 Complete the following phrase:  In December 2014, the Swedish regulator required that all Swedish reactors should be equipped with an Independent Core Cooling System - ICCS - before 31 December 2020. The system should be able to cool the reactor during 72 hours without any supply of water, power, fuel or other consumables, and should survive external events seismic events, hard weather etc with an estimated probability of exceedance of 106yr. The requirements are influenced by the so called Forsmark-event 25 July 2006 and the 