Transcript Comparison of human and non human dose

Terrestrial Assessment
Comparison of human and non human
dose assessments for prospective new
nuclear power stations
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Outline
•
Background
•
Human assessment (assumptions)
•
Non-human assessment (assumptions)
•
Comparison of the results from the two assessments
•
Discussion of results?
•
Summary/Issues for PROTECT
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Background
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Background
• Assessment loosely based on proposed build of new nuclear power
stations (AGR and PWR types)
• Terrestrial assessment looking at exposure to
– humans via foodstuff/living nearby
– Non-human species living in a (protected) Natura 2000 site
at approximately the same distance as that for humans
• Uses probable permitted discharge limits as input
• Single source of radioactivity to assessment assumed
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Map of proposed facility
Agricultural land used for
food crops/milk production
500m from aerial discharge
Facility with
sea discharge
Humans living at
100m from site
Terrestrial Natura
2000 site 500m from
aerial discharge
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Permitted discharge limits
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AGR
PWR
H-3
6
8
C-14
5
0.6
S-35
0.16
Noble
Gases
60
300
Other beta
I-131
0.001
0.005
0.01
In TBq
per year
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Human assessment
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Approach
• Modelled using the Environment Agency Initial Radiological
Assessment Tool
• Prospective assessment
• Simple spreadsheet tool
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Assumptions
• Assumes a ground level release & uniform windrose
• Exposure to humans is at 100m from discharge point; assumed to
be consuming high levels of locally sourced foods such as milk,
beef, lamb, offal, green vegetables, root vegetables and fruit
(sourced 500m from discharge point)
• Other beta modelled as I-131
• Noble gases modelled as C-14 (not available in ERICA)
• No direct shine assessment included (can’t do it for non-human
species yet)
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Non-human assessment
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Assumptions
• Modelled terrestrial input concentrations through IAEA SRS19
transfer model
• Assumed ground level release
• Distance to receptor = 500m
• Used ERICA tool Tier 2, assuming reference organisms in the
assessment and using all default concentration ratios, occupancy
factors, etc for terrestrial environment
• Other beta modelled as I-131
• Noble gases modelled as C-14
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AGR - Screened against 10 µGy/h
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PWR - Screened against 10 µGy/h
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Results comparison
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Predicted dose rates - human
Inhalation
dose
External dose (cloud
and deposited)
Food
dose
Total
dose
AGR
%
Contrib
ution
uSv/y
uSv/y
uSv/y
uSv/y
Tritium
4.0E+00
0.0E+00
9.0E-01
4.9E+00
0.2%
Carbon-14
1.2E+03
3.1E-02
1.9E+03
3.1E+03
97.0%
Sulphur-35
3.2E+00
2.7E-04
5.8E+01
6.1E+01
1.9%
Other beta/gamma
1.8E+00
2.6E-01
2.8E+01
3.0E+01
0.9%
Total doses
1.2E+03
3.0E-01
2.0E+03
3.2E+03
uSv/y
Tritium
5.4E+00
0.0E+00
1.2E+00
6.6E+00
0.05%
Carbon-14
5.4E+03
1.4E-01
8.7E+03
1.4E+04
99.61%
Other beta/gamma
3.0E+00
4.4E-01
4.6E+01
4.9E+01
0.35%
Total doses
5.4E+03
5.8E-01
8.8E+03
1.4E+04
uSv/y
PWR
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Predicted dose rates - human
Inhalation
dose
