Fuel pumping mode

Catalytic reactors, where the incorporation of an appropriate catalyst can increase the conversion and lead to an increase in selectivity. These reactors can operate according to either a pumping mode or a "fuel-cell mode . 

Principles of PCMR for methane coupling (a) pumping mode (b) fuel cell mode (c) permeation mode. 

Gas Pump Control Shutoff Gas stations employ fuel pumps that are designed to stop flow of gas when the car s gas tank is full. When the gas pump control fails to function, the car s gas tank is overfilled. The fuel pump shutdown represents an example of a protective system operating in high-demand mode, as there are several demands on the fuel pump shutoff a day. 

The model results are compared to experimental data based on cesium contamination of a fuel cell operated in hydrogen pump mode. 

This chapter has provided the basic equations to understand and to model the effects of cation contamination in polymer membranes. This is a relatively new field with much left to be understood. The effects of different cations on water uptake and membrane structure have not specifically been addressed, but the modeler can apply these effects using the equations we have discussed. We have not specifically discussed operation in the fuel cell mode, but have concentrated on the hydrogen pump. The differences are in the electrodes, not in the membrane. 

For ESD isolation valves (i.e., EIVs) a fail safe mode is normally defined as fail closed in order to prevent the continued flow of fuel to the incident. Blowdown or depressurization valves would be specified as fail open to allow inventories to be disposed of during an incident. Special circumstances may require the use of a foil steady valve for operational or performance reasons. These applications are usually at isolation valves at components, i.e., individual vessels, pumps, etc., where a backup EIV is provided at the battery limits that is specified as fail closed. The fail safe mode can be defined by the action that is taken when the ESD system is activated. Since the function of the ESD system is to place the facility in its safest mode, by definition the ESD activation mode is the foil safe mode. 

Experimental studies of features of the alloy-structure interaction were carried out by tests of mock-ups, models and real primary components. Fuel subassemblies, control and safety system components, primary pumps, steam generators, sections of main and auxiliary pipelines and their valves have been tested. In the course of tests requirements have been worked out for the temperature conditions of heating up and cooling down modes, as well as for separate structures designed for avoiding damages at multiple condition changes. 

The system has two operating modes ACTIVE and DORMANT. In the ACTIVE mode, aU pumps in the tanks are activated and fuel is fed from the collector tank into the engine. The transfer of fuel from the main and the wing tanks depends on the level in the coUector tank. In the DORMANT mode there is no fuel transfer and the pumps are shut down. 

The low-pressure ECCSs consist of two separate and independent systems, the CS system and the LPCI mode of the residual heat removal system. The CS system consists of two separate and independent pumping loops, each capable of pumping water from the suppression pool into the reactor vessel. Core cooling is accomplished by spraying water on top of the fuel assemblies. The LPCI mode of the residual heat removal system provides makeup water to the reactor vessel for core cooling under LOCA conditions. 

---