OSLO (Reuters) - Vattenfall’s Forsmark 1 and 2 reactors in Sweden have safety clearance to operate for another decade, taking them beyond their initial 40-year planned lifetime, the Swedish radiation safety authority said on Monday.

The two reactors have a combined capacity of about 2 gigawatt (GW) and are important to Sweden’s power supply.

Forsmark 1 was commissioned in 1980 and Forsmark 2 in 1981. Clearance from the regulator, required every 10 years in Sweden, mean both units can continue operations until 2028.

“During the coming period, until the next comprehensive assessment for Forsmark 1 and 2, the two reactors will pass the originally analyzed operating time of 40 years,” SSM said in a statement.

Vattenfall has invested in Forsmark to extend the lifespan of its reactors and increase their capacity. The firm has said it aims to keep them running for at least 50 years from the commissioning date.