only occur in the INES categories 4 to 7, while NAMS does not have such a limitation. The NAMS scale still does not take into account the radioactive contamination of liquids such as an ocean, sea, river or groundwater pollution in proximity to any nuclear power plant. An estimation of its magnitude seems to be related to the problematic definition of a radiological equivalence between different type of involved isotopes and the variety of paths by which activity might eventually be ingested, e.g. eating fish or through the food chain. See also Nuclear meltdown Core damage frequency Fuel element failure Loss-of-coolant accident Nuclear power Nuclear power debate Radioactive contamination Radioactive waste Vulnerability of nuclear plants to attack NRC Emergency Classifications Nuclear and radiation accidents and incidents Lists of nuclear disasters and radioactive incidents List of civilian nuclear accidents List of civilian radiation accidents List of military nuclear accidents United States military nuclear incident terminology List of nuclear reactors Nuclear safety and security Criticality accident List of hydroelectric power station failures Notes and references External links Nuclear Events Web-based System (NEWS), IAEA International Nuclear Event Scale factsheet, IAEA International Nuclear Event Scale, User's manual, IAEA, 2008 Nuclear safety and security Nuclear