1. Why does the United States (or any nuclear power) need to build new nuclear weapons?
Plutonium, the essential ingredient of nuclear weapons, ages. It becomes brittle and undergoes other changes which are not fully understood by physicists. The mechanical and electrical components of the bomb and the delivery system wear out. How often do you replace your car or your TV set? Any nuclear weapon eventually reaches a point where it will no longer function as designed.
2. Can plutonium be recycled into new bombs?
No, because of the aging problems mentioned.
3. Can ex-bomb plutonium be used for nuclear power generation?
No. The particular isotope of plutonium used in nuclear weapons is good for only one thing: use in nuclear weapons.
4. Do new bomb designs have to be tested?
No. The last live nuclear test by the United States was circa 1992. The United States is a signer of both the
Limited Nuclear Test Ban Treaty and the
Comprehensive Nuclear Test Ban Treaty (although it has not ratified the latter) which do not allow live nuclear testing. Testing is now done by computer modeling.
5. Why do we need a new warhead design?
Plutonium is difficult to make and is very expensive. If you can design a new warhead which uses less plutonium to achieve a given result, the cost savings are tremendous. A reduced warhead size also permits a smaller, more inexpensive delivery system.
6. Why doesn't the United States get rid of its nuclear weapons?
The United States (as well as Russia) has been steadily reducing the size of its nuclear arsenal for some time.
7. Why does the United States need x number of nuclear weapons?
This is a function of nuclear strategy which is too big a topic for this brief discussion. Google it or look it up in Wikipedia.