问答题
{{B}}Directions:{{/B}}
Read the following text carefully and then translate
the underlined segments into Chinese. Your translation should be written clearly
on ANSWER SHEET 2.
All U. S. nuclear weapons production facilities are presently
closed down, and if the various agreements are adhered to, those facilities will
never be required except for one critical capability. All modern nuclear weapons
use uranium (铀), plutonium (钚), and tritium (氚). Uranium and plutonium have very
long half-lives, and there is large surplus of these materials.
Tritium, however, has a relatively short half life of about 12.6 years, so
about 5 percent of the amount on hand must be replaced each year to maintain the
current inventory. (46) {{U}}Because of the large retirement of nuclear weapons by
the United States in compliance with early agreements and national policy,
tritium from retired weapons has been used to make up that lost through natural
decay.{{/U}} (47) {{U}}However, in about 10 to 15 years, depending on future
negotiations, the United States will need a guaranteed supply of tritium to
maintain its stockpile at whatever level is agreed on.{{/U}}
In
anticipation of this future need to produce tritium, Defense Office Executive is
pursuing two technologies. One uses a nuclear reactor that could also produce
electricity whose sale would recover not only the capital cost of the reactor
but also its annual operational cost. (48) {{U}}Unfortunately, the present
Administration has a definite bias against nuclear power, so an alternative
method is also being pursued even though it is agreed that it will cost twice as
much as a reactor and use as much electricity as a reactor would produce.{{/U}}
This technology uses an accelerator to produce high-energy protons that in turn
produce neutrons.
The main argument for the accelerator is that
it produces no conventional nuclear wastes. (49) {{U}}Proponents readily admit
that it will produce radioactive materials, but with a relatively short
half-life compared with that of wastes from spent nuclear fuel.{{/U}} The fact
that the accelerator will require the equivalent of a nuclear power plant to
supply its electricity is ignored.
(50) {{U}}Proponents also
neglect to mention that about 22 percent of all electrical energy generated in
the United States comes from nuclear power plants, so that 22 percent of the
power used by the accelerator will generate conventional nuclear wastes, in
addition to those the accelerator produces.{{/U}} There is an alternative to
either the reactor or the accelerator, which is simply to buy the required
tritium from Canada or Russia.