* FPL to add about 400 MW of new nuclear capacity * Company planned to spend about $1.5 billion on uprates Sept 25 (Reuters) - The U.S. Nuclear Regulatory Commission (NRC) approved a power uprate for Unit 2 at Florida Power & Light's (FPL) St. Lucie nuclear power plant in Florida to increase the reactor's output by 17 percent from about 853 megawatts (MW) to 1,002 MW. The NRC approved a similar uprate for St. Lucie Unit 1 in July from 853 MW to 982 MW, the federal agency said in a release late Monday. One megawatt can power about 340 homes in South Florida, FPL has said. FPL, a unit of Florida power company NextEra Energy Inc , planned to spend about $1.5 billion to add about 400 MW of capacity in total at four reactors - two at St. Lucie and two at Turkey Point in Florida. The company said it has already completed the uprate at St. Lucie 1 and was in the process of finishing St Lucie 2. Turkey Point 3 is currently ramping up following its uprate and refueling outage and Turkey Point 4 was expected to shut later in the autumn for its uprate and refueling. In June, the NRC approved of the Turkey Point 3 uprate from about 700 MW to 823 MW. Turkey Point 4 currently has a capacity of about 693 MW, according to federal data. St. Lucie is located on Hutchinson Island about 110 miles (177 km) north of Miami. Turkey Point is located in Florida City about 25 miles (40 km) south of Miami. Separately, FPL has proposed to build two of Westinghouse Electric's new 1,100-MW AP1000 reactors at the Turkey Point site. Westinghouse Electric is a unit of Japanese multinational Toshiba Corp. FPL filed with the NRC to build and operate the new reactors in June 2009. The NRC however is revising the schedule for deciding on the new reactors at Turkey Point in addition to most other applications for new reactors. The most recent date for a decision on Turkey Point on the NRC website was 2014. FPL meanwhile has not yet decided to build the new reactors, but has said on its website that the two units would cost about $12 billion to $18 billion and could enter service around 2022 and 2023.