CSA N288.1-14 (R2019)
- standard by CSA Group, 03/01/2014
- Guidelines for Calculating Derived Release Limits for Radioactive Material in Airborne and Liquid Effluents for Normal Operation of Nuclear Facilities
- Category: CSA GROUP
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Full Description
Scope
1.1 Facilities This Guideline and the CDG are intended to apply primarily to CANDU® nuclear power stations in Canada. However, the radionuclides and environmental pathways addressed make this Guideline applicable to releases from many other nuclear facilities, including research reactors, radioisotope processing facilities, waste processing facilities such as incinerators, and power reactors other than those of CANDU® design, subject to the limitations detailed in Clauses 1.2 to 1.8. Application to other types of facilities such as fuel fabrication plants and refineries is limited by the radionuclides considered here (see Clause 4.3).
This Guideline may be adapted to cover part of the needs of such facilities, but additional models or methodologies might be necessary for other parts. However, neither the radionuclides nor the models included in this Guideline are complete enough to cover releases from sources such as uranium mines and mills, permanent geologic disposal facilities, and other facilities where extensive modelling of groundwater pathways is required.
1.2 Release paths This Guideline covers releases to the atmosphere and to surface water (both fresh and marine). It does not address releases to groundwater, although transfers from other media to groundwater wells and ponds are considered. Direct gamma irradiation from radioactivity inside the facility is not modelled because it does not involve a release.
1.3 Release duration The methods specified in this Guideline are designed for routine, continuous, low-level emissions. They also apply to periodic, short-term releases (see Clause 8.2), provided that
(a) the releases are controlled and associated with normal operations;
(b) the release rate is roughly the same from event to event;
(c) for atmospheric releases, the total release duration exceeds approximately 1000 h in the year; for aquatic releases, at least one or two releases occur in each month of the year; and
(d) the releases occur randomly over time.
Where the requirement of Item (d) is not met but the releases are known to occur at a particular time of day or year, this Guideline applies only if the air (water) concentrations are calculated using the meteorological (hydrological) data in effect for that time.
Notes:
(1) Where non-random releases are calculated using time-appropriate data, it might be possible to relax the conditions on the release frequencies.
(2) Releases that do not meet these conditions can use another model, such as that specified in CAN/CSA-N288.2 for atmospheric releases.
(3) For some facilities, intermittent releases occur predictably as spikes on a continuous base release. Such releases can be considered part of routine emissions and included in the DRL without special treatment if the total activity released in intermittent form is less than approximately 30% of the total release from the facility. The 30% cut-off is considered a small fraction of the overall uncertainty of the DRL estimates.
1.4 Contaminants This Guideline applies to the radiation effects of radionuclides. It does not apply to chemicals or to the chemical toxicity of radionuclides.
1.5 Receptors DRLs are derived for a representative person having the average characteristics of a group of individuals who, by reason of their location and habits, are likely to receive the highest exposures to a given radionuclide released from a particular source (see Clause 4.2). By maintaining release rates well below the DRL, the annual dose to these individuals (and therefore to all members of the public) will be below regulatory limits. This Guideline does not apply to nuclear energy workers (NEWs), or to non-NEWs working at a nuclear facility, who are assumed to be covered by on-site radiation protection programs. The DRLs calculated using the models specified in this Guideline apply to human end-points only; non-human biota are not covered.
1.6 Downwind distance of validity This Guideline is not applicable to receptors located close to a source affected by building-induced turbulence because the atmospheric dispersion model does not simulate the cavity that forms in the lee of the building. Because the cavity extends approximately three building heights downwind, this Guideline applies only beyond this distance.
Moreover, the dispersion model should be used with caution beyond an approximate distance of 20 km from the facility because the assumption of steady-state meteorological conditions implicit in the model becomes less valid at greater distances. This is not an issue in practice because the representative person is usually found closer to the facility than 20 km.
