PORT CLINTON, Ohio (AP) -- Nuclear regulators have canceled a meeting about whether cracks found at the Davis-Besse nuclear plant in northern Ohio should be part of the decision on renewing the plant's license.

The federal Atomic Safety and Licensing Board had planned to meet Friday in Port Clinton.

But the U.S. Nuclear Regulatory Commission says opponents of the plant asked to reschedule the hearing so that they can revise their arguments. The opponents say regulators should take into account small cracks found last year in a concrete shell that protects the reactor when they decide whether to renew the plant's license.

Operators of the plant near Toledo say the cracks trace back to a 1978 blizzard when wind, rain and a drastic temperature drop caused moisture to penetrate a concrete containment shell.