Nickel reactor construction

Fig. 10.15, Metal vacuum systems for handling fluorine and reactive fluorides, (a) A design used extensively at Argonne National Laboratory constructed of nickel tubing and Monel valves (A) with cone joints (illustrated in Fig. 10.13) (D) nickel U-trap (E) Monel Bourden gauge (0-1000 ion) (F) 130-mL nickel reactor can (Fig. 10.17) (G) 1,500-mL nickel storage or measuring can, (H) 85-mL nickel can, (i) brass valve (K) soda-lime trap to protect vacuum pumps (L) Monel valve. (Reproduced by permission of the copyright holder, The University of Chicago Press, from Nobel Gas Compounds, H. H. Hyman (Ed.), Chicago, 1963.)...

A reactor constructed of stainless steel 410 was used for pyrolysis since it contained no nickel. The coke layer formed during pyrolysis was usually thin and greyish. Less frequently, a piece of black coke was found on the surface. The metal surface (Surface C) was always grey. Figure 5 shows the two types of coke formed at Surface A in the stainless steel 410 reactor. The black (less frequent) coke appeared to be a floe of fine filaments, about 0.05 / m in diameter, with occasional 0.4- m filaments. The predominant deposit seems to be platelets of coke that include metal crystallite inclusions, the lighter area. The metal particles in the coke deposits, as detected by EDAX, were chromium rich compared with the bulk metal, as reported in Table III. Some sulfur also was present in the deposit the sulfur was present, no doubt, because of the prior treatment of the surface with hydrogen sulfide. Surfaces B and C for the stainless steel 410 reactor are also shown in Figure 6. Surface B indicated porous coke platelets. Surface C was covered mostly with coke platelets, and cavities existed on the surface. Metal crystallites rich in iron apparently were pulled from the metal surface and were now rather firmly bound to Surface B. Surface C was richer in chromium than the bulk metal. 

A very satisfactory general type of reactor, constructed of either nickel or Monel, is shown in Fig. 30. This imit is suitable for all the preparations to be de.scribed, as well as for many others involving use of either fluorine or anhydrous hydrogen fluoride. Modifications may be made, but most of the design features are the result of considerable experience deviations, particularly by inexperienced workers, should be made with caution. It is well to use nickel tubing with silver-soldered joints for connections, although copper may also be used. Hoke blunt-point brass needle valves are satisfactory wherever valves are indicated, unless otherwise specified. 

The nickel reactor already described (Fig. 30) and two traps, constructed as shown in Fig. 35, are needed for this preparation. The complete setup is shown in Fig. 36. 

Excessive reaction between the container material and the products or reactants must be avoided, and this may impose a limit upon the peak temperature which is allowable, or upon the materials of reactor construction. Reactors take different forms and are made from or lined with a variety of refractory materials. Lime, magnesia, electrically fused dolomite, calcium fluoride, nickel, stainless-steel, molybdenum, tantalum, niobium or graphite have all been used, for different purposes. 

Significant wall activity was observed in reactors constructed of low carbon steel, nickel, and other alloys. Such activity may result in excessive carbon and hydrogen formation as well as increased conversion. Low carbon steel is an especially active reactor material with a rather unusual and long transient profile. 

Nickel-manganese-palladium brazes are resistant to attack by molten alkali metals and And applications in sodium-cooled turbine constructions. Their freedom from silver and other elements of high thermal neutron-capture cross-section allows them to be used in liquid-metal-cooled nuclear reactors. 

The principal elements deriving from the construction materials of exhaust system and catalyst can are iron, nickel, chromium, and copper. Iron is the major component of the debris retained by the catalyst nickel and chromium are usually components used to fabricate high-temperature materials for thermal reactors incorporated in some systems upstream of the catalyst. Copper may originate in engine bearings or in the copper lines used for air injection. As it is known that metals often cause deterioration of the high catalytic activity of platinum, all of them must be regarded as potential poisons. 

Stainless steel contains iron and nickel—important materials in nuclear power reactors and possible constituents of the materials used to construct nuclear test devices or their supporting structures.8 9 During nuclear weapons tests, stable Fe and Ni isotopes are neutron activated, giving rise to radioactive Fe and Ni along with fission products. In nuclear power plants, moreover, stable Fe and Ni isotopes are released from stainless steel through corrosion, become activated, and are transported to different parts of the reactor system. 

High processing temperatures cause corrosion problems. High-grade construction materials such as nickel or nickel alloy are needed for the reactor. 

