{
  "url": "https://openlegislation.uk/ionising-radiations-regulations-2017/schedule-7/part-4",
  "json_url": "https://openlegislation.uk/ionising-radiations-regulations-2017/schedule-7/part-4.json",
  "legislation": "uksi/2017/1075",
  "legislation_title": "The Ionising Radiations Regulations 2017",
  "legislation_url": "https://openlegislation.uk/ionising-radiations-regulations-2017",
  "path": "schedule/7/part/4",
  "kind": "part",
  "number": "4",
  "heading": "Table of quantities of radioactive material defining high-activity sealed sources",
  "text": "For radionuclides not listed in the table below, the relevant quantity value is the same as the D-value defined in section 2 Table 1 of the IAEA publication: Dangerous quantities of radioactive material (D-values), (EPR-D-VALUES 2006)\n1 The activity given is that of the alpha-emitting radionuclide.\nRadionuclide\nQuantity (Bq)\nCo-60\n3 × 1010\nSe-75\n2 × 1011\nSr-90 (Y-90)\n1 × 1012\nCs-137\n1 × 1011\nPm-147\n4 × 1013\nGd-153\n1 × 1012\nTm-170\n2 × 1013\nYb-169\n3 × 1011\nIr-192\n8 × 1010\nRa-226\n4 × 1010\nPu-238\n6 × 1010\nPu-239/Be-91\n6 × 1010\nAm-241\n6 × 1010\nAm-241/Be-91\n6 × 1010\nCm-244\n5 × 1010\nCf-252\n2 × 1010",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/2017/1075/schedule/7/part/4",
    "retrieved_at": "2026-10-28T23:06:45.309431+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}