Environment (radiation)

D-values are used by the Environment Agency (EA), SEPA and the UK police advisers (CTSA) to determine the source category and appropriate security measures for sealed sources, where this cannot be assessed directly from the use/practice. D (Danger) values are in TBq, and the quotient A/D (where A is the activity of a source in TBq) are used to determine source category. In the UK some sources are already categorised for security and this will then take precedence over A/D. For those into dosimetry calculations and assessments behind D values, section 3 onwards explain in detail how the values are derived.

These regulations (amended 2018) cover many environmental factors, although for this site only radioactive substances and waste are relevant. The regulations only cover England and Wales and make provisions for environmental permits that regulate the holding of radioactive material and the accumulation and disposal of radioactive waste. (Regulation in Scotland is still based on compliance with the Radioactive Substances Act 1993, and the Scottish statutory instruments made under it.