Which property is most important to minimize neutron losses due to absorption?

Which property is most important to minimize neutron losses due to absorption?

• A. High scattering cross section
• B. Inexpensive and abundant
• C. Low absorption cross section
• D. High fractional energy loss per collision

Answer: (C)

Minimizing neutron absorption losses comes down to the likelihood that a neutron will be captured by the material. The probability of absorption is governed by the absorption cross section: the larger this cross section, the more neutrons get absorbed when they encounter the material. So, using materials with a low absorption cross section directly reduces these losses and helps keep neutrons in circulation. The other properties affect different aspects of reactor behavior. A high scattering cross section can help slow or reflect neutrons, but it doesn’t by itself reduce the chance of absorption. Being inexpensive or abundant is a practical consideration, and a high fractional energy loss per collision relates to moderation efficiency, not to the intrinsic rate of absorption.

Minimizing neutron absorption losses comes down to the likelihood that a neutron will be captured by the material. The probability of absorption is governed by the absorption cross section: the larger this cross section, the more neutrons get absorbed when they encounter the material. So, using materials with a low absorption cross section directly reduces these losses and helps keep neutrons in circulation.

The other properties affect different aspects of reactor behavior. A high scattering cross section can help slow or reflect neutrons, but it doesn’t by itself reduce the chance of absorption. Being inexpensive or abundant is a practical consideration, and a high fractional energy loss per collision relates to moderation efficiency, not to the intrinsic rate of absorption.