Pump Design Safety

Second, consider all the myriad forms of harm that can come from healthcare complications of surgery, infection from unsafe injections, infection from over crowded hospitals, adverse drug reactions, overdoses from badly designed infusion pumps and so on. Should we assume that all these are necessarily due to error If we equate patient safety with error reduction, we run the risk of not addressing any form of harm which is either not due to error, or only partly due to error. 

ELECTRIC POWER SYSTEM Clas I,II and III Electnc System CSAB290 5 The Class III system pow ers designated safety -related and economic equipm i protection loads pump motors, valv es etc) Normally Class IV power supplies the Class III power W. cn the Class IV system fails two redundant standby diesel generators provide Class ni power The ac Class II and dc Class I systems supply un-mtermptible power to the control and safety svstems... 

The procurement of a properly designed pump and the proper design of ttie associated piping system are of primary importance to pump safety. The actions to take when designing a pumping system and buying a pump indude the following ... 

The traditional function of a PWR reactor coolant pump is to deliver cooling water to the reactor during both normal operations at power and for fission product heat removal when shutdown. The reactor coolant pump type adopted in the US for currently operating plants is the shaft seal pump, which can be made large and can have high hydraulic and electrical efficiencies. The potential design options for the AP600 were numerous ac powered shaft seal pumps, dc powered safety pumps, canned motor pumps, no pumps (natural circulation) and others. 

A small (25-kg), portable apheresis system, available in 1993, is designed to meet a wide variety of blood cell separation needs. The role of the apheresis system is to control the behavior, separation, and collection of blood components from the bowl while maintaining maximum donor safety. The system controls the flow rates of blood and components through variable pump speeds. It directs the flow of components out of the bowl, by fully automatic opening and closing of valves based on the output of the system sensors. The system monitors the separation of blood components in the bowl by an optics system that aims at the shoulder of the bowl. A sensor on the effluent line monitors the flow of components out of the bowl. 

Liquid metals, however, present several disadvantages. Their weights must be considered with regard to equipment design. Additionally, Hquid metals are difficult to contain and special pumps must be used for system safety. Alkali metals react violentiy with water and bum ia air. Liquid metals also may become radioactive whea used for cooling auclear reactors (qv). 

The reservoir may be either pressurized or atmospherie. It must have suffieient eapaeity to eontain all oil during drain-baek or shutdown. It must be equipped with an oil level indieator, a low-level alarm switeh, safety relief valve, a pump for oil makeup during operation, drain valve, heater, mist eliminator, strainers, and required valves. Expander reservoirs must be designed and eonstrueted in aeeordanee with applieable ASME eodes. Reservoir retention time is typieally between 5-18 min depending on turboexpander size and manufaeturer s sizing eriteria. This is an area where the owner/purehaser should ask for the manufaeturer s assistanee. 

The report presents the findings from the analysis of the RCP failures. Estimates of the annual frequency for the spectrum of leak rates induced by RCP seal failures and their impact on plant safety (contribution to coremelt frequency) are made. The safety impact of smaller RCP seal leaks was assessed qualitatively, whereas for leaks above the normal makeup capacity, formal PRA methodologies were applied. Also included are the life distribution of RCP seals and the conditional leak rate distributions, given a RCP seal failure the contribution of various root causes and estimates for the dependency factors and the failure intensity for the different combinations of pump designers and plant vendors. 

The component failure rate data used as input to the fault tree model came from four basic sources plant records from Peach Bottom (a plant of similar design to Limerick), actual nuclear plant operating experience data as reported in LERs (to produce demand failure rates evaluated for pumps, diesels, and valves), General Electric BWR operating experience data on a wide variety of components (e.g., safety relief SRV valves, level sensors containment pressure sensors), and WASH-1400 assessed median values. 

In the example the manufacturer has been specified from available performance curves, and the details of construction must be obtained. The pump is selected to operate at 22 GPM and 196 to 200 feet head of fluid, and must also perform at good efficiency at 18 GPM and a head which has not been calculated, but w hich will be close to 196 to 200 feet, say about 185 feet. Ordinarily the pump is rated as shown on the specification sheet. This insures adequate capacity and head at conditions somewhat in excess of normal. In this case the design GPM w as determined by adding 10 percent to the capacity and allowing for operation at 90 percent of the rated efficiency. Often this latter condition is not considered, although factors of safety of 20 percent are not unusual. However, the efficiency must be noted and the increase in horsepower recognized as factors w hich are mounted onto normal operating conditions. 

Project cost data were reported for 43 of the 100 pump-and-treat projects in the dataset these include data for both ongoing and completed projects. In most cases, the components that make up the project costs were not reported. However, it is likely that these costs incorporate different components, such as treatment, monitoring, design, oversight, and health and safety. Table 24.21... 

Several recovery scenarios were considered for remediation. Initially, construction of a narrow, permeable trench parallel to the canal appeared to be an appropriate interception system. The construction technique considered was use of a specially designed deep trenching unit. This type of trench would have included a tile drain leading to a single two-pump recovery well. However, a review of the subsurface site plans and interviews with long-term employees determined that an unknown number of buried pipes traverse the area intended for the trench construction. Disruption of refining operations and safety considerations resulted in rejection of this option. 

The second option considered was use of interception wells. One- or two-pump wells could be constructed at calculated spacings to create a hydraulic trough parallel to the canal to intercept the product. This design was considered more acceptable to the safety officer and the facility engineer, but was rejected by the maintenance foreperson because of the relative complexity of the operation system. The number of submersible pumps and sophisticated electronic controls would have required employment (or training) of technical specialists beyond the cost budgeted under normal operations. 

The cell is usually connected to the rest of the system using stainless steel tubing. Both needle and ball valves are available as are check valves that only allow the flow to travel in one direction. The gas is delivered from a cylinder with a pump or compressor in order to provide the required pressures. For safety, two forms of pressure relief are available. Most simply, burst discs can be included to prevent catastrophic system failure due to over pressurization. These are designed... 

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