Reactor emergency discharge

Operating pressure There are three modes of operation of a quench tank atmospheric pressure operation, nonvented operation, and controlled venting operation. Atmospheric operation is usually feasible when the effluent Being emitted has a bubble point well above the maximum ambient temperature. A very small quantity of vapor escapes with the air that is displaced as the tank fills with the emergency discharge (typically about 0.2 percent of the reactor contents). Depending on the toxic or flammable properties of the vapor, the vent from the quench tank can be routed to the atmosphere or must be sent to a scrubber or flare. 

Fig. 6 is an enlarged vertical longitudinal sectional view taken through the reactor and coffin, shown partially in elevation, and showing the steel and water shield below the reactor and the mechanism employed for effecting an emergency discharge of the moderator from the system Fig. 7 is a top plan view of the reactor shown in Fig. 6 Fig. 8 is a transverse sectional view taken on line 8—8 of Fig. 7, and shown partially in elevation ... 

Example 4.4 Determination of the time available for an emergency discharge of a reactor... 

According to [18] a conservative ( pessimistic ) assessment shows that 18 s are available to discharge the reactor contents safely into the emergency discharge tank. Is this enough if a coefficient of discharge of p = 0.82 (cylindrical connection) is used ... 

The temperature control loop is equipped with temperature alarm TAl. Its signal is to prompt the operator to open the bypass of the temperature control, to stop the hexamine supply and to discharge the reactor contents by pushing an emergency button, which in addition activates the stirrer motor M2 of the emergency discharge tank. 

The temperature would reach 25 °C and remain there despite full cooling power, if the reactor contents were not discharged to the emergency discharge tank after about 70 s. If the hexamine feed is stopped by TSH2, the discharge would take place after 419 s. After that the reaction comes to a standstill and the reactor temperature drops to —3.5 °C. 

Provide for addition of diluent, poison, or inhibitor directly to reactor. Provide for automatic or manual actuation of bottom discharge valve to drop batch into a dump tank with diluent, poison or inhibitor, or to an emergency containment area. 

Install high temperature interlock on discharge of condenser to shutdown reactor and initiate emergency cooling... 

The initial calibration of the ionization chamber 400 is such that the relay coil 406 is energized only in the event lo that the neutron density in the reactor 18 reaches a value greater than that sufficient to operate either circuits A or B. In other words, circuit D operates to discharge the heavy water from the active portion of the reactor only as a last resort in the case of emergency, and only after li> circuits A or B have failed to operate or otherwise to prevent the neutron density in the system from rising above that required to operate circuit A or B. 

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

In addition to the automatic discharge just described the reactor may be emptied by pushing emergency pushbuttons, which are installed both in the control room and in the plant and provide an opening signal to SVl and a starting signal to M2. 

When the reactor pressure exceeds a certain value, the relief valve (9) is automatically actuated. This valve is located on the upper part of the pressurizer and discharges steam in a discharge collecting tank (10), partly filled with cold water and provided with an emergency rupture disc (11), which avoids its excessive pressurization. When the pressure within the tank reaches the intervention level of the rupture... 

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