Trip mechanisms defined

A reactor trip signal acts to open two trip breaker sets connected in series, feeding power to the control rod drive mechanisms (CRDMs). The loss of power to the mechanism coils causes the mechanisms to release the RCCAs, which then fall by gravity into the core. There are various instrumentation delays associated with each trip function including delays in signal actuation, in opening the trip breakers, and in the release of the rods by the mechanisms. The total delay to trip is defined as the time delay from the time that trip conditions are reached to the time the rods are free and begin to fall. 

The third criterion that animal systems should demonstrate with respect to the psychedelic trip in man is the observed tolerance to both the mental effects and mydriasis. This appears to be complete after several daily doses and to be lost after 4 days without LSD. With respect to biologic mechanisms, occurrence of acute tolerance in both man and animals (20) poses a problem. Whether tachyphylactic or other processes are entailed remains to be defined. 

Class 1 safety instrumentation loops include alarms and trips on storage tanks containing flammable or toxic liquids, devices to control high temperature and high pressure on exothermic-reaction vessels, and control mechanisms for low-flow, high-temperature fluids on fired heaters. Other Class 1 instruments include alarms that warn of flame failure on fired heaters, and vapor detectors for emergency valve isolation and sprinkler-system activation. All of these alarms, shutdown valves, and other critical instruments are regularly proof-tested to a well-defined schedule. 

Stationary-Container Systems (SCS) Collection systems in which the containers used for the storage of wastes remain at the point of waste generation, except for occasional short trips to the collection vehicle, are defined as stationary-container systems. Labor requirements for mechanically loaded stationary-container systems are essentially the same as for hauled-container systems. There are two main types of stationary-container systems (1) those in which self-loading compactors are used and (2) those in which manually loaded vehicles are used. 

The Safety Setting Input Units (SSIUs) are three redundant devices, one for each trip unit. Each SSIU has a front panel, which provides as many sets of thumbwheels as Safety System Settings (SSS) are required by its related trip unit. Appropriate values for these SSS are defined by an authorised operator through these thumbwheels and they are read into RAM only once every time the trip unit is power-on. Each SSIU has a panel-door, which is mechanically locked in its closed position, to allow no changes of its SSS while its related Trip Unit is operating. In case this mechanical protection is overridden, the unlock SSIU shall power-off its related trip unit. 

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