Part 8.1

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Ceramic fuel — nuclear fuel consisting of high-heat compounds, e.g. oxides,
carbides, nitrides.
Coefficient of set power use (CSPU) — relation of actual energy production of
a reactor plant for the period of operation to energy production at nominal power; it
characterizes effectiveness and security of NPS operation.
Wastes classification — process of distributing of wastes by special categories
adopted to guarantee that wastes are processed in a secure for people and environment
way.
Security classes — classification of NPP equipment and systems by their roles
in providing NPP security (class 1 includes fuel and NS elements, whose failures are
initial events of off-project accidents leading to fuel elements damage with exceeding
limits of project accidents).
Containment — protective concrete hermetic cover of reactor hall.
Radiation control — gathering information about radioactive conditions in the
organization, environment and about the levels of population exposure to radiation
(includes dissymmetrical and radiometrical control).
Nuclear reactor vessel — hermetic container designed for active zone and
other plants and for organization of nuclear fuel safe cooling by coolant flow.
Tank reactor — nuclear reactor whose active zone is in a tank capable to bear
heat loads and coolant pressure. High pressure of coolant in light-water reactors that
are constructionally vessel require thick-wall steel vessel.
Space radiation — energy particles including protons that get to the Earth from
the space.
Reproduction coefficient — characteristics of chain fission reaction reflecting
the correlation of the number of neutrons of a given generation to the number of neutrons
of the previous generation.
Security criteria (levels) — parameters and (or) characteristics of a NS set by
normative and legal acts and (or) state regulative authorities according to which the
security of the station is estimated.
Critical mass — smallest mass of nuclear fuel in which self-keeping chain fission
reaction can occur. It is determined by the construction, active zone composition
and other factors.
Critical condition of the reactor — stationary condition of a reactor at which
the number of neutrons doesn’t change (Reproduction coefficient).