According to Vattenfall, the fault is stated to be a broken generator which causes the reactor to run at about a third of its normal power.
– The power is on the way up now and is at 492 MW, previously it was around 330, says press secretary at Vattenfall Markus Fischer to Aftonbladet on Saturday morning.
The reactor usually has a capacity of around 1100 MW.
According to Markus Fischer, a fault finding is underway and they hope to know more about what happened at lunchtime on Saturday.