Gillian Hirth | |
---|---|
Education | PhD |
Employer | Australian Radiation Protection and Nuclear Safety Agency |
Known for | Radiation safety |
Gillian Anne Hirth AO , also known as Gillian A. Hirth, is a health scientist and CEO of Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). [1] She was appointed an Officer of the Order of Australia for "service to environmental science, nuclear and radiation safety and the development of national and international regulatory standards", [2] and worked with the United Nations following the Fukushima accident, advising on environmental radiology. [3]
Hirth graduated in 1999, with a PhD in environmental radiochemistry. She began work at Australian Nuclear Science and Technology Organisation (ANSTO) as a Post-Doctoral Research Fellow from 2000 to 2003. [4] After her position at ANSTO, Hirth worked in the Australian Defence Organisation in the field of hazardous materials and environmental management. [5] [6]
Hirth was previously Chief Radiation Health Scientist of Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), [7] and as at July 2024, is CEO of ARPANSA.
From 2020 to 2023 she was a member of the Commission on Safety Standards of the International Atomic Energy Agency (IAEA). She is also on the Board of Council of the International Union of Radioecology. [8] Hirth was Chair of the United Nations Scientific Committee on the Effects of Atomic Radiation for 2019 to 2020. [9]
Hirth's career has involved developing safety codes and standards, including radionuclide activity concentrations in wildlife in ecosystems around uranium mining. [10] [11]
Hirth has published on radiation safety, radionuclide activity, and on the radiation levels in wildlife in uranium mining ecosystems.
Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred to one of its electrons to release it as a conversion electron; or used to create and emit a new particle (alpha particle or beta particle) from the nucleus. During those processes, the radionuclide is said to undergo radioactive decay. These emissions are considered ionizing radiation because they are energetic enough to liberate an electron from another atom. The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay. However, for a collection of atoms of a single nuclide the decay rate, and thus the half-life (t1/2) for that collection, can be calculated from their measured decay constants. The range of the half-lives of radioactive atoms has no known limits and spans a time range of over 55 orders of magnitude.
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, nuclear decommissioning, rare-earth mining, and nuclear weapons reprocessing. The storage and disposal of radioactive waste is regulated by government agencies in order to protect human health and the environment.
A nuclear and radiation accident is defined by the International Atomic Energy Agency (IAEA) as "an event that has led to significant consequences to people, the environment or the facility." Examples include lethal effects to individuals, large radioactivity release to the environment, or a reactor core melt. The prime example of a "major nuclear accident" is one in which a reactor core is damaged and significant amounts of radioactive isotopes are released, such as in the Chernobyl disaster in 1986 and Fukushima nuclear disaster in 2011.
Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases, where their presence is unintended or undesirable.
Nuclear safety is defined by the International Atomic Energy Agency (IAEA) as "The achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, the public and the environment from undue radiation hazards". The IAEA defines nuclear security as "The prevention and detection of and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear materials, other radioactive substances or their associated facilities".
Environmental radioactivity is part of the overall background radiation and is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium-90 (90Sr) and technetium-99 (99Tc), are only found on Earth as a result of human activity, and some, like potassium-40 (40K), are only present due to natural processes, a few isotopes, e.g. tritium (3H), result from both natural processes and human activities. The concentration and location of some natural isotopes, particularly uranium-238 (238U), can be affected by human activity, such as nuclear weapons testing, which caused a global fallout, with up to 2.4 million deaths by 2020.
Uranium in the environment is a global health concern, and comes from both natural and man-made sources. Beyond naturally occurring uranium, mining, phosphates in agriculture, weapons manufacturing, and nuclear power are anthropogenic sources of uranium in the environment.
This article compares the radioactivity release and decay from the Chernobyl disaster with various other events which involved a release of uncontrolled radioactivity.
Radioecology is the branch of ecology concerning the presence of radioactivity in Earth’s ecosystems. Investigations in radioecology include field sampling, experimental field and laboratory procedures, and the development of environmentally predictive simulation models in an attempt to understand the migration methods of radioactive material throughout the environment.
Nuclear power has various environmental impacts, both positive and negative, including the construction and operation of the plant, the nuclear fuel cycle, and the effects of nuclear accidents. Nuclear power plants do not burn fossil fuels and so do not directly emit carbon dioxide. The carbon dioxide emitted during mining, enrichment, fabrication and transport of fuel is small when compared with the carbon dioxide emitted by fossil fuels of similar energy yield, however, these plants still produce other environmentally damaging wastes. Nuclear energy and renewable energy have reduced environmental costs by decreasing CO2 emissions resulting from energy consumption.
Radiation monitoring involves the measurement of radiation dose or radionuclide contamination for reasons related to the assessment or control of exposure to radiation or radioactive substances, and the interpretation of the results.
The Church Rock uranium mill spill occurred in the U.S. state of New Mexico on July 16, 1979, when United Nuclear Corporation's tailings disposal pond at its uranium mill in Church Rock breached its dam. The accident remains the largest release of radioactive material in U.S. history, having released more radioactivity than the Three Mile Island accident four months earlier.
The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) is a regulatory agency under the Commonwealth of Australia that aims to protect Australian citizens from both ionising and non-ionising radiation. ARPANSA works under the guidance of the Australian Radiation Protection and Nuclear Safety Act of 1998 as the national regulatory body of radiation in Australia, with independent departments within each state and territory that regulate radiation within each of their jurisdictions.
From 1946 through 1993, thirteen countries used ocean disposal or ocean dumping as a method to dispose of nuclear/radioactive waste with an approximation of 200,000 tons sourcing mainly from the medical, research and nuclear industry.
The following outline is provided as an overview of and topical guide to nuclear power:
Radioactive sources are used for logging formation parameters. Radioactive tracers, along with the other substances in hydraulic-fracturing fluid, are sometimes used to determine the injection profile and location of fractures created by hydraulic fracturing.
Bioremediation of radioactive waste or bioremediation of radionuclides is an application of bioremediation based on the use of biological agents bacteria, plants and fungi to catalyze chemical reactions that allow the decontamination of sites affected by radionuclides. These radioactive particles are by-products generated as a result of activities related to nuclear energy and constitute a pollution and a radiotoxicity problem due to its unstable nature of ionizing radiation emissions.
The Philippine Nuclear Research Institute (PNRI) is a government agency under the Department of Science and Technology mandated to undertake research and development activities in the peaceful uses of nuclear energy, institute regulations on the said uses, and carry out the enforcement of said regulations to protect the health and safety of radiation workers and the general public.
Uranium acid mine drainage refers to acidic water released from a uranium mining site using processes like underground mining and in-situ leaching. Underground, the ores are not as reactive due to isolation from atmospheric oxygen and water. When uranium ores are mined, the ores are crushed into a powdery substance, thus increasing surface area to easily extract uranium. The ores, along with nearby rocks, may also contain sulfides. Once exposed to the atmosphere, the powdered tailings react with atmospheric oxygen and water. After uranium extraction, sulfide minerals in uranium tailings facilitates the release of uranium radionuclides into the environment, which can undergo further radioactive decay while lowering the pH of a solution.