TY - BOOK
T1 - Near-field chemistry of a HLW/SF repository in Boom Clay - scoping calculations relevant to the supercontainer design
AU - Wang, Lian
N1 - RN - ER-17
CN - CCHO 2000-773/00/00
Score = 2
PY - 2009/12
Y1 - 2009/12
N2 - This report presents results of computer simulations to assess the time dependent evolution of near-field chemistry from a cementitious repository in Boom Clay. Because of large quantity of concrete used in the repository design and the very slow ingress of Boom Clay pore water by diffusion, an alkaline condition with a high pH > 12 is expected to sustain for at least 80,000 years based on model calculations assuming chemical equilibrium and diffusion transport in concrete. As a result of Boom Clay pore water and concrete interactions, three types of concrete pore fluids are derived as concrete degradation proceeds: a young concrete fluid with pH > 13 at the beginning stage (hundreds of years), an evolved concrete fluid with pH 12.5 for more than 80,000 years, and a calcium-silicate-hydrates (CSH) fluid. Redox condition within the near-field will likely be very reducing before the complete depletion of the metallic barriers due to corrosion. Afterwards, the redox will be governed mainly by the in- diffusing pore water from Boom Clay. Key factors influencing model simulation are porosity change of concrete and its influence on transport, boundary conditions, and diffusion coefficient in concrete
AB - This report presents results of computer simulations to assess the time dependent evolution of near-field chemistry from a cementitious repository in Boom Clay. Because of large quantity of concrete used in the repository design and the very slow ingress of Boom Clay pore water by diffusion, an alkaline condition with a high pH > 12 is expected to sustain for at least 80,000 years based on model calculations assuming chemical equilibrium and diffusion transport in concrete. As a result of Boom Clay pore water and concrete interactions, three types of concrete pore fluids are derived as concrete degradation proceeds: a young concrete fluid with pH > 13 at the beginning stage (hundreds of years), an evolved concrete fluid with pH 12.5 for more than 80,000 years, and a calcium-silicate-hydrates (CSH) fluid. Redox condition within the near-field will likely be very reducing before the complete depletion of the metallic barriers due to corrosion. Afterwards, the redox will be governed mainly by the in- diffusing pore water from Boom Clay. Key factors influencing model simulation are porosity change of concrete and its influence on transport, boundary conditions, and diffusion coefficient in concrete
KW - Cement
KW - Near-field
KW - Boom Clay
KW - Geochemical modeling
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/ezp_103591
M3 - ER - External report
VL - 1
T3 - SCK•CEN Reports
BT - Near-field chemistry of a HLW/SF repository in Boom Clay - scoping calculations relevant to the supercontainer design
PB - SCK CEN
ER -