Probability of U-235 fission happening

In summary, the probability of U-235 fission happening is determined by the likelihood of a neutron striking the nucleus of a U-235 atom and causing it to split, releasing energy and more neutrons. This probability can be increased by slowing down the neutrons and using a moderator, such as water or graphite, to enhance the chances of a successful fission reaction. Additionally, the likelihood of U-235 fission can be influenced by the amount and quality of U-235 present in the fuel, as well as the design and configuration of the reactor. Overall, the probability of U-235 fission is a crucial factor in the efficient and safe operation of nuclear reactors.
  • #1
NewPhysi
2
0
Where can I find information about the ~82% of U-235 nuclear fission happening and ~18% not happening?
 
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  • #2
NewPhysi said:
Where can I find information about the ~82% of U-235 nuclear fission happening and ~18% not happening?

Where did you find those numbers? What do these percentages correspond? like 82% of what?
 
  • #4
snorkack said:
One possible link:
https://wwwndc.jaea.go.jp/cgi-bin/Tab80WWW.cgi?lib=J40&iso=U235
What do you want to choose as denominator?

yea I figured that it was somewhat related to ## \dfrac{\sigma (\text{slow }n \text{ fission})}{\sigma (\text{slow }n \text{ total})} \approx 84 \%## the other important processes are just elastic scattering and production of U-236* which decays via gamma to U-236
 

FAQ: Probability of U-235 fission happening

What is the probability of U-235 fission happening?

The probability of U-235 fission happening depends on various factors such as the energy level of the nucleus, the presence of other particles, and the stability of the nucleus. However, on average, the probability is estimated to be around 1 in 2.5 x 10^17, meaning that for every 2.5 x 10^17 U-235 nuclei, one will undergo fission.

How is the probability of U-235 fission calculated?

The probability of U-235 fission is calculated using the concept of cross-section, which is a measure of the likelihood of a nuclear reaction occurring. It takes into account the size of the target nucleus, the speed of the incoming particle, and the energy required for the reaction to take place.

What factors affect the probability of U-235 fission happening?

The probability of U-235 fission happening can be affected by the energy level of the nucleus, the presence of other particles, and the stability of the nucleus. Additionally, the probability can also be influenced by the type of particle used to induce the reaction and the amount of energy it carries.

Is the probability of U-235 fission happening the same for all nuclei?

No, the probability of U-235 fission happening varies for different nuclei. It depends on the stability and energy level of the nucleus, as well as the type and energy of the particle used to induce the reaction. For example, U-238 has a lower probability of fission compared to U-235 due to its higher stability.

Can the probability of U-235 fission happening be increased?

Yes, the probability of U-235 fission happening can be increased by using a higher energy particle, increasing the number of U-235 nuclei present, or by using a moderator to slow down the particles and increase the chances of a successful reaction. Additionally, controlling the conditions of the reaction, such as temperature and pressure, can also affect the probability of fission.

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