"The public" means the general people of a country. These are people who don't have special positions or special information:

The ultimate goal is to have it available to the public by the end of the year.

When you're talking about news and government, "the public" can mean sort of the opposite of "the government":

People have accused the government of holding back important information from the public.

This is how "the public" is used in the example at top. It means the general people of the country, who aren't in the government and aren't able to make decisions about nuclear power directly.