Chapter 31, Problem 10Q

To determine

The reason why the uranium cannot be enriched by the chemical means.

Answer to Problem 10Q

The enrichment of uranium is not used because it absorbs neutrons during the reaction and increase the chain reaction. Therefore, uranium can’t be enriched by chemical means.

Explanation of Solution

Introduction:

In a nuclear fission reaction, a heavy nucleus splits in to two or more small nuclei and energy releases. In fission reaction, neutrons are absorbed and produce other nuclear reaction with other nuclei.

In case the light water reactor the ${}_1^1\text{H}$ nuclei absorb the neutrons in the ${}_{92}^{239}\text{U}$ in the given reaction as,

  $n{+}_{92}^{238}\text{U}{\to }_{92}^{238}\text{U}+\gamma$

Consider the naturally occurring contains 99.3% of ${}_{92}^{238}\text{U}$ and only 0.70 percent is fissionable

In order to increase the probability of the fission of ${}_{92}^{235}\text{U}$ , the nuclei of the natural uranium should be enriched so that the increase in the percentage is up to ${}_{92}^{235}\text{U}$ by the diffusion of the centrifugation.

The enrichment is not necessary for reactors using heavy water as moderator because heavy water does not absorb neutrons.

The enrichment of uranium is not used because it absorbs neutrons during the reaction and increase the chain reaction. Therefore, uranium can’t be enriched by chemical means.

Conclusion:

Therefore, the enrichment of uranium is not used because it absorbs neutrons during the reaction and increase the chain reaction. Therefore, uranium can’t be enriched by chemical means.