Some of your argument may depend a little on where you are.
France is one of the 5 members of the non-proliferation treaty group (NPT) as it was one of the first 5 to detonate a bomb. France was motivated by the Suez Crisis and diplomatic tension between the USSR and the USA. It was keen to retain its great power status, alongside the United Kingdom.
You might want to look at http://en.wikipedia.org/wiki/France_and_weapons_of_mass_destruction
To look at 'Rights' you might want look at some of the various Bills of Rights, see http://en.wikipedia.org/wiki/Bill_of_Rights
Why does the US have the right to nuclear arms? Right seems to be a political word, it means what the country asserting the right wants. Arms means: nuclear explosives.
Arguing about this reminds me of Henny Penny. Everyone listened to Henny Penny's argument, but in the end, only Foxy-Loxy gained. In the world of Nuclear Arms, only those that have them can assert their "rights" to keep them.
what are some reasons that france have the right to nuclear arms? i know that in general it's for security and power but i don't know the specifics......
Here is the reasoning France has a right to nuclear arms:
1) The French say they do.
2) None of the powerful in the world are willing to take the arms away from France.
3) It has been encoded by the NPT that France has them, and can keep them.
Trying to make a rational argument over a political matter is very much like the argument of Henny Penny, as I stated. The rational arguments don't mean as 1) and 2) as I listed above. Rights only exist as long as you can keep them, you keep them by 1) claiming and asserting them, and 2) no one takes them away from you. If there is ever a legal justificiation, it is because of 1) and 2), not any basis of fundamental God-Given rights.