Abstract: An expansion gap radiation shield is formed from a flexible container housing a radiation shielding fluid, that is located within a variable gap in permanent shielding. The invention reduces radiation dose rates outside the gap when the radiation sources are located on the opposite side of the gap. The device accommodates varying gap sizes with no loss of shielding capability.

Abstract: An expansion gap radiation shield is formed from a flexible container housing a radiation shielding fluid, that is located within a variable gap in permanent shielding. The invention reduces radiation dose rates outside the gap when the radiation sources are located on the opposite side of the gap. The device accommodates varying gap sizes with no loss of shielding capability.

Abstract: The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel to form a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive valving also includes bistable vents at the upper end of the thermal insulating barrier for releasing steam. A removable, modular neutron shield extending around the upper end of the reactor cavity below the nozzles forms with the upwardly and outwardly tapered transition on the outer surface of the reactor vessel, a labyrinthine channel which reduces neutron streaming while providing a passage for the escape of steam during a severe accident, and for the cooling air which is circulated along the reactor cavity walls outside the thermal insulating barrier during normal operation of the reactor.

Abstract: A nuclear reactor having a chemical decontamination clean-up system is provided in which every component of the chemical decontamination clean-up equipment which processes radioactive fluids is located within a shielded room of an existing on-site support building. Those components of the clean-up system not in direct contact with radioactive fluids are housed in portable trailers. The decontamination clean-up system is designed to provide for adequate shielding to minimize personnel exposure and also incorporates a modular design for component transportation and storage.

Abstract: System and method for abrading radioactive contaminants from the inside surface of a pipe. The system includes a nozzle block capable of mixing a liquid and an abrasive grit into a suitable liquid-abrasive grit cleaning composition and impinging the cleaning composition against the inside surface of the pipe. The system further includes an inflatable torus-shaped seal for confining the liquid-abrasive grit cleaning composition to a predetermined portion of the inside surface of the pipe so that substantially all of the contaminants and cleaning composition can be suitably vacuumed from the surface.

Abstract: A first plurality of water filled shielding tanks is introduced through a nuclear reactor containment building hatch and placed between the stored core internals and the reactor vessel. A support structure for this vertical wall is previously shipped, disassembled, introduced into containment and erected between the reactor vessel and the stored internals. A second plurality of water filled shielding tanks is placed on the containment building operating floor level to cover the stored internals. Once in place, the tanks allow manned activity in the reactor vessel area, such as preparations for annealing.

Abstract: A temporary hot cell and related method for handling high radiation level sources having wall, ceiling and floor structures comprised at least in part of temporary structures forming an enclosure to reduce to acceptable levels radiation of the surround from high level radiation sources handled within the enclosure. Preferably one or more manipulator arms extended through a wall structure of the enclosure to permit handling of the high level radiation sources within the enclosure by an operator located external to the enclosure. A window is positioned in the wall structure of the enclosure to allow an external operator to view handling of the radiation sources. The hot cell preferably also has a false floor, a filter and vent system sheeting to cover portions of the inner surface of the temporary structure forming the enclosure hot cell.

Abstract: A reactor cavity dosimetry system and method in a nuclear power plant having a reactor vessel and a primary biological shield substantially surrounding the reactor vessel thereby forming a reactor cavity between the vessel and the shield, the system and method providing for remotely and repeatedly positioning a plurality of neutron dosimeters at preselected locations within the cavity, and for withdrawing the dosimeters for analysis thereof and replacing them at the same preselected positions. Assessment of the long-term effects of neutron irradiation on the vessel is enhanced by accurate and repetitive placement of the dosimeters.