Richmond, Va. (AP) — Dominion Resources is looking at extending the lifespan of its nuclear power reactors in Virginia and Connecticut for another 20 years.

There are two reactors at Dominion's North Anna Power Station and two at its Surry Power Station in Virginia. The company's Millstone Power Station in Connecticut also has two reactors.

The Nuclear Regulatory Commission already has extended the plants' original 40-year operating licenses for 20 years.

The Richmond Times-Dispatch reports that Dominion is conducting preliminary internal reviews to support license extensions for an additional 20 years.

Dominion spokesman Rick Zuercher says the review will identify what needs to be done to preserve the plants for another 20 years.

Sierra Club Virginia Chapter president Glen Besa says extending the plants' licenses would expose Virginians to unacceptable risks.