he Tennessee Valley Authority yesterday accused 10 foreign and three domestic uranium producers of conspiring to eleminate competition in the world uranium market by fixing minimum prices and contract conditions.

In antitrust suits filed in U.S. District Courts in Chattanooga, Denver and New York City, TVA asked for treble the amount of damages it has sustained because of the alleged antitrust violations.

A quasi-government corporation,TVA operates the nation's largest electric power system.

TVA officials contended that the agency will have to pay as much as $200 million more for uranium already under contract to fuel its nuclear reactor units than it would have, had the cartel not existed. TVA currently operated three nuclear power units and has 14 more in design or under construction.

The U.S. companies named in the suits were Gulf Oil Corp., Engelhard Minerals & Chemicals Corp. and Rio Algom Corp. The foreign companies are based in Britain, Canada, France, Germany and South Africa.

The suits allege that beginning as early as 1972 and continuing through at least 1974, the uranium producers met on numerous occasions throughout the world and agreed to fix world uranium prices and allocate world markets. They also agreed not to sell uranium for delivery after 1978 except at a negotiated price prevailing at or near the time of delivery, the suit alleges.

As a result of the alleged conspiracy, the suits contend, TVA received no responsive bids when it sought in November 1973 to purchase up to 86 million pounds of uranium for delivery from 1979 to 1990.

Later, TVA was forced to purchase or sign contracts to purchase more than 20 million pounds of uranium under the terms and conditions and at the prices fixed by the uranium producers, the suits contend. The contracts have a current market value of more than $500 million, TVA said.

Besides the U.S. companies, the foreign firms named in the suits were Rio Algom Ltd., Gulf Minerals Canada Ltd., Uranerz Canada Ltd., Noranda Mines Ltd., and Denison Mines Ltd., all of Canada: as well as Rio Tinto Zinc Corp. Ltd. and R.T.Z. Services Ltd., of Britain; Uranex of France; Nuclear Fuels Corp. of South Africa (Proprietary) Ltd. (known as Nufeor); and Urangesellschaft mbH & Co. of Germany.