How is the steady-state loss of reactivity due to Xe poisoning calculated for a high-power reactor?

How is the steady-state loss of reactivity due to Xe poisoning calculated for a high-power reactor?

• A. ρ = - (σX)/(ν Σ_f)
• B. ρ = - (λ_x + σX)/(ν Σ_f)
• C. ρ = (γ_x + γ_i)/(ν Σ_f)
• D. ρ = (γ_i + λ_x)/(ν Σ_f)

Answer: (A)

The correct approach to calculate the steady-state loss of reactivity due to fission products such as xenon-135 (Xe) in a high-power reactor involves understanding the balance between production and absorption in the reactor core. The formula used for this calculation includes several important parameters: 1. **σX**: This represents the microscopic absorption cross-section for xenon-135. It quantifies how effectively xenon-135 captures neutrons, which significantly contributes to the reactivity loss in the reactor. 2. **ν**: This is the average number of neutrons produced per fission event. It is crucial because it indicates how many neutrons are available to sustain the fission chain reaction. 3. **Σ_f**: This is the macroscopic fission cross-section, representing the probability of fission occurring in the reactor per unit volume. The equation ρ = - (σX)/(ν Σ_f) indicates that the loss of reactivity (ρ) due to xenon poisoning is directly related to the absorption characteristics of xenon-135 compared to the neutron economy of the reactor. As xenon absorbs neutrons more efficiently, the reactivity decreases, resulting in a negative value for ρ. This calculation is essential for

The correct approach to calculate the steady-state loss of reactivity due to fission products such as xenon-135 (Xe) in a high-power reactor involves understanding the balance between production and absorption in the reactor core.

The formula used for this calculation includes several important parameters:

1. σX: This represents the microscopic absorption cross-section for xenon-135. It quantifies how effectively xenon-135 captures neutrons, which significantly contributes to the reactivity loss in the reactor.

2. ν: This is the average number of neutrons produced per fission event. It is crucial because it indicates how many neutrons are available to sustain the fission chain reaction.

3. Σ_f: This is the macroscopic fission cross-section, representing the probability of fission occurring in the reactor per unit volume.

The equation ρ = - (σX)/(ν Σ_f) indicates that the loss of reactivity (ρ) due to xenon poisoning is directly related to the absorption characteristics of xenon-135 compared to the neutron economy of the reactor. As xenon absorbs neutrons more efficiently, the reactivity decreases, resulting in a negative value for ρ.

This calculation is essential for