Publications Details

Effective Access Monitoring at Geological Repositories

Finch, Robert F.; Horowitz, Steven M.; Smartt, Heidi A.; Shoman, Nathan; Rechard, Robert P.; Haddal, Risa

Access points at a deep, mined geological repository (GR) for the disposal of spent nuclear fuel (SNF) and other nuclear wastes present potential diversion paths for nuclear material. Because C/S measures are not likely to be used underground, access to a GR will require unprecedented reliance on C/S measures to maintain continuity of knowledge (CoK) on SNF buried underground. We develop a model GR based on common features of GR designs from national programs in order to develop and optimize C/S measures for GR access points that maximize confidence that CoK is maintained on SNF underground. Critical access points identified in this study are surface entrances to (1) the GR ramp (2) the excavation shaft, (3) the main elevator shaft, and (4) the ventilation shaft. The first three are considered critical detection points (DPs), whereas the fourth is considered a non-critical DP. The reason for the distinction is due to the different design capabilities of shaft components: the first three (ramp, excavation shaft, main elevator) are all capable of being used to move material from the underground to the surface, whereas the ventilation shaft is not. Such capabilities are verified during periodic design information verification (DIV) inspections.