Actual standard, namely Rules for design and safe operation of equipment and pipelines of nuclear power installations (2015) does not regulate strength and tightness testing of pipeline parts, located between valves and pressureless tanks of nuclear systems at nuclear power plants. This paper introduces arguments for strength and tightness test conduction of such areas of nuclear power plant pipelines, designed in accordance with Russian standards. It was also proposed some amendments for the norm aimed to improve safety and reliability of nuclear power plant systems with radioactive contamination. It was suggested to apply the result of current study to Leningradskaya-2 in order to improve safety and decrease the number of failures of the liquid radioactive waste storage system. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0