Các thuật ngữ trong ISO (8)
gaseous radioactive wastes
wastes that contain radioactive material in gas form for which no further use is foreseen and have radionuclides at concentrations or activities greater than clearance levels as established by a regulatory body
ISO 18417:2017(en), 3.1
mass transfer zone
defined zone (range) of sorbent volume in which the phenomena of substance mass transfer from gas to solid phases takes place
ISO 18417:2017(en), 3.3
free volume
void between grains or crushed grains of the sorbent inside the whole volume containing the sorbent
where
| Vfr | free volume; | |
| χ | fraction free volume in sorbent volume; | |
| Vsorb | sorbent volume. |
ISO 18417:2017(en), 3.5
bulk density
<span class="inline-formula"><img class="math" alt="mml_m3" src="/obp/graphics/std/iso_std_iso_18417_ed-1_v1_en/mml_m3.png"></span>
ratio between granulated or crushed grains sorbent mass (definite granulation) and the total volume containing the sorbent
ISO 18417:2017(en), 3.7
discharge
planned and controlled release of (gas or liquid) radioactive material to the environment
ISO 18417:2017(en), 3.2
iodine sorbent
sorbent intended for trapping radioiodine in gaseous radioactive wastes
ISO 18417:2017(en), 3.4
contact time
gas flow transit time through sorbent layer
where
| Qcol | the volumetric gas flow rate in the inlet sectional column. |
Note 2 to entry: The contact time defined here does not consider the geometric volume of the sample, but only its free volume.
ISO 18417:2017(en), 3.6
sorption capacity index
<b><i>ξ</i></b>
criterion indicating the degree of reduction of gaseous radioiodine in the gas flowing through the sorbent under specified test conditions
Note 1 to entry: The index is valid only for a specific chemical form of the radioactive gas. In this document, the index has been calculated for radioactive methyl iodide. The index can also be calculated with other gaseous species, such as radioactive iodine, but the results cannot be compared with the ones obtained with radioactive methyl iodide.
ISO 18417:2017(en), 3.8