Fill in the gaps (1-6) with the words from the box below the text. There is one extra word which you don’t need to use.

 

Figure 6 shows the distribution of the stable nuclides plotted on the same 1__________ as the Chart of the Nuclides. As the 2__________ become higher, the ratio of neutrons to protons in the nucleus becomes larger. For helium-4 (2 protons and 2 neutrons) and oxygen-16 (8 protons and 8 neutrons) this ratio is unity. For indium-115 (49 protons and 66 neutrons) the ratio of neutrons to protons has increased to 1.35, and for uranium-238 (92 protons and 146 neutrons) the neutron-to-proton ratio is 1.59.

 

 

If a heavy nucleus were to split into two fragments, each fragment would form a nucleus that would have approximately the same 3__________ ratio as the heavy nucleus. This high neutron-to-proton ratio places the fragments below and to the right of the 4__________ displayed by Figure 6. The instability caused by this 5__________ of neutrons is generally rectified by successive beta emissions, each of which converts a neutron to a 6__________ and moves the nucleus toward a more stable neutron-to-proton ratio.

 

neutron-to-proton	Proton	stability curve	mass numbers
excess	Axes	nucleon

Give the definitions of the notions below.

1. chart is …

2. axis is …

3. average thermal neutron absorption cross section is …

4. thermal neutron activation cross section is …

5. neutron-to-proton ratio is …

 

Work in pairs. Complete the table below.

Element	Atomic number	Atomic weight	Melting point	Boiling point	Specific gravity	Valence	Electronic config.
oxygen
indium
thorium
radium

Translate the sentences below paying attention to the emphatic constructions.

 

It is... that (which, who)

Example:

1. It was the temperature change that accounted for the resistance change.

Именно изменение температуры объяснило (обу­словило) изменение сопротивления.

2. It was Kamcrlingh Onnes who anticipated large scale application of superconductivity. Именно К. Оннес предвидел использование сверхпроводимости в больших масштабах.

 

1. It was this accuracy that enabled us to detect the errors as small as+ 2 percent.

2. It was De Broglie who suggested in 1924 that moving particles, e.g. electrons, should exhibit properties of waves.

3. It was owing to this remarkable invention that we have avoided auxiliary operations.

4. It is this ancient alloy that is likely to contain distinct traces (след) of radioactivity.

5. It is because the Maxwell equations are invariant under those transformations that they can be written in a beautiful form.

6. It is after the discovery of X-rays that these conditions could be arrived at (достичь, приводить к).

 

Make up a report on the topics below.

«The Arrangement of the Elements in the Chart of the Nuclides»

(See appendix 4)

TEXT 3

Before reading the text below complete the sentences 1-3.

1. Natural uranium …

2. Enriched uranium …

3. Depleted uranium …

For spaces 1-5, read the text below and decide which answer A, B or C best fits each space.

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.

Example

Plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe is a sink.

 

1. A body that absorbs all radiation and radiates it all away is …

2. A quantum of electromagnetic radiation. An elementary particle that is its own antiparticle is …

3. A physical mechanism that transports heat and energy as electromagnetic waves is …

4. The force on a positive test charge per Coulomb due to other electrical charges is …

5. A property of a substance showing how well it radiates is …

6. The ability of a system to do work is …

7. The force on a moving positive test charge, per Coulomb, from magnets or moving charges is …

8. The law of physics that says the energy of a closed system doesn’t change unless external influences act on the system is …

9. ………………………………………………………………………………

10. …………………………………………………………………………..

11. …………………………………………………………………………..

12. …………………………………………………………………………..

13. …………………………………………………………………………..