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Corrosion lifetime evaluation

In order to evaluate the corrosion resistance of materials in a laboratory, simplified laboratory HTC tests such as the ash-embedded or ash-coating method have been used, depending on the purpose. These simplified tests are effective for the purposes of comparing and evaluating the corrosion tendencies of materials over a short period of time, because they realize only some of the corrosion factors. However, they are difficult to use when evaluating the long-term corrosion lifetime of materials because they test only relatively moderate corrosion environments and it is difficult to exactly reproduce the CRs experienced in actual equipment." ... [Pg.579]

Considering the above-mentioned conditions, and aiming at improving the accuracy of laboratory HTC tests and evaluating the corrosion lifetime of various materials more easily and quickly, a new temperature gradient test (TGT) with a thermal cycle component has been developed. The application of the TGT is mainly for waste combustion environments in which thermal cycles and A Ts strongly influence corrosion. " " ... [Pg.579]

The lifetime of a THFA tube was evaluated by consecutive 40 jiL injections of a 40 /tg/L copper solution in n-heptane, using instrumental conditions already defined in Ref. [14]. Figure 10 shows a slight increase in peak area absorbance, possibly due to some memory effect. The lifetime can be considered to last around 900-1000 firings. The visual inspection of TOTA components shows limited corrosion of the ends of the filter. However, the used fiber can be removed and replaced by a new one. [Pg.67]

Water reaches the disposal drifts via small fractures, and saturates bentonite in a few decades. Minimum container lifetime due to anaerobic general corrosion is 20,000 years, although in the evaluation it is assumed that a few (up to 10) canisters fail much earlier due to a fabrication defect. After canister failure, and since no credit is given to the cladding as a barrier, there is an instantaneous release of some volatile radionuclides, such as C1 and Cs. When the water reaches the waste, the gradual release of the radionuclides in the UO2 matrix starts. [Pg.1683]

Selection criteria may be based on a required level of corrosion resistance to meet safety and reliability requirements. More likely, selection will be based on economic considerations. Least first-cost usually is not appropriate and some type of evaluation of life-cycle cost is preferred. There are many methods for making such life-cycle cost analyses. The discounted cash flow method is ideally suited to life-cycle cost analyses that consider both first costs and costs for maintenance and repair over the system lifetime [3]. [Pg.717]

Adoption of the concept of kinetic criteria allows a simple optimization of protective installation working parameters. In many cases it is unnecessary to fully retard the corrosion of a protected metal structure. Deep cathodic polarization is an expensive process. It requires the application of high power equipment, developed anodic systems, and is connected with high operation costs. For practical reasons, partial protection is sufficient in most cases, ensuring a decrease of the corrosion rate to such a level at which the assumed lifetime of the structure is attained. Evaluation of the effectiveness of cathodic protection based on a criterion taking into account the degree of decrease of corrosion process rates can become in the near future a new, important application element in the anticorrosion protection technology. [Pg.401]

One of the key factors in any corrosion situation is the environment. The definition and characteristics of this variable can be quite complex. One can use thermodynamics, e.g., Pourbaix or -pH diagrams, to evaluate the theoretical activity of a given metal or alloy provided the chemical makeup of the environment is known. But for practical situations, it is important to realize that the environment is a variable that can change with time and conditions. It is also important to realize that the environment that actually affects a metal corresponds to the microenvironmental conditions that this metal really sees, i.e., the local environment at the surface of the metal. It is indeed the reactivity of this local environment that will determine the real corrosion damage. Thus, an experiment that investigates only the nominal environmental condition without consideration of local effects such as flow, pH cells, deposits, and galvanic effects is useless for lifetime prediction. [Pg.13]

One of the maj or ways of protecting oil and gas production and operating systems against corrosion is by applying corrosion inhibitors. The corrosion inhibitors are evaluated in order to determine if the corrosion preventive measures applied are necessary, and if the required lifetime can be achieved with a particular inhibitor, as the effective life of corrosion inhibitors varies with the quantity of water intrusion. The purpose of this chapter is to evaluate the on-line monitoring of corrosion and corrosion inhibitor effectiveness under different conditions. [Pg.247]

For comparative evaluation of various technological solntions of the given corrosion problem the results of individual calculations should be converted to a common denominator, e.g. cost per day, cost per year, cost over lifetime, or any other snitable financial base. [Pg.380]


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See also in sourсe #XX -- [ Pg.592 , Pg.595 ]




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