July 20 (Reuters) - Canadian nuclear regulators on Friday approved the restart of Bruce Power's 750-megawatt (MW) Unit 1 at the 6,200-MW Bruce nuclear power station in Ontario, the Canadian Nuclear Safety Commission (CNSC) said in a statement. This authorization will allow Bruce Power to restart Unit 1 and bring it up to 50 percent of full power to perform several safety tests, the CNSC said. The CNSC said it would have to approve of any power increases over 50 percent. In the past, Bruce Power said Unit 1 was expected to begin operating in the middle of the third quarter of 2012. Bruce Power operates the Bruce A and Bruce B nuclear units located on the eastern shore of Lake Huron near Tiverton. Bruce A, which began operating in 1972, has four reactors with a capacity to produce 750 MW each. Of these reactors, Units 3 and 4 are operating at full power, while Units 1 and 2 are shut for refurbishment to bring them up to present-day operating standards, the CNSC said. In May, Bruce Power said the in-service date for Unit 2 would be delayed. The company did not say when the reactor would enter service. In June, Bruce Power submitted a request for a force majeure claim to the Ontario Power Authority as a result of an external even that delayed startup of Unit 2. Unit 2 had been expected to enter service in the second quarter of 2012 but an incident occurred in the generator system on the non nuclear side of the plant that caused some damage. Bruce Power is owned by Canadian energy company TransCanada Corp, Canadian uranium miner Cameco Corp, and others. TransCanada said it owns 49 percent of Bruce A and 32 percent of Bruce B. TransCanada has said its share of the total net capital cost for the refurbishment of Bruce A was expected to be about C$2.4 billion. Cameco owns about 32 percent of Bruce B and none of the Bruce A units that are being refurbished. TransCanada has said its share of the total net capital cost for the refurbishment of Bruce A was expected to be about $2.4 billion.