Part 8.1

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Natural radiation background — space radiation and radiation created by
natural radio nuclides contained in soil, water, air, other elements of biosphere, in
food products, in the organisms of people and animals.
LRW — liquid radioactive wastes.
Unremovable (fixed) surface contamination — radioactive substances that
are not transferred to other objects with contacts and not removed at decontamination.
Removable (unfixed) surface contamination — radioactive substances that
are transferred to other objects with contacts and removed at decontamination.
Radioactive contamination — presence of radioactive substances on the surface
or inside a material, in the air, in a human body or in any other place in the
amount exceeding the adopted levels.
Uranium oxide (U3O8) — compound having several modifications depending
on conditions of its preparation, formed at oxidation of uranium dioxide and at burning
of any uranium oxide, oxide hydrate or uranium salt and acid.
Inhibitor — material for example light or heavy water, graphite used in the reactor
for inhibition of fast neutrons by their collision with lighter nuclei to facilitate further
fission of nuclear fuel.
Closed nuclear fuel cycle — nuclear fuel cycle in which worked out nuclear
fuel is unloaded from the reactor and processed for extraction of uranium and plutonium
for repeated production of nuclear fuel.
Burial of radioactive wastes — safe placement of radioactive wastes without
intention of their further usage.
Protective cover of the reactor — technical means designed for preventing
output of excess amount of radioactive substances out of the nuclear reactor to the
environment even in case of accident.
Protective security systems (elements) — systems (elements) designed for
prevention or limitation of damages of nuclear fuel, fuel elements, equipment and
pipelines containing radioactive substances.
Siewert (Sv) — equivalent and effective radiation dose unit in measurement
system, named after Swiss scientist G. R. Siewert.
Reproduction zone — part of nuclear reactor containing reproducing nuclear
material and designed for getting secondary nuclear fuel.
Observation zone — territory outside the sanitary protection zone where radiation
monitoring is carried out.
Radiation accident zone — territory where the fact of radiation accident has
been proved.