Nuclear waste in the context of "High-level waste"

Nuclear chemistry is the sub-field of chemistry dealing with radioactivity, nuclear processes, and transformations in the nuclei of atoms, such as nuclear transmutation and nuclear properties.

It is the chemistry of radioactive elements such as the actinides, radium and radon together with the chemistry associated with equipment (such as nuclear reactors) which are designed to perform nuclear processes. This includes the corrosion of surfaces and the behavior under conditions of both normal and abnormal operation (such as during an accident). An important area is the behavior of objects and materials after being placed into a nuclear waste storage or disposal site.

Long-term nuclear waste warning messages are communication attempts intended to deter human intrusion at nuclear waste repositories in the far future, within or above the order of magnitude of 10,000 years. Nuclear semiotics is an interdisciplinary field of research that aims to study and design optimal signage techniques and messages for this purpose; it was first established by the American Human Interference Task Force in 1981.

A 1993 report from Sandia National Laboratories recommended that such messages be constructed at several levels of complexity. They suggested that the sites should include foreboding physical features which would immediately convey to future visitors that the site was both man-made and dangerous, as well as providing pictographic information attempting to convey some details of the danger, and written explanations for those able to read it.

Low-level waste (LLW) or low-level radioactive waste (LLRW) is a category of nuclear waste. The definition of low-level waste is set by the nuclear regulators of individual countries, though the International Atomic Energy Agency (IAEA) provides recommendations.

LLW includes items that have become contaminated with radioactive material or have become radioactive through exposure to neutron radiation. This waste typically consists of contaminated protective shoe covers and clothing, wiping rags, mops, filters, reactor water treatment residues, equipments and tools, luminous dials, medical tubes, swabs, injection needles, syringes, and laboratory animal carcasses and tissues.

A fast-neutron reactor (FNR) or fast-spectrum reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons (carrying energies above 1 MeV, on average), as opposed to slow thermal neutrons used in thermal-neutron reactors. Such a fast reactor needs no neutron moderator, but requires fuel that is comparatively rich in fissile material.

The fast spectrum is key to breeder reactors, which convert highly abundant uranium-238 into fissile plutonium-239, without requiring enrichment. It also leads to high burnup: many transuranic isotopes, such as of americium and curium, accumulate in thermal reactor spent fuel; in fast reactors they undergo fast fission, reducing total nuclear waste. As a strong fast-spectrum neutron source, they can also be used to transmute existing nuclear waste into manageable or non-radioactive isotopes.

Environmental dumping can refer to two distinct but interrelated types of dumping: One is the trans-frontier shipment and improper disposal of hazardous waste (household waste, industrial/nuclear waste, etc.), and the second is environmentally harmful product dumping, the unethical marketing in and exporting to developing countries of new products that are inferior in economic, environmental, and technical performance, with these products often requiring the use of obsolete and/or hazardous chemicals. The export of used products (commercial buses and trucks, heavy equipment) with poor energy-efficiency and environmental performance also falls into this category of dumping as does products that are at or near end-of-life. In all cases, the goal is to take advantage of countries with less strict environmental laws or environmental laws that are not well-enforced. The economic benefit of this practice is cheap disposal or recycling of waste outside of the economic and environmental regulations of the country of origin or the maximization of revenue from old products that are unwanted or not permitted for sale in the country of origin.

The dumping of hazardous waste has been possible because less-developed countries often did not: 1) know what entering the country through importers, 2) know the hazards and trade-offs, 3) have the enforcement structure in place to apprehend and halt imports, or 4) possess the political consensus and necessary independence to look out for their own national interests.