Terminology, concepts and definitions - Probabilistic Safety Assessment for Optimum Nuclear Power Plant Life Management (PLiM) - page 37

of the main circulation pipeline; mitigation of this accident requires the
solicitation of many safety systems.
Destruction of the of the pressure vessel of the VVER- or PWR-
type reactors is the beginning of the failure not foressen in design. The
probability of such failure is not greater than 10 -7 1/ (reactor · year).

1.4 Strength reliability and its connection with
nuclear safety and service life of NPP

of nuclear power plant

Buildings
and
installations
of NPP

Containment SSCs
(4th safety barrier)

Safety systems SSCs

SSS LSS

￿ ￿ ￿ ￿ ￿

nuclear power plant with VVER-440 [5] reactor: ECCS - system for emergency

systems; CSS - controlling safety systems; SS - safety systems;