Open AccessThermal-Hydrologic-Mechanical Study of Pre-Closure Off-Normal Thermal Scenarios at the Proposed Yucca Mountain Nuclear Waste Repository
Author(s) -
Jong-Han Leem,
Mark Po-Hung Lin,
Yiming Sun,
Dwayne C. Kicker
Publication year - 2005
Language(s) - English
Resource type - Reports
DOI - 10.2172/838907
Subject(s) - environmental science , closure (psychology) , thermal , thermal conduction , radioactive waste , ventilation (architecture) , decay heat , hydrology (agriculture) , heat transfer , nuclear engineering , geology , geotechnical engineering , waste management , mechanics , materials science , meteorology , engineering , mechanical engineering , economics , market economy , physics , composite material
The proposed nuclear waste repository at Yucca Mountain, Nevada currently includes a minimum of 50 years forced ventilation inside of emplacement drifts prior to repository closure. To regulate the heat generated from emplaced waste packages, the ventilation during the pre-closure period should be continuous. Off-normal thermal scenarios that consider temporary shutdown of the pre-closure ventilation are investigated to determine the impacts of ventilation shutdown on the thermal-hydrologic-mechanical behaviors of the emplacement drifts. In-drift heat transfer processes including radiation, convection, and conduction are studied. The analysis provides a ventilation heat removal ratio that varies on the drift location and the ventilation duration. The heat removal ratio is transferred and utilized in the NUFT thermal-hydrology software. The NUFT software is used to investigate the thermal-hydrologic impacts on the repository rock mass for the off-normal thermal scenarios with various shutdown durations at various pre-closure times. The predicted rock mass temperature evaluated from the thermal-hydrologic analysis is applied for the thermal-mechanical analysis of the off-normal thermal scenarios. The results show that degradation and rockfall of the emplacement drifts due to the off-normal thermal scenarios will be minimal, and it is concluded that the impacts of off-normal thermal scenarios on the stability of the emplacement drifts will be insignificant