Environmental Engineering Reference
In-Depth Information
Current R and D efforts focus on reprocessing spent fuel without separating the
plutonium, with the goal of rendering it virtually useless to potential proliferators.
Much of the reprocessed fuel could be reused in commercial reactors to generate
electricity.
In February 2006, DOE announced the Global Nuclear Energy Partnership
(GNEP) program, characterizing it as an extension of the AFCI program. GNEP
furthers the R and D goals of the AFCI program, accelerating the R and D efforts
and introducing a global component. DOE's intent is to work with other nations
that reprocess spent fuel to supply fuel to countries for the purpose of generating
electricity. The countries then would return the spent fuel to the supplier nations
for reprocessing. Once reprocessed, this fuel would be returned to the countries
for reuse. The intent of the program is to encourage these “reactor-only” countries
not to develop their own independent nuclear technologies, thereby reducing
proliferation risks. Details of the program are still being developed. DOE
requested $243 million for the combined AFCI and GNEP programs in fiscal year
2007. According to DOE officials, the GNEP program would need about $5
billion over the next 5 years.
The Generation IV program focuses on developing new, fourth generation,
advanced reactor technologies intended to be commercially available by about
2020 to 2030. The program, including the United States and 12 international
partners, identified six advanced reactor designs from which DOE has focused on
two reactor designs: (1) a sodium-cooled fast reactor and (2) a gas-cooled very
high temperature reactor. A fast reactor manages nuclear reactions somewhat
differently than current commercial reactors, in which neutrons interact with the
low-enriched uranium fuel atoms to induce fissions—or the splitting of the
uranium atom—that emits more neutrons and leads to a self-sustaining chain
reaction. The fissioning of uranium releases large amounts of energy that is
captured as heat to drive turbines and generate electricity. Because the fission
neutrons are born at high energy, they are not inherently efficient at causing more
fissions, so commercial nuclear reactors are filled with water that functions both
to slow the neutrons down and act as a coolant and heat removal system. The
lower energy neutrons in current commercial reactors are much more effective at
sustaining the uranium fission chain reaction. In contrast, a fast reactor manages
these nuclear reactions at a higher energy level. Fast reactors use coolants such as
liquid sodium metal that do not slow down the neutron energy. Because fast
reactors are more effective than current commercial reactors at inducing fissions
in a wider variety of nuclear materials, including plutonium and other materials
that might otherwise become wastes from the current commercial reactor fuel
cycle, they can potentially reduce the total amount, temperature, and radiotoxicity