Synthetic gas can be produced from a variety of feedstocks. Natural gas is the preferred feedstock when it is available from gas fields (nonassociated gas) or from oil wells (associated gas). The first step in the production of synthesis gas is to treat natural gas to remove hydrogen sulfide. The purified gas is then mixed with steam and introduced to the first reactor (primary reformer). The reactor is constructed from vertical stainless steel tubes lined in a refractory furnace. The steam to natural gas ratio is 4—5 depending on natural gas composition (natural gas may contain ethane and heavier hydrocarbons) and the pressure used. A promoted nickel-type catalyst contained in the reactor tubes is used at temperature and pressure ranges of 700 800°C and 30—50 atm, respectively. The product gas from the primary reformer is a mixture of H2, CO, C02, unreacted CH4, and steam. The main reforming reactions are ... 

Ductility is an essential requirement for steels used in the construction of reactor vessels therefore, the NDT temperature is of significance in the operation of these vessels. Small grain size tends to increase ductility and results in a decrease in NDT temperature. Grain size is controlled by heat treatment in the specifications and manufacturing of reactor vessels. The NDT temperature can also be lowered by small additions of selected alloying elements such as nickel and manganese to low-carbon steels. 

Nickel is a hard, grey-white metal, malleable, and resistant to corrosion when exposed to air. Slowly attacked by dilute hydrochloric and sulphuric acid and readily attacked by all concentrations of nitric acid. It is particularly resistant to concentrated sodium and potassium hydroxide and is therefore often used for vessels which contain them. There are several commercially produced grades of nickel which, although expensive, may be fabricated easily they are used in the construction of pumps, pipes, and fittings, valves, heating coils, drums, tanks, and reactors, and components for glass-lined vessels. It is also used extensively for nickel plating and in alloys, particularly Monel metal and stainless steels. 

Original trend curves given in the Russian Code were constructed on the basis of test results obtained after irradiation within the material qualification programmes in experimental reactors. Thus, their lead factor (relation between neutron flux in the experiment and in the RPV) was more than 100, and such a large factor is not allowed by current standards. Moreover, the database of results was relatively small at that time and irradiation embrittlement of 15Kh2NMFA-type steel was studied only on steePwelds with nickel content lower than 1.5 mass %, as this was the original intention for this type of steel. 

The plane electrodes are separated by isolating spacers, which may lead to the formation of parallel flow channels. In any case, the electrodes are plane sheets which can be replaced and thus made out of any plain material, e.g. nickel, lead, glassy carbon or graphite. Recent technolo cal developments made at the Institute of Microtechniques, Mainz [6, 7], have led to the construction of versatile microchannel electrochemical reactors. Indeed, the pressure can be elevated to up to 35 bar and the electrodes can be stacked in order to increase the overall electrode area. Moreover, polymer electrolyte membranes can be inserted, separating anodic and cathodic compartments if necessary, and finally heat exchangers may be integrated. 

The corrosion problem could be avoided by using highly corrosion resistive material. Nickel alloys like Inconel 625 or Hastelloy C-276 are examples. Even some noble metals are used for the cartridge. Since the thickness of the wall of the cartridge can be reduced in dual shell type reactors, the cost for constructing the SCWO reactor can be drasticaUy reduced. 

Reactivity worths of major reactor materials were measured in this 600-llter, nickel-reflected core. Average worths found were U-235, 36.5 Ih/kg U-238, -1.3 iVhs 0, 21.7 Ih/kg Na, 13.7 Wkg and steel, 2.2 Ih/kg (relative to void). Local sodium worths were extensively investigated since this was the first large volume, high sodium content core constructed in ZPR-ni. Sodium worths were found to decrease from 18.8 Ih/kg at the core center to 12 Ih/kg at the radial edge of the core in the center plane. Experiments to determine the effect of sodium density on its worth showed little correlation. 

ZPR-III Assemblies-51 and -52a through -52f were constructed by Argonne National Laboratory for Battelle Northwest as a part of the early effort in support of the design of the Fast Test Reactor (FTR). Material compositions approximated those of the PuO,-UOi driver zone and nickel-sodium reflectors of the reference design of the FTR. 

The flow system used in this investigation is shown in Figure 1. The reactors were constructed from 0.635 cm O.D. (1/4-inch O.D., 20-gauge) tubing. The tubing was coiled to a diameter of 12.7 cm, and about 4.52 to 4.62 m of tube were immersed in a fluidized sand bath to obtain the desired temperatures. A total of seven reactors were used in this study. Reactors were constructed of 304 stainless steel, low-carbon steel, nickel, inconel, and incoloy, all commercially available. 

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