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Nuclear Theft: Risks and Safeguards
from the nuclear power industry and related activities because
of the magnitude of the flows of nuclear weapon materials that will
necessarily build up as the industry develops and expands, and
because of the importance of effective safeguards against nuclear
theft as an element of any future U.S. energy policy.
In this
chapter, therefore, we describe the fuel cycles of the kinds of
nuclear power plants that are operating or under construction
today, that have been ordered by electric utilities from the
various reactor manufacturers, or that are now under intensive
development for commercial use as part of the federal government's
energy R & D program. We consider in this chapter the industry
as it is expected to develop until 1980. This can be foreseen quite
clearly because almost all the nuclear power plants that could be
operating by 1980 have already been ordered. We will cover the same
major questions, more speculatively, in Chapter 4 for the period
1980–2000, during which a number of different paths could be
followed in the development of nuclear power.
POWER
REACTOR FUEL CYCLES
The basic
type of reactor for most of the nuclear power plants expected to be
operating in the United States through 1980 is the light water
reactor (LWR). A few plants will use another type, the high
temperature gas-cooled reactor (HTGR). The first prototype of a
liquid metal-cooled fast breeder reactor (LMFBR) is not expected to
be in operation until 1980 at the earliest, but a large scale LMFBR
research and development program has been underway since the
mid–1960s as the nation's top priority energy R & D
effort.
LWR Fuel
Cycle
The
Reactors. A good place to begin a description of the materials
in a nuclear fuel cycle is at the nuclear reactor itself. A brief
overview of basic reactor technology can also be helpful in showing
why certain materials are used in the fuel cycle, where they are,
and the forms they take. There are two kinds of LWR—the
pressurized water reactor (PWR) and the boiling water reactor
(BWR). Both use water as the coolant and also as the moderator to
slow down neutrons in order to make them more efficient in
producing fissions. In PWR's nuclear fission which occurs in fuel
contained inside metal-covered fuel rods heats pressurized water
surrounding the rods. The hot water is circulated through a closed
loop, which provides heat through a heat exchanger to generate
steam that is then used to drive the large turbines that generate
electricity. In BWR's a mixture of water and steam is discharged
from the reactor vessel and dried, and the steam is then used
directly to drive turbines. In both types of nuclear power plants
the overall efficiency with which fission energy is converted to
electricity is typically about 30 percent; the remaining 70 percent
is generally discharged as waste heat.