Title: AM products for nuclear energy in Finland
Author(s): Jukka Mononen
Affiliation: Radiation and Nuclear Safety Authority (STUK)
Keywords: ADDITIVE MANUFACTURING, NUCLEAR ENERGY, QUALIFICATION, REGULATION, PRESSURE EQUIPMENT, FUEL ASSEMBLY

Current Finnish legislation and regulatory guidelines do not specifically recognize additive manufacturing (AM) as a manufacturing method. However, they set the requirements for the standardization and qualification of cast and formed metals. For AM materials, the same principles are applied: The AM manufacturer and nuclear power plant must identify and evaluate the risks of AM materials in relation to lifetime phases: Before manufacturing (design and qualification), during manufacturing (manufactured as designed) and during use (in-service follow up).

Material approval practices for nuclear power plants do not strictly refer to specific codes and standards. For nuclear fuel assemblies, manufacturers own comprehensive qualification may be proposed. For pressure parts (pipes, vessels, valves etc.), the licensee and manufacturer may apply AM qualification to “factory standards” from STUK. Both routes require a remarkable qualification effort

The currently preliminary standard prEN 13445-14 is to be published and harmonized in Europe. Expectation is, that the use of additively manufactured materials will then be easier and more comparable to the use of pressure vessel materials mentioned in other EN 13445 series standards.