A fireproof structure includes: a first heat-absorbing material that includes an inorganic porous formed body that has absorbed water, or a second heat-absorbing material that includes particles that include magnesium phosphate hydrate and a binder; and a fibrous heat-insulating material that includes inorganic fibers having a shrinkage ratio of 5% or less when allowed to stand at 1,100° C. for 24 hours.

A method of loading fuel in multiple reactor cores associated with a plurality of fuel cycles. The method includes, in a first fuel cycle, loading a first reactor core with a first fuel assembly selected from a first batch of fuel, loading the first reactor core with a first partially spent fuel assembly from a second batch of fuel, loading a second reactor core with a second fuel assembly from the first batch of fuel, and loading the second reactor core with a second partially spent fuel assembly from the second batch of fuel. In a second fuel cycle, which is performed after a completion of the first fuel cycle, the method includes loading the second reactor core with a fresh fuel assembly, and loading the second reactor core with the first fuel assembly from the first batch of fuel.

A probabilistic method for determining an operability interval for fasteners in a nuclear power plant assembly is provided. The probabilistic method includes determining or assuming a geometric distribution of a given initial condition of fasteners in the nuclear power plant assembly at an initial time T0; determining a future fastener failure probability model of the geometric distribution over time; generating a plurality of random future fastener failure patterns by applying the fastener failure model to the geometric distribution at a given time T1>T0; postulating fastener spacing rules designed to evaluate the acceptability of fastener failure patterns for the fasteners in the nuclear power plant assembly; applying the fastener spacing rules to a plurality of randomly generated fastener failure patterns for the given time T1 to determine the probability of the randomly generated fastener failure patterns passing the fastener spacing rules at the given time T1; iterating, by a processor of a computer, the applying step for a given range of time values T2, T3, . . . , Tx>T0 and determining a maximum future time Tmax at which a predetermined acceptable probability of the fastener failure patterns passing the fastener spacing rules is met, thereby justifying the acceptability of the fasteners for continued operation of the nuclear power plant assembly; and determining the operability interval as being Tmax-T0.

A photocatalyst injection system including: a reactor primary system coolant collection section collecting a reactor primary system coolant containing a noble metal or noble metal ion from a reactor primary system; a photocatalyst addition section adding a photocatalyst to the collected reactor primary system coolant; an ultraviolet irradiation section irradiating, with ultraviolet rays, the coolant to which the photocatalyst has been added for producing, in the coolant, a noble metal-carrying photocatalyst in which the noble metal is carried on a surface of the photocatalyst; and a noble metal-carrying photocatalyst injection section injecting the coolant containing the noble metal-carrying photocatalyst into the reactor primary system.

The group of inventions relates to constructing structures, such as the buildings of nuclear power plants, which are erected from monolithic blocks or slabs made of concrete or reinforced concrete. A block or a slab contains a built-in container with components for the sorption extraction, from water, of radionuclides or toxic substances. The container has elements for feeding-in contaminated water and for evacuating treated water. An erection method includes building a structure using the said blocks or slabs. A method for manufacturing a building block or slab includes forming a body out of concrete, embedding into same at least one container having water-treatment components, and having fittings or flanges for feeding-in contaminated water and for evacuating treated water. The invention provides for safe operations when erecting structures, and prevents the spread of radionuclides beyond the boundaries of a structure.

This disclosure describes new high temperature, radiation-resistant, ferritic-martensitic steel compositions. The new steels generally contain 9.0-12.0 wt. % Cr, 0.001-1.0 wt. % Mn, 0.001-2.0 wt. % Mo, 0.001-2.5 wt. % W, and 0.1-0.3 wt. % C, with the balance being primarily Fe. More specifically, steels having from 10.0-12.0 wt. % Cr are considered particularly advantageous. Small amounts of N, Nb, V, Ta, Ti, Zr, and B may or may not also be present, depending on the particular embodiment. Impurities may be present in any embodiment, in particular impurities of less than 0.01 wt. % S, less than 0.04 wt. % P, less than 0.04 wt. % Cu, less than 0.05 wt. % Co, and less than 0.03 wt. % As are contemplated. Examples of these steels exhibit improved fracture toughness and reduced thermal creep and swelling.

A power system can connect to a nuclear reactor through a standardized connection. The standardized connection is configured so that the nuclear reactor may be designed independently of the power system. Systems include a reactor core in fluid communication with a heat exchanger. A fluid loop passes through the heat exchanger. The system includes an output and inlet manifolds at the ends of the fluid loop, terminating in ports that include a standardized connection mechanism. When the secondary system is coupled to the connection mechanism, the fluid loop and the secondary system define a distal loop. A working fluid can then flow through the distal loop and transfer heat from the reactor core to the secondary system.

Illustrative embodiments provide methods and systems for migrating fuel assemblies in a nuclear fission reactor, methods of operating a nuclear fission traveling wave reactor, methods of controlling a nuclear fission traveling wave reactor, systems for controlling a nuclear fission traveling wave reactor, computer software program products for controlling a nuclear fission traveling wave reactor, and nuclear fission traveling wave reactors with systems for migrating fuel assemblies.

A system for removing thermal energy generated by radioactive materials is provided. The system comprises an air-cooled shell-and-tube heat exchanger, comprising a shell and plurality of heat exchange tubes arranged in a substantially vertical orientation within the shell, the heat exchange tubes comprising interior cavities that collectively form a tube-side fluid path, the shell forming a shell-side fluid path that extends from an air inlet of the shell to an air outlet of the shell, the air inlet at a lower elevation than the air outlet; a heat rejection closed-loop fluid circuit comprising the tube-side fluid path, a coolant fluid flowing through the heat rejection closed-loop fluid circuit, the heat rejection closed-loop fluid circuit thermally coupled to the radioactive materials; and the air-cooled shell-and-tube heat exchanger transferring thermal energy from the coolant fluid flowing through the tube-side fluid path to air flowing through the shell-side fluid path.

A safety system for a nuclear reactor includes a first containment structure and a second containment structure. The double containment configuration is designed and configured to meet all design basis accidents and beyond design basis events with independent redundancy. The remaining systems that control reactivity, decay heat removal, and fission product retention may be categorized and designed as business systems, structures, and components, and can therefore be designed and licensed according to an appropriate quality grade for business systems.