European Pressurized Reactor (EPR)

Jean-Baptiste Ruffio
March 20, 2017

Submitted as coursework for PH241, Stanford University, Winter 2017


Fig. 1: Computer designed picture of the planned European Pressurized Water Reactor (EPR). (Courtesy of the Framatome ANP. Source: Wikimedia Commons)

The European Pressurized Reactor (EPR, or Evolutionary Power Reactor) is a third generation nuclear reactor under construction (Fig. 1) developed by the French companies Areva NP and EDF (Eléctricité De France). The generation classification is based on the construction cycle of nuclear plants with the each generation building on the experience gained from its predecessor. As of 2016, almost all working reactors in service in the world have been built in the 1970s and 1980s and represent the second generation of nuclear reactor. There is no important technological breakthrough with the third generation but it is designed to be safer and more efficient. The surgeneration, which would address the issue of nuclear waste, will only appear in the fourth generation. This concept relies on fast neutrons to allow the production of more fissile atoms than the reactor consumes. [1,2]


The EPR is the product of the French N4 and the German KONVOI reactors. It is one of the most powerful reactor in the world with a gross electrical production of 1770 MW and a thermal output of 4590MW. It is designed to last 60 years, while the current generation nuclear reactor's life expectancy is 40 years. The efficiency of the reactor is also improved by running the turbine at a higher pressure and therefore higher temperature. [3]

The design allows the use of combustible with a Mixed Oxide fuel (MOX) content of 50% to 100%. The MOX is usually made out of plutonium and low enriched uranium, which is interesting because it can be produced from used nuclear fuel as well as from the surplus of weapon grade Plutonium. Besides, the EPR is expected to use 22% less natural uranium and reduce the quantity of produced Plutonium by 15% compared to its predecessor. [2]

In addition, the probability of an accident has been reduced by having four redundant safety features allowing the maintenance of the installations while keeping a suitable level a redundancy. In the extreme scenario of a core melting, a core catcher has been designed under the reactor to prevent any contamination of the environment from the corium (i.e., a melted mixture of the active material and the structure of the core). [3]


There are currently four EPR in construction: one in Olkiluoto, Finland, one in Flamanville, France and two in Taishan China. Despite the bright promises, the project has been crippled with delays, cost overrun and technical difficulties especially in Finland and France. For example, the construction started in Olkiluoto in 2005 and was scheduled for 4 years and an estimated budget of 3 billion euros. The project is now 9 years behind schedule and more than 5 billions over budget with a similar fate for the french project. One of the numerous setbacks has been the discovery of critical anomalies in the steel of the reactor vessel. The public opinion has become very distrustful of the project, with some already calling it a failure. The recent accident in Fukushima has also diminished the general support toward nuclear energy. Supporters of the project argue that delays and overruns are very common when building cutting edge prototypes. [4,5]

© Jean-Baptiste Ruffio. 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.


[1] J.G. Marques, "Evolution of Nuclear Fission Reactors: Third Generation and Beyond," Energy Convers. Manage. 51, 1774 (2010).

[2] J.G. Marques, "Environmental Characteristics of the Current Generation III Nuclear Power Plants," WIREs Energy Environ. 3, 195 (2014).

[3] Y. Wang, J. Ma, and Y. Fang, "Generation III Pressurized Water Reactors and China's Nuclear Power," J. Zhejiang Univ. Sci. A 17, 911 (2016).

[4] T. Burgis, K. Stacey, and M. Stothard, "EDF's Nuclear Troubles Rooted in Caution," Financial Times, 20 Mar 16.

[5] B. Barré, Pourquoi le Nucléaire? (De Boeck Supérieur, 2017) [Why Nuclear].