Regional Basic Professional Training Course in Korea

monitors are part of the safety system. Some of them have an alarm level.
❙ 781 ❙
12. Surveillance Programmes
The monitoring of structure born sound for loose parts detection is a permanently
installed monitoring system that detects sound emissions of the primary cooling circuit in
order to detect loose parts. The sound emissions can be analyzed automatically. The
sound emission signals are divided in those that are unknown and those that are known.
Known signals are usually sound emissions due to operation. Sound emissions from loose
parts differ from those of operation so that they can be separated. In the case of unknown
signals or signals due to loose parts, an automatic alarm is sent to the control room. All
signals are recorded.
Leakage monitoring systems are also permanently installed. Some of monitoring systems
measure the dew point in exhaust air of a room. The depression of the dew point indicates
an increase of air humidity. Inside the containment, air humidity can only increase due to
steam coming from a leakage in the cooling circuit. Some of monitoring systems measure
radioactivity level. If the level is exceeded the set point level, the leakage flow is blocked
automatically. The leakage monitoring system gives automatically an alarm in case that it
measures a depression of the dew point or high radioactivity set point.
Vibration, temperature and pressure monitoring systems are usually installed
permanently. Sometimes it can be necessary to install such monitors for one or two
periods in order to find areas in piping systems that have unexpected high local loads. If
no unexpected loads are found, the monitors will be uninstalled, as there is no need for a
further surveillance. In case unexpected local loads are found, there is the possibility for
corrective actions in order to avoid these loads. If this is impossible, the surveillance of
the area will be continued, possibly in addition to periodic non‐destructive testing.
Vibration, temperature and pressure monitoring systems are also a main part of the
fatigue monitoring system. They are used to control whether the loads on pipes and