Uranium producer Cameco Corp.'s shares were trading down more than eight per cent Monday after the company received a smaller sum than it was seeking in an arbitration dispute.

Downward pressure that sent the stock price down $1.46 to $13.05 on the Toronto Stock Exchange followed what the company called a "disappointing" award of damages.

Cameco says a tribunal of international arbitrators ruled that a Japanese utility did not have the right to leave a supply agreement and awarded Cameco US$40.3 million, far less than the US$700 million in damages that it was seeking.

The utility Tokyo Electric Power Co. said in 2017 that it would terminate a long-term contract because of measures the Japanese government took after the 2011 Fukushima Daiichi nuclear disaster.

The ruling, which can't be appealed, overshadowed a positive decision from the U.S. to refrain from imposing import restrictions on uranium due to national security concerns.

Cameco, which sells about 25 per cent of its product to the U.S., says it was pleased by the decision.