Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Deep Borehole Disposal Waste Emplacement Mode Cost-Risk Study - 16346

Conference ·
OSTI ID:22838176
; ; ; ;  [1];  [2];
  1. Sandia National Laboratories, PO Box 5800 MS 0747, Albuquerque, NM 87185-0747 (United States)
  2. Insight Decisions, LLC, 2200 Quitman St., Denver, CO 80212 (United States)

An engineering study has developed alternative concepts for waste packaging and for emplacing/retrieving packages in deep boreholes. The study compared costs and risks associated with emplacement using wire-line vs. drill-string technologies. Selection of a method is needed to proceed with demonstration as part of the Deep Borehole Field Test being conducted by the U.S. Department of Energy, Office of Used Nuclear Fuel Disposition. Each emplacement method was described as a series of steps, and each step was analyzed for potential to cause any of four off-normal events including drops and getting stuck. Each such event was supported by a fault tree. The hazard analysis identified a number of improvements including: 1) impact limiters; 2) safety systems; 3) instrumentation; and 4) methods to mitigate casing collapse or borehole debris during operations. Off-normal events were related in a top-level event tree with normal and off-normal outcomes. Costs were estimated for each outcome (including recovery and decontamination). A panel of subject matter experts was convened to review the study and provide key inputs. The wire-line method is less costly for normal operations, while the drill-string method has advantages if waste packages become stuck. The wire-line method has a lower aggregate probability of accidents resulting in waste package breach. The integrated probability of off-normal events is on the order of a few percent per borehole, and engineered measures are quite important to prevent and mitigate accidents, limiting radiological consequences. Development of these measures during design will help to further improve system reliability. (authors)

Research Organization:
WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
OSTI ID:
22838176
Report Number(s):
INIS-US--19-WM-16346
Country of Publication:
United States
Language:
English