Dutch reactor operating with MOX fuel for the first time

By Shaun Burnie, with Mycle Schneider

On July 1st, 2014 the forty-one year old Borssele nuclear reactor in the Netherlands was reported to have generated electricity for the first time using plutonium-uranium mixed oxide fuel (MOX). Eight assemblies of MOX have been loaded into the 482 MW Boiling Water Reactor (BWR), with plans to load a further 12 assemblies from 2015 onwards. The reactor is licensed to operate with 40 percent MOX share of core. Until now, the Borssele reactor has operated with 121 uranium fuel assemblies amounting to 38.8 tons. Over the coming years, Borssele operators intend to load a further 36 MOX assemblies to reach its license limit.

The Netherlands for over thirty years has shipped spent fuel arising from its two power reactors, Borssele and Dodewaard to the reprocessing sites at la Hague in France and Sellafield in the UK. The MOX fuel was manufactured by French company AREVA at its Melox plant in Marcoule. In 2004, the then operator of Borssele, EPZ, announced the extension of its reprocessing contract with AREVA. While stating that it was committed to separation and use of plutonium, it was declared that, "it won't recycle its plutonium in Borssele as mixed-oxide (MOX) fuel "because our plant is too small" ("Dutch utility announces renewal of reprocessing with Cogema", Ann MacLachlan, Nuclear Fuel, March 15th, 2004).

French state utility Électricité de France (EDF) has taken title to previous quantities of plutonium separated from Dutch spent fuel in La Hague. Dutch utilities have paid EDF for keeping the plutonium as plutonium has a zero book- and a negative market-value. The decision to use MOX in one of the oldest operating reactors in the world is thus a noteworthy strategic change from earlier policy. This is all the more remarkable considering the fact that spent MOX fuel will certainly not be reprocessed anymore and the Netherlands will have to deal with a category of spent fuel that either needs over 100 years additional cooling prior to final disposal or several times larger storage volume in the disposal site.

The license approving MOX fuel use in Borssele is based upon a safety case prepared not by Dutch authorities but by Gesellschaft für Anlagen-und Reaktorsicherheit (GRS). As the GRS states,

"Since the Netherlands operate only one nuclear power plant, they do not have their own TSO. GRS fulfils the role of a Technical Safety Organisation in Germany. As it has the technical competence required, GRS is now also assuming to a growing extent the role of TSO for the Netherlands... One of the tasks involved in the scientific and technical support was e.g. the assessment of the use of so-called MOX fuel assemblies at Borssele."