Vattenfall has announced that an emergency shutdown of the Fosmark 1 nuclear reactor was initiated after a fault occurred in connection with a test.

The company revealed that, during a planned test that involved turning off the external power supply, a partial emergency shutdown took place as expected. However, it was not possible to restart the reactor in accordance with normal procedures.

During a new attempt to restart the reactor in connection with work to trace the fault, the so-called v-chain, which introduces the control rods to shutdown the reactor, was tripped. An emergency shutdown was then initiated manually in accordance with instructions.

Vattenfall said that work to trace the fault is underway but that it does not estimate being able to restart the reactor until October 12, 2006 at the earliest.