Boron worth is defined as which of the following?

Boron worth is defined as which of the following?

• A. Boron worth is the reactivity change per unit boron concentration, accounting for depletion and temperature effects.
• B. Boron worth is the amount of boron in the coolant.
• C. Boron worth is the thermal conductivity of boron.
• D. Boron worth is the color of boron solution.

Answer: (C)

Boron worth measures how sensitive the reactor’s reactivity is to changes in boron concentration. Since boron absorbs neutrons, adding or removing boron shifts the neutron population and the tendency for the reactor to be critical. It is defined as the change in reactivity per unit change in boron concentration (often expressed as pcm per ppm). This definition accounts for depletion (boron concentration changing with burnup) and temperature effects (temperature changes the neutron spectrum and cross sections, altering boron’s effectiveness). That’s why the description focusing on reactivity change per unit boron concentration is the right one. The other ideas—amount of boron in the coolant, thermal conductivity, or color—do not describe how reactivity responds to boron changes.

Boron worth measures how sensitive the reactor’s reactivity is to changes in boron concentration. Since boron absorbs neutrons, adding or removing boron shifts the neutron population and the tendency for the reactor to be critical. It is defined as the change in reactivity per unit change in boron concentration (often expressed as pcm per ppm). This definition accounts for depletion (boron concentration changing with burnup) and temperature effects (temperature changes the neutron spectrum and cross sections, altering boron’s effectiveness). That’s why the description focusing on reactivity change per unit boron concentration is the right one. The other ideas—amount of boron in the coolant, thermal conductivity, or color—do not describe how reactivity responds to boron changes.