Breaking The Cycle Of Submarine Cable Failures
10 Dec 2020
Forensic study of submarine cable failures reveals material choice, manufacturing processes and, significantly, quality controls all have the potential to introduce failure modes. Selecting the right materials and manufacturing processes is at the heart of a fit and forget system where 30 years life with zero leaks is required. In addition to mechanical adhesion, chemical bonding between materials at molecular level is essential for achieving long-term sealing. Materials offer different properties; their bonding requiring disparate degrees of specialist chemical and processing knowledge. One polymer is notoriously difficult to process and bond; the other is slightly hygroscopic, absorbing moisture at a rate which increases as temperature increases. Platforms fitted with the latter typically have planned replacement programmes at every refit providing a lucrative resupply market at odds with resolving the engineering challenges which result in its short life expectancy. The former is not so affected. The study reveals how some test and inspection protocols relied on to offer the quality assurance requisite for first-level items may create false confidence about product life. Radiography used to demonstrate moulded cable integrity utilising processes used for x-raying metallised components provide images that do not reveal potential problems. Only specialist, low power radiography profiles the chemical bonding at molecular levels to identify bond failures which will eventually create leak paths for water ingression resulting in performance degradation or critical failure. The study reveals how the pitfalls of the past can be avoided and essential systems safeguarded, to provide optimal future system performance.