I’m sure I’m late to the party here, but OSD’s “Nuclear Matters Handbook”:http://www.acq.osd.mil/ncbdp/nm/nm_book_5_11/index.htm looks to be a pretty nice resource.
bq. The Nuclear Matters Handbook is an expanded and revised version of the earlier Nuclear Matters: A Practical Guide. Originally published in 1991 for the use of Action Officers associated with the Nuclear Weapons Council, previous editions have been modified over time to meet the needs of the larger U.S. nuclear community as well as those outside the community who seek a better understanding of the subject area. Since the early 1990s, the U.S. nuclear program has evolved significantly as a result of unilateral and bilateral arms reductions, the end of underground nuclear testing in the United States, and in response to the growing threats of nuclear proliferation and nuclear terrorism.