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Safety of Fusion Reactors Chapter | 14 425

TABLE A.14.1.1 Linear Coefficients of Radiation Risks [9]
Population Cancer Risk Risk of Hereditary Total
−2
−1
−2
−1
−1
−2
Incurring Radiation (×10 Sv ) Effects (×10 Sv ) (×10 Sv )
All population 5.5 0.2 5.7
Adults 4.1 0.1 4.2
Averaged risk coefficient used to establish dose limits for staff and population is taken to be
0.05 Sv . Annual dose limits for ‘normal’ exposure to sources of ionising radiation are established
−1
based on the following individual lifetime risk standards: 0.001 for staff and 5 × 10 for the
–5
−6
population. Risk taken to be negligibly small is 10 .
TABLE A.14.1.2 Main Dose Limits [9]
Dose limit
Standardised metric a Staff (Group A) b Population
Effective dose 20 mSv/year over any 1 mSv/year over any
consecutive 5 years, not consecutive 5 years, not
exceeding 50 mSv/year exceeding 5 mSv/year
Equivalent dose
For the eye lens c 150 mSv/year 15 mSv/year
For skin d 500 mSv/year 50 mSv/year
For palms and feet 500 mSv/year 50 mSv/year

a Multiple simultaneous exposure (across all metrics) is allowed if within specified standardised limits.
b Main dose limits, like other acceptable exposures for Group B staff are 1/4 of dose limits for Group
A staff. Hereinafter, ‘staff’ means ‘Group A staff’.
c For a 300 mg/cm depth of penetration.
2
2
2
2
d Averaged for a 1 cm piece of a 5 mg/cm -thick skin basal layer covered by a 5 mg/cm -thick epidermis
2
layer. Palm epidermis layer is 40 mg/cm thick. This standard allows total human skin exposure, if average
exposure of any square centimetre of skin is within specified limit. Face skin exposure is considered to be
within limits if dose limit for eye lens exposure to beta-particles is not exceeded.
Specific activity, activity concentration: a radionuclide activity per mass (vol-
ume) unit of a matter. Measurement unit: becquerel per kilogram (Bq/kg) (spe-
3
cific activity) and becquerel per cubic meter (Bq/m ) (activity concentration).
Decisions regarding population protection in case of a radiation emergency
involving area radioactive contamination are made after comparing expected
dose, prevented with the protective measures, with levels A and B given in Table
A.14.1.3. If averted exposure is below level A, there is no need to take measures
interfering with normal public life activity and socioeconomic functioning. If
avertable exposure is above level A and below level B, the decision regarding pro-
tective measures is made depending on the situation and local conditions. If avert-
able exposure is above level B, relevant protective measures are mandatory even
if they interfere with normal public life activity and socioeconomic functioning.