Water injection systems continued

BWRs do not operate with dissolved boron like a PWR but use pure, demineralized water with a continuous water quality control system. The reactivity is controlled by the large number of control rods (>100) containing burnable neutron poisons, and by varying the flow rate through the reactor for normal, fine control. Two recirculation loops using variable speed recirculation pumps inject water into the jet pumps inside of the reactor vessel to increase the flow rate by several times over that in the recirculation loops. The steam bubble formation reduces the moderator density and... 

The safety improvements use redundancy and diversity to prevent and mitigate lents. The safety injection system (SIS) and emergency feedwater system (EFWS) are dedicated four train systems. Containment spray and safety injection pumps take water from the in-containment water storage tank (IRWST), thus, eliminating the need to switch from an external source and provide a. semi-closed system with continuous recirculation. Emergency core coolant flows direc nto the... 

Several classical ion-selective electrodes (some of which are commercially available) have been incorporated into continuous systems via suitable flow-cells. In fact, Lima et al. [112] used a tubular homogeneous crystal-membrane (AgjS or AgCl) sensor for the determination of sulphide and chloride in natural and waste waters. However, the search for new active materials providing higher selectivity and/or lower detection limits continues. Thus, Smyth et al [113] tested the suitability of a potentiometric sensor based on calix[4]arene compounds for use in flow injection systems. They found two neutral carriers, viz. methyl-j3-rerr-butylcalix[4]aryl acetate and... 

An important feature of the distributed control system chosen is that the PCMs can communicate over a microwave link, thus allowing the well pad manifold modules to be included in the GC control system the hardwire data highway is limited to a distance of 5000 ft. (1524m) from the Host. The well chokes and manifold controls will remain on the SCAOA system, but the well pad will require continuous process control of the test separator, water injection flow control, and artificial lift gas flow control. 

Wittmann, C. and R.D. Schmid (1994). Development and application of an automated quasi-continuous immunoflow injection system to the analysis of pesticide residues in water and soil. J. Agric. Food Chem., 42 1041-1047. 

FIGURE 8.9 Recovery factors and water cuts for continuous injection cases of different microemulsion systems. 

To this end, loop-based injection is preferred and the sample aspiration tube (Fig. 6.9) behaves as a sampling probe, as demonstrated in the landmark work of Thomsen et al. who determined reactive silicate in coastal waters during a cruise from Monterey Bay to San Francisco Bay in the USA [3]. The sample was continuously aspirated from a water layer about 2 m below the sea surface and a situation of "infinite sample volume" was attained in the main channel of a shipboard reagent injection (reversed flow) flow injection system. A reagent aliquot was injected into the flowing sample every 45 s and the resulting coloured zone was quantified by spectrophotometry. The height of the recorded peak was directly related to the reactive silicate concentration at the specified location and depth. 

The feasibility of using a portable flow injection system for the in situ monitoring of river water was demonstrated by the design and deployment of a field instrument with spectrophotometric detection for the determination of phosphate [4], Solid-state technology (LED source and photodiode detector) was used to construct a compact, battery-operated analyser that could operate without maintenance for several weeks, yielding reliable, pseudo-continuous results. The monitor was further applied to the determination of nitrate [5] and ammonium [6] in river waters. Details of the instrumentation were also reported [7,8]. 

A continuous SPE system coupled to a gas chromatograph was used for the preconcentration and determination of A-methylcarbamates in water samples. The continuous system (Figure 24.4) comprised a peristaltic pump furnished with pumping tubes, an injection valve, and a laboratory-made adsorption column placed in the loop of the injection valve. Also, a LLE derivatization module coupled online to a gas chromatograph was used for the determination of carbamate pesticides in aqueous samples. The manifold consisted of a peristaltic pump, pumping... 

The boric acid and demineralized water control system is necessary to adjust the boron concentration in the reactor coolant system. To increase boron concentration in the coolant, boric acid solution is injected through the volume control system to reduce boron concentration, an adequate volume of coolant is replaced by demineralized water. This system (as well as the other systems discussed here) is a purely operational system and is not required for control of a design basis accident the extra borating system fulfils the necessary safety functions. However, to guarantee continued supply to the volume control system during emergency power operation, the pumps and motor-operated valves of the system are connected to the emergency power supply system. 

Kroon H. 1993. Determination of nitrogen in water comparison of a continuous-flow method with online UV digestion with the original Kjeldahl method. Anal. Chim. Acta 276 287-293. Oms M.T., Cerda A., and Cerda V. 2003. Sequential injection system for online analysis of total nitrogen with UV-mineralization. Talanta 59 319-326. 

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