Questions tagged [nuclear-physics]

Nuclear physics is the study of the composition, behavior and interaction of atomic nuclei and their constituent parts.

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Why were all 8 eight pums active in chernobyl?

In INSAG-7 on page 8 it is stated: Just prior to and at the start of the accident at Chernobyl, all eight pumps were running. [...] The use of all eight pumps increased the coolant ...
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Why was turbine feed valves closed in chernobyl?

If I understood the test correctly that lead to the Chernobyl disaster, then it was planned as follows: Reduce power of reactory to 500 - 700 MW Shut down reactor by pressing AZ-5 Measure electricity ...
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Neutron capture calculation

So, the problem state is: Neutron beam radiates sample A with initial number of atoms $N_0$. With neutron capture nuclei (cores) of A are transitioning to nuclei B (they are just one neutron richer ...
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Anti-matter propulsion system

I watched an interview with Bob Lazar where he drew detailed plans for alien spacecraft that propels itself with anti-matter. His explanation is that the spacecraft would create a gravitational field ...
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Producing a pair of pions

I know that two protons colliding at high energies can produce a pion $$p+p \rightarrow p+p+\pi^0$$ But is it possible for two protons to produce a pion pair? $$p+p \rightarrow p+p+\pi^{-}+\pi^{+}$$...
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Could the end cap of the Pascal B (1) survive its trip through the atmosphere?

In 1957, the US had a nuclear test where a shaft was dug 152 meters into the ground. A 100 mm thick, 900 kg steel plug was installed and welded at the top of the shaft. Under it was 2 feet of ...
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How can beta plus decay be possible?

$\beta +$ decay is where a proton gets turned into a neutron and a positron and a neutrino. However, a neutron is heavier than a proton, so obviously this reaction is endothermic. So then, why does ...
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Nuclear Physics Question

How could I calculate the chance of a proton actually joining the nucleus and 2 protons and 3 and so on? Assuming a large number of protons are fired at a substance?
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Can a Bose Einstein Condensate and a Fermonic Condesate create an interference pattern that causes nuclear fusion? [on hold]

Okay so to begin here is a paragraph about superposition. Superposition is the combination of two waves at the same location. Constructive interference occurs when two identical waves are ...
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radon daughters vs radon progeny [closed]

Physicists sometimes use the term "radon progeny" instead of "radon daughters". Is it an entirely equivalent synonym or does it have another connotation? For example, this (ccnr.org web page) suggests ...
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Baryon number conservation

Can someone explain me why the Hamiltonian for the nucleon field (derived from the corresponding Lagrangian) $$H_N=\int d^3xN^\dagger(\textbf{x})\Big(-\frac{\nabla^2}{2M_0}+M_0\Big)N(\textbf{x})$$ ...
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Intermediate product of CNO cycle

CNO cycle of stellar nucleosynthesis involves several steps in which different isotopes of Carbon, Nitrogen, and Oxygen are transmuted into each other when hit by a ...
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Ground state of an odd, deformed nucleus: intuition for what happens to the $j_x$ and $j_y$ of the odd particle

This is something that relates closely to my long-ago PhD research, and it's a point that I never satisfied myself thoroughly on. I have a copy of a standard text that covers this general topic, de ...
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Understanding the Level scheme of a nucleus from Nuclear Data Base

Sorry If this Question is not eligible to be posted here. Nuclear database shows observed nuclear electronic energy levels of $O^{17}$ having neutron separation energy 4143 keV. I want to find ...
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Does a proton have a binding energy?

When calculating the $Q$-value, $Q = \Delta M \cdot c^2$, of this reaction: $$ ^6Li \ (\alpha, p)\ ^9Be \quad \iff \quad \alpha + \ ^6Li \ \longrightarrow \ ^9Be + p $$ The $Q$-value can also be ...
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Shell model label symmetry

I'm working through the quark model Hadron wavefunctions, and trying to figure out the flavour-spin part of the wave functions. This is easy enough for S shell spatial states, since the space wave ...
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Is this a radioactive meteorite? [closed]

Can a neutron beam emission from a strong naturally-occurring radioisotope deflect a small sewing needle hung by a thread an inch from the source? I have someone reporting to me of such a thing ...
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Trinity vs Nagasaki

From what I read the radiation levels in Nagasaki today are equivalent to the natural background radiation levels in the surrounding areas. On the other hand, the radiation levels at the Trinity test ...
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Shell Model of the Nucleus Holes

Can someone help me how to determine whether there is a hole or a particle in a given shell? Is it as simple as if the number of particles is close to the number of the maximum particles in each shell,...
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Why doesn't a deuterium-deuterium reaction usually yield Helium-4?

I assume the above reaction is less energetically favorable than the creation of He-3 (plus a neutron) or tritium plus a proton? But why/how? Or are the hard, hot, fast collisions too much for it to ...
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How exactly did lowering of the graphite parts of the control rods on Chernobyl's RBMK reactor result in reactivity surge?

There are many sources giving different data on the initial position and the dimensions of the rods, but most suggest that the absorber was located just outside the core when AZ-5 was pressed, and the ...
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How does the strong interaction “create” the nuclear force?

I’ve recently read that the strong interaction, that holds the quarks together to form protons and neutrons, also creates a residual force called the nuclear force, which holds the neutrons and ...
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Direction of neutron scattering

When neutrons interact with matter scattering, what direction to they scatter? Is it random, or some probability distribution of directions? I'm trying to understand why neutron reflectors reflect ...
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Why does fusion above nickel 56 require energy?

I've always struggled with the concept of fission and fusion. I mean I can show a mass deficit with math easily enough but I have always struggled understanding the fundamental concept of why things ...
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How does heat is generated during nuclear reaction

In a nuclear reaction 235-U is being constantly divided under high neutron flux. After the division we get 2-3 neutrons with high energy and fission products with its own energy. My question is from ...
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Is fission/fusion to iron the most efficient way to convert mass to energy?

Is fission/fusion of any element to iron-56 (or nickel-62?) the best way to convert mass to energy, that doesn't involve black holes? In other words, will we be always limited to convert only about 1%...
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Irradiated persons as sources of radiation?

The new HBO series "Chernobyl" is supposedly filled with misconceptions about radioactivity, among other things, according to an opinion piece published in "Forbes". In particular: "The most ...
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Why don't we coat the pressure vessels of nuclear reactors in boron to reduce neutron embrittlement?

Neutron embrittlement is a big problem in reactor design, as high energy neutrons cause lattice defects in materials like steel by slamming into iron nuclei. This limits the lifetime of the reactor, ...
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What was the vertical beam of light in Chernobyl?

In the HBO miniseries Chernobyl after the initial explosion we see a clear bright light shooting vertically up from the plant. I presume this was a thing that actually happened and not some creative ...
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Did the Chernobyl power station's water cistern really hold $7000\:\rm m^3$? [closed]

In he HBO TV miniseries Chernobyl, they talk about a cistern holding 7000 cubic meters of water. That is the content of Loch Ness, the deepest lake in the UK. Would the Chernobyl reactor really hold ...
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Why neutrons production is falling along beam axis in proton/nucleus collisions?

I'm studying a case where I simulate a protons beam (~70 MeV) on a spherical target composed of light nuclei such as carbon and oxygen. I'm looking for the angular distribution of neutrons produced by ...
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Why is the graphite moderator in a nuclear reactor radioactive?

Some nuclear reactors (like the RBMK in Chernobyl) use graphite as a neutron moderator. As far as I understand, this graphite material, either in rods or as blocks with embedded channels, surrounds ...
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Why does steam in Chernobyl reactors speed up nuclear reaction?

After watching the TV series Chernobyl I am struggling to understand why steam in a reactor core would increase the rate of the nuclear reaction. My first guess would be that liquid water would ...
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How to determine which force mediates an interaction?

I have been given an assignement gives me a number of interactions, asks me to determine which, among these interactions are permitted under conservation laws (Charge, Baryon number, Leptonic numbers, ...
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How do nuclear properties influence the atomic properties and vice versa?

I was wondering how the nucleus can influence the atomic properties (chemical and physical). I found that the mass number influences the boiling, melting and density of an atom. Also the electron wave ...
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How can Sun burn in space?

If there is no oxygen in space how can sun burn in space. (even though I know fire is caused by nuclear reaction inside sun)
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How does an ordinary object become radioactive?

In the 2019 miniseries "Chernobyl", ordinary objects are depicted as being capable of becoming radioactive, such as clothes, water, stones. How exactly does something composed of a non-radioactive ...
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How does the Earth remain in its shape?

I know only stars do nuclear fusion to keeps its shape from gravity. Then what about the Earth? Earth doesn't do nuclear fusion. How does the Earth keep its shape even though the gravity keeps pushing ...
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Why do we think of a nucleus as nucleons held together by a strong force rather than a cluster of quarks? [duplicate]

The implication of this point of view is that protons and neutrons retain their structure in a nucleus. That is the 3 quarks making up nucleons still closely interact and interactions with quarks from ...
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What if a fusion reactor had moving parts?

I have never dug into fusion physics, but from what I gather one of the main problems is confining the fusion in a small region of space for long enough to get enough helium fused to counterbalance ...
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Whats the next step after commercial fusion reactors? [closed]

I'm trying to write some science fiction where they've had nuclear fusion working for quite sometime, interplanetary travel is no problem, and they're debating making the next step to a radical new, ...
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Released energy during fusion reaction

Click to view the video at required time According to the video in the link above the binding energy for deuterium is about 2 MeV and the binding energy for tritium is about 8 MeV so the total for ...
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Why is the D+P fusion reaction not considered for large-scale power production?

I know that D+D (fusion of deuterium + deuterium nuclei) as well as D+T (fusion of deuterium and tritium nuclei) are the reactions most commonly considered for large-scale power production. Why not D+...
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1answer
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Possible spins and parities of $^{38}_{17}Cl$

In my introductory nuclear physics course, the following question came up: Consider the odd-odd nucleus $^{38}_{17}Cl$, which has 17 protons and 21 neutrons. Its 17th proton sits in the $1d_{3/2}$ ...
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Could the plume from an exploded nuclear reactor corrode helicopter blades?

I was recently watching the new TV series Chernobyl and was curious if something that occurred was even physically possible. In the show, the physicist instructs the pilots of a helicopter not to fly ...
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1answer
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Why are lighter nuclei dominated by $\beta$-decay and heavier ones by $\alpha$-decay?

While I'm trying to understand the nature of radioactive decay, I found that the lighter nuclei mostly have $\beta$-decay while heavier nuclei have $\alpha$-decay. From what I know is that the $\...
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Nuclear isomers with a long lifetime

A lot of nuclear isomers with long half-lives have N and Z numbers in a range from 39-49 or 69-81. What is the reason for this? Is it possible to explain this with the nuclear shell model?
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Why can radon be held in your hand without harm but if it's inhaled it very dangerous?

Why can radon be held in your hand without harm but if it's inhaled it very dangerous? I was thinking that because radon emits alpha particles they wouldn't penetrate your hand? but if they were ...