An assembly is provided that includes first and second end plates adapted to be coaxially aligned when in use. One or more members extend from the end plates or an annular ring, the annular ring provided between the end plates, the other of the end plates or annular ring comprising one or more first slots at one end thereof to be aligned with and for receiving the one or more members of the first end plate, and one or more second slots at the other end thereof to be aligned with and for receiving the one or more members. Resilient sealing members are provided around the one or more members between the end plates and annular ring, and an urging mechanism urges the first and second end plates towards the annular ring to deform the first and second resilient sealing members to engage the inner wall of the pipe.

An assembly configured to seal an end plug on a plugged end of a fuel tube is disclosed. The assembly includes a seal weld chamber assembly and a helium flow stop assembly (HFSA) removably coupled to the seal weld chamber assembly. The seal weld chamber assembly includes a welding chamber and a plunger fluidically coupled to the welding chamber. A helium source is configured to supply helium to the welding chamber. The end plug of the fuel tube is positionable within the welding chamber via the plunger. The HFSA is configured to prevent helium from escaping the welding chamber through the plunger.

A method for purging air from a structure to be joined by welding by feeding a liquid cryogen to the structure. The liquid cryogen will enter the structure, warm up and enter the gaseous phase very rapidly. The gaseous cryogen will displace the air that is present in the structure out of the structure and reduce the content of oxygen in the structure to about 10 parts per million when welding can begin.

Apparatuses and methods for repairing a defect in a nuclear reactor are provided. The apparatus includes a body for insertion in a tubular structure, the body includes: an end effector having a weld torch operable to deposit weld material by forming molten weld droplets and depositing the weld droplets the tubular structure. A drive unit includes a brace for selectively anchoring against said tubular structure; at least one linear actuator for moving the apparatus relative to the brace; and a rotational actuator coupled to rotate the weld torch. The method includes inserting a repair apparatus into tubular structure of the nuclear reactor; moving the repair apparatus to a defect location; depositing a protective weld layer over the defect by sequentially depositing weld droplets atop a weld pool on the tubular structure, wherein the protective weld layer bonds to the tubular structure surrounding the defect.

A purge system useful in welding applications to provide a shielding or purging gas to a weld site, preferably of a tube, pipe or construction, while also providing controlled release of an exhaust gas and pressure relief through the use of a permeable body. The purge system is also flame resistant allowing use in close proximity to the weld site. The design facilitates ease of insertion, holding and retraction in a tube, pipe or other construction.

A gas-diffusing water-degradable welding purge dam apparatus for purging a weld zone of a pipe assembly having first and second pipes with respective first and second pipe ends to be welded together at a root gap. The purge dam apparatus includes a first air flow blocking member, a second air flow blocking member, and an interconnecting member interconnecting the first and second air flow blocking members. The interconnecting member has a hollow purge gas-receiving interior and a gas-diffusing sidewall that allows a pressurized purge gas in the gas-receiving interior to pass through the sidewall and exit therefrom in a diffused state into a weld zone external to the interconnecting member. An external purge gas entry port in the purge dam apparatus in fluid communication with the gas-receiving interior. The purge dam apparatus includes one or more water degradable materials so it can be flushed from the pipe assembly following welding.

A mounting attachment with a connection area for a gas line includes a first cylindrical fastening medium and a second cylindrical fastening medium, which are in particular screwable into each other. The first fastening medium and/or the second fastening medium are prepared in a 3D-plastic printing process. A pipe to be welded is inserted into the first cylindrical fastening medium by means of an essentially central lead trough in the first cylindrical fastening medium, with a cylindrical area of insertion for the pipe to be welded in the second fastening medium. The area of application includes an attachment ring area and a connection area for a gas feed hole for feeding forming gas to a gas-use point by means of a forming gas pipe in the pipe to be welded. The pipe used is sealed against the cylindrical fastening media by one or more flexible seals.

An apparatus for providing an inert atmosphere to the inside of a piping assembly prior to and during welding, including a cannister, and a bladder which surrounds the cannister and fits inside of a piping assembly to be welded. The cannister including a purge gas inlet connection fluidically connected to a bladder fill conduit, a bladder return conduit fluidically connected to a pressure relief device, the pressure relief device fluidically connected to a reduced pressure purge gas conduit, a primary purge gas diffuser, a secondary purge gas diffuser, a tertiary purge gas diffuser, and purge gas exit holes. Wherein the bladder fill conduit is configured to introduce purge gas into the bladder. Wherein the bladder is configured to expand and form a seal between the cannister and the piping assembly to be welded. And, wherein the bladder return conduit is configured to evacuate excess purge gas from the bladder.

An orbital welding device (1) for welding two pieces of pipe, the orbital welding device (1) having a welding current source (10) in a welding current source housing (11) and an orbital welding head (20), which is separate from the welding current source housing (11) and is connected to the welding current source (10) by a cable (2), the orbital welding head (20) having a chamber (50) for the use of shielding gas (50) and/or the orbital welding device (1) having a purging device (90) for the use of shielding gas, preferably back-up shielding gas or purge gas, the orbital welding device (1) having an oxygen sensor (40), wherein the oxygen sensor (40) is arranged in or on the welding current source housing (11).

An assembly configured to seal an end plug on a plugged end of a fuel tube is disclosed. The assembly includes a seal weld chamber assembly and a helium flow stop assembly (HFSA) removably coupled to the seal weld chamber assembly. The seal weld chamber assembly includes a welding chamber and a plunger fluidically coupled to the welding chamber. A helium source is configured to supply helium to the welding chamber. The end plug of the fuel tube is positionable within the welding chamber via the plunger. The HFSA is configured to prevent helium from escaping the welding chamber through the plunger.