NOVELTY - A nitric acid regeneration fuel cell system comprises: a catholyte flowstream including nitric acid for reacting at the cathode to yield cathode reaction products that include nitric oxide in a catholyte effluent flowstream; and a hydrogen peroxide flowstream configured to contact and react hydrogen peroxide with the nitric oxide at a hydrogen peroxide oxidation zone to yield a regenerated nitric acid flowstream.    USE - For operating an electronic device (claimed).    ADVANTAGE - The invention provides a fuel cell system having a recirculating nitric acid catholyte flowstream that is regenerated with a secondary oxidant flowstream, and that incorporates microfluidic and microelectromechanical systems (MEMS) technologies to achieve a high power density within a small form factor.    DETAILED DESCRIPTION - A nitric acid regeneration fuel cell system comprises: an anode; a cathode confronting and spaced apart from the anode; an anolyte flowstream (116) configured to flowingly contact the anode and including a fuel for reacting at the anode; a catholyte flowstream (118) configured to flowingly contact the cathode and including nitric acid for reacting at the cathode to yield cathode reaction products that include nitric oxide and water in a catholyte effluent flowstream (120); and a hydrogen peroxide flowstream (122) configured to contact and react hydrogen peroxide with the nitric oxide of the catholyte effluent flowstream at a hydrogen peroxide oxidation zone (124) to yield a regenerated nitric acid flowstream (126).    An INDEPENDENT CLAIM is also included for a method of operating an electronic device comprising: providing and operating the nitric acid regeneration fuel cell system to generate an electric current; and connecting the electrical current to the electronic device to effectuate its operation.    DESCRIPTION OF DRAWING(S) - The figure shows a flow diagram of a nitric acid regeneration fuel cell system.    Anolyte flowstream (116)    Catholyte flowstream (118)    Catholyte effluent flowstream (120)    Hydrogen peroxide flowstream (122)    Hydrogen peroxide oxidation zone (124)    Regenerated nitric acid flowstream (126)    Catholyte recirculation reservoir (128)    First inlet port (130)    First outlet port (132)    Anolyte recirculation reservoir (134)    Second inlet port (136)    Second outlet port (138)    Degassed anolyte effluent flowstream (140)    Gas separation zone (142)    Anolyte effluent flowstream (144)    Carbon dioxide flowstream (146)    Carbon dioxide storage reservoir (148)    Third inlet port (150)    Hydrogen peroxide storage reservoir (152)    Third outlet port (154)