In reactor physics, which condition describes a reactor that is supercritical due to more than one neutron causing fissions?

In reactor physics, which condition describes a reactor that is supercritical due to more than one neutron causing fissions?

• A. k=1
• B. k<1
• C. k>1
• D. k=0

Answer: (C)

The key idea is the neutron multiplication factor, k, which tells how the neutron population changes from one generation to the next. If more than one neutron on average goes on to cause a fission, the chain reaction grows and the reactor is supercritical. That's what k > 1 means: each generation produces more fission opportunities than the previous one, so the neutron population—and the power—rises. If k = 1, the neutron population stays the same (critical). If k < 1, it declines (subcritical). If k = 0, no neutrons cause fission at all. So the description “supercritical due to more than one neutron causing fissions” corresponds to k > 1.

The key idea is the neutron multiplication factor, k, which tells how the neutron population changes from one generation to the next. If more than one neutron on average goes on to cause a fission, the chain reaction grows and the reactor is supercritical. That's what k > 1 means: each generation produces more fission opportunities than the previous one, so the neutron population—and the power—rises. If k = 1, the neutron population stays the same (critical). If k < 1, it declines (subcritical). If k = 0, no neutrons cause fission at all. So the description “supercritical due to more than one neutron causing fissions” corresponds to k > 1.