| 976 / | HD | NUCLEAR TECHNOLOGY |
| DIG 5 | DD | NUCLEAR REACTORS [G21C-1/00] *** (fusion reactors H05H-1/00; nuclear explosives DIG. 423; analogue computers therefor G06G-7/54) {4} |
| DIG 16 | DD | .~ Thermal reactors; Epithermal reactors [G21C-1/04] {2} |
| DIG 17 | DD | .~.~ Heterogeneous reactors (i.e., in which the fuel and moderator are separated) [G21C-1/06] {4} |
| DIG 18 | | .~.~.~ Pebble-bed reactors; Reactors with granular fuel [G21C-1/06B] |