Auxiliary systems water sources

In addition, it should be demonstrated analytically that the mechanical systems can withstand a single active failure including failure of any auxiliary electric power source and not prevent delivery of sufficient cooling water to maintain the plant in a safe shutdown condition. A technique suitable for this analysis is a Failure, Modes, and Effects Analysis (FMEA). IEEE Std. 353-1975, "Guide for General Principles of Reliability Analysis of Nuclear Power Generating Station Protection Systems," provides additional guidance on the preparation of FMEAs. 

The AFWS is a 2 division and 4 train system. The AFWS is designed to supply feedwater to the SGs for RCS heat removal in case of loss of main/startup feedwater systems. The reliability of the AFWS has been increased by use of two 100% motor-driven pumps, two 100% turbine-driven pumps and two independent safety-related auxiliary feedwater storage tanks as a water source instead of condensate storage tank. 

Maintenance of the Integrity of the water barrier will probably call for more control and maintenance of auxiliary systems than otherwise. The techniques for limiting the sources of water in the process area may include, in addition to cmtrols on routinely added moderator, controls on coolant and hydraulic systems and on firefighting. 

The PEM fuel cells utilize environmentally friendly fuel—oxygen and hydrogen that can be produced via electrolysis of water. Electrolysis of water when using renewable resources (i.e., solar or wind) provides a clean source of fuel that is then reverted to the water by the fuel cell. Currently however, the majority of the world s hydrogen is generated from hydrocarbon fuels since the economics are more favorable than electrolysis of water. The current high cost of electrolysis is related to the raw material cost of cell hardware and the limited volume of cell hardware within the market. If widely adopted, low pressure electrolysis can be reasonably cheap, if auxiliary systems are utilized for gas cleanup (humidity removal) and gas compression. 

The auxiliary feedwater system (AFWS) normally operates during startup, hot standby and shutdown to provide feedwater to PWR steam generators. In conjunction with a Seismic Category I water source, it also functions as ah... 

In this method the soil sample is dried overnight at 85 °C and ground into an homogeneous mixture. A 1 g soil sample is placed into a beaker and 10 ml of concentrated nitric acid added. The solution is heated to dryness and 5 ml of concentrated nitric acid is added. The uranium is redissolved in 5 ml of 8 N nitric acid and diluted to 25 ml with distilled water. The inductively coupled plasma mass spectrometry system used was an ELAN Model 250. The ion source consists of a modified plasma Thermal Model 2500 control box. The forward power was set at 1200 W with the plasma flow, auxiliary flow and nebuliser pressure set at 131/min, 1.0l/min and 0.27 MPa, respectively. The focusing lenses B, El, P and S2 are set at +5.3 V, -12.5 V, -18.0 V and -7.6 V, respectively. The m/z238 ion was monitored for two sec-... 

The consumption of these last auxiliary components might be partially reduced with a specific design of the FCS for a real vehicle, but the energy losses due to the air and water management system would be quite difficult to be lowered. In this respect, the maximum FCS efficiency (55% at medium load, see Fig. 6.6) takes in regards to the only loss sources due to the air compressor, hydrogen purge, and water pump. 

Cathodic protection (CP) is an electrical method of mitigating corrosion on metallic structures that are exposed to electrolytes such as soils and waters. Corrosion control is achieved by forcing a defined quantity of direct current to flow from auxiliary anodes through the electrolyte and onto the metal structure to be protected. Theoretically, corrosion of the structure is completely eliminated when the open-circuit potentials of the cathodic sites are polarized to the open-circuit potentials of the anodic sites. The entire protected structure becomes cathodic relative to the auxiliary anodes. Therefore, corrosion of the metal structure will cease when the applied cathodic current equals the corrosion current. There are two basic methods of corrosion control by cathodic protection. One involves the use of current that is produced when two electrochemically dissimilar metals or alloys (Table 19.1) are metallically connected and exposed to the electrolyte. This is commonly referred to as a sacrificial or galvanic cathodic protection system. The other method of cathodic protection involves the use of a direct current power source and auxiliary anodes, which is commonly referred to as an impressed-current cathodic protection system. Then cathodic protection is a technique to reduce the corrosion rate of a metal surface by making it the cathode of an electrochemical cell [3]. 

An auxiliary heat source can also be installed as an after-heater. The solar part of the system would thus become a preheater. Only when draw-off occurs would the solar-heated water flow into the after-heater, at whatever the temperature it is, and be brought up to the required temperature level. This after-heater may be a flow-through-type (instantaneous) or a storage-type device. Under favorable conditions it may not be called on to operate, but it would serve as a standby unit. Table II shows a classification of solar DHW systems according to seven attributes. 

The well water tem for K-Reactor provided water for the auxiliary services, mainly in Buildings 105-K and 184-K, and replaced the original river wat suppfy to the water treatment plant (Building 183-2K). The well water system continues to provide a source of water for service clarified water, filtered water, fire water, and domestic water. 

The code Iode has been developed to calculate iodine behavior in a reactor containment and the auxiliary building it is part of the French computer system Escadre which, similar to the US Source Term Code Package, describes the whole sequence of a severe reactor accident. The general philosophy of Iode is to model the main phenomena which may influence the behavior of iodine in the reactor containment IS chemical reactions are modelled, concerning both the water phase and the gas phase (Gauvain et al., 1991). Similar to Impair, radiolysis is not described in detail but is taken into account over its global effect on iodine species. The kinetic data of the reactions were taken from the literature as far as inorganic iodine thermal reactions are concerned other kinetic data were compiled from the elaboration of the Impair 2 code. 

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