Regional Basic Professional Training Course in Korea

❙ 783 ❙
12. Surveillance Programmes
Testing the interlocking circuitry of components within a system (e.g. pump to
pump, valve to valve, pump to valve, etc.)
The surveillance tests on safety relevant instrumentation and control, such as, the reactor
protection system, including safety signaling, limitations, accident instrumentation,
instrumentation and control for the emergency power generation and operating room, and
the emergency operating room are complex. Depending on the complexity of the test, the
signalization path can be subdivided into several smaller sections, each being tested on its
own, with defined overlapping of smaller sections. As an example, in the reactor
protection system the following tests are performed:
Measuring the analogue circuit;
Computing circuits;
Limiting values (comparators, timing circuits, etc.);
Logic tests;
Output signals, with actuation of components;
Alarms (cubicle, operating room, process computer, etc.).
12.4.3.2 Surveillance of reactor vessel embrittlement
Neutron induced embrittlement is the main factor in the ageing of the reactor pressure
vessel. If not controlled, the embrittlement can reach a state at which the reactor pressure
vessel cannot stand the loads anymore. To avoid this, a surveillance program has to be
planned and implemented.
The embrittlement depends on the material of the pressure vessel and on the neutron
fluency in the wall of the vessel. The embrittlement due to the material is determined by
the content of copper, nickel and phosphor. There are standard curves for a different