Valve plate failure

Both pulsation problems and inadequate valve lift, or valve speed, raise the cylinder s internal peak discharge pressure. For example, a piston-rod failure on one compressor was precipitated when weak valve-plate springs were replaced with stronger springs requiring a greater valve-plate pressure differential to open. 

Pulsations and vibrations should be kept to a minimum (e.g. pumping and valve switching) because they reduce the life of plates by mechanical damage leading to fatigue failure. To ensure product security, plates should be crack tested on a regular basis (annually). 

The Control plug supports the 12 absorber drive mechanisms, sleeves which house thermocouples for measurement of outlet temperature of each fuel subassembly and three selector valves with sodium sampling from each fuel SA for failed fuel location. Use of bellows has been avoided for CSRDM to extend the life of the mechanisms and to enhance reactor availability, as bellows failure has been responsible for replacement of CRDMs in reactors using this concept. V-ring seals are used between the stationary sheath and mobile assembly of CSRDM. The core thermocouples are located at a fixed distance of 90 mm from the top of the SA during reactor operation and no Core Cover Plate Mechanism (CCPM) is provided as in FBTR. Thermohydraulic analysis indicates that the thermocouples are immersed in their respective streams at all power levels thereby ensuring adequacy of temperature measurement. 

Personnel working with fluorine cylinders must be protected by use of a cylinder enclosure or barricade and remote control valves, preferably ones operated by manual extension handles passing through the barricade. The main function of a barricade is to dissipate and prevent the breakthrough of any flame or flow of molten metal, which, in case of equipment failure, could issue from any part of a system containing fluorine under pressure. Barricades of 0.25-inch (6.4-mm) steel plate, brick, or concrete provide satisfactory protection for fluorine in cylinder quantities. Adequate ventilation of enclosed working spaces is essential. Installation in a fume hood is recommended for laboratory use of fluorine cylinders. 

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