Naturally occurring radium incorporated in the concrete material is a constant source of radon production, therefore, the exhalation of radon from the near-surface disposal facility should be carefully controlled within an allowable limit. Preliminary investigations about the natural radon release from concrete structures of the near-surface disposal have been carried out in this report.
Before the closure of the module, the radox flux into atmophere is calcualted for two contrasting cases: one assumes the refreshment rate of the air is large enough to replace the entire volume of air inside the module, the other assumes that there is very limited air flow over the modules and thus only radon from the upper two layers of monoliths enters the atmosphere. After the closure of the module, the movement of radon within the module is diffusion dominant. The effect of inhalation of 222Rn originating from the repository is negligible. All calculated dose rates related to the exhalation of radon released by the repository are lower than background levels resulting from radon (i.e. 0.47 mSv/yr or 54 nSv/hr).
|Number of pages
|Published - May 2011
|Studiecentrum voor Kernenergie