Emergency trip

Safety systems are typically divided into emergency trip/shutdown functions, controlled (slow) shutdown, alarm activation, or startup annunciation of auxiliary equipment such as oil pumps. 

An emergency trip of the expander or generator requires fast closing of the trip valve and inlet control valve. An emergency trip also must not adversely affect the differential pressure between the reactor and regenerator. 

Steam Admission Volve(s) Governor Controlled Single, Emergency Trip Valve Combine d with Throttle Valve ... 

Also, gamma ray monitoring equipment with alarms and emergency trips was installed on the separators to protect the downstream gas-compression trains. 

Permanent gamma ray scanning equipment was installed on each separator along with foam density and level recorders in the process control room. An emergency trip system that automatically shuts a valve in the appropriate separator gas line to isolate the separator from the compressor suction drums when a high foam level occurs was added also. A similar trip system was insulted in the gas feed line from the HP separator to the power station... 

Effects of Increasing Sinian Crude GOR. Following the installation of the foam monitoring equipment and emergency trip systems, the Ninian crude GOR was increased to 47 scf/bbl (8.5 std mJ/mJ]. The flow of HP separator gas to the power station was maintained while LP separator gas continued to be flared. 

A demonstration was given of a reactor trip from full power using the emergency trip button with the automatic initiation of the Reactor Shutdown Sequence... 

Avoidance of damage by emergency interventions and emergency trips to avoid leaving the region of specified operation... 

In what follows the principle of a passive safety measure is explained using the design and functioning of the passive emergency trip system shown in Fig. 4.4 as an example [15]. 

Fig. 4.9 Emergency trip system for reactor discharge in case of runaway...

Figure 4.13 shows a sharp increase of the temperature to about 30 °C, which is, however, contained by cooling so that a stationary process at 12 °C would result. This implies that the cooling operates at its maximum. Yet, this scenario would not occur in reality because TSHH2 would trigger an emergency trip shortly after the... 

In case the hexamine feed were stopped by TSH2, which would occur approximately 0.33 s after the start of operation, the emergency trip would be activated as well by TSHH2. However, the temperature would be much lower in... 

If no protection via TSH2 were available, the emergency trip would occur after 1,130 s in the first place, and after 4,049 s in the second, because temperature increases sharply. 

NO or NOT No electricity supply Grid failure, transformer failure and such like No cooling, reaction temperature rises Emergency trip... 

If the temperature rises an emergency trip is carried out by dumping the reactor contents into the receiving emergency vessel located below it. 

Probability of failure of the independent protection barriers (total probability of failure on demand) emergency trip system (0.01) not yet installed additional safety function (0.01) = 0.0001... 

Scenario number 1 Equipment number Scenario title Cooling control failure and failure of the emergency trip system ... 

Scope of supply to include speed governor, hand controls, emergency trips, moisture separator with steam trap for incoming steam and instrumentation (as below). 

Other machines, like rubber mills and calenders, use reversing current in the drive motor to stop the rolls when someone activates an emergency trip wire or switch. According to some standards, the rolls must stop within W2% of the peripheral no-load surface speed of the roll. 

Whether hand controls and emergency trips are provided. 

Screw conveyors, often used to move very viscous substances, must be provided with either fixed guards or covers to prevent accidental access. People should be prohibited from riding on belt conveyors and emergency trip wires or stop buttons must be fitted and operational at all times. 

Answer The possibility of a power excursion resulting from lack of control at turnaround is considered as an operating problem rather than a safety problem. In normal reactor operation it is extremely unlikely that a transient as fast as one inhour per minute (2.5 c-mk/min) would occur at turnaround after running out of control rod. Such fast rod movement Just prior to turnaround would surely be noticed and remedial action taken before actually running out of rod. However, assuming that the reactor would gain reactivity at the rate of 2.5 c-mk per minute, the i>ower level would Increase two per cent in the first five minutes. Under these circumstances, plenty of time would be available for operator action (manual scram of the VSR s) some time before emergency trips would take place. 

Control, emergency trip, and relief valves can be equipped with electrohydrauhc... 

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