Regional Basic Professional Training Course in Korea

6. Safety Classification Of Structures, Systems and Components
stored outside the reactor coolant system, but within the site, during all
operational states;
(q) To remove decay heat from irradiated fuel stored outside the reactor coolant
system, but within the site;
(r) To maintain sufficient sub‐criticality of fuel stored outside the reactor coolant
system, but within the site;
(s) To prevent the failure, or limit the consequences of failure, of a component or
structure whose failure would cause the impairment of a safety function;
Objectives of the safety functions are:
1) To provide a reference list to determine whether a system, component or structure
performs or contributes to one or more safety functions.
2) To establish an appropriate order of importance to safety of each function, and to
group these functions into categories termed “safety classes.” One purpose of
establishing safety classes is to provide a basis for gradation of design requirements.
The establishment of safety classes may also prove useful for other considerations such as
seismic requirements, quality assurance, or in‐service inspection.
6.1.2. Methodology for Classification
6.1.2.1. Ranking of safety functions
In general, the ranking of safety functions depends on the consequences that a failure to
accomplish a safety function would mean with respect to reduction of safety in terms of
the possible increase in radiation exposure.
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