Diffusion-ordered spectroscopy, separating NMR signals by molecular translational diffusion.

Coupled relaxation of nuclear-spin populations through their mutual interactions.

Indirect coupling of nuclear spins mediated by bonding electrons.

A spin system with two distinguishable, mutually coupled spins A and B, each coupled to three equivalent X spins. An ethoxy methylene with nonequivalent hydrogens can display this pattern; small A/B chemical-shift separation relative to their coupling produces second-order distortion.

nuclear magnetic resonance of the spin-one-half isotope ${}^{29}\mathrm{Si}$. Equivalent silicon sites give the same isotropic chemical shift, while condensation and silanol substitution can distinguish environments. Line heights alone are not quantitative populations.

The number and relative intensities of lines into which an NMR signal is split by scalar spin coupling.

Use of integrated peak areas to estimate relative numbers of resonant nuclei.

The linked production, use and subsequent management of nuclear fuel. A closed cycle recovers some material for reuse; it still generates radioactive wastes.

Control of radioactive wastes from generation through treatment, conditioning, storage and disposal. Concentrating a radionuclide in a smaller stream changes its location, not its radioactive decay law.

Administrative and technical actions bringing a permanently shut-down nuclear facility to a demonstrated end state permitting removal of some or all regulatory controls. Waste management and site-release evidence are integral to completion.

Unwanted radioactive material on or in an object, substance or environment. It is distinct from activation of the object itself.

Nuclear material accountancy records and reconciles inventories and transfers of nuclear materials. It combines records of what entered and left a defined accounting area with measurements of what is physically present. A basic balance isAll four terms must describe the same material quantity and accounting period. The difference $\Delta$ is called material unaccounted for: it compares the amount inferred from the records with the closing physical inventory.^[ref]

A nonzero difference requires interpretation using measurement uncertainty, including uncertainties in the individual balance terms. It is not automatically evidence that material has disappeared. For example, equal true opening and closing amounts can yield a nonzero measured difference when the two measurements have different errors. This makes nuclear material accountancy an application of mass balance together with statistical inference and measurement control.^[ref]

The coupled analysis of heat generation, heat transfer and coolant fluid mechanics in a nuclear reactor. A change in fuel geometry can affect neutron moderation, hydraulic resistance and thermal margins together, so holding one quantity fixed does not generally hold the others fixed.

Prevention of unwanted dispersal of radioactive material by barriers, enclosures and controlled transfers. It differs from shielding, which attenuates a radiation field without necessarily retaining the radioactive source.

Attenuation of an ionising radiation field by intervening material. A shield can reduce external exposure without preventing contamination from a released radioactive substance.

The posterior part of the vertebrate central nervous system, derived from the neural tube.

A nervous-system cell with specialised support, insulation or regulatory functions distinct from the principal signalling role of neurons.

The anterior central nervous system of a vertebrate, developing principally from the neural tube rather than directly from neural crest.

The brain and spinal cord, including both neurons and glial cells.