Eta (Reproduction Factor) Impact of Fuel Leg Change

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The discussion centers on the decline of the eta (Reproduction Factor) when the fuel leg is altered from its maximum yield level. It highlights the relationship between neutron energy spectral effects and temperature, noting that an increase in neutron velocity (v) can lead to a decrease in the fission cross-section while increasing absorption due to resonance absorption. The importance of considering both fissile and fertile species, along with other materials and coolant, is emphasized in understanding these dynamics. Clarification on the specific phrasing of the question is sought to better address the issue. Understanding these factors is crucial for optimizing fuel performance in nuclear reactions.
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why does eta(Reproduction Factor) fall down when we change fuel leg from maximum level of yield?
 
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ms.shafeie said:
why does eta(Reproduction Factor) fall down when we change fuel leg from maximum level of yield?
I don't quite follow the question, specifically the part "when we change fuel leg from maximum level of yield". Please elaborate on this statement.

η = Ʃi (vi Ʃf,i) / Ʃa, where Ʃa is the weighted sum of the macroscopic absorption cross-section of the fuel material mixture. The index i refers to the fissile (and fertile) species. Fertile nuclides fission mainly with fast neutrons.

There are neutron energy spectral effects and temperature effects. If v (nu) increases, the fission cross-section decreases and the absorption increases (due to increased resonance absorption). One has to look at the fissile and fertile species, as well as other materials and coolant.
 
thanks a lot for ur good respond to my question.ur suggetion is right and I try to solve my problem in asking questions.
 

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