Appendix CRF - Part 3 - Northamptonshire County Council

Radiological Assessment 0820-2
Version 2
Scenario name Description Hazards
Normal post-closure
evolution
Bathtubbing
Inadvertent
excavation
During this time, the landfill
Gas Release
engineering is assumed to
gradually degrade. Doses to
Liquid release (leachate)
the public are considered. Direct irradiation (through
cover)
Blockage of the drainage
system causes overflow of
leachate laterally from the
landfill onto the soil. Doses to
the public are considered.
Waste is inadvertently
excavated and re-distributed,
e.g., during building or
farming. Doses to the intruder
and the subsequent user of the
site are considered.
Liquid release (leachate)
Direct irradiation
Solid release (dust)
Solid release (waste)
Table 3.2: Post-closure scenarios included in the SNIFFER methodology and the
associated hazards (SNIFFER 2006a).
3.1.3 Dose calculations
This section describes the potential pathways identified within the SNIFFER
methodology. Not all of these pathways will be necessarily be relevant to the
assessment of a specific site, and the methodology requires both the identification and
characterisation of the exposure pathways associated with a particular landfill. The
pathways considered in the assessment of the ENRMF are discussed in Section 3.2
and Section 4.
External irradiation from standing near radioactively-contaminated waste.
This pathway will be minimised when the waste is covered, and will then only
apply to gamma-emitting wastes.
Inhalation of contaminated dust. Because the waste will be emplaced in
sacks/drums and be buried on emplacement, creation of contaminated dust is
not considered as an exposure pathway during the normal operation of the
landfill. However, deliberate intervention to maintain, remediate or reengineer
the site (including the drilling of boreholes for landfill gas
abstraction), or inadvertent excavation during unrelated development of the
site after closure, could lead to the creation of contaminated dust.
Inhalation of aerosols from leachate. Leachate treatment potentially generates
aerosols that could be inhaled by workers or members of the public near the
site or any off-site treatment facility. The spraying of leachate back onto the
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