International Reactor Innovative and Secure

International Reactor Innovative and Secure
Name	International Reactor Innovative and Secure
Othernames	IRIS
Designer	Westinghouse Electric Company; consortium participants
Concept	Small modular pressurized water reactor
Status	Concept/Development
Firstcritic	2000s
Coolant	Light water
Fuel	Low-enriched uranium
Power	~1000 MWth/335 MWe (integral design scalable)

International Reactor Innovative and Secure

The International Reactor Innovative and Secure concept is a small modular pressurized water reactor developed by a multinational consortium led by Westinghouse Electric Company during the early 21st century. It was proposed as a generation III+ design emphasizing integral primary systems, passive safety, and modular construction to serve utility projects, export markets, and research programs. The design attracted attention from nuclear organizations, vendors, and national laboratories seeking alternatives to large reactor projects and was discussed in policy forums, academic conferences, and industry roadmaps.

Design and Technical Features

The design incorporated an integral reactor pressure vessel combining the core, steam generators, pressurizer, and coolant pumps into a single unit, drawing on concepts tested in designs such as the Pressurized water reactor family and influenced by research at Argonne National Laboratory, Oak Ridge National Laboratory, and vendor programs like Westinghouse Electric Company and AREVA (now Framatome). Reactor thermal-hydraulic characteristics referenced experience from AP1000, VVER, and CANDU studies, and system layout considered lessons from Shippingport Atomic Power Station and Atucha. The core design used low-enriched uranium fuel assemblies similar to those in PWR operations at sites like Beznau Nuclear Power Plant and Dukovany Nuclear Power Station, and the secondary side targeted established steam turbine suppliers serving Siemens and Toshiba. Modular construction techniques referenced practices in Rolls-Royce marine reactors, NuScale Power, and shipyard production models from Newport News Shipbuilding and Mitsubishi Heavy Industries.

Safety Systems and Innovations

Safety approaches combined passive and active measures informed by findings from the Three Mile Island accident, the Chernobyl disaster, and the Fukushima Daiichi nuclear disaster independent assessments. The integral vessel reduced large-break loss-of-coolant accident scenarios evaluated in probabilistic risk assessments developed by NRC analysts and researchers at Princeton Plasma Physics Laboratory and Massachusetts Institute of Technology. Containment strategies were informed by studies from Electric Power Research Institute and emergency planning guidance used by International Atomic Energy Agency. Redundancy and diversity followed standards set by organizations including IEEE, ASME, and ISO, and instrumentation and control concepts referenced suppliers such as GE Hitachi Nuclear Energy and Siemens digital control solutions.

Fuel Cycle and Waste Management

Fuel concepts relied on conventional light-water reactor fuel fabrication practiced by suppliers like Framatome, Urenco, and Areva NC; enrichment levels aligned with safeguards overseen by International Atomic Energy Agency and treaties including the Non-Proliferation Treaty. Spent fuel handling assumed wet storage practices at pools like those at Zion Nuclear Power Station and dry cask storage technologies developed by Holtec International and GNS Gesellschaft für Nuklearservice. Long-term waste strategies referenced repository research at Yucca Mountain and programs in Finland at Onkalo, as well as multinational initiatives promoted by OECD Nuclear Energy Agency and European Commission frameworks.

Development History and Timeline

Conceptual work originated in multinational collaborations during the 2000s with major contributors including Westinghouse Electric Company, DOE, and university partners such as University of Pittsburgh and University of California, Berkeley. Design maturity advanced through industry workshops at venues like American Nuclear Society meetings and presentations at International Atomