What is Nuclear reaction: Definition and 65 Discussions

In nuclear physics and nuclear chemistry, a nuclear reaction is semantically considered to be the process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformation of at least one nuclide to another. If a nucleus interacts with another nucleus or particle and they then separate without changing the nature of any nuclide, the process is simply referred to as a type of nuclear scattering, rather than a nuclear reaction.
In principle, a reaction can involve more than two particles colliding, but because the probability of three or more nuclei to meet at the same time at the same place is much less than for two nuclei, such an event is exceptionally rare (see triple alpha process for an example very close to a three-body nuclear reaction). The term "nuclear reaction" may refer either to a change in a nuclide induced by collision with another particle, or to a spontaneous change of a nuclide without collision.
Natural nuclear reactions occur in the interaction between cosmic rays and matter, and nuclear reactions can be employed artificially to obtain nuclear energy, at an adjustable rate, on demand. Perhaps the most notable nuclear reactions are the nuclear chain reactions in fissionable materials that produce induced nuclear fission, and the various nuclear fusion reactions of light elements that power the energy production of the Sun and stars.

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  1. Phil App

    Termination of a nuclear reaction

    I have long pondered the question of whether it is possible to extinguish an ongoing atomic explosion. From a practical standpoint, it is certainly possible that currently it is a supernatural, if not impossible, task. However, from a theoretical standpoint, I cannot stop thinking about all...
  2. freddie_mclair

    I What kind of energy is released in a nuclear fusion reaction?

    Hi, I have a fundamental (and maybe silly question) but I couldn't find a proper answer anywhere yet: For example, for a nuclear fusion reaction of Tritium (T) and Deuterium (D), we get an alpha particle (##\alpha##) a neutron (n) and energy release due to the mass difference ##\Delta...
  3. K

    How Do You Calculate m3 and m4 in Nuclear Reaction Equations?

    En=0 Ek(B)=0 Q=Ek3(α)+Ek4(Li) --Q=Ek3(1+m3/m4) (1) p3=p4 /^2 -- 2*m3*Ek3=2*m4*Ek4 --- Ek4=m3/m4 * Ek3 (2) (1) and (2) Ek4= m3/(m3+m4) * Q, but I'm not sure how to find m3 or m4 and if this is true
  4. duchuy

    Available energy in β+ and β- nuclear reaction

    Hi, I understood that to calculate the available energy in these two reactions could be calculated from Ed = [Mn(X) – (Mn(Y) + m(e))] c^2, but when I have to change use the atoms' mass instead of the nucleons' mass, it gives out two different formulas : Ed = [M(X) – M (Y)] c2 for β- Ed = [M(X)...
  5. P

    Finding the reqiured fuel mass for a nuclear reaction

    Hi I need to find the amount of fuel needed for a nuclear reaction to produce 800MW daily . The reaction is n + 𝟗𝟒𝑷𝒖 𝟐𝟑𝟗 → 𝟓𝟐𝑻𝒆 𝟏𝟑𝟒 + 𝟒𝟐𝑴𝒐 𝟏𝟎𝟑 + 𝟑 𝒏 Can you please give me a hint on how to do this? Thank you very much for your help
  6. Stephen Bulking

    What is the formula for calculating reaction energy in an α decay?

    I tried momentum conservation, which gives: -pα = pdaughter <=> 2mKα = 2mKdaugther (squaring two sides) Using the given mass ratio, I found Kdaughter to be 0.0864MeV Adding the two Kinetic energy of the product particles and converting it to Joules, I got A But I don't understand why adding the...
  7. patric44

    The Q factor of the nuclear reaction problem?

    after using the conservation of energy and momentum for a nuclear interaction i arrived to the following equation for the q factor as the book did , but can't get my head around deriving the second equation from the Q equation ? i will appreciate any help . thanks
  8. S

    Energy change in a nuclear reaction

    I got 6.5 MeV but I don't understand how to determine whether the energy is released or absorbed. My guess: the energy is absorbed because mass defect of neon is bigger? Thanks
  9. A

    Calculate the mass deficit in this nuclear reaction

    I have tried using the formula $$Δm=[Zmp+(A−Z)mn−M]$$ But either I plug the wrong thing into the wrong part or it just isn't working. Essentially I want to know the method I need to use. I will then try to solve it and hopefully get it correct. Thanks
  10. C

    Nuclear Reaction - How to determine variables as much as possible

    Hey Guys, exercise: "It is desired to study the first excited state of 16O which is at energy of 6.049 MeV. Using the (alpha, n) reaction on target of 13C, what is the minimum energy of incident alphas which will populate the excited state? So, i suggest to define first the reaction equation...
  11. A

    A Influence on Neutron spectrum due to energy loss of beam

    Suppose some protons are impacted on a Lithium target to produce neutrons with energies close to the proton energy. If one considers Energy-loss due to proton-target collision (ionization of the target atoms), will this kind of energy loss influence neutron energy spectrum? I am asked by my...
  12. maxd23

    A Nuclear Reaction: Determining the velocity of neutrons

    Homework Statement Fission, the process that supplies energy in nuclear power plants, occurs when a heavy nucleus is split into two medium-sized nuclei. One such reaction occurs when a neutron colliding with a 235U (uranium) nucleus splits that nucleus into a 141Ba (barium) nucleus and a 92Kr...
  13. spareine

    B How to pronounce a nuclear reaction written in AZE notation?

    Pronouncing a nuclear reaction like as "one,zero,neutron + 235,92,uranium yields 141,56,barium + 92,36,krypton + 3,1,0,neutron" is awkward. How is it pronounced by physicists in practice?
  14. M

    B Can Classical Forces Explain Nuclear Fission and Fusion Reactions?

    good morning, I'd like to know if exsists a classical explanation and, of course, qualitative about the nuclear fission / fusion reactions. I would like to explain the development of external energy to considering only nuclear forces system in terms of internal mechanical energy and the fact...
  15. moenste

    Control rods nuclear reaction equation, moles liberated, pressure

    Homework Statement A control rod to limit the rate at which a nuclear reactor is working is made from boron which is sealed in a casing. A boron atom (105B) is able to capture a neutron; an atom of lithium (Li) and an alpha particle being produced in the process. As a result helium gas is...
  16. kiwaho

    I How many barns above could make nuclear reaction rate 100%?

    All guys know the importance of cross section. In a sense, it stands for the possibility of a reaction. I am wondering how many barns above could make nuclear reaction rate almost 100%? Generally speaking, the cross section can span a couple of decades order of magnitude, e.g. 10^-10 to 10^6...
  17. D

    Calculating Energy of Th-232 Nuclear Reaction

    Homework Statement Th-232 ---> He-4 + Ra-228 + energy How much is the energy? Homework Equations The Attempt at a Solution my solution is this: [m(Th-232)-90m(electron)] - m(He-4) - [8m(Ra-228)-88m(electron)] My book skipped the electrons, why?
  18. S

    Any models that can predict nuclear reactions?

    Are there any good models, software or codes that can predict the probabilities of nuclear reactions where an atom of a given type strikes another atom of another type with a given energy? Or is this information only obtainable experimentally? To further clarify, I am interested determining...
  19. Stephanus

    Star Nuclear Reaction: P+P, D+P, He3 and CNO Cycle

    Dear PF Forum, I'm just wondering about P+P reaction in star. Because of its pressure, in the core of the star, hydrogens fuse to become deuterium. Its the complete reaction P + P -> D D + P -> He3 He3 + He3 -> He3 + P + P and if the star is big enough, it can undergo CNO cycle, But what if...
  20. W

    Gamow peak and nuclear reaction rate

    It's known that the nuclear reaction rate (inside a Star) can be determined with $$R_{ab}=n_a n_b\left<\sigma v\right> \, \approx \, n_a n_b \Big(\frac{8}{\pi m_e}\Big)^{1/2} \frac{S(E_0)}{(k_BT)^{3/2}} \Delta \frac{\sqrt{\pi}}{2} e^{-3E_0/k_BT},$$ where ##k_B## is Boltzmann constant, ##T##...
  21. K

    Nuclear Reaction: Neutron & Plutonium-239

    Homework Statement A neutron strikes a Plutonium-239 (239Pu) nucleus and creates Barium-142 (142Ba). What other element is created? Homework EquationsThe Attempt at a Solution I actually have no idea...could someone just start me off? Thanks!
  22. N

    Atoms splitting in a nuclear reaction and Bacterial Growth

    Homework Statement Investigate The number of atoms splitting up in a nuclear reaction and Bacterial growth Your investigation should use appropriate formulae and graphs and include information from records of real events. You should aim to show how good the mathematical models are in...
  23. T

    Does fusion nuclear reaction produce alpha ridation

    does fusion nuclear reaction produce alpha and jamma ridation or just alpha
  24. Crazymechanic

    Exploring the Impact of Nuclear Reactions on Water Heating in Reactors

    Hi, in nuclear reactors the water is heated while traveling through the core , now this heat comes from the nuclear reaction taking place in the core fuel assemblies, the part that I wnat to know is which of the elementary particles that come out of that reaction heat the water more and which...
  25. Z

    How do you get the energy of products in nuclear reaction?

    The radionuclide X has a half life of 2.58hours and is produced in a cyclotron at a constant rate by bombarding a Y target with 2.10 MeV deuterons. The target contains only the stable isoptope Y and the reaction that produces X is Y + deuteron -> X + proton show that energy is released in...
  26. V

    What was the principal nuclear reaction of Fermi's nuclear pile

    I've known about the basic story of the first nuclear pile since before I can remember, but never found information on what the associated nuclear reaction actually was and was wondering if anyone here knew or could point me in the right direction.
  27. L

    Role of Bosons in Nuclear Reaction

    It seems that no matter how far and wide I look, I can find no concise explanation as to the roles of bosons in a nuclear reaction, fusion and/or fission. Thus, my inquiry: What role do bosons play in nuclear reactions, fusion and fission? What is the sequence of events that result in such a...
  28. J

    Kinetic Energy of the Products of Nuclear Reaction?

    Homework Statement Calculate the total kinetic energy of the products of the reaction d+C-13 --> N-14 + n if the incoming deuteron (d) has 36.3 MeV. Homework Equations Q=(Parent Mass - Daughter Mass - Decay Particle Mass)*c^2 1u = 931.5 MeV C-13 = 13.00335u N-14 = 14.003241u Neutron...
  29. D

    Is this nuclear reaction exothermic or endothermic?

    Is this nuclear reaction exothermic or endothermic?? Homework Statement Is this nuclear reaction exothermic or endothermic?? alpha particle + beryllium -> carbon12 + neutron Homework Equations The Attempt at a Solution Im not quiet sure which one it is, I don't know what...
  30. X

    Calculating Energy from Nuclear Reactions

    1. It has been found by experiment that the molar mass of the Rn nucleotide is 221.9703 g and that of the Po nucleotide is 217.9630 g. The molar mass of helium is 4.00150 g. Given this information, and the information from the class, calculate the energy evolved, in kJ, for the following nuclear...
  31. A

    What are the unknowns in this nuclear reaction sequence?

    Hi there problem is: given the following nuclear reaction sequence, determine X and Y: _{9}^{15}N+_{1}^{1}H\rightarrow_{8}^{16}O+\gamma _{8}^{16}O+_{1}^{1}H\rightarrow_{9}^{17}F+X _{9}^{17}F\rightarrow_{8}^{17}O+Y+\nu_{e} My Attempted answer is: As far as I can see, Y must...
  32. O

    What happens during a nuclear meltdown?

    With all the events happening in Japan right now, I was wondering, what exactly happens during a nuclear meltdown? I have a decent idea of how the plant produces power, but I have no idea what happens during the meltdown to create such a hazardous situation.
  33. Topher925

    T or F: Mass can only be created or destroyed in a nuclear reaction

    T or F: "Mass can only be created or destroyed in a nuclear reaction" "Mass can only be created or destroyed in a nuclear reaction", quote anonymous authority figure. Someone, perhaps an educator at my university, repeatedly makes the above statement and states its because of the relationship...
  34. J

    Kinetic energy of nuclear reaction

    reaction B10(n,alpha)Li7, Q=2.79Mev. the He4 and Li7 are oppositely directed away from the site of the compound nucleus and form one straight track. a) what is the initial kinetic energy (KE) of He4? b) what is the initial KE of Li7 nucleus? c) estimate the ratio of the specific ionization...
  35. R

    Modifying Endoergic Nuclear Reaction to Exoergic

    How an endoergic nuclear reaction can be modified physically to get exoergic one?
  36. I

    Why protons/neutrons are not destroyed in nuclear reaction?

