Dangerous structural flaws at South Carolina's Savannah River nuclear plant were known to the Energy Department and the facility operator, E.I. du Pont de Nemours & Co., three years before the plant was closed, The New York Times reported Monday.

Internal memorandums show that du Pont, plant manager for nearly four decades, began amassing volumes of evidence describing structural problems in 1985, three years before growing public awareness of structural defects forced the closing of Savannah River in 1988, the Times said.The du Pont documents reportedly include information about such serious structural flaws as cracks in the plant's cooling pipes and defects in the emergency cooling system. A summary written in 1985 described 30 accidents at the plant, the newspaper said.

The records show that Energy Department officials associated with Savannah River in some instances were shown the documents and made aware of structural flaws, yet failed to take action.

In other cases the government officials were not told about defects, the Times said.

Last year the Energy Department in Washington began investigating the Savannah River plant's safety problems.

The probe has focused on the gravity of the structural flaws and the extent of the information that plant personnel and operators had about safety hazards.