CSA N288.2-2019 pdf free download.Guidelines for calculating the radiological consequences to the public of a release of airborne radioactive material for nuclear reactor accidents.
Effective release height — the height of the plume centreline above ground level after the processes of plume rise. downwash, and entrainment have acted on the plume.
Note: These processes can contribute singly or In combination to plume height, depending on the characteristics of the stack, the meteorological conditions and the proximity of buildings.
Emergency reference level — represents the total residual dose as a result of an emergency that the
AHJ would plan not to exceed.
Entrainment — the process of capture of a plume released close to a building into the disturbed flow of the building wake, with an attendant lowering of the plume centreline.
Eulerian grid model numerical solution to the advection-diffusion equation using a finite-difference technique in Eulerian coordinates (the frame of reference Is fixed).
Source: VDI 3945-3.
Fumigation — the process in which a plume released into an elevated stable layer is quickly mixed to the ground when it intersects the boundary between the stable layer and the unstable air beneath. Note: Fumigation can occur when the plume is released above the thermal internal boundary layer.
Gaussian plume — steady state two-dimensional Gaussian distribution of concentration, which is derived from statistical turbulence theory or from the steady-state advection-diffusion equation under a number of limiting boundary conditions (e.g., flat terrain) and on the assumption that turbulent diffusion in the wind direction is negligible compared with advection.
(Source: VDI 3782-1.1
Gaussian puff — initially a small puff from a single point source emitted in a short period of time, which is transported by the wind and grows in size (following the Gaussian distribution of concentration) in all three directions.
Note: The Gaussian puff model is a non-stationary analytical solution to the three-dimensional advection-diffusion equation that takes into account spatial and temporal variation of dispersion conditions. Under special stead ys tote conditions, the numerical superposition of a sequence of puffs from a continuous source asymptotically approaches the Gaussian plume solution (see VDI 3945-1).
Intervention level — radiation dose above which protective actions for the public, such as evacuation, sheltering in place, and administration of stable iodine tablets, are introduced.
Note: Intervention levels are usually expressed in terms of effective dose or equivalent dose to the thyroid.
Lagrangian particle — small fluid parcels which are dispersed numerically in the continuous atmospheric phase and which are considered discrete particles.
Note: In the Lagrangian description, the frame of reference follows the fluid parcel.CSA N288.2-2019 pdf free download.