1.7 Site specificity Local parameter values should be used wherever possible in
1.1 Facilities This Guideline and the CDG are intended to apply primarily to CANDU® nuclear power stations in Canada. However, the radionuclides and environmental pathways addressed make this Guideline applicable to releases from many other nuclear facilities, including research reactors, radioisotope processing facilities, waste processing facilities such as incinerators, and power reactors other than those of CANDU® design, subject to the limitations detailed in Clauses 1.2 to 1.8. Application to other types of facilities such as fuel fabrication plants and refineries is limited by the radionuclides considered here (see Clause 4.3).
This Guideline may be adapted to cover part of the needs of such facilities, but additional models or methodologies might be necessary for other parts. However, neither the radionuclides nor the models included in this Guideline are complete enough to cover releases from sources such as uranium mines and mills, permanent geologic disposal facilities, and other facilities where extensive modelling of groundwater pathways is required.
1.2 Release paths This Guideline covers releases to the atmosphere and to surface water (both fresh and marine). It does not address releases to groundwater, although transfers from other media to groundwater wells and ponds are considered. Direct gamma irradiation from radioactivity inside the facility is not modelled because it does not involve a release.
1.3 Release duration The methods specified in this Guideline are designed for routine, continuous, low-level emissions. They also apply to periodic, short-term releases (see Clause 8.2), provided that
(a) the releases are controlled and associated with normal operations;
(b) the release rate is roughly the same from event to event;
(c) for atmospheric releases, the total release duration exceeds approximately 1000 h in the year; for aquatic releases, at least one or two releases occur in each month of the year; and
(d) the releases occur randomly over time.
Where the requirement of Item (d) is not met but the releases are known to occur at a particular time of day or year, this Guideline applies only if the air (water) concentrations are calculated using the meteorological (hydrological) data in effect for that time.
Notes:
(1) Where non-random releases are calculated using time-appropriate data, it might be possible to relax the conditions on the release frequencies.
(2) Releases that do not meet these conditions can use another model, such as that specified in CAN/CSA-N288.2 for atmospheric releases.
(3) For some facilities, intermittent releases occur predictably as spikes on a continuous base release. Such releases can be considered part of routine emissions and included in the DRL without special treatment if the total activity released in intermittent form is less than approximately 30% of the total release from the facility. The 30% cut-off is considered a small fraction of the overall uncertainty of the DRL estimates.
1.4 Contaminants This Guideline applies to the radiation effects of radionuclides. It does not apply to chemicals or to the chemical toxicity of radionuclides.
1.5 Receptors DRLs are derived for a representative person having the average characteristics of a group of individuals who, by reason of their location and habits, are likely to receive the highest exposures to a given radionuclide released from a particular source (see Clause 4.2). By maintaining release rates well below the DRL, the annual dose to these individuals (and therefore to all members of the public) will be below regulatory limits. This Guideline does not apply to nuclear energy workers (NEWs), or to non-NEWs working at a nuclear facility, who are assumed to be covered by on-site radiation protection programs. The DRLs calculated using the models specified in this Guideline apply to human end-points only; non-human biota are not covered.
1.6 Downwind distance of validity This Guideline is not applicable to receptors located close to a source affected by building-induced turbulence because the atmospheric dispersion model does not simulate the cavity that forms in the lee of the building. Because the cavity extends approximately three building heights downwind, this Guideline applies only beyond this distance.
Moreover, the dispersion model should be used with caution beyond an approximate distance of 20 km from the facility because the assumption of steady-state meteorological conditions implicit in the model becomes less valid at greater distances. This is not an issue in practice because the representative person is usually found closer to the facility than 20 km.
1.7 Site specificity Local parameter values should be used wherever possible in
Product Details
- Edition:
- 3rd
- Published:
- 03/01/2014
- ISBN(s):
- 9781771394079
- Number of Pages:
- 522
- File Size:
- 1 file , 4.1 MB
- Product Code(s):
- 2422780, 2423220, 2422780
- Note:
- This product is unavailable in Russia, Ukraine, Belarus
Document History
CSA N288.1:20
CSA N288.1-14 (R2019)
CSA N288.1-08 (R2013)
