Question

Nuclear (Please show work)

9) Which one of the following is a reason for neutron flux shaping in a reactor core? A. To minimize local power peaking by more evenly distributing the core thermal neutron flux B. To reduce thermal neutron leakage by decreasing the neutron flux at the edge of the reactor core C. To reduce the size and number of control rods needed to ensure the reactor remains subcritical following a reactor trip D. To increase differential control rod worth by peaking the thermal neutron flux at the top of the reactor core 10) For a slightly supercritical reactor operating below the point of adding heat (POAH), what reactivity effects are associated with reaching the POAH? A. There are no reactivity effects. B. The increase in moderator temperature will begin to create a positive reactivity effect. C. A decrease in moderator temperature will begin to create a negative reactivity effect. D. An increase in moderator temperature will begin to create a negative reactivity effect.

Answer 1

9) Answer: Option A

To minimize local power peaking by more evenly distributing the core thermal neutron flux is the reason for the neutron flux shaping in a reactor core because the flux in the core is more evenly distributed when the size of the core is bigger.

10) Answer: Option D

An increase in moderator temperature will begin to create a negative reactivity effect. as fuel temperature increases the negative reactivity or rective reactivity also increases because temperature directly proportional to the reactivity.

$\frac{dk}{dT}=\alpha _{T}k^{2}$

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