Spanish decommissioning and waste management firm Enresa has started work to dismantle the dome of the containment building of the José Cabrera (Zorita) nuclear plant in Almonacid de Zorita, Guadalajara.
The Zorita plant, which was Spain’s first nuclear station, is the first to be decommissioned in Spain. Enresa said the first section of the containment dome - measuring 8m in diameter, 16mm in thickness and weighing 5.2 tonnes - had been cut and removed. Two large cranes were used to manoeuvre the piece from the top of the containment building to the ground. This is the first of the 330 pieces into which this structure will be segmented. The dome has a total weight of 225.2 tonnes and a diameter of 31.4m. Dismantling the dome is expected to be completed by the end of the year.
Dismantling of Zorita has now reached "execution progress of close to 89%". The 142MWe single-loop pressurised water reactor operated from 1968 until 2006 when it was closed by ministerial order. Pre-dismantling activities were carried out between 2006 and 2009 under the responsibility of the facility's operator, Union Fenosa, and comprised mainly the management of used fuel and the conditioning of operational waste.
Ownership of the plant was then transferred to Enresa for decommissioning. Dismantling began in February 2010 and decommissioning work should be finished by the end of 2020. In 2010 Westinghouse - the original reactor supplier - won a contract from Enresa to dismantle the reactor vessel internals. This was followed by another contract in 2013 to dismantle the reactor pressure vessel. These operations have been undertaken in the former used-fuel pool, using remotely operated cutting tools.
It is estimated that about 104,000 tonnes of materials will arise from the dismantling of the plant, some 4% of which will be classified as radioactive waste. Conventional materials are sent to the relevant specific processing plants. Very-low-, low- and intermediate-level waste is periodically sent to the disposal facility at El Cabril. Since dismantling began approximately 29,000 tonnes of materials have been generated. Of this, 7000t is conventional waste, 5500t is very low activity radioactive waste, 2300t is low and medium activity radioactive waste, and 14,200 tons is unclassified. The high activity waste is contained in the 377 fuel elements that were managed in 12 containers in the initial phases of dismantling.
In 2010 the cost of decommissioning Zorita was estimated at €160 million ($178m).
Photo: Dismantling dome at Zorita nuclear plant (credit: Enresa)