Cooling water piping pressure losses

Low-pressure cool or warm water washing uses water at pressures less than about 200 kpa (50 psi) and temperatures less than about 30°C. Water is applied with hoses that do not focus the water excessively, avoiding the loss of plants and animals. Flooding is a process in which a large flow or deluge of water is released on the upper portion of the beach. Water can be applied to the beach using hoses without nozzles to reduce the impact of the spray. Sometimes a special header or pipe is used to distribute the water. Booms are then used to contain the flow and direct the recovered oil to a calm area where it can be recovered with mechanical skimmers. 

Figure XIII-4 illustrates the basic concept of the present KAMADO design. The heat generated by a fuel rod is not removed directly with cooling water but via graphite blocks of a fuel element, i.e., cooling water is heated by high temperature graphite of the fuel element. In case of a loss of coolant or flow, such as a pipe break, turbine trip, etc., the decay heat is removed by passive heat transfer from surfaces of the fuel elements to the reactor water pool operating at atmospheric pressure and low temperature.

Pressure drop around the cooling water loop is estimated as follows Pioop = 15 psi (pipe losses) + 5... 

The capacities of the emergency core cooling systems suffice to provide water under all postulated pipe break conditions. This statement is also valid assuming that only two of the four redundant subsystems are operable. The postulated loss-of-coolant conditions include a hypothetical 80 cm leak at the bottom of the reactor vessel In this context, it can be noted that the capacity of the low pressure coolant injection punq)S has been reduced for BWR 90, following comprehensive core cooling analyses. As a secondary effect, it has been possible to simplify the auxiliary power supply systems. 

The RCIC system maintains sufficient water in the reactor pressure vessel to cool the core and then maintains the nuclear boiler in the standby condition in the event the vessel becomes isolated from fhe furbine steam condenser and from feedwater makeup flow. The system also allows for complete plant shutdown under conditions of loss of the normal feedwater system by maintaining the necessary reactor water inventory until the reactor vessel is depressurized, allowing the operation of the shutdown cooling function of the RHR system. The system delivers rated flow within 30 s after initiation. A water leg pump keeps the piping between the pump and the discharge shutoff valve full of water to ensure quick response and to eliminate potential hydraulic damage on system initiation. 

Penetrations to the reactor vessel are all small in diameter and located at elevations significantly above the core to increase the quantity of water available to cool the core. Small penetrations also minimize the energy loss to the containment for pipe leaks, resulting in lower containment pressures during design basis events. 

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