| Parameter | Value | Notes |
|---|---|---|
| Dose limit (individual member of the public / critical group) | 1 mSv per year | May be compared with UK average background radiation dose of ~2.7 mSv per year |
| Dose constraint (source-related) | 0.3 mSv per year | Single source constraint; if not achievable, the operator must demonstrate doses are ALARP |
| Dose constraint (site-related) | 0.5 mSv per year | Total from all operations on a nuclear site, irrespective of site size or number of installations |
| Risk target (for underground disposal) | 10^-6 per year | If estimated risk exceeds this, the operator must show further reductions are only achievable at disproportionate cost |
| Maximum dose from waste disposal | 0.1 mSv per year | Any waste disposal site must be designed so maximum individual dose does not exceed this value |
Key point: The dose limit of 1 mSv/yr is a legal limit. The dose constraints of 0.3 mSv/yr and 0.5 mSv/yr are design targets used for optimisation. Facilities must demonstrate that actual doses are ALARP and in all cases within the legal dose limits.