Overnight costs - These are the costs which would be incurred if a given power plant could be built overnight, and therefore the investment excludes financing costs. They include pre-construction or owners costs, engineering, procurement, construction and contingency costs.

Financing costs - The high costs of a nuclear power plant mean that its overall economics also depend greatly on the cost of capital or financing costs (the interest rate). These rates are the rate of return on investment. The cost of capital (which may range from roughly 3 to 10%) depends on potential investors assessments of the risk factors involved. This will vary depending on who the investors are (for example, governments, large utilities or private investors), the legal and regulatory framework in which the plant will be built, as well as national energy policy and the political background.

Despite having lower lifetime costs (per unit of electricity produced) than renewable technologies, nuclear power is the most sensitive technology to discount rates. Higher discount rates also have the effect of reducing the benefits from longer operating lifetimes of nuclear power plants. Hence the structure and cost of financing is of considerable importance to investments in nuclear capacity.

Construction time - the longer the project takes to complete, the longer interest payments accrue without investors recouping their investment. Construction delays, which are common in new nuclear programThe competitiveness of nuclear power compared with other technologies is also affected by location (i.e. specific siting conditions), electricity prices, the price of carbon and gas prices.

Electricity prices - The profitability of an operational nuclear power plant depends considerably on electricity prices. The higher they are, the better nuclear power fares in both relative and absolute terms from an investors perspective, because electricity prices determine nuclear powers profit margin, given the relatively low operating costs.

Carbon prices - Carbon pricing will increase the competitiveness of nuclear energy against coal and to a lesser extent against gas (see Carbon pricing and the competitiveness of nuclear power). In the competition between nuclear and gas, carbon pricing will favour nuclear in a range up to EUR 50/ tCO (the five-year 2005-2010 EU ETS average was slightly over EUR 14), provided that unmitigated coal stays in the market. Otherwise, increasing carbon prices continue to favour nuclear over carbon-emitting technologies.

Gas prices - What capital costs are to the competitiveness of nuclear energy, gas prices are to the competitiveness of gas-fired power generation, which spends a full two-thirds of its lifetime costs on fuel (for nuclear, fuel accounts for a far lower proportion of costs at around 10 16%). From an investors perspective, if gas prices are low, the relative profitability of gas increases. If they are high, in relative terms nuclear power is more profitable.

The economics of new nuclear power plants is a controversial subject, since there are diverging views on this topic, and multi-billion dollar investments ride on the choice of an energy source. Nuclear power plants typically have high capital costs for construction and for decommissioning as well as the ongoing and future costs of storing nuclear waste. The current benefits of nuclear energy include low fuel costs and low greenhouse gas emissions.Capital costsCapital cost, the building and financing of nuclear power plants, represents a large percentage of the cost of nuclear electricity. In 2014, the US Energy Information Administration estimated that for new nuclear plants going online in 2019, capital costs will make up 74% of the levelized cost of electricity; higher than the capital percentages for fossil-fuel power plants (63% for coal, 22% for natural gas), and lower than the capital percentages for some other nonfossil-fuel sources (80% for wind, 88% for solar PV).[40]Operating costsIn general, coal and nuclear plants have the same types of operating costs (operations and maintenance plus fuel costs). However, nuclear has lower fuel costs but higher operating and maintenance costs.[Fuel costsNuclear plants require fissionable fuel. Generally, the fuel used is uranium, although other materials may be used (See MOX fuel or Thorium). In 2005, prices on the world market for uranium averaged US$20/lb (US$44.09/kg). On 2007-04-19, prices reached US$113/lb (US$249.12/kg).[58] On 2008-07-02, the price had dropped to $59/lb.[59]

Fuel costs account for about 28% of a nuclear plant's operating expenses.[58] As of 2013, half the cost of reactor fuel was taken up by enrichment and fabrication, so that the cost of the uranium concentrate raw material was 14 percent of operating costs.[60] Doubling the price of uranium would add about 10% to the cost of electricity produced in existing nuclear plants, and about half that much to the cost of electricity in future power plants.[61Waste disposal costsAll nuclear plants produce radioactive waste. To pay for the cost of storing, transporting and disposing these wastes in a permanent location, in the United States a surcharge of a tenth of a cent per kilowatt-hour is added to electricity bills.[64] Roughly one percent of electrical utility bills in provinces using nuclear power are diverted to fund nuclear waste disposal in Canada.[DecommissioningAt the end of a nuclear plant's lifetime, the plant must be decommissioned. This entails either dismantling, safe storage or entombment. In the United States, the Nuclear Regulatory Commission (NRC) requires plants to finish the process within 60 years of closing. Since it may cost $500 million or more to shut down and decommission a plant, the NRC requires plant owners to set aside money when the plant is still operating to pay for the future shutdown costsSafety, security and accidentsNuclear safety and security covers the actions taken to prevent nuclear and radiation accidents or to limit their consequences. With the ageing of reactors built in the 1960 and 1970s, there are increased risks of major accidents. This is partly due to design faults but also as a result of radiation causing embrittlement of pressure vessels.[75] New reactor designs have been proposed but there is no guarantee that the reactors will be designed, built and operated correctly.[76] Mistakes do occur and the designers of reactors at Fukushima in Japan did not anticipate that a tsunami generated by an earthquake would disable the backup systems that were supposed to stabilize the reactor after the earthquake.[77][78] According to UBS AG, the Fukushima I nuclear accidents have cast doubt on whether even an advanced economy like Japan can master nuclear safety.[79] Catastrophic scenarios involving terrorist attacks are also conceivable.[76]