Enriched and Depleted Uranium

Natural uranium 1__________ from the earth contains the isotopes uranium-238, uranium-235 and uranium-234. The majority (99.2745%) of all the atoms in natural uranium are uranium-238. Most of the remaining atoms (0.72%) are uranium-235, and a slight trace (0.0055%) is uranium-234. Although all isotopes of uranium have similar chemical properties, each of the isotopes has 2__________ different nuclear 3__________. For reasons that will be discussed in later modules, the isotope uranium-235 is usually the desired material for use in reactors.

A vast amount of equipment and energy are expended in processes that separate the isotopes of uranium (and other elements). The details of these processes are beyond the scope of this module. These processes are called enrichment processes because they selectively 4_________ the proportion of a particular isotope. The enrichment process typically starts with feed material that has the proportion of isotopes that occur naturally.

In the case of uranium, the natural uranium ore is 0.72 a/o uranium-235. The desired outcome of the enrichment process is to produce enriched uranium. Enriched uranium is defined as uranium in which the isotope uranium-235 has a concentration greater than its natural value. The enrichment process will also result in the byproduct of depleted uranium. Depleted uranium is defined as uranium in which the isotope uranium-235 has a concentration less than its natural value. Although depleted uranium is referred to as a by-product of the enrichment process, it does have uses in the nuclear 5_________ and in commercial and defense industries.

1. A undermined B mined C sourced

2. A meaningly B emphatically C significantly

3. A qualities B properties C traits

4. A increase B extend C supplement

5. A area B sphere C field

Read the following definitions and decide what they mean. Share your ideas with other students in your group. Use a dictionary if necessary. Then enlarge the list of definitions and ask your groupmates to guess what they mean.

Date: 2015-05-18; view: 502; Нарушение авторских прав