ClassNK announced that a consortium it formed with IHI Corporation, JFE Steel Corporation, Tohoku University, and Institute of Science Tokyo was selected by New Energy and Industrial Technology Development Organization  to participate in the Feasibility Study Program on Energy and New Environmental Technology. The consortium will promote the development of Stress Corrosion Cracking  Probability Evaluation Tools for Fuel Ammonia Storage Tank and Transportation Equipment. The consortium’s proposal to carry out the project was approved in May 2025 and an outsourcing agreement was concluded with NEDO recently.

Initially, the consortium will conduct a detailed study of the SCC mechanism involved in steel cracking due to the combined effects of mechanical stress and corrosion caused by liquid ammonia. Thereafter, the consortium plans to develop tools for easily and accurately assessing SCC probability. Finally, opinions will be solicited from stakeholders to formulate risk-based maintenance*1 procedures for fuel ammonia storage and transportation facilities, and marine fuel tanks ultimately to promote the expanded use of fuel ammonia.

Ammonia, which does not emit CO2 when burned, offers great potential under Japan’s Green Growth Strategy as a low-impact fuel for thermal power stations and ships. Accordingly, the safe and rational operation of fuel ammonia storage tanks and transportation facilities is critical. However, because liquefied ammonia for storage and transportation poses SCC risks to steel surfaces, reasonable and practical assessment procedures for inspection and maintenance are required.

In this project, ClassNK will be responsible for investigating SCC mechanism of liquid ammonia and the actual use and condition of marine ammonia transport equipment, conducting long term SCC testing, and developing tools for easily and accurately assessing SCC probability. The findings obtained through this project are planned to be reflected and released in ClassNK’s various guidelines.

To support customers’ smooth transition to zero-emission, ClassNK provides “ClassNK Transition Support Services”. ClassNK will continue to contribute to the social implementation of alternative fuels, including ammonia, and the realization of a decarbonization society through various initiatives, such as this project.