Disclosed herein is a nuclear power plant main steam system, which reduces the atmospheric discharge of radioactive materials generated in an accident, the system including: a decontamination water tank containing decontamination water; and a connection pipe for connecting the decontamination water tank from a main steam pipe which connects a steam generator and a turbine, wherein the connection pipe is connected to the decontamination water tank through a main steam safety valve or a connection valve, wherein the main steam safety valve or the connection valve is configured by a three-way valve and is configured to discharge the generated steam to the air when an accident occurs within a design basis and to transfer the generated steam to the decontamination water tank when a severe accident occurs. A main steam system according to the present invention has an effect of reducing discharge of radioactive materials to the air when a containment bypass accident including a steam generator tube rupture caused by high-temperature steam occurs.

This invention relates to compositions and methods for the at least partial dissolution, disruption and/or removal of deposit, such as scale and other deposit, from heat exchanger components. The heat exchanger components can include pressurized water reactor steam generators. In accordance with the invention, elemental metal is added locally to the surface of the deposit and/or anodic or cathodic current is applied locally to the deposit surface to destabilize or weaken the deposit. Subsequently, mechanical stress is applied to the weakened deposit to disrupt and remove the deposit from the surface of the heat exchanger component.

Electrolytic interior surface treatment apparatus (100) for the electrolytic treatment of an internal surface (102) of a metallic pipe (1) includes at least two oppositely polarised electrodes (3, 4). The apparatus (100) includes: an electrically insulating centralisation arrangement (106) to keep, in use, the electrodes (3, 4) centred within the pipe (1); and an electrically insulating flexible connection arrangement (104) located between the two electrodes (3, 4) to permit movement of one electrode relative to the other. The centralisation arrangement (106) includes a plurality of spaced apart centralisation devices (5, 6). Each centralisation device (5, 6) includes an electrically insulating mounting (7) for mounting the respective centralisation device (5, 6) to the apparatus (100). Each centralisation device (5, 6) includes a plurality of flexible elements (108), each of which is fixed to the mounting (7) and extends outwardly from the mounting (7).

Provided herein are separation processes for metal ions present in aqueous solutions based on methods involving liquid-liquid extraction. The separation process involves a chelator that can selectively bind to at least one of the metals at a relatively low pH. This can be used, for example, for recovery and purification of actinides from lanthanides, separation of metal ions based on their valence, and separation of metal ions based on the pH of the extraction conditions.

Provided herein are separation processes for metal ions present in aqueous solutions based on methods involving liquid-liquid extraction. The separation process involves a chelator that can selectively bind to at least one of the metals at a relatively low pH. This can be used, for example, for recovery and purification of actinides from lanthanides, separation of metal ions based on their valence, and separation of metal ions based on the pH of the extraction conditions.

A method of removing nuclear contamination from a surface comprising applying a DC-biased AC waveform in an electro-pickling process using nitric acid as the electrolyte.

Disclosed herein are systems, methods, processes, and apparatuses for treating radioactive waste, through systems designed to bind and dry radioactive media and to mechanical devices and techniques that are utilized for removal of granular media from confined spaces (vessels and tanks). In some of its various embodiments, the system processes spent ion exchange media for long-term storage.

Provided is a long-lived fission product (LLFP) processing method using neutrons that enables generation of high-intensity neutrons using only an accelerator without a fast-neutron reactor or an accelerator-driven nuclear reactor and thereby enables efficient nuclear transmutation of long-lived fission products. In the processing method, neutron-containing primary particles such as deuterons are accelerated under specific conditions inside an FFAG accelerator (10) and are caused to collide with a plate-shaped target (18) to generate high-energy first neutrons that form a beam in a single direction through the break-up of the primary particles and low-energy diffuse second neutrons through excitation of atomic nuclei in the plate-shaped target. A first LLFP (20) is located in the direction of travel of the beam of the first neutrons and a second LLFP (24) is located in proximity to the plate-shaped target (18).

Methods for isolating Pb and/or Pb isotopes from various sources are provided. Compositions comprising Pb and/or Pb isotopes free of certain amounts of various contaminants are also provided.

A radioactive gas assay system comprises a scintillation cell production assembly, a detector assembly, a computer assembly, and a scintillation cell destruction assembly. The scintillation cell production assembly is configured to produce a scintillation cell comprising a glass scintillator shell containing a volume of radioactive gas. The detector assembly is configured to receive the scintillation cell and to detect photons emitted thereby. The computer assembly is configured to receive data from the detector assembly to automatically calculate an absolute activity of the volume of radioactive gas of the scintillation cell and radiation detection efficiencies of the detector assembly. The scintillation cell destruction assembly is configured to receive the scintillation cell and to rupture the substantially non-porous glass scintillator shell to release the volume of radioactive gas. A method of assaying a radioactive gas, and a scintillation cell are also described.