Question

Uranium-235 undergoes fission to produce two neutrons per fission event. If a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 0.5 neutrons per fission event, which of the following will be effective at achieving a critical mass? Check all that apply.

Surround the sample with a deflective material to prevent neutrons from escaping to the surroundings.

Add more absorbent material.

Compress the uranium-235 sample.

Answer 1

The answers that apply;

1. Surround the sample with a reflective material to prevent neutrons from escaping to the surroundings.
2. Compress the uranium-235 sample

Compressing the uranium sample ensures that the few neutrons emitted per fusion event, have a higher probability of hitting another uranium atom.

The neutron that manages to pass through the sample without hitting a uranium atom to continue to the fusion chain reaction is deflected by the deflective material back to the sample hence doubling it the probability of colliding with a uranium atom.

Answer 2

Answer:

A) Surround the sample with a deflective material to prevent neutrons from escaping to the surroundings.

C) Compress the uranium-235 sample.

Explanation:

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