External dose (cloud
and deposited)
Food
dose
Total
dose
AGR
%
Contrib
ution
uSv/y
uSv/y
uSv/y
uSv/y
Tritium
4.0E+00
0.0E+00
9.0E-01
4.9E+00
0.2%
Carbon-14
1.2E+03
3.1E-02
1.9E+03
3.1E+03
97.0%
Sulphur-35
3.2E+00
2.7E-04
5.8E+01
6.1E+01
1.9%
Other beta/gamma
1.8E+00
2.6E-01
2.8E+01
3.0E+01
0.9%
Total doses
1.2E+03
3.0E-01
2.0E+03
3.2E+03
uSv/y
Tritium
5.4E+00
0.0E+00
1.2E+00
6.6E+00
0.05%
Carbon-14
5.4E+03
1.4E-01
8.7E+03
1.4E+04
99.61%
Other beta/gamma
3.0E+00
4.4E-01
4.6E+01
4.9E+01
0.35%
Total doses
5.4E+03
5.8E-01
8.8E+03
1.4E+04
uSv/y
PWR
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Non- human results – total doses µGy/h
Organism
AGR
PWR
Amphibian
1.3E+00
6.1E+00
Bird
1.4E+00
6.4E+00
Bird egg
8.9E-01
4.1E+00
Detritivorous invertebrate
4.3E-01
2.0E+00
Flying insects
4.3E-01
2.0E+00
Gastropod
4.3E-01
2.0E+00
Grasses & Herbs
8.8E-01
4.1E+00
Lichen & bryophytes
8.8E-01
4.1E+00
Mammal (Deer)
1.4E+00
6.4E+00
Mammal (Rat)
1.4E+00
6.4E+00
Reptile
1.4E+00
6.4E+00
Shrub
8.8E-01
4.1E+00
Soil Invertebrate (worm)
4.3E-01
2.0E+00
Tree
1.3E+00
6.2E+00
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Non- human results – total doses µGy/h
Organism
AGR
PWR
Amphibian
1.3E+00
6.1E+00
Bird
1.4E+00
6.4E+00
Bird egg
8.9E-01
4.1E+00
Detritivorous invertebrate
4.3E-01
2.0E+00
Flying insects
4.3E-01
2.0E+00
Gastropod
4.3E-01
2.0E+00
Grasses & Herbs
8.8E-01
4.1E+00
Lichen & bryophytes
8.8E-01
4.1E+00
Mammal (Deer)
1.4E+00
6.4E+00
Mammal (Rat)
1.4E+00
6.4E+00
Reptile
1.4E+00
6.4E+00
Shrub
8.8E-01
4.1E+00
Soil Invertebrate (worm)
4.3E-01
2.0E+00
Tree
1.3E+00
6.2E+00
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Non- human results – total doses µGy/h
Organism
AGR
PWR
1.3E+00
6.1E+00
1.4E+00
6.4E+00
Bird egg
8.9E-01
4.1E+00
Detritivorous invertebrate
4.3E-01
2.0E+00
Flying insects
4.3E-01
2.0E+00
Gastropod
4.3E-01
2.0E+00
Grasses & Herbs
8.8E-01
4.1E+00
Lichen & bryophytes
8.8E-01
4.1E+00
Mammal (Deer)
1.4E+00
6.4E+00
Mammal (Rat)
1.4E+00
6.4E+00
Reptile
1.4E+00
6.4E+00
Shrub
8.8E-01
4.1E+00
Soil Invertebrate (worm)
4.3E-01
2.0E+00
Tree
1.3E+00
6.2E+00
Amphibian
Bird
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C-14 is the main
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Risk Quotients
• Human results compared to 1mSv/y
• Biota results compared to 10 and 40 µGy/h
• (EA uses 40 as action value currently)
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Risk Quotients
• Human
– AGR = RQ of 3
– PWR = RQ of 14
• Biota v 10 µGy/h (using reptile as most affected)
– AGR = RQ of 0.14
– PWR = RQ of 0.64
• Biota v 40 µGy/h (using reptile as most affected)
– AGR = RQ of 0.035
– PWR = RQ of 0.16
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Risk Quotients
• Human
– AGR = RQ of 3
– PWR = RQ of 14
0.36 (using Ar-41 not C-14)
0.23 (using Ar-41 not C-14)
• Biota v 10 µGy/h (using reptile as most affected)
– AGR = RQ of 0.14
– PWR = RQ of 0.64
• Biota v 40 µGy/h (using reptile as most affected)
– AGR = RQ of 0.035
– PWR = RQ of 0.16
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Open discussion of results
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Summary/Issues for PROTECT
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Issues/Future
• Include noble gases in the non-human assessments (unsure of
actual dose predictions)
• However human and biota results should change ‘proportionally’
if/when noble gases are included in biota assessments
• This is a simple terrestrial only assessment (note in E&W’s no
terrestrial habitat assessments ever triggered at Stage 2)
• Need to expand evaluation for purposes of ICRP Committee 4
(include ICRP approach in assessment?)
– Combine terrestrial and aquatic assessments
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