Sen. Gary W. Hart (D-Colo.) announced yesterday that his Environment and Public Works subcommittee on nuclear regulation will hold hearings Oct. 13 on the role of the Nuclear Regulatory Commission in a 1973 case involving a Virginia nuclear power plant.

A Justice Department probe recently said NRC actions were "ill considered and inept . . . demonstrating a pervasive bias against (public) scrutiny" in the case, which involved a three-month delay in public revelation of a geological fault under the Virginia Electric and Power Co. plant on the North Anna River.

The Justice Department memo said it might have been able to prosecute Vepco for concealing the fault "but for the action of the NRC in sanctioning the continued construction by Vepco and concealing on its own part . . . the discovery of the fault."

Both Vepco and current and past NRC officials have vigorously denied that any concealment took place, and said that in any case practices have been altered so as to speed public knowledge of any future problems in reactor sites or construction.

"Even if no laws have been violated, incidents such as this one are at the root of the lack of public credibility for the licensing process for nuclear power plants," Hart said. His office said the hearings would focus on the NRC and its role in the Vepco case rather on anything Vepco did or did not do.

Witnesses are scheduled to include NRC chairman Dr. Joseph Hendrie and executive director Lee Gossick as well as Edson Case, deputy director of nuclear reactor regulation when the fault discovery occurred in 1973 and now acting director; and June Allen, president of the North Anna Environmental Caolition which has opposed the North Anna plant for years and whose inquiries brought the case to light.