RESEARCH ARTICLE Gray wolf optimizer approach to the reliability‐cost optimization of residual heat removal system of a nuclear power plant safety system Anuj Kumar 1 | Sangeeta Pant 1 | Mangey Ram 2 1 Department of Mathematics, University of Petroleum & Energy Studies, Dehradun, India 2 Department of Mathematics, Graphic Era University, Dehradun, India Correspondence Mangey Ram, Department of Mathematics, Computer Science & Engineering, Graphic Era Deemed to be University, Dehradun 248002, India. Email: drmrswami@yahoo.com Abstract To ensure the safety of nuclear power plants (NPPs), nuclear regulatory agen- cies set technical specifications (TSs). TSs define the safety‐related operational measures and specify essential requirements and set specific limitations that is necessarily be followed by a nuclear industry to meet the requirements for the safety of an NPP. One of the important bases for the setting of TSs is the esti- mates of the availability and reliability of various systems and costs associated with an NPP. In this work, authors have presented a framework based upon a hodiernal nature‐inspired metaheuristic called multiobjective gray wolf opti- mizer (MOGWO) algorithm, which mimic the hierarchal and hunting behavior of gray wolves (Canis lupus), for technical specifications optimization of resid- ual heat removal system (RHRS) of an NPP safety system. The efficiency of MOGWO in optimizing the TSs is demonstrated by comparing its results with a very popular swarm‐based optimization technique named multiobjective par- ticle swarm optimization (MOPSO). KEYWORDS gray wolf optimizer, multiobjective optimization, nuclear power plants, reliability engineering 1 | INTRODUCTION Nuclear power is universally needed as it is an alternative to power generated by fossil fuels. Electricity is generated in a nuclear power plant (NPP) by a nuclear reactor. At the same time, safety is an important aspect in relation to the NPPs and nuclear regulatory agencies set technical specifications for ensuring the safety of NPPs. 1-4 Though, NPPs are designed to be safe in their operations but entirely risk free industrial activity is unimaginable. There have been some major accidents occurred during 50 years history of the civil nuclear power generation. The three significant accidents are Three Mile Island (U.S.A. 1979), Chernobyl (Ukraine 1986), and Fukushima (Japan 2011). The onus of auditing of world nuclear safety is on The international atomic energy agency (IAEA) which is set up by United Nation in 1957. In short, the reliability of a system can be viewed as “the probability that the system will not fail during delivery of service.” 6-9 With the intensified quality consciousness faced by every industry, modern world is now more focused on developing different ways to enhance the reliability of the component of complex systems like NPP in the design stage. Due to the higher complexities in the design of those types of complex systems, the consequences of its less reliable behavior have become grievous in terms of cost, effort, and more importantly, in terms of lives. Hence, in this compet- itive world, the guarantee of low cost and high system reliability is essential for a growing industry. During the design stage of a system, there always arise an important question that is related to striking a fine balance between the Received: 2 August 2018 Revised: 7 January 2019 Accepted: 14 March 2019 DOI: 10.1002/qre.2499 Qual Reliab Engng Int. 2019;1–12. © 2019 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/qre 1