The Swiss nuclear safety regulator has reaffirmed the measures that must be taken by utility BKW to ensure that its 372MWe Mühleberg nuclear power plant can continue operating until 2019.

BKW had an unlimited operating licence for Mühleberg, but announced in late 2013 that the plant will be permanently shut down in 2019 instead of 2022 as originally planned because of "uncertainty surrounding political and regulatory trends". The single boiling water reactor began operating in 1972. In January, the Federal Nuclear Safety Inspectorate (ENSI) approved upgrades proposed by BKW for the continued operation of the plant and said it would provide a report to the Federal Nuclear Safety Commission (NSC) for a second opinion. NSC approved the upgrades, and ENSI reaffirmed the requirement for the.

These include non-destructive tests on the reactor core shroud during each annual safety review at Mühleberg. ENSI set two technical criteria for cracks found in Mühleberg’s core shroud, which may not be exceeded. Based on current knowledge, ENSI does not expect the cracks to reach these limits before its final decommissioning in 2019.

BKW is also required to upgrade the emergency cooling pumps at the plant, as well as to install a new emergency reactor cooling water system and reinforce the emergency cooling system for the used fuel pools. The company had earlier said that, by implementing these measures, it will exceed the safety margin stipulated by ENSI.