Safeguard arrangement for plant

A safeguard arrangement for a plant, which comprises a plant auxiliary provided with a lid and so designed that the lid is opened for maintenance of the inside thereof, switching means installed on a piping connected to said plant auxiliary, and driving means to give a driving output to the switching means in response to an opening or closing instruction signal for said switching means, and which is employed when operations for maintenance of the aforesaid plant auxiliary are executed, is provided additionally with lid opening detecting means to detect the opening of the lid of the afore-said plant auxiliary or the release of locking means thereof, in gearing with either of them, and checking means to check the opening of the aforesaid switching means on the basis of the opening instruction signal for the switching means when it is detected by said lid opening detecting means that the lid is opened or to be opened.