Repairs in cementitious and metallic structures using molten bismuth alloy


Rawwater Engineering Company Limited is an established business with a global customer base in the oil and gas sector.

Pioneers in the use of bismuth metal alloy plugs for sealing onshore and offshore oil and gas wells during decommissioning, Rawwater has adapted its alloy technology for the nuclear sector to develop a system capable of underwater crack repair, sealing holes and full encapsulation of complex cementitious and metallic shapes.


The innovative bismuth plug was developed by Rawwater as a superior option to cement for plugging and abandonment of onshore and offshore oil and gas wells.  Bismuth has the unusual property of expanding upon freezing, like water as it becomes ice.  Bismuth can be combined with various other metals to produce a wide range of fusible (low melting temperature) alloys.  Once molten, these alloys have a very low viscosity, allowing them to conform to the profile of any surface they meet.

Rawwater have developed a suite of metal alloys with compositions that can be tailored to expand, contract or remain neutral when they solidify according to need, in a process called Molten Metal Manipulation (M3).


The M3 technology has been proven to be capable of sealing large openings, or filling small micron sized cracks or pores, preventing leakage of fluids in a wide range of applications, for example the recovery of a leaking cracked civil structure from the side not submerged in fluid. The process can also be used to fully encapsulate complex shapes to stabilise a structure and provide radioactive shielding.

The process:

  • Can be used both underwater and in air
  • Is reversible and the alloys are recyclable
  • Can be deployed at low temperatures
  • Is fast and easy to use in a range of situations
  • Reduces cost associated with recovery
  • Is designed for extreme life (3,000 years in the oil and gas sector)
  • Can be designed through alloy selection to operate at different temperatures (based on the use case).


A portfolio of patents covering several inventions with priority dates dating from the year 2000 onwards and with protection in a number of territories.


Rawwater’s M3 technology is currently available to organisations for trial and deployment and has already been commercially deployed in the oil and gas industry.

The company is currently working with the Ministry of Defence on encapsulation technology, namely engineering the process into a portable backpack for instant metal patch (IMP) repairs for use on the front line.

Rawwater has attracted the interest of a Tier 2 company within the nuclear industry to support the development and active deployment of the technology, and is keen to hear from Site Licence Companies in the nuclear sector for further deployment opportunities.


Please contact the Game Changers team for any enquiries or requests for further information regarding this technology and the challenges it addresses:

Paul Knight, NNL / 07900 906244

Frank Allison, FIS360 / 07714 980164

Rawwater Molten Metal Manipulation for Nuclear Decommissioning at Sellafield

Rawwater Engineering Company Ltd
Culcheth Enterprise Centre
Withington Avenue
Cheshire WA3 4JE

Figure 1. The alloys can be cast on water.

Figure 2. An encapsulated eggshell. Not only was the egg uncooked, this delicate structure was converted into a pressure vessel which was able to withstand a hydraulic pressure to 70psi before failure.

Figure 3. Example of crack in concrete repaired underwater using Rawwater’s molten bismuth alloy technology.

Figure 4. Example of Cryoroc Freeze Cast Ceramic encapsulated by the bismuth alloy.