Temperature, Humidity, and Airflow in the Emplacement Drifts Using Convection and Dispersion Transport Models

Abstract

A coupled thermal-hydrologic-airflow

A Turbulent Transport Network Model in MULTIFLUX Coupled with TOUGH2

“…A manual OBI loop was used for obtaining the NTCF model and the process continued only to the 11 th iteration. -4 -This number was found adequate for convergence for an equivalent dispersion in-drift model and was accepted for the in-drift convective model as well [1,7].…”

“…A review of the models regarding the coupled in-drift and inrock processes are given in a previous paper [1]. Previous models used various levels of simplifications in capturing the in-drift processes in their thermal-hydrologic interactions to those in the near-field and far-field rockmass.…”

“…The input data for the equivalent dispersion coefficient were provided by a limited-scale, simplified numerical study, assuming a 70-m long emplacement drift segment with assumed boundary conditions [5]. The natural air recirculation field and the resulting convective heat and mass transport were first simulated using MULTIFLUX coupled to TOUGH2 in a previous paper [1]. Some simplifications such as line heat load and a symmetric waste package arrangement with long unheated sections were used.…”

“…It has been shown before that the unheated drift end sections can significantly affect the in-drift humidity during post-closure [6,7]. Another technical limitation was also applied in the previous work [1] by limiting the number of NTCF model updates. A manual OBI loop was used for obtaining the NTCF model and the process continued only to the 11 th iteration.…”

“…The key elements of the coupled modeling approach are described in a previous publication [1]: (1) the separation of the rock-mass model from the in-drift model; (2) the solution of the rockmass model with TOUGH2 [8] combined with the NTCF technique [9] for generalization; (3) the solution of the internal components of the emplacement drift with an integrated-parameter CFD model; and (4) the recoupling of the separate tasks (2) and (3) iteratively at each time instant and boundary element on the drift wall.…”