Questions tagged [nuclear-engineering]

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

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52 views

How bad would it be to dump nuclear waste into the atmosphere?

Before I say any further, this is just a thought experiment, it's a crazy idea and I'm not suggesting otherwise! A key pro/anti nuclear argument goes like so: nuclear waste storage is hard, but on the ...
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3answers
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Could there (at least theoretically) ever be a way to prevent radioactive atoms from decaying?

I mean, in such a way as to make it feasible to have a collectible sample of an element like astatine, francium, or protactinium (ignoring their chemical toxicity, which could probably be contained in ...
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Why do Xe-135 and Zr-88 have a surprisingly large thermal neutron capture cross-section?

Why do Xe-135 and Zr-88 have surprisingly large thermal neutron capture cross-sections? The probability that a nucleus will absorb a neutron—the neutron capture cross-section—is important to many ...
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52 views

In the Tchernobyl nuclear plant of the 1986 accident, were there a secondary circuit, or were there only a primary circuit? [closed]

In a typical modern nuclear plant, there are : a primary circuit, which allows to transfert the heat of the fission (transfered to the water) to a secondary circuit. a secondary circuit, which ...
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Why is the French Wikipedia of Tchernobyl plant stating the the power is of 1000 MW while English version states that this is 3200 MW?

The power of a given reactor for the Tchernobyl plant is, according to Wikipedia : 3200 MW (12800 /4 reactors) Reference : https://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant "Reactors ...
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2answers
70 views

What is the origin of radioactivity that appears *sometimes* in rivers close to a nuclear plant? [closed]

What is the origin of radioactivity that appears sometimes in rivers close to a nuclear plant? (due to nuclear plant activity) ? In particular, is it due to primary circuit that would contaminate the ...
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What substance is being sprayed during this scene in Chernobyl?

In HBO's Chernobyl series, after reactor no. 4's meltdown, soldiers (Chernobyl's liquidators) splash a light-brown liquid onto the ground, both streets and forest, and for washing vehicles; for this ...
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1answer
38 views

Would neutron moderator anisotropy improve nuclear reactor performance?

Nuclear fission reactors require the presence of a neutron moderator in order to sustain a chain reaction, as it slows down neutrons sufficiently in order for them to be absorbed by fuel (e.g. U-235) ...
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What is thermal capacity in a nuclear power plant?

I am looking at a nuclear powerplant reactor that has 3.2GW "thermal capacity" and 1GW "nameplate capacity". What does the thermal capacity entail? Is it how much heat the reactor ...
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1answer
52 views

Can Uranium-235 absorb neutrons and become U-238 instead of splitting?

Does that happen, on occasion? Does anyone know? I suppose it is quite rare, ... To absorb three neutrons without once fissioning... Could U-235 absorb three neutrons at once? Or just one, becoming ...
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What is exact *average* energy released by uranium fission?

There are many possible decay products for uranium 235 fission. I'm interested in the average value of the energy released (not an order of magnitude : a rather "precise" value of the ...
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How to make the connection between the *energy* released by the fission of uranium and the *power* of a nuclear plant?

How to make the connection between the energy released by the fission of uranium and the power of a nuclear plant ? How to vary the power in a nuclear plant since the energy released by fission of ...
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1answer
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Neutrino or antineutrino detection during Chernobyl disaster

In the HBO series Chernobyl, they keep dumping sand on top of the reactor and worrying about it melting down into the groundwater. They said they had no way of telling what was happening in the core. ...
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3answers
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In a civil nuclear reaction, how the very first nuclear fission *starts* : is it spontaneous, or is it induced by another mechanism?

A civil nuclear reaction remains on the principle that uranium fission drives to production of neutrons that then create another uranium fission and so on. The reaction is controlled by various ...
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Can uranium-233 mixed with natural uranium be used as a replacement for light-enriched uranium?

My idea is to make a new form of enriched uranium fuel (or more accurately, a substitute for enriched uranium) that's made by mixing uranium-233 (transmuted from thorium in a breeder reactor) with a ...
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Doppler broadening of nuclear cross section: Peak reduction

What is the cause of the reduction in peak microscopic cross section with increasing temperature, shown here for a nuclear resonance? The nuclear properties of the target material do not actually ...
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69 views

Difference between neutron flux and fluence?

I was skimming through the ITER Technical Basis and in page 16 of the PDF, under the subheading "Design Requirements", it says that the engineering requirements are: I'm confused because ...
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1answer
62 views

Is there naturally-occurring Cherenkov Radiation on Earth?

I'm postulating a natural fission reactor, like Oklo in Gabon. My understanding of Oklo is that the reaction occurred entirely underground. Would it be possible for a Uranium deposit nearer the ...
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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
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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
66 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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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
37 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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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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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....
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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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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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71 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
91 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 ...
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2answers
109 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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Identify the Origin of each term in Weizsäcker's Semi-Empirical Mass formula?

I was hoping someone could explain each term in Weizsäcker's semi-empirical mass formula in simple English because I don't understand it. Any help will be appreciated thank you. $$M_{Z,A} = ZM_{H} + (...
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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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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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80 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
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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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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 ...
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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
108 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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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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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 ...
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1answer
128 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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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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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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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
68 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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59 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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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?
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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 ...
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1answer
129 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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