Nuclear

The ability to control nuclear fission reactions, in which atoms of radioactive elements such as uranium split apart into smaller atoms and liberate energy in the process, represents one of the great technological feats of the twentieth century. Harnessed as heat, the released energy boils water, producing steam that drives turbines, thereby being converted to mechanical energy that generates electricity. Nuclear energy currently provides 20% of total electricity  generation in the United States and 9.5% of total energy consumed.

Nuclear energy currently provides 20% of total electricity  generation in the United States.

According to the U.S. Energy Information Administration’s 2015 estimates, output from nuclear power plants is expected to remain flat through 2040. Nuclear capacity could decline by as much as 30% by 2035 unless existing plants are updated, licenses are extended, or new plants are constructed and operated in the very near future. Four reactors were removed from service in 2013 and one entered service in 2014, leaving a total of 60 commercially operating plants (with 100 reactors) in 30 states as of 2015. But of those, 72 reactors received license renewals that allow longer operation. And in 2015 four new plants were under construction and proposals for eight more were under review by the Nuclear Regulatory Commission.

In 2015, U.S. commercial nuclear power reactors bought 56.5 million pounds of uranium from both domestic and foreign suppliers; domestic production accounted for only 3% of that total. According to the International Atomic Energy Agency, worldwide identified resources totaled about 7.6 million metric tons in 2014. If there is renewed U.S. interest in nuclear fission power generation, sufficient uranium supplies will likely be available.

Some countries have made substantial commitments to nuclear power generation: For example, nuclear power plants produce more than three-quarters of all electricity in France. In the United States, the issue prompts considerable debate, including concern about plant safety (which has been strong since the 1979 Three Mile Island accident), security (keeping nuclear material out of the hands of criminals), and arguments about where and how to dispose of nuclear waste, a contentious issue that remains unresolved after decades of effort. Additionally, the low cost of natural gas is making it more difficult for nuclear power to compete in U.S. energy markets.

According to the Congressional Research Service, as of December 2011, there were more than 67,000 metric tons of spent nuclear fuel (SNF) from U.S. reactors in “interim” storage at 77 sites in the United States (including four U.S. Department of Energy facilities), increasing at a rate of roughly 2,000 metric tons per year. At present, there is no plan to store this SNF at any permanent waste site.

Many countries re-process SNF from commercial reactors to increase its radioactive content, although the United States does not.

Another nuclear energy source, fusion, is the process that powers the Sun and the stars. In theory, it could offer a virtually unlimited supply of energy with significantly reduced quantities of long-lived radioactive waste compared to fission, if successfully harnessed in a reactor. To date, several large new research facilities have been built to investigate alternative technologies for generating energy from fusion. Although continuous progress is being made, none of the facilities has achieved “ignition,” the point at which a fusion reaction sustains itself, despite decades of research. Absent a significant breakthrough, fusion reactors are unlikely to be ready for commercial deployment in the foreseeable future.