Russian nuclear reactor shut down after defect

A reactor at a western Russian nuclear plant has been automatically shut down because of faults in the power control loop.

The latest problem comes a week after a defect was discovered at another reactor at the same plant.

No rise in radiation or casualties were reported in the incident at Reactor Number 1 at the Smolensk nuclear plant.

The cause of the problem is being investigated.

Last Tuesday, operators halved output at Smolensk's Reactor No. 3 after a problem was discovered in a generator.

The plant is about 350 kilometres (210 miles) southwest of Moscow.

Russia's aging nuclear plants frequently experience minor breakdowns but energy officials insist the malfunctions cause no serious safety threat.