Metallic fuel

Lithium (Li) is a silver-colored soft metal, and the lightest of aU the metallic elements. li is oxidized by atmospheric nitrogen to form lijN. Though li melts at 453.7 K, its boiling point temperature is very much higher at 1620 K. A deep-violet flame is formed when Li is burned in air. Its standard potential is about 3.5 V and a relatively high electric current is formed when it is used in batteries. 

Beryllium (Be) is a gray-colored brittle metal. Be bums in air to form BeO or B03N2, releasing a high heat of combustion. However, Be and its compounds are known as highly toxic materials. 

Sodium (Na) is a silver-colored soft metal and the lightest after Li and K. Na reacts violently and exothermically with water according to  

Na bums in air when heated above its melting point temperature of 371 K according to  

When Na reacts with O2 at high pressure and temperature, Na202 is decomposed to form Na20. A luminous yellow flame is formed when Na is heated in a flame as a result of emission of the characteristic D-Une at 588.997 and 589.593 nm. 

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Polymer-based rocket propellants are generally referred to as composite propellants, and often identified by the elastomer used, eg, urethane propellants or carboxy- (CTPB) or hydroxy- (HTPB) terrninated polybutadiene propellants. The cross-linked polymers act as a viscoelastic matrix to provide mechanical strength, and as a fuel to react with the oxidizers present. Ammonium perchlorate and ammonium nitrate are the most common oxidizers used nitramines such as HMX or RDX may be added to react with the fuels and increase the impulse produced. Many other substances may be added including metallic fuels, plasticizers, stabilizers, catalysts, ballistic modifiers, and bonding agents. Typical components are Hsted in Table 1. 

Another reactor that was approved for development was a land-based prototype submarine propulsion reactor. Westinghouse Electric Corp. designed this pressurized water reactor, using data collected by Argonne. Built at NRTS, the reactor used enriched uranium, the metal fuel in the form of plates. A similar reactor was installed in the submarine l autilus. 

A more recently developed pyrometaHurgical process is that of the proposed integral fast reactor, which would use metallic fuel (U—Pu—Zr alloy) and a molten salt electrorefiner as follows ... 

In this process, uranium metal is electrodeposited at the cathode, while plutonium and other transuranium elements remain in the molten salt as trichlorides. Plutonium is reduced in a second step at a metallic cathode to produce Cd—Pu intermetallics. The refined plutonium and uranium metals can then be refabricated into metallic fuel (137). 

CP-1 was assembled in an approximately spherical shape with the purest graphite in the center. About 6 tons of luanium metal fuel was used, in addition to approximately 40.5 tons of uranium oxide fuel. The lowest point of the reactor rested on the floor and the periphery was supported on a wooden structure. The whole pile was surrounded by a tent of mbberized balloon fabric so that neutron absorbing air could be evacuated. About 75 layers of 10.48-cm (4.125-in.) graphite bricks would have been required to complete the 790-cm diameter sphere. However, criticality was achieved at layer 56 without the need to evacuate the air, and assembly was discontinued at layer 57. The core then had an ellipsoidal cross section, with a polar radius of 209 cm and an equatorial radius of309 cm [20]. CP-1 was operated at low power (0.5 W) for several days. Fortuitously, it was found that the nuclear chain reaction could be controlled with cadmium strips which were inserted into the reactor to absorb neutrons and hence reduce the value of k to considerably less than 1. The pile was then disassembled and rebuilt at what is now the site of Argonne National Laboratory, U.S.A, with a concrete biological shield. Designated CP-2, the pile eventually reached a power level of 100 kW [22]. 

An important class of expl materials contains metallic fuels and inorganic oxidants. Examples are Tritonal (TNT/A1, 80/20), Amatols (TNT/AN, 28/80 80/20), and Minol-2 (TNT/AN/A1, 40/40/20). Oxidants other than nitrates, such as chlorates and perchlorates, may be employed. Water solns containing these cations are highly corrosive to metals. Alkaline metal salts, for example, in the presence of moisture, will pit A1 quickly (Ref 6)... 

Small arms ammo can be so severely affected by moisture that a special indicating lacquer was developed for 20mm rounds which changes color from grey to black on w exposure (Ref 59) Effect of Moisture on Pyrotechnics Pyrot formulations usually contain finely powdered metal fuels such as Mg, Al, Fe, Cu, etc, all of which can react with moisture to yield H2. This effect has been dubbed gassing in pyrot circles, and is the major problem associated with the storage of hermetically sealed ammo of this... 

The influence of metal type on the specific impulse of propints has been described previously in this article (Table 16). The max theoretical specific impulse and density impulses (ISp x p ) for the oxidizers AN, AP and hydrazinium nitrate with 15 weight percent -fCH2)- binder have been calculated for various fuels (Ref 24). These data are in Tables 49-51. The ISp performance of nitronium perchlorate, lithium perchlorate and potassium perchlorate and metallized fuels with 4CH2>- binder are given in Table 52 (Ref 43)... 

Photo flash powders are loose mixts of powdered oxidizers such as Ba nitrate and K perchlorates with metallic fuels, principally Mg, A1 and Zr. These ingredients have such small particle sizes that they bum with expl violence for durations of less than 0.1 sec. At present photoflash powders are used exclusively in military aerial photography, whereas civilian applications are served by electrically ignited Zr or Hf wire containing flashbulbs. Since 1970. non-electric, pyrotechnically functioned, flash cubes have appeared on the market (USPs 3535063,3540813 3674411)... 

Weldon et al, Evaluation of Metal Fuels for Use in Pyrotechnic Delays , Australian Weapons Research Establishment Technical Memorandum CPD 162 (1970) 37) R.H. Weldon et al,... 

Binary liquid metal systems were used in liquid-metal magnetohydrodynamic generators and liquid-metal fuel cell systems for which boiling heat transfer characteristics were required. Mori et al. (1970) studied a binary liquid metal of mercury and the eutectic alloy of bismuth and lead flowing through a vertical, alloy steel tube of 2.54-cm (1-in) O.D., which was heated by radiation in an electric furnace. In their experiments, both axial and radial temperature distributions were measured, and the liquid temperature continued to increase when boiling occurred. A radial temperature gradient also existed even away from the thin layer next to the... 

Metals, fuels, and explosives these were the spoils of the first unknown conquest in an undeclared war. Von Schnitzler described it happily to his colleagues as the fulfillment of "a long-cherished plan of uniting the chemical industry of Austria."... 

In only 30 months, the Manhattan Project built 554 buildings including reactors, separation plants, laboratories, craft shops, warehouses, and electrical substations. The Hanford Site plutonium production reactors (B, D, and F) were rectangular, measured 36 feet long by 28 feet wide by 36 feet high, used 200 tons of uranium metal fuel and 1200 tons of graphite, were water cooled, and operated at an initial power level of 250 million watts (thermal). They dwarfed the reactors at other sites. 

These early studies were carried out on metals of typically 90-99% purity, which sufficed to determine at least their gross properties. During the 1960s, interest diminished somewhat in actinide metallurgy due in part to the increasing use of ceramic rather than metallic fuel elements in nuclear reactors. The bulk of actinide metal research was for secret military purposes and only a fraction of the fundamental research was published. 

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