Fission yield of fission products

In summary: The fission yield curve is the double hump curve with maximum frequencies at around atomic masses of 90 and 140. The depth of the valley in between depends on the stored energy of the compound nucleus. In general, fissions induced by thermal neutrons demonstrate a very shallow valley, whereas fast neutrons will render the double peaks less distinguishable. This means that the fission products present in the nuclear fuel at any given time will be relatively evenly distributed.The APWR and PBMR are both thermal reactors. So, unless future designs dictate a more exotic fuel (e.g. MOX, actinide fuel) or a faster neutron spectrum, the double hump fission yield is a good approximation. You can find the curve on
  • #1
friendboy
9
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Does anyone know where to find fission products' fission yield data of APWR and PBMR?
 
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  • #2
Fission product yield is primarily a function of two things:

1. The type of fissile nuclide
2. The energetics of the compound nucleus post-absorption and pre-fission.

As far as I know, both the APWR and PBMR will still use U-235 as its primary fissile nuclide. They may be in unique geometries or forms (e.g. PBMR's TRISO fuel kernels), but in general, for commercial applications, U-235 enrichment would still be very low. Consequently, the distribution of fissile materials, including the transuranic elements produced during operation, will probably be the same as current LWR's.

For U-235, the fission yield curve is the double hump curve with maximum frequencies at around atomic masses of 90 and 140. The depth of the valley in between depends on the stored energy of the compound nucleus. In general, fissions induced by thermal neutrons demonstrate a very shallow valley, whereas fast neutrons will render the double peaks less distinguishable. APWR and PBMR are all thermal reactors.

So, unless future designs dictate a more exotic fuel (e.g. MOX, actinide fuel) or a faster neutron spectrum, the double hump fission yield is a good approximation.

You can find the curve on wiki or any introductory nuclear engineering textbook.
 
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  • #3
friendboy said:
Does anyone know where to find fission products' fission yield data of APWR and PBMR?
The fission yield of the APWR or AP1000 would be similar that of fuel for the standard 17x17 PWR, which should be well published.

The PMBR should be closer to that of an AGR.
 
  • #4
@Sourceless: I need numbers, not just curve, and as you said that in wiki and textbook, they only provide the curve.

@Astronuc: I've been searching with APWR as keyword, I guess I should use PWR instead, thanks for the tips.
 
  • #5
Presumably one needs this as a function of burnup?

In LWRs and AGRs, as the U-235 depletes and U-238 is converted to Pu-239, fissions from Pu-239 increase.
 
  • #7
@Astronuc: well, actually I need this data to calculate how much toxicity from fission product on a fuel of APWR and PBMR

@Xnn: thanks, but on the link, the data are unspecific for a particular nuclear reactor, I'm still searching on for the specific ones.
 
  • #8
friendboy;

Read message #2
 
  • #9
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  • #10
Thanks guys for the links and the explanations :)
 
  • #11
For background information see:
http://www.nucleonica.net/wiki/index.php/Help:Fission_Products_and_Yields [Broken]

On the Nucleonica website (www.nucleonica.net), there is a fission yield module with which you can obtain tables of data. These can be downloaded as an Excel spreadsheet.

For your PWR reactors, look at the fissioning of U-235 with thermal neutrons.
 
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1. What is fission yield of fission products?

Fission yield of fission products is the measure of the amount and type of radioactive isotopes produced during nuclear fission. It is expressed as a percentage of the total number of fissions that occur.

2. How is fission yield of fission products calculated?

Fission yield of fission products is calculated by measuring the number of fissions that occur and the types and quantities of radioactive isotopes produced. This information is then compared to the total number of fissions and expressed as a percentage.

3. Why is fission yield of fission products important?

Fission yield of fission products is important because it helps scientists understand the composition and behavior of nuclear reactions. It also plays a crucial role in the design and safety of nuclear reactors and weapons.

4. What factors can affect the fission yield of fission products?

The fission yield of fission products can be affected by various factors such as the type of nuclear fuel used, the energy of the neutrons involved in the fission process, and the presence of impurities in the fuel. It can also vary depending on the type of reactor and the conditions under which the fission occurs.

5. How does fission yield of fission products impact nuclear waste disposal?

The fission yield of fission products is an important factor in determining the level and type of radioactive waste produced during nuclear fission. Higher fission yields can result in more radioactive waste that needs to be safely stored and disposed of. Understanding the fission yield can help in developing strategies for managing and disposing of nuclear waste.

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