Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course (BPTC) on Nuclear Safety
inspection intervals and the probabilities and characteristics of component failures. The
inspection interval for the evenly distributed programme may be chosen to be from a few
years to about ten years; in the variably distributed schedule these intervals may be
shorter in the early years of the plant life and then lengthened as experience permits.
Whichever programme is adopted, however, information on flaw changes may require a
shortening of the interval towards the end of plant life.
The inspection interval is subdivided into inspection periods in the course of which a
required number of examinations should be completed, depending upon the component,
the type of examination, or the accessibility allowed by the normal plant operations or by
scheduled outages. These examinations may be considered as a portion of the total
inspection required for the whole interval.
Examinations which require the disassembly of components (such as disassembly of
pumps or valves to examine large bolting volumetrically) or the removal of fuel or of
core support structures in reactor vessels to examine welds or nozzle radius sections, may
be deferred until the end of each inspection interval except where, on the basis of results
of examination conducted on analogous components, an earlier inspection is necessary.
This in no way diminishes the requirements on the examination frequencies formulated in
the appropriate design codes (for example ASME, KEPIC etc.).
12.3.4. Test requirement
Pressure‐retaining systems and components are subjected to:
A system leakage and hydrostatic pressure test as part of the pre‐service inspection;
A system leakage test, undertaken before resuming operation, following each
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