| 976 / | HD | NUCLEAR TECHNOLOGY |
| DIG 139 | DD | EMERGENCY PROTECTION ARRANGEMENTS STRUCTALLY ASSOCIATED WITH THE REACTOR (e.g., safety valves provided with pressure equalization devices) [G21C-9/00] *** (emergency cooling arrangements DIG. 196) {6} |
| DIG 140 | DD | .~ Pressure suppression [G21C-9/00B] {2} |
| DIG 141 | | .~.~ By rupture discs or diaphragms [G21C-9/00B2] |