| Nucleotide chain | 16 |
| Nucleobase compound | 19 |
| Nucleic-acid initials | 21 |
| Nucleic initials | 16 |
| Nucleic acids: Abbr. | 20 |
| Nucleic acids, for short | 24 |
| Nucleic acids, abbr. | 20 |
| Nucleic acids | 13 |
| Nucleic acid: Abbr. | 19 |
| Nucleic acid, for short | 23 |
| Nucleic acid, abbr. | 19 |
| Nucleic acid sugar | 18 |
| Nucleic acid initials | 21 |
| Nucleic acid base | 17 |
| Nucleic acid briefly | 21 |
| Nucleic acid | 12 |
| Nuclei of experts | 17 |
| Nuclei | 6 |
| Nuclear-weapon unit | 19 |
| Nuclear-treaty subjects | 23 |
| Nuclear-reactor part | 20 |
| Nuclear-reaction process | 24 |
| Nuclear-powered Soviet subs | 27 |
| Nuclear-powered poet? | 21 |
| Nuclear-plant measurements | 26 |
| Nuclear-plant component | 23 |
| Nuclear-physics devices | 23 |
| Nuclear-fission apparatuses | 27 |
| Nuclear-explosion hot spot | 26 |
| Nuclear-energy source | 21 |
| Nuclear-energy org. | 19 |
| Nuclear-arsenal weapon, for short | 33 |
| Nuclear ___ | 11 |
| Nuclear __: social unit | 23 |
| Nuclear weapons-testing dept. | 29 |
| Nuclear weapons | 15 |
| Nuclear weapon, in old headlines | 32 |
| Nuclear weapon delivery device, for short | 41 |
| Nuclear weapon (Abbr.) | 22 |
| Nuclear weapon | 14 |
| Nuclear vessel, for short | 25 |
| Nuclear unit | 12 |
| Nuclear tryouts | 15 |
| Nuclear trials | 14 |
| Nuclear trial, for short | 24 |
| Nuclear trial prohibition | 25 |
| Nuclear trial | 13 |
| Nuclear treaty subjects | 23 |
| Nuclear treaty subject | 22 |
| Nuclear treaty result | 21 |
| Nuclear treaty | 14 |
| Nuclear Threat Initiative co-chairman Sam | 41 |
| Nuclear threat | 14 |
| Nuclear theorist Niels | 22 |
| Nuclear test unit | 17 |
| Nuclear submarine | 17 |
| Nuclear sub weapon | 18 |
| Nuclear splitting in the cosmos? | 32 |
| Nuclear restraint pact | 22 |
| Nuclear regulatory grp. 1946-74 | 31 |
| Nuclear reading: Abbr. | 22 |
| Nuclear reactors | 16 |
| Nuclear reactor tube | 20 |
| Nuclear reactor parts | 21 |
| Nuclear reactor part | 20 |
| Nuclear reactor needs | 21 |
| Nuclear reactor need | 20 |
| Nuclear reactor fuel | 20 |
| Nuclear reactor fluid | 21 |
| Nuclear reactor component | 25 |
| Nuclear reactor | 15 |
| Nuclear reaction starter? | 25 |
| Nuclear radiation weapon, for short | 35 |
| Nuclear proliferation | 21 |
| Nuclear power since 1998: Abbr. | 31 |
| Nuclear power resource | 22 |
| Nuclear power plants | 20 |
| Nuclear power plant measures | 28 |
| Nuclear power apparatus | 23 |
| Nuclear power agency until 1975 (abbr.) | 39 |
| Nuclear power acronym | 21 |
| Nuclear power | 13 |
| Nuclear plant units | 19 |
| Nuclear plant structure | 23 |
| Nuclear plant sight | 19 |
| Nuclear plant feature | 21 |
| Nuclear plant employee of note | 30 |
| Nuclear plant | 13 |
| Nuclear pioneer Enrico | 22 |
| Nuclear physics prefix | 22 |
| Nuclear physics | 15 |
| Nuclear physicist's sign-off? | 33 |
| Nuclear physicist Szilard | 25 |
| Nuclear physicist Niels | 23 |
| Nuclear physicist Meitner | 25 |
| Nuclear physicist Hans who won the 1967 Nobel Prize | 51 |
| Nuclear physicist Enrico | 24 |
| Nuclear particles | 17 |
| Nuclear particle | 16 |
| Nuclear pact | 12 |