The third Spanish nuclear power plant: Vandellós I

It was a GCR (graphite-natural uranium) type plant, cooled by gas (the only one of this kind built in Spain). It operated between the years 1972 and 1995 with an electric potency of 480 MWt.

1989 – First nuclear incident in Spain

On October 19th 1989, and due to a mechanical failure, there was a fire in the site. The event was classified as level 3 (important incident) on the INES Scale.

The fire seriously affected the installations, though there were no consequences whatsoever, as regards radioactive emissions, for the environment. According to all the reports, there were no repercussions to the outside, nor was there any environmental or personal damage.

The event began through a fire in a conventional building of the plant, the turbine building, which has no relation to radioactive components. The fire started because of the rupture of lubrication pipes. This caused a considerable oil leak in a very short time. Following this, and as a consequence of the fire, there was a chain of system failures, especially due to the flooding of the lower floors at the turbine building with a water leakage from various circuits as well as from the water used to extinguish the fire. This all caused considerable damage to the electric systems.

Consequences of the incident

The site’s owner decided to proceed to shut down and dismantling, due to the high cost of the site’s return to activity after the fire, complying with all the requisites established by the Nuclear Safety Council for this purpose.

Step by step dismantling of the nuclear power plant

Once its commercial exploitation ended after the fire on October 19th 1989, partial dismantling was started under the Ministerial Order issued on January 28^th 1998. This order transferred ownership of the facility to Enresa, while at the same time authorizing the performance of the dismantling activities reflected in the Vandellós I dismantling and decommissioning plan.

Level 1. Preliminary conditioning activities

After definitive cessation of the site’s exploitation, the owner company Hifrensa carried out the reactor discharge, spent fuel removal, conditioning of the operational waste and extraction of the waste stored in the graphite silos. Additionally, the carbon dioxide deposits and main turbine-alternators were disassembled. These tasks were completed between 1991 and 1997.

Level 2. Structure dismantling

Enresa carried out the Level 2 dismantling of Vandellós I in two stages:

• First stage (February 1998-February 1999):
• Conditioning of the site for dismantling.
• Removal from the site of unnecessary conventional structures.
• Second stage (March 1999-June 2003)
• Performance of the Active Parts Dismantling Plan, with the disassembly of all the structures, components and systems except the reactor shroud, which remained confined and covered by a newly built protective structure.
• Continuation of the dismantling of conventional components.
• Performance of the Declassification Plan, in order to ensure that the conventional materials were not contaminated and could be managed as such.
• Transfer of conventional waste to recycling centres and specialized tips.
• The low and intermediate level radioactive waste was sent to the El Cabril centralized disposal facility.
• Most of the site was released.

Dormancy period

The reactor shroud must remain as a regulated area, restricted and under surveillance for 25 years, the time required for its radioactivity to decay sufficiently for complete dismantling to be addressed (see photograph).

Level 3. Dismantling of the reactor shroud

The last stage of decommissioning of the plant will be carried out by Enresa upon completion of the dormancy period, around 2028, and will consist of removing the reactor shroud and all the internal structures. The site will then be completely released.

The Directorate General of Energetic and Mine Politics at the Ministry of Industry, Tourism and Commernce authorized, on January 17^th 2005, the beginning of the nuclear site’s dormancy period, making Enresa the owner and the company in charge of the performance of surveillance and maintenance activities.