Appendix CRF - Part 3 - Northamptonshire County Council

Radiological Assessment 0820-2
Version 2
Dgamma7 is the skin equivalent dose rate for radionuclide Rn to the basal layer
of the skin epidermis for gamma irradiation (Sv h -1 per Bq cm -2 ).
Dbeta4 is the skin equivalent dose rate for radionuclide Rn to the basal layer
of the skin epidermis for face for beta irradiation, skin thickness 40
m (4 mg cm -2 ), (Sv h -1 per Bq cm -2 ).
10 4 converts Bq m -2 to Bq cm -2 .
dface is the thickness of the contaminated layer on the face (m).
waste is the density of the waste (kg m -3 ).
Wskin is the tissue weighting factor for skin (dimensionless).
Areaface is the area of skin in contact with the contaminated dust (cm 2 ).
Areabody is the total exposed skin area of the adult body (cm 2 ).
T is the time the worker is exposed to the material (hours year -1 ).
A.3.2 Dose to Site Resident after Excavation
It is assumed that following, or as part of the reason for, the excavation, the waste and
the cover are mixed together and re-laid, creating a soil layer partly contaminated with
the radioactivity that was in the waste. The initial concentration of radionuclide Rn in
the material, CRn,soil,excavate (Bq kg -1 ), immediately after the excavation event is
calculated by:
C
Rn,
soil,
excavate
A
V
Galson Sciences Limited 71 14 July 2009
Rn
( t)
Dil
where ARn(t) is the activity of radionuclide Rn in the landfill at the time of
excavation, t (Bq).
Dil is the dilution factor given by the ratio of the volume of contaminated
landfill waste to the volume of other material that is mixed in to form
the soil (dimensionless).
Vlandfill is the volume of the landfill (m 3 ).
soil is the density of the soil (kg m -3 ).
landfill
Dose from ingesting contaminated soil that may be attached to crops is given by:
where Qsoil
soil
Dose D
ing,
soil Qsoil
CRn,
soil,
excavate
is the soil consumption rate (kg year –1 ).
Ding is the dose coefficient for ingestion of radionuclide, Rn (Sv Bq -1 ).
Dose from crops grown on contaminated soil is given by:
Rn
Q
crop C
Rn,
soil excavate TFcrop
Dose ing , crops
,
crop
D
where Qcrop is the crop consumption rate (kg year –1 ).
TFcrop is the soil to crop transfer factor for radionuclide, Rn (Bq kg -1 fresh
weight of crop per Bq kg -1 of soil).
Ding is the dose coefficient for ingestion of radionuclide, Rn (Sv Bq -1 ).
Rn
ing
Rn
ing
WS010001/ENRMF/CONSAPPCRF 621