A description fig1 shows an embodiment of the invention a mixture of lithium pellets including large lithium pellets 11 and small lithium pellets 12 is placed into boiler 20 of a lithium reaction vessel large lithium pellet 11 is roughly spherical in shape with a diameter of about 1 25 centimeters cm small lithium pellet 12 is roughly spherical or cylindrical in shape with a diameter of about 1 5 millimeters mm and for a cylindrical pellet a length of about 1 5 mm because of their smaller size small lithium pellets 12 react more readily than large lithium pellets 11 so small lithium pellets 12 are used to initiate a reaction in boiler 20 large lithium pellets 12 in turn are used to maintain the reaction for the desired period of time those skilled in the art will recognize that the size and shape of lithium pellets used in the mixture of pellets is a design choice and the invention is not limited to any particular size and shape of lithium pellets similarly while lithium is used as an example because it is the metal most commonly used as fuel other alkali metals particularly sodium and potassium may also be used after large lithium pellets 11 and small lithium pellets 12 have been placed in boiler 20 fluorinated oil 30 is poured into boiler 20 fluorinated oil 30 is a liquid and it fills the spaces between and around large lithium pellets 11 and small lithium pellets 12 commercially available fluorinated oils that can be used in connection with the invention include oil and grease products sold under the trademark krytox u00ae.