Swedish utility Vattenfall will invest SEK900m ($107m) to update Ringhals 3&4, in which it owns a 70.4% stake, by installing independent core cooling systems. The legally-required safety upgrade will enable the two reactors to continue operating beyond 2020. 

Vattenfall's Forsmark and Ringhals nuclear power plants have already undergone comprehensive upgrading for life extension. However, in October 2014, the Swedish Radiation Safety Authority announced that all operating Swedish reactors must have independent core cooling systems. 

Specifically, the regulator requires reactors to have a "robust permanent installation that includes power supply and systems for pumping of water and an external water source independent of those used in existing emergency cooling systems". 

The decision to install independent core cooling systems at Ringhals 3&4 was taken on 17 November by the board of directors of both Ringhals NPP and Vattenfall. The board decided in June 2016 to install independent core cooling at Forsmark 1-3, in which Vattenfall holds a 66% stake. 

The two older units at Ringhals are to be closed. In April 2015, Vattenfall informed co-owner E.ON of its decision to close Ringhals  1&2 in 2018-2020 instead of 2025 as previously planned. Ringhals 2 is expected to be decommissioned in December 2020 and Ringhals 1 in December 2019.