What are the consequences of internal leakage of high pressure main valve of 600MW steam turbine?

We know that steam enters the high-pressure cylinder through the high-pressure main valve-the high-pressure regulating valve. If there is leakage in the high-pressure main steam valve, steam will directly reach the front of the regulating valve through the high-pressure main steam valve when the unit is started and after the high-pressure pipeline is established. If the regulating valve is too tight, there will be no other consequences. Just drain the water before opening the regulating valve to prevent water from accumulating in the pipeline. However, because the control valve plays a throttling role in operation, if the sealing surface of the control valve is not tight due to long-term wear, then steam will directly enter the high-pressure cylinder to impulse the turbine. Similarly, when stopping, the speed may not reach zero because the steam cannot be completely cut off. Both situations are very dangerous. Therefore, for the sake of safety, it is best to solve the problem before starting the unit after discovering the internal leakage.