The Oyster Creek nuclear reactor in New Jersey owned by Exelon Corp. was allowed to operate for another 20 years yesterday.

The plant in Ocean County is the nations' oldest nuclear reactor. The U.S. Nuclear Regulatory Commission voted 3 to 1 favoring its use despite several appeals from environmentalist groups.

One aspect of the plant which raised concerns involved a water leak which caused part of the material liner around the reactor to rust. However operators of the plant applied a coating material to the liner and removed sand at the base of the reactor to keep it from retaining moisture.

Groups opposing the plant's operation included the Nuclear Information and Resource Service; Jersey Shore Nuclear Watch Inc.; Grandmothers, Mothers and More for Energy Safety; New Jersey Public Interest Research Group; New Jersey Sierra Club; and New Jersey Environmental Federation.

The license is likely to be granted by April 9, NRC spokesman Neil Sheehan said.