Regional Basic Professional Training Course in Korea

❙ 1169 ❙
Introduction Of e‐FAST and Exercise
3.2 ACCIDENT & INCIDENT SIMULATION
3.2.1. SGTR(Steam Generator Tube Rupture)
1) SGTR overview
If guillotine break of single tube occurs, the reactor automatically trips within 20 minutes
after break without the operator action. In case of multiple tube failure, the reactor will
trip within the faster time. However, in case of smaller break, due to automatic operation
of PLCS (Pressurizer Level Control System), the pressure and level of pressurizer will
stop without continuous decrease. Therefore, the automatic reactor scram may not occur
and the operator should find a method to trip the reactor safely and to prevent core
damage using AOP (Abnormal Operating Procedure) and EOP (Emergency Operating
Procedure).
2) Safety Significance of SGTR
There are two safety functions directly affected by SGTR accident. One is safety function
for RCS Inventory and the other is safety function for Containment Isolation. The reason
why the safety function is especially applied to containment Isolation is that the
containment building is the final barrier of radioactive material release to the
environment.
The strategic goal to maintain RCS inventory and isolate the radioactive materials can be
obtained, first by minimizing the leakage from the primary system to the secondary
system, second, by isolating the failed steam generator, and third, by preventing the