Contents lists available at ScienceDirect Nuclear Engineering and Design journal homepage: www.elsevier.com/locate/nucengdes Recent achievement and future prospects of the ATLAS program Ki-Yong Choi, Kyoung-Ho Kang, Chul-Hwa Song ⁎ Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon 34057, Republic of Korea ARTICLE INFO Keywords: ATLAS Integral effect test Light water reactor Thermal-hydraulics Nuclear safety ABSTRACT As a critical thermal-hydraulic test facility, the ATLAS facility has been widely utilized since its first commission test in 2006 to resolve urgent safety concerns raised by nuclear industries and regulatory body, to verify the performance of new safety systems, to validate safety analysis codes, and to provide a cooperation network for developing safety analysis capabilities. In the first phase of the ATLAS program, major R&D efforts were put into producing code validation data to support the standard design approval of the APR1400 when design basis accident (DBA) scenarios were the main interest of the program. In the following phase, the ATLAS program’s focus shifted to beyond DBA scenarios, and the OECD-ATLAS international joint project started reflecting the safety concerns of many NEA countries following the Fukushima Daiichi disaster in 2011. In this paper, the current status of the ATLAS program, including the OECD-ATLAS Phase-1 and 2 projects, are briefly described together with their major outcomes. The next R&D program based on the ATLAS platform is also briefly dis- cussed. 1. Introduction Korea Atomic Energy Research Institute (KAERI) has been operating an integral effect test (IET) facility, ATLAS (Advanced Thermal- Hydraulic Test Loop for Accident Simulation) for accident simulations for the APR1400 since 2007 (Baek et al., 2005). The ATLAS facility has been extensively utilized to address major design basis accidents (DBAs) of the APR1400 (Song et al., 2007) as well as other light water reactors (LWRs). It has also contributed to the verification of the safety of ex- isting or advanced nuclear power plants (NPPs) as well as the validation of system-scale safety analysis codes such as MARS-KS (Jeong et al., 1999) and SPACE (Ha et al., 2011). ATLAS started to generate IET data from 2007 following the completion of several commissioning tests by the end of 2006. The ATLAS program can be divided into three tem- poral phases as shown in Fig. 1. Each phase corresponds to a national research and development (R&D) plan promoted by the Korean gov- ernment. In the first phase from 2007 to 2011, ATLAS was fully in- volved in generating data for validating DBAs simulation such as large break loss of coolant accidents (LBLOCAs), small break LOCAs (SBLOCAs) and typical non-LOCA scenarios. The generated database has been used by safety authority and nuclear industries to license the APR1400 and to validate the SPACE code for its application to LWRs. In https://doi.org/10.1016/j.nucengdes.2019.110168 Received 30 May 2019; Received in revised form 21 June 2019; Accepted 21 June 2019 Abbreviations: ATLAS, Advanced Thermal-Hydraulic Test Loop for Accident Simulation (test facility operated by KAERI); ACC, accumulator; AM, accident man- agement; APR1400, advanced power reactor 1400 MWe; APR+, advanced power reactor plus (1500 MWe); bDBA, beyond design basis accident; CAP, containment analysis package; CDF, core damage frequency; CL, cold leg; CUBE, containment utility for best-estimate evaluation; CUPID, component unstructured program for interfacial dynamics; DBA, design basis accidents; DSP, domestic standard problem; DVI, direct vessel injection; ECC, emergency core cooling; HL, hot leg; IBLOCA, intermediate break LOCA; IET, integral effect test; LBLOCA, large break LOCA; LOCA, loss-of-coolant accident; LPI, low pressure injection; LPP, low pressurizer pressure; LSC, loop seal clearing; LSTF, large scale test facility; LWR, light water reactor; MARS-KS, multi-dimensional analysis of reactor safety-KINS standard; MOTIE, ministry of trade, industry and energy of the Korean government; MSLB, main steam line break; MFIV, main feedwater isolation valve; MSIT, ministry of science and ICT of the Korean government; MSIV, main steam isolation valve; MSSV, main steam safety valve; NEA, nuclear energy agency of OECD; NPP, nuclear power plant; NSSC, nuclear safety and security commission of the Korean government; OECD-ATLAS, international joint project organized by OECD/NEA based on the ATLAS program; OPR1000, optimized power reactor 1000 MWe; PAFS, passive auxiliary feedwater system; PCCS, passive containment cooling system; PCCT, passive condensation cooling tank; PCHX, passive condensation heat exchanger; PCT, peak cladding temperature; PECCS, passive emergency core cooling system; POSRV, pilot operated safety relief valve; PSA, probabilistic safety assessment; PZR, pressurizer; RCP, reactor coolant pump; RCS, reactor coolant system; RHRS, residual heat removal system; RPV, reactor pressure vessel; R&D, research and development; SBLOCA, small break LOCA; SBO, station blackout; SET, separate effect test; SG, steam generator; SGTR, steam generator tube rupture; SIP, safety injection pump; SIT, safety injection tank; SLB, steam line break; SPACE, safety and performance analysis code; TLOFW, total loss of feedwater; UH, upper head (inside RPV); UP, upper plenum (inside RPV) ⁎ Corresponding author. E-mail address: chsong@kaeri.re.kr (C.-H. Song). Nuclear Engineering and Design xxx (xxxx) xxxx 0029-5493/ © 2019 Published by Elsevier B.V. Please cite this article as: Ki-Yong Choi, Kyoung-Ho Kang and Chul-Hwa Song, Nuclear Engineering and Design, https://doi.org/10.1016/j.nucengdes.2019.110168