The first Spanish nuclear power plant: José Cabrera
In depth - February 16, 2012

The first Spanish nuclear power plant: José Cabrera

On July 17th, 1968, only five years after a group of companies and visionary professionals led the launching of nuclear energy in Spain, and three and a half years after construction started, the José Cabrera Nuclear Plant, also known as Zorita, began its operation.

It was Spain’s first nuclear experience, a site whose characteristics included the world’s greatest circulation pump

The site became a pioneer of nuclear-originated electric generation in Spain, the driving force of national engineering and industry, a starting point for many activities and companies and the basis for many nuclear energy professionals. Each moment of the process was followed with maximum attention by experts, institutions and public opinion, with a high degree of Spanish participation, greater than one would think of a “turnkey” power plant. It was Spain’s first nuclear experience, a site whose characteristics included the world’s greatest circulation pump.

How the idea came to be

In 1951, José María Otero Navascúes, created through the Head of State the Nuclear Energy Board (JEN is the Spanish acronym), which is currently the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Ciemat, for the purpose of developing the industrial use of nuclear energy. At that time, thanks to the investigations initiated in developed countries, Spanish entrepreneurs from the electric sector knew about the benefits offered by this new source of energy.

On February 26th 1962, Madrid’s Electric Union (UEM), which is currently known as Gas Natural Fenosa, presented to the Ministry of Industry a “preliminary project” to build a nuclear power plant with capacity for 60 MW (though it would finally reach 160 MW). The authorization came a year later, conditioned by the presentation of a “complete project”.

Among the offers that were requested for its construction, UEM chose the one from Westinghouse Electric International because it included a greater degree of national participation. The path was cleared once the Ministry of Industry received authorization to enrich natural Spanish uranium in the United States, and  the beginning of construction was announced in June 1965.

Between 1963 and 1965, Spanish entrepreneurs agreed on the construction of the first three Spanish nuclear power plants, pioneered by José Cabrera, named after UEM’s president at the time. Decisions regarding Zorita’s construction took into consideration the capacities of Spanish professionals and the use of national uranium. The chosen technology was a pressurized water reactor (PWR) with a 160 MW gross power.

The construction of José Cabrera nuclear power plant began 9 years after the launch of the world’s first nuclear power plant for the production of electric energy.

Public opinion couldn't believe that only 5 tons of fuel would be enough to produce over 1,000 million annual kWh


The abundance of water, the existing hydroelectric resources, the polls that confirmed the land’s adequate geotechnical characteristics and good accessibility, among other factors, led UEM to purchase 65 hectares at La Alcarria, on the left bank of the Tajo river between the Bolarque and Zorita dams.


July 6th 1965 was the day construction began for Spain’s first nuclear power plant. The site’s cost was estimated at 1,700 million pesetas, and the cost of the first fuel load at 400 million pesetas.

However, public opinion could not believe that only 5 tons of fuel in the form of slightly enriched uranium would be enough to produce over 1,000 million annual kWh. At that time, they compared this data with the fact that, in order to produce the same amount, 50,000 railway carriages full of carbon were needed.


In December 1967, only two and a half years after the foundation stone was laid down, the first hydrostatic test was run on the site. On March 31st 1968 the first hot functional test was run, and two and a half months later the nucleus load took place. By the end of June that same year the first criticality arrived, and two weeks later the first synchronization, only three years after construction work began.

The plant’s annual production was 1,200 million kWh. This amount equals the average annual consumption of a population of 260,000.

The first Spanish nuclear power plant: José Cabrera
José Cabrera nuclear power plant (currently being dismantled)

During 39 years of commercial operation, it produced 36,515 million kilowatt-hour

When did definitive decomissioning take place?

Definitive decommissioning of exploitation at this site was declared by the Ministry of Industry, Tourism and Commerce through a Ministerial Order on April 20th 2006. Currently it’s at the dismantling stage, according to the authorization granted by the aforementioned Ministry through the Ministerial Order of February 1st 2010.

During 39 years of commercial operation, it produced 36,515 million kilowatt-hour.

According to the current Spanish regulation, the responsibility of planning and carrying out the dismantling of nuclear plants belongs to the National Radioactive Waste Company (Enresa). This company is also in charge of the final handling of nuclear used fuel and of any radioactive residues produced. For this reason, the Ministerial Order from February 2010 also establishes that Enresa is in charge of the dismantling activities. For this reason it was necessary to change ownership of the site, from Gas Natural Fenosa to Enresa. This process ended on February 11th 2010. On this date, dismantling began.

How is the dismantling project being carried out?

The alternative selected for the dismantling of the José Cabrera nuclear power plant has been its total and immediate dismantling with a 6-year long temporary horizon. The dismantling of the radiological parts of the commercial site will begin approximately one year after authorization, a period that is being used for the dismantling of the site’s conventional parts and the setup of the necessary systems for the execution of the planned activities.

The nuclear spent fuel from the site will be temporarily stored at the Individual Temporary Storage  (ATI) facility. Before shutdown is granted, the fuel must have been evacuated to the future Centralised Storage Facility (ATC), and the ATI must have been dismantled. After shutdown was announced there are plans to use the liberated location for industrial purposes.

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