proton accelerator?

I'm in high school and I had read in this paper https://cds.cern.ch/record/849079/files/thesis-2005-033.pdf That deuterons can be better in spallation process. I was curious how we can use the proton ...
1 vote
0 answers
38 views

How can I couple MCNP with FLUKA? To attain reactor dynamics and simulate an ADS(Accelerator Driven System) experiment?

I'm new in Particle Physics based Computing. I want to simulate an ADS experiment (Accelerator Driven System) in subcritical fast system. I was advised to simulate the experiment with FLUKA with MCNP ...
0 votes
1 answer
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Can Anti-Particle like Anti-Proton give advantage in ADS (Accelerator Driven System) for Neutralizing Nuclear Waste?

I was going through a thesis of Adonai Martinez for "Transmutation of Nuclear Waste in Accelerator-Driven Systems" published in 2004. I saw he used Proton for ADS but it occured to me that, ...
0 votes
2 answers
72 views

What is leftover of MOX fuel after being burned in a fast reactor?

My understanding is that basically the U-238 and P-239 play off each other and it can keep reacting essentially as long as the neutron density is enough. The U-238 that doesn't fission eventually ...
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1 vote
2 answers
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Tokamak and Lithium "blankets"

I am working on planning out nuclear fusion for a fictional world, and I am wondering if two ideas are able to work together, or if they contradict each other. So Dueterium-Tritium fusion releases ...
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0 votes
1 answer
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Will helium produced during a Nuclear fusion go back to Hydrogen?

I don’t know whether I’m right or wrong, but my argument is that, When hydrogen is converted into helium during fusion, a large amount of energy is produced roughly of order of 18Mega eV(At least that’...
-1 votes
1 answer
49 views

Radiation shield with moving electrons - where would this idea fail?

Disclaimer: I'm a total layman, please go easy on me. :) On some Youtube video some time ago (yes, sounds promising, but it was a quality video, I swear!) I saw some nuclear physicist talking about ...
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7 votes
4 answers
742 views

China's "Artificial sun"

So I heard in the radio today about China's "Artificial sun". There is this hype about it having 5x the temperature of the core of the sun. It is, as I suspected, a fusion reactor. I admit I ...
3 votes
2 answers
98 views

Alternatives to Steam Engines [closed]

Since the 18th century, humankind relied on steam engines to convert heat into electricity on mass scale even in fission and fusion (in the future) power plants. However, this process involves several ...
0 votes
2 answers
156 views

How do you contain a nuclear explosion? [closed]

What properties would a material need to contain a nuclear explosion (I'll go with the Tsar Bomba) such that it has no effect on outside conditions. For specificity I'll go with: Ultimate tensile ...
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