Calculating burnup/consumption rates in thermal/fast reactor

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In summary, you need to find the molar mass of Pu-239, the capture-to-fission ratio, and the absorption cross section for 239Pu to calculate fuel burnup and consumption rates for fast reactors.
  • #1
Matthew92
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Homework Statement



I am currently taking an introductory course in nuclear engineering. We are using Lamarsh's Introduction to Nuclear Engineering, 3rd Ed.

My question revolves around calculating fuel burnup and consumption rates for thermal reactors and fast reactors. In particular, problem 9 from chapter 4:

If a nuclear reactor is assumed to have a recoverable energy per fission of 200 MeV, calculate the fuel burnup and consumption rates in g/MWd for:
(a) thermal reactors fueled with 233U or 239Pu; and (b) fast reactors fueled with 239Pu.
[Note: In part (b), take the capture-to-fission ratio to be 0.065]

2. The attempt at a solution

For part a, I was able to find thermal data for fissile nuclides (Table 3.4) and was able to come up with this solution:
jUCyqnX.jpg


I however can not find any relevant data to perform part b. I am a bit confused as to how to approach this last portion. Any help and guidance would be truly appreciated.
 
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  • #2
Matthew92 said:

Homework Statement



I am currently taking an introductory course in nuclear engineering. We are using Lamarsh's Introduction to Nuclear Engineering, 3rd Ed.

My question revolves around calculating fuel burnup and consumption rates for thermal reactors and fast reactors. In particular, problem 9 from chapter 4:

If a nuclear reactor is assumed to have a recoverable energy per fission of 200 MeV, calculate the fuel burnup and consumption rates in g/MWd for:
(a) thermal reactors fueled with 233U or 239Pu; and (b) fast reactors fueled with 239Pu.
[Note: In part (b), take the capture-to-fission ratio to be 0.065]

2. The attempt at a solution

For part a, I was able to find thermal data for fissile nuclides (Table 3.4) and was able to come up with this solution:
jUCyqnX.jpg


I however can not find any relevant data to perform part b. I am a bit confused as to how to approach this last portion. Any help and guidance would be truly appreciated.
Which relevant data specifically are you looking for? You know how much energy each fission yields (approx. 200 MeV / fission), the molar mass of Pu-239, and the ratio of captures to fissions of 0.065.

This article also has a table of thermal neutron cross sections for various fissile isotopes:

http://en.wikipedia.org/wiki/Breeder_reactor
 
  • #3
SteamKing said:
Which relevant data specifically are you looking for? You know how much energy each fission yields (approx. 200 MeV / fission), the molar mass of Pu-239, and the ratio of captures to fissions of 0.065.

This article also has a table of thermal neutron cross sections for various fissile isotopes:

http://en.wikipedia.org/wiki/Breeder_reactor

Thank you for your response. After taking what you said into consideration, I came up with this work for part b:
PXIE6lh.jpg


I am however unsure as to what value would be input into the "absorption x-section" value. For part a, I was able to use a table in my textbook that had all of these values for thermal reactors, but a similar table does not exist for fast reactors.

I really do appreciate the continued help!
 

1. What is burnup/consumption rate in a nuclear reactor?

Burnup/consumption rate refers to the amount of fuel (usually measured in gigawatt days per metric ton of heavy metal) that is consumed or burned up in a nuclear reactor over a certain period of time. This is an important factor in determining the efficiency and lifespan of a reactor.

2. How is burnup/consumption rate calculated in thermal/fast reactors?

Burnup/consumption rate is calculated by measuring the amount of fuel that is present before and after a certain period of time in the reactor. This data is then used to calculate the amount of energy produced by the fuel and the amount of fuel consumed. The calculation also takes into account factors such as neutron flux, reactor power, and fuel enrichment.

3. What is the difference between thermal and fast reactors in terms of burnup/consumption rate?

Thermal reactors use slow-moving neutrons to sustain the nuclear reaction, while fast reactors use fast-moving neutrons. This results in a higher burnup/consumption rate in fast reactors, as they are able to use more of the fuel's energy before it is depleted.

4. How does burnup/consumption rate affect the safety of a nuclear reactor?

A higher burnup/consumption rate can lead to the production of more radioactive byproducts, which can pose safety concerns if not properly managed. However, a higher burnup rate also means that less fuel is required to produce the same amount of energy, which can decrease the amount of nuclear waste generated.

5. What factors can influence the burnup/consumption rate in a nuclear reactor?

The burnup/consumption rate in a nuclear reactor can be influenced by several factors, including reactor design, fuel type and enrichment, reactor operating conditions, and the presence of neutron-absorbing materials. Additionally, the burnup rate can also be affected by the management of the reactor, such as the frequency of refueling and the use of control rods to regulate the nuclear reaction.

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