The FuTure oF nuclear Fuel cycle - MIT Energy Initiative

to judge fuel cycles. Some of the criteria (economics, safety, and environment) are similar
to criteria used to evaluate any other energy system; but, the criteria of waste management,
uranium utilization, and nonproliferation are unique to nuclear fuel cycles.
Resource utilization. The existing once-through fuel cycle uses less than 1% of the energy
in the uranium that is mined. Other fuel cycles with other types of reactors can extract
50 times as much energy per ton of natural uranium. These reactors can use the depleted
uranium byproduct of the enrichment process, the uranium in the SNF, and the plutonium
in the SNF to produce energy. More efficient use of uranium would assure fuel for nuclear
reactors for thousands of years. This is not done today in the United States because, among
other reasons, it is uneconomic.
Nonproliferation. Fissile nuclear materials can be used to make nuclear weapons. Uranium
enrichment plants can be used to make weapons-grade materials (>90% uranium-235).
The SNF can be chemically processed to recover weapons-useable plutonium. The technical
ease or difficulty of recovering weapons-usable materials is dependent upon the choice of
fuel cycle, as the cycle affects the amount and concentration of the weapons-usable material
in the fuel, and the associated intensity level of radioactivity, which makes handling
the material more difficult. Ultimately though, nonproliferation is influenced more by the
internationally applied policies as disincentives for nuclear weapons proliferation.
Waste Management. Spent nuclear fuel is the primary waste from the once-through fuel
cycle. It contains greater than 99% of the radioactivity. It has unique characteristics compared
to wastes from fossil plants. Only about 5% of the energy value has been consumed
in the reactor. It can be considered either a waste or a future energy resource. The energy
release from nuclear fission per ton of fuel is about a million times greater than the energy
release from the burning of fossil fuels. The waste volume generated is about a million
times less. The quantity of SNF is small per unit of energy produced. The small quantity
(~20 tons per reactor per year) makes economically feasible multiple waste management
options: multiple direct disposal options and multiple options to chemically process the
SNF for recovery of selected materials for recycle and/or conversion into different waste
forms.
Economics. Economics is the primary criterion
by which a market-based system
chooses reactors and fuel cycles. Table 2.2
shows the cost breakdown for new nuclear
and fossil plants where costs are divided
into capital costs, operating and maintenance
costs, and fuel costs. There are also
significant regional differences in relative
costs of various energy sources. With today’s
once-through fuel cycle, fuel-cycle
costs for an LWR are about 10% of the total
busbar cost of electricity and include
everything from the purchase of uranium
ore to disposal of the SNF. The uranium
costs (0.25 ¢/kwh) are approximately a
third of the fuel costs or about 3% of elec-
Table 2.2 Breakdown of the Levelized Cost of Electricity
CoStS
nuClear ¢/kwh
(% oF total)
riSK
premium 1
no riSK
premium 1
Coal ¢/kwh
(% oF total)
natural GaS 2
¢/kwh
(% oF total)
capital costs 6.6 (79) 4.9 (74) 2.8 (45) 1.0 (15)
operations and Maintenance 0.9 (11) 0.9 (14) 0.8 (14) 0.2 (3)
Fuel costs 0.8 (10) 0.8 (12) 2.6 (41) 5.3 (82)
Total 8.4 (100) 6.6 (100) 6.2 (100) 6.5 (100)
1. In the u.S. there is a financial risk premium with new nuclear plants that increases capital
costs. The federal first-mover incentives for new plants is to eliminate that financial
risk premium.
2. Because of large variations in gas prices over the last decade, we assessed levelized
cost of electricity for three gas prices: 4, 7, and 10 $/10 6 BTu. The corresponding levelized
costs of electricity were 4.2, 6.5, and 8.7 ¢/kwh.
chapter 2 — Framing Fuel cycle Questions 21