The Nuclear Regulatory Commission has agreed to the demands of three state governors who threatened to shut down the nations's only repositories for civilian nuclear waste, Gov. Robert List of Nevada announced yesterday.

List and Govs. Dixy Lee Ray of Washington and Richard W. Riley of South Carolina have insisted that stiffer regulation of waste shipment has to be enacted by Aug. 1 or they will close the facilities in their states. List tole a congressional subcommittee yesterday that the NRC agreement in a June 18 letter was "only the beginning" of a move toward uniformity in what are now chaotic rules around the country.

"This is a national problem with national ramifications," List told a House Interior subcommittee investigating nuclear safety. "Virtually every county in America has low-level nuclear waste. It comes from thousands of hospitals and thousands of clinics, and it is transported every day on our national highway system."

The NRC, he said, has agreed to have trained inspectors check waste shipment containers and security before they go out on the highways. Results of the inspections will be reported to the states, violators will be punished and all places that generate radioactive waste will be told about the new plan.

"I cannot emphasize too strongly the significance of this agreement by the NRC," List said. "The NRC and the Department of Transportation simply are unaware of one another's actitivies...the buckpassing simply must stop."

List suspended some operations at the Beatty, Nev., waste disposal site of the Nuclear Engineering Co. in May after a waste shipment caught fire at the facility gates.

He enlisted support from the other two state executives at the National Governors Association meeting in Louisville, when his attempts to get action from the NRC began to look "like a screenplay from a vintage Keystone Kops comedy," List said.

There were overlapping jurisdictional questions, fruitless promises of new rules and changes and several meetings. Nothing happened, List said, until another shipment arrived at the Beatty site leaking radioactive fluid. Then he shut down operations there and went to the other governors.

List and Gov. Bruce Babbit of Arizona, who also testified, recommended tougher NRC action on enforcing safety regulations, Babbitt said his state's commission on atomic energy is "schizophrenic" in trying to promote and regulate nuclear facilities at the same time, and asked that the NRC offer more technical guidance and firmer rules on the formation, role and jurisdiction of such state agencies.