Abstract: A method for operating a fuel cell power plant. The fuel cell can include a reactant passage (22) with an upstream portion and a downstream portion for providing reactant to an electrode (16, 18), at least one liquid passage (24), and a plate (20) made from a porous material that is liquid permeable and conductive. The porous material separates the reactant passage and the liquid passage. A pressure profile is controlled to provide a positive pressure difference in the upstream portion and a negative pressure difference in the downstream portion. A positive pressure difference is one where the liquid pressure is higher than that of the reactant. A negative pressure difference is one where the liquid pressure is less than that of the reactant. The pressure profile can be used to provide enhanced humidification of the reactant in the upstream portion and effective liquid water removal in the downstream portion to maximize both the performance and the life of the fuel cell.

Abstract: A method for operating a fuel cell power plant. The fuel cell can include a reactant passage (22) with an upstream portion and a downstream portion for providing reactant to an electrode (16, 18), at least one liquid passage (24), and a plate (20) made from a porous material that is liquid permeable and conductive. The porous material separates the reactant passage and the liquid passage. A pressure profile is controlled to provide a positive pressure difference in the upstream portion and a negative pressure difference in the downstream portion. A positive pressure difference is one where the liquid pressure is higher than that of the reactant. A negative pressure difference is one where the liquid pressure is less than that of the reactant. The pressure profile can be used to provide enhanced humidification of the reactant in the upstream portion and effective liquid water removal in the downstream portion to maximize both the performance and the life of the fuel cell.

Abstract: In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion characteristics of the assembly.

Abstract: A valve control apparatus for generating an anticipatory output response for controlling a fluid flow in a fluid flow line includes a valve provided inside the fluid flow line, at least one sensor for providing at least one input signal, said at least one input signal responsive to properties of said fluid flow in advance of said valve, and a letdown back-pressure controller receiving said at least one input signal and providing a tunable output signal for selectively opening and closing said valve to vary flow in the flow line responsive to said at least one input signal.

Abstract: A filtration system for concentrating radioactive debris particulate provides efficient filtration, concentration and transport to collection canisters of radioactive particles from a refueling cavity, spent fuel pool, or other water volume where small particles must be removed from the water. The system includes a flushing pump module that draws contaminated water from a cut zone enclosure. The flushing pump module has a separator that removes large size particulate from the contaminated water. A solid media filter module receives the contaminated water from the flushing pump module and removes medium size particulate from the contaminated water. The solid media filter module has a structure for ejecting the medium size particulate and passing the ejected particulate to a concentrate handling module having a purge tank and a slurry transfer pump. A disposal canister station receives the medium size particulate from the slurry transfer pump and fills disposal canisters for transport and storage.

Abstract: An automatic self-testing system includes a plurality of sensor processing channels or paths each having a sensor for providing, either directly or indirectly, a digital value to a comparator which compares the measured value with predetermined value that is, in turn, provided to coincidence logic that evaluates the output of its comparator with the output of the comparators of the other paths to provide an output indicative of a pass/fail condition. Each sensor processing path includes two sub-paths that can be associated with or switched into the processing path while the disassociated sub-path undergoes off-line testing by a test processor. Testing is effected by providing a digital value to the sub-path under test while sensing the output to determine the functional validity of the sub-path under test. The combinational logic state of the system is monitored and converted into a decimal value that is compared with the set of decimal values corresponding to the finite known-good logic states of the system.

Abstract: A nuclear reactor coolant system includes a primary coolant circuit connected to a secondary coolant circuit. A desired amount of coolant is bled from the primary circuit to the secondary circuit for purification and controlling chemical composition of the coolant. Variable speed charging pumps are provided in the secondary circuit to pump coolant back into the primary circuit at variable pressures and flow rates. A pressurizer level control system is also disclosed for controlling pump speeds.

Abstract: A magnetic filtration system for separating radioactive cut material from a fluid stream containing a mixture of the radioactive cut material and an abrasive cutting material. The system comprises a magnetic filter in fluid communication with the fluid stream. By selecting an abrasive cutting material having a different magnetic susceptibility than the radioactive material being cut, the abrasive cutting material can be separated from the radioactive cut material with the magnetic filter. The amount of high level radioactive material is thereby reduced for handling and disposal. The magnetic filter is part of a closed-loop system that extracts a fluid stream containing a mixture of abrasive cutting material and radioactive cut material from an enclosure in which an abrasive waterjet cutting tool is operated. Other filters are provided in the system for removing the radioactive cut particulate from the fluid stream in multiple stages according to a size of the particulate.