Is this your challenge?

On a nuclear site, ensuring the integrity of pipework, tanks, joints or flanges is essential. Erosion, corrosion, chemical attacks, abrasion and wear, water infiltration and weathering can all create industrial challenges on pipework, up to the point solutions are needed to restore functionality, ensure containment or provide emergency solutions.

Industrial patch repair solutions offering mechanical resistance do exist to seal leaks in-situ and offer solutions to many engineering challenges and repair situations.

Often, existing solutions can be time consuming, involve a manually applied composite paste and come with the requirement to stop the process/flow and prepare the surface. In the highly regulated nuclear sector, a novel method for the rapid recovery of leaks and cracks on pipework could potentially be a major relief.

inTechBrew’s insight

UK-based Rawwater has built its reputation on providing world-class solutions for the oil & gas industry. For more than 20 years, the company has been developing high- integrity bismuth alloy seals for oil and gas reservoir plugging & abandonment.

Calling on its considerable experience of the highly regulated oil and gas sector, and using its extensive knowledge of specialist alloy formulations, Rawwater has developed M3 Molten Metal Manipulation: a range of low-melting-point, instantly curing and reversible alloy seals to support various nuclear decommissioning challenges. These specially developed alloys and application techniques offer exciting opportunities for the rapid recovery of leaks and cracks in civil structures, seals, joints, flanges and pipelines, as well as planned preventive maintenance.

At inTechBrew, we believe that the reversible alloy seals technology developed by Rawwater, with its pedigree of leak- sealing in the most challenging of environments, could be a gamechanger for the nuclear decommissioning and maintenance sectors:

• It offers corrosion-resistant metal alloys that can be applied on a variety of materials with little or no surface preparation,
• It can be applied in air or underwater, to offer secure, high-strength, reversible metal seals,
• It is a novel method offering the ability to seal large openings or fill micron-sized cracks or pores to prevent leaks,
• It has a variety of application methods, including a low-temperature alloy spray (M3Spray) and M3CollarCast…

User case

NGET, Deeside Centre for Innovation, Deeside, UK

• Currently used in existing high-voltage equipment as an insulator, Sulphur Hexafluoride (SF6) is to be replaced with a greener alternative. Although SF6 equipment is permanently sealed, as it ages the potential for leaks increases, especially for equipment located outside and exposed to harsh environments over many decades.
• In September 2021, NGET successfully trialled Rawwater’s novel M3 Molten Metal Manipulation leak-sealing capabilities as a way of sealing harmful SF6 greenhouse gas leaks from electrical equipment. The capability was applied as a leak mitigation method in difficult-to-access areas to demonstrate its deployability in restricted environments.
• As well as Rawwater’s M3 Spray, the company’s easily deployed M3 CollarCast (a process where molten alloy is cast into a custom-made, reusable mould) was also used to heavily mitigate flowing nitrogen leaks (used to simulate SF6) at pressures of up to 7 bars, without the need for a system outage.
• The reversibility of M3 (a simple process involving reheating) was also demonstrated, to show that equipment can be returned to its original state for decommissioning, with any recovered alloy being retained for reuse.

The technology: M3 molten metal manipulation

Using specially developed alloy classes that can be applied in air or under water, Rawwater offers secure metal seals and collars that can be used for sealing and encapsulation, recovery of leaks and cracks in civil structures, seals, joints, flanges and pipelines, as well as planned preventive maintenance.

The M3 technology is based on the ability to manipulate low-melting-point bismuth alloys prior to solidification, to achieve repairs or provide metallic coatings. The low viscosity of the molten alloy enables penetration into porous substrates with pore throats as tight as 25 microns, with expansion on solidification giving a tenacious gas-tight seal. The high density of the alloy displaces water to enable sealing underwater or against large leaks, while at the same time being easily removable by re-melting if required.

As an indication of the uncompromising standards to which Rawwater operates, its alloys for plugging & abandonment meet the 3,000-year design life specified by Oil & Gas UK for plugs in the North Sea and have been subjected to a strict technical qualification programme overseen by Bureau Veritas.

Rawwater’s M3 Molten Metal Manipulation technology is suited to a variety of operational challenges facing the nuclear industry. Its ability to seal, encapsulate and secure components using a corrosion-resistant metal alloy applied at low temperature and without hot work (welding) is unparalleled.

The capabilities of M3 enable fragile components to be reinforced or sealed, as part of decommissioning activities or other operational processes. M3 can be applied to integrity management, decommissioning, materials handling and emergency response (e.g., loss of containment) demands. The attributes of M3 include:

• Rapid repair of leaks and cracks in civil structures, seals and pipelines,
• Can be applied to metals, concrete, ceramics, elastomers, polymers, composites and combinations, with surface contaminants,
• Can seal large openings or fill micron-sized cracks or pores,
• Low-temperature application process (usually <150°C), instant curing,
• Applied in air or under water – using different techniques for different applications,
• For both low pressure and higher-pressure leaks,
• For emergency or planned works, temporary or long-term repair,
• Little or no surface preparation time,
• Fully reversible that does not impact waste processing/disposal,
• In-service application against a flowing leak. No need to drain systems/shut down processes,
• Reduced recovery costs and extreme longevity.

Rawwater’s M3 technology is versatile enough to be suited to a variety of scenarios and offers different techniques for different applications:

M3Spray

• Typically for leaks of up to 10 mm diameter,
• Versions for manual application and remote operations in development,
• Applies alloy spray or “molten bullet” depending on leak size,
• Range of hose lengths depending on application,
• TRL 7 – achieved in a non-nuclear environment.

M3CollarCast – alloy casting collar

• Specially developed process for sealing pipes and flanges,
• Application-specific collar design, modularisation in development,
• Cast molten alloy or melt pre-cast alloy in-situ,
• After casting, collar can be removed for re-use or left in place,
• TRL 7 – achieved in a non-nuclear environment.

What do you think about this instant pipework & tank integrity repair system?

Any questions ? Interested in another innovative instant pipework & tank integrity repair system ? Do not hesitate to contact us directly, we will help you find a fit-for-purpose, cost-efficient solution to your challenge.