Leaks of a highly potent greenhouse gas from electricity infrastructure could be tackled by metal sprays, according to the National Grid.
The network operator is testing the use of Molten Metal Manipulation (M3) technology from Rawwater at its Deeside Centre for Innovation.
The trials aim to demonstrate the application of M3 technology to stopping leaks of sulphur hexafluoride (SF6) from the grid’s pipework. SF6 is commonly used in electricity infrastructure to prevent short circuits and maintain safety and reliability, but the highly insulating gas is the most potent known greenhouse gas, 23,500-times more potent than carbon dioxide (CO2).
The M3 process involves the use of either a ‘leak extinguisher’ alloy spray, or an easily deployed ‘CollarCast’, where molten alloy is cast into a custom-made, reusable mould. Both techniques are relatively low temperature and require no curing time, National Grid said, allowing for in-service application to flowing leaks.
The operator tested the M3 alloy spray in difficult-to-access areas, while the CollarCast process was trialled to heavily mitigate flowing nitrogen leaks – used to simulate SF6 – at pressures of up to 7bar, without the need for a system outage.
The tests also demonstrated the reversibility of M3 with a simple process that involves reheating, showing that equipment can be returned to its original state for access to pipework.
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