Although nuclear energy is considered clean energy its inclusion in the renewable energy list is a subject of major debate. To understand the debate we need to understand the definition of renewable energy and nuclear energy first.
Renewable energy is defined as an energy source/fuel type that can regenerate and can replenish itself indefinitely. The five renewable sources used most often are biomass, wind, solar, hydro and geothermal.
Nuclear energy on the other hand is a result of heat generated through the fission process of atoms. All power plants convert heat into electricity using steam. At nuclear power plants, the heat to make the steam is created when atoms split apart - called fission. The fission releases energy in the form of heat and neutrons. The released neutrons then goes on to hit other neutrons and repeat the process, hence generating more heat. In most cases the fuel used for nuclear fission is uranium.
Most supporters of nuclear energy point out the low carbon emission aspect of nuclear energy as its major characteristic to be defined as renewable energy. According to nuclear power opponents, if the goal to build a renewable energy infrastructure is to lower carbon emission then there is no reason for not including nuclear energy in that list. 
But one of the most interesting arguments for including nuclear energy in the renewable energy portfolio came from Bernard L Cohen, former professor at University of Pittsburg. Professor Cohen defined the term 'indefinite'(time span required for an energy source to be sustainable enough to be called renewable energy) in numbers by using the expected relationship between the sun (source of solar energy) and the earth. According to Professor Cohen, if the Uranium deposit could be proved to last as long as the relationship between the Earth and Sun is supposed to last (5 billion years) then nuclear energy should be included in the renewable energy portfolio. 
In his paper Professor Cohen claims that using breeder reactors (nuclear reactor able to generate more fissile material than it consumes) it is possible to fuel the earth with nuclear energy indefinitely. Although the amount of uranium deposit available could only supply nuclear energy for about 1000 years, Professor Cohen believes actual amount of uranium deposit available is way more than what is considered extractable right now. In his arguments he includes uranium that could be extracted at a higher cost, uranium from the sea water and also uranium from eroding earth crust by river water. All of those possible uranium resources if used in a breeder reactor would be enough to fuel the earth for another 5 billion years and hence renders nuclear energy as renewable energy. 
One of the biggest arguments against including nuclear energy in the list of renewable is the fact that uranium deposit on earth is finite, unlike solar and wind. To be counted as renewable, the energy source (fuel) should be sustainable for an indefinite period of time, according to the definition of renewable energy.
Another major argument proposed by the opponents of including nuclear energy as renewable energy is the harmful nuclear waste from nuclear power reactors. The nuclear waste is considered as a radioactive pollutant that goes against the notion of a renewable energy source.  Yucca Mountain is one of the examples used quite often to prove this point. Most of the opponents in the US also point at the fact that while most renewable energy source could render the US energy independent, uranium would still keep the country energy dependent as US would still have to import uranium. 
It seems like at the heart of debate lies the confusion over the exact definition of renewable energy and the requirements that needs to be met in order to be one. The recent statement by Helene Pelosi, the interim director General of IRENA (International Renewable Energy Agency), saying IRENA will not support nuclear energy programs because its a long, complicated process, it produces waste and is relatively risky, proves that their decision has nothing to do with having a sustainable supply of fuel.  And if that's the case then nuclear proponents would have to figure out a way to deal with the nuclear waste management issue and other political implications of nuclear power before they can ask IRENA to reconsider including nuclear energy in the renewable energy list .
© Navid Chowdhury. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 K. Johnson, "Is Nuclear Power Renewable Energy," Wall Street Journal, 21 May 09.
 B.L. Cohen, "Breeder Reactors: A Renewable Energy Source," Am. J. Phys. 51, 75 (1983).
 J. Kanter, "Is Nuclear Power Renewable," New York Times, 3 Aug 09.