Spainish nuclear regulator, Consejo de Seguridad Nuclear (CSN), has approved the restart of the single-unit Santa Maria de Garoña NPP in Burgos, on condition it undertakes a series of modifications.

At a CNS meeting on 8 February, four of its five Board members voted in favour of approving the conditional continued operation of the 446MWe boiling water reactor. This followed a review of documentation submitted by Nuclenor – a joint venture of Endesa and Iberdrola – to support its operating licence renewal application.

Nuclenor closed the nuclear plant in December 2012, six months before its operational licence was due to expire, after it missed the deadline to submit an operating licence renewal application. This meant that Garoña would have to close before its licence expired in July 2013 but would be liable for a full year of retroactive tax charges, which Nuclenor said made the plant economically unviable.

In February 2014, the Spanish nuclear industry successfully pressed for regulatory changes making it possible for a reactor closed for reasons unrelated to safety or radiological protection to be granted a new operating licence within 12 months of its shutdown. Nuclenor then submitted an application for Garoña to the former Ministry of Industry, Energy and Tourism in May 2014, requesting a licence for the plant to operate until 2031. This was then forwarded to CSN for evaluation.

CNS said Nuclenor would be required to make a number of safety modifications to the plant, in line with requirements introduced for all Spanish NPPs following the March 2011 Fukushima accident. These include installation of a filtered containment venting system, construction of alternative emergency management centres and installation of a passive autocatalytic hydrogen recombiner.   Nuclenor also is required to undertake a number of administrative procedures regarding documentation and safety plans for Garoña.

Nuclenor said it would "analyse all aspects of the report, together with the rest of the applicable conditions, to decide on the future of the plant".

Garoña began commercial operation in 1971. CSN updated its operational and safety requirements in 2012 and in 2014 as a result of European Union-mandated post-Fukushima stress tests. Spain has seven commercial nuclear reactors which accounted for 21.38% of Spain’s total electricity output in 2016, up from 20.34% in 2015 and more than any other source.