    In a nuclear reaction, protons and neutrons are separated from each other. My question is, why can protons and neutrons separate, but quarks can not separate from each other. When the nucleus is intact, the gauge bosons for the strong nuclear force, gluons are responsible for holding quarks...
  37. B

    (Very) Short Question on Nuclear Reaction

    Homework Statement The nuclear reaction X yields Y + Z occurs spontaneously. If MX, MY, and MZ are the masses of the three particles, which of the following relationships is true? A Mx - Mz < My B Mx = Mz + My C Mx < My + Mz D Mx - My < Mz E Mx > My + Mz The Attempt at a Solution...
  38. H

    Nuclear reaction leading to formation of C^14 ?

    Nuclear reaction leading to formation of C^14 ? Hello. I've got two questions from the NPRE class. One of them is to estimate how old the certain wook piece contained some amount of C^14 is. I solved it. The real question is the second one which is " Write down the nuclear reaction...
  39. R

    Physics Nuclear Reaction Mechanics Question

    Homework Statement For some isotopes of some very heavy nuclei, including nuclei of thorium, uranium, and plutonium, the nucleus will fission (split apart) when it absorbs a slow-moving neutron. Plutonium-239, with 94 protons and 145 neutrons, can fission when it absorbs a neutron and...
  40. S

    Potential energy diagram for a nuclear reaction

    Saw this on a test question today, it asked if you had 1 mole of reactant (don't know what kind of reactant though...), what would the nuclear reaction potential energy diagram look (don't know if its fusion or fission or exothermic or endothermic it just said nuclear reaction...)? (The...
  41. A

    Q value of 3H(p,n)3He nuclear reaction

    Problem: I'm trying to calculate the Q-value for the nuclear reaction H-3 + p > He-3 + n, where H-3 is Deuterium, p is a proton, He-3 is Helium 3 and n is of course a neutron. Doing the calculation, I get -1.2715 MeV for the Q, but my textbook and an online 'Q-calculator' both give -763.15...
  42. S

    Very Basic Nuclear Reaction Q Value Problem

    Hello, I looked around before and could not find an answer to this question. So given the reaction neutron + X -> Y + gamma and we assume that both initial particles are at rest. Then using momentum balance we can find that the energy of the gamma is: Egamma = -m_Y*c^2 + sqrt(...
  43. T

    Calculating energies for a nuclear reaction?

    So I was doing physics homework today, and wound up spending a couple hours on wikipedia, browsing through topics far out of my league- particularly nuclear physics. I'm left with an aching question that I hope someone here can help me out with. In a nuclear reaction that requires a certain...
  44. P

    Spontaneous endothermic nuclear reaction?

    is such a thing possible? I am curious to know if this could/does exist. An alternative would be if someone gave an example of a reaction where electron capture occurs and the product ends up being stable enough to not decay into anything further. Thanks (btw, does cold fission exist...
  45. T

    Nuclear reaction cross section

    Suppose we consider a beam of neutrons incident upon a thin target with an intensity of 10^12 neutrons/(cm^2.s). Suppose further that the total cross section for the nuclei in this target is 4 b. Using this information, determine how long one would have to wait, on the average, for a given...
  46. E

    Find Z and A for nuclear reaction

    Homework Statement Homework Equations ? The Attempt at a Solution In our previous homework, this is the only problem I got wrong, I feel the book does a very poor job at explaining over this subject. I went to physics help room but because its summer the guy was only there for...
  47. P

    Is possible some elements absorb neutrons, without any nuclear reaction?

    Is possible some elements (like Cadmium or Bohr) absorb neutrons, without any nuclear reaction in their atomic nucleus? If the answer is YES, then why there isn't any nuclear reaction?
  48. M

    Inclusive, semi-exclusive and exclusive nuclear reaction

    Hi all, What is the difference among inclusive, semi-exclusive and exclusive nuclear reaction? Thanks