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weqwewe [10]
3 years ago
8

In a liquid metal fast breeder reactor, no neutron moderation is desired and sodium is used as a coolant to minimize fission-neu

tron thermalization. How many elastic scatters with sodium, on the average, would it take for 2-MeV neutrons to reach an average thermal energy of 0.025 eV?
Physics
1 answer:
ololo11 [35]3 years ago
5 0

Answer:

219 scatterings

Explanation:

Given that:

The Coolant used In the liquid metal fast breed reactor = Sodium

The atomic weight (A) of sodium = 23

The initial energy E_{i} = 2 - MeV

The final energy E_{f} = 0.025 eV  (thermal energy)

The number of elastic neutron scatterings (n) needed to reach the given average thermal energy can be computed as:

n = \dfrac{log \bigg(\dfrac{E_f}{E_i} \bigg)}{log \bigg [ \dfrac{A^2+1}{(A+1)^2} \bigg]}

n = \dfrac{log \bigg(\dfrac{0.025}{2 \times 10^6} \bigg)}{log \bigg [ \dfrac{23^2+1}{(23+1)^2} \bigg]}

n = \dfrac{log \bigg(1.25\times 10^{-8} \bigg)}{log \bigg [ 0.92014\bigg]}

n = 218.643

n ≅ 219 scatterings

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<h3>Work</h3>

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\int\limits_{v_1}^{v_2} P \ dv = \ n \ R \ T \int\limits_{v_1}^{v_2} \frac{1}{V} \ dv

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T = 27 \° C = 300.15 \ K

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E= c_v n R T

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