Nuclenor confirms soundness of Garoña vessel

13 April 2015

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Inspections of the reactor vessel of Spain's shut down Garoña nuclear power plant show that it is in good condition to operate safely when restarted, plant operator Nuclenor recently reported to the country's regulator.

Garoña's boiling water reactor (Image: Nuclenor)

Nuclenor announced in late March that inspections conducted in November and December 2014 indicated no manufacturing defects in the vessel and that it was in a good condition, enabling the unit to operate safely when restarted.

The company said the latest assessment of the vessel has been the most comprehensive to date. It said a team of more than 40 experts from the USA's GE Hitachi and Spain's Tecnatom spent more than 1000 hours collecting data from some nine million points on the vessel's surface, including the welds. The team did this using advanced ultrasound systems as well as submersible robots.

Nuclenor said the results demonstrate that the plant's reactor vessel is able to operate safely and complies with international standards for mechanical requirements of pressure vessels. The company said it has sent the results to the regulator, the Nuclear Safety Council (Consejo de Seguridad Nuclear, CSN).

The 446 MWe boiling water reactor began operation in 1971 and was deemed by the CSN to be suitable for operation until 2019 given certain technical upgrades.

However, in September 2012, Nuclenor - a joint venture of Endesa and Iberdrola - missed the deadline to submit an operating licence renewal application for Garoña meaning that it had to shut by the time its licence expired on 6 July 2013. However, the reactor was closed in mid-December 2012 to avoid a full year of retroactive tax charges for which Nuclenor would have been liable if it was operating on 1 January 2013.

In February 2014, industry succeeded in lobbying for regulatory changes that made 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 submitted a licence renewal application for Garoña to the Ministry of Industry, Energy and Tourism on 27 May, requesting a licence for Garoña to operate until 2031. The ministry subsequently forwarded this to CSN for evaluation. That application is still under consideration.

The CSN had requested inspections of Garoña's reactor vessel as part of Nuclenor's licence application. The vessel was manufactured by Rotterdam Drydock Company, which was later found to have supplied vessels to two Belgian units - Tihange 2 and Doel 3 - featuring manufacturing anomalies.

Garoña's vessel was constructed using the same process as that for Doel 3. However, CSN has previously noted significant differences between the Garoña and Doel 3 vessels - including the size, thickness, number of forged pieces and the type of reactor.

Researched and written

by World Nuclear News

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