Production of Polysilicon using a Modified Siemens Process

Sequence Diagram for Use Case 2
Use Case 3: Maintenance
The third use case addresses the need to perform regular maintenance and inspections on
the plant and ensure the process is operating properly. The maintenance operator should be able
to inspect each reactor and the sensors and piping attached to them. The operator will proceed
with each reactor in sequence and the equipment attached to them. If there is a problem
appropriate actions should be taken to rectify the problem. In the end the time and date of
maintenance should be documented to verify that everything is working as it should. The number
of different possibilities for maintenance issues is too large to comprehensively cover, but the
following scenarios address common/simplified possibilities: