Define the effective multiplication factor k_eff and state what k_eff = 1, k_eff > 1, and k_eff < 1 imply for reactor operation.

• A. k_eff is the ratio of neutrons produced by fission to neutrons absorbed.
• B. k_eff is the ratio of the number of neutrons in one generation to the previous generation, accounting for leakage.
• C. k_eff is the total neutron population in the reactor.
• D. k_eff is the ratio of neutrons created to neutrons lost to leakage.

Answer: (B)