Temperature Effects on seepage Fluid Compositions at Yucca Mountain

Spycher, Nicolas ; Sonnenthal, Eric

United States. Department of Energy. Yucca Mountain Project Office.

关键词: Boiling;    Ventilation;    Wastes;    Temperature Dependence;    Water;   

DOI  :  10.2172/786552
RP-ID  :  MOL.20010808.0254
RP-ID  :  NONE
RP-ID  :  786552

美国|英语

来源: UNT Digital Library

【 摘 要 】

This project investigated the effect of two repository operating temperature modes on coupled thermal, hydrological, and chemical processes around potential nuclear waste-emplacement tunnels (drifts) at Yucca Mountain, Nevada. The main objective of this study was to evaluate the composition of fluids (water and gas) that could enter the drifts, because these data directly relate to the performance of waste canisters and other in-drift engineered systems over the life of the potential repository. Multicomponent reactive transport simulations were performed using TOUGHREACT, initially written by T. Xu and K. Pruess at LBNL and modified here to handle high-temperature and boiling environments. Two repository operating temperature modes were investigated: (1) a ''high-temperature'' mode, which considered a short preclosure ventilation period (50 years) and gave rise to above-boiling temperatures in rocks around the drift for hundreds of years, and (2) a ''low-temperature'' mode with a smaller heat load and longer preclosure ventilation (300 years), yielding temperatures at the surface of the waste package below 85 C (a design threshold) and thus below boiling conditions. Simulations under ambient conditions (no heat load) were also conducted to serve as a baseline for comparing results of thermal-loading simulations.