# The efficiency of a nuclear power plant

## QUESTION: What is the efficiency of a nuclear power plant?

ANSWER : the efficiency of a nuclear power plant is of the order of 30%.

EXPLANATION: This means that 70% of the "atomic" energy produced by the fission of uranium 235 is "wasted" as heat in the cooling towers.

For a 2 GW electric power plant with 1,3 reactors, this corresponds to a thermal loss of the order of 6 GW and an atomic power of 8,6 GW.

These 6 GW are "evacuated" in the cooling towers of French power plants, there is one tower per reactor (you can therefore easily know the number of reactors in a plant by counting the number of towers).

The heating needs of a modern house are roughly (smoothed over the year) 60 W per m2. Or for a house of 100 m2, 6 kW.

The thermal energy "lost" from a single 2-reactor power station therefore corresponds to the heating of a million houses!

Assuming (which is not the case but it is for the image) that this energy was recoverable in the form of cogeneration, 14 16 to nuclear reactors would be enough to heat the whole of France without any consumption of heating or electrical or fuel oil or gas!

Read also:  The cost of electric kwh

## More: - Is nuclear cogeneration possible? - France Map of nuclear power plants - Map of nuclear power plants worldwide - Forum nuclear energy - Followed by the nuclear accident in Japan following the earthquake of March 11, 2011 - All your questions about nuclear energy to a nuclear specialist - The power of a nuclear reactor - Nuclear and wind load factor

#### 7 comments on “The efficiency of a nuclear power plant”

1. einstein30 says:

the number of "cooling towers" not corresponding to the number of reactors, eg the "Bugey" plant
has 4 "PWR 900 MW" reactors; two reactors (bugey 2 and 3) do not have cooling towers and two 900 mw rep reactors (bugey 4 and 5) have two cooling towers per reactor; another example: Tricastin power station, two cooling towers for
4 reactors, therefore, no relationship between the "number of cooling towers / number of reactors".

2. Pollet says:

We should install a dozen small nuclear reactors in the middle of Paris. They would only be started in winter and the heat "lost" (70%) would be sent to the district heating network. As I live in the province, I do not care much about the risk of a nuclear accident in Paris.

3. kigcats says:

you just killed me with laughter

4. CHANEL says:

Where do you think the SMRs will be deployed? Look carefully, it will be near the cities.

5. Yvon says:

Uh there is a difference between energy (kWh) and power (kW) and in the presentation evoking the energy lost by a nuclear power plant and that which could be used by the habitat, there is a sacred mixture!

6. Fresh_Career2022 says:

Many nuclear power plants simply dump the waste heat into a river, lake or ocean instead of having cooling towers. Many other power plants, such as coal-fired plants, also have cooling towers or these large bodies of water. This similarity exists because the process of converting heat into electricity is almost identical between nuclear power plants and coal-fired power plants. The efficiency of a nuclear power station is determined in the same way as for other heat engines, since, technically, the power station is a large heat engine. The amount of electrical energy produced for each unit of thermal energy gives the plant its thermal efficiency, and due to the second law of thermodynamics, there is an upper limit to the efficiency of these plants.