Nuclear power plants produce electricity through a heat-generating process known as "fission," in which neutrons split uranium atoms to produce large amounts of energy.  
In the plant’s nuclear reactor, neutrons from uranium atoms collide with each other, releasing heat and neutrons in a chain reaction. This heat is used to generate steam, which powers a turbine to generate electricity.  Under the right conditions, a uranium atom will split into two smaller atoms and throw off two or sometimes three neutrons in the process.

Nuclear power generates a number of radioactive by-products, including tritium, cesium, krypton, neptunium and forms of iodine.

An ongoing problem of all nuclear plants, is nuclear waste.
Nuclear waste is the spent nuclear fuel from a reactor. The fuel is considered spent when the fission byproducts -- the atoms left over from the splitting process -- prevent free neutrons from splitting more uranium or plutonium. It takes three or four years to get to this point in the process.

According to the Department of Energy, as of 2003, nuclear reactors in the United States have created well over 50,000 tons of highly radioactive waste.
Some countries, like Japan and France, reprocess their nuclear waste to extract the unspent uranium and plutonium. This can be returned to use in nuclear power plants or used to create a nuclear bomb.

The US is still without a long-term storage plan, although pressure is mounting to have Congress overrule the people of Nevada and open the Yucca Mountain site to waste shipments. Meanwhile, waste is piling up in storage pools and casks at plants across the country.

There is an ongoing debate about the use of nuclear energy.  Proponents, such as the World Nuclear Association and IAEA, contend that nuclear power is a sustainable energy source that reduces carbon emissions.  Opponents, such as Greenpeace International and NIRS, believe that nuclear power poses many threats to people and the environment.

Nuclear power plant accidents include the Chernobyl disaster (1986), Fukushima Daiichi nuclear disaster (2011), and the Three Mile Island accident (1979).  There have also been some nuclear-powered submarine mishaps.  Despite these accidents, the safety record of nuclear power, in terms of lives lost per unit of electricity delivered, is better than every other major source of power in the world.  With research into safety improvements continuing  and nuclear fusion may be used in the future.

China has 25 nuclear power reactors under construction, with plans to build many more, while in the US the licenses of almost half its reactors have been extended to 60 years, and plans to build another dozen are under serious consideration. However, Japan's 2011 Fukushima Daiichi nuclear disaster prompted a rethink of nuclear energy policy in many countries. Germany decided to close all its reactors by 2022, and Italy has banned nuclear power.  Following Fukushima, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.

Neighborhood Nukes
Power lines consume an enourmous amount of energy. To reduce this loss we must integrate power generation in our towns and neighborhoods called; “District Energy”, mentioned earlier. One possible solution is a Micro Nuke as outlined here.

A tall, thin, single-vessel design. NuScale Power’s compact  reactor, designed to be modular.
Water heated by the core ascends in a chimney-like metal structure inside the reactor, then spills over the top of the chimney and sinks back down along the inside walls of the reactor to repeat the journey.
Water passes over a long coil of pipe, transferring much of its heat to water inside the coil. Lower pressure in the coil allows the water to boil, and the resulting steam travels up the pipe to power a turbine. The NRC is expected to approve it in 2015.
Multiple units could replace existing large reactors, simplifying the design and reducing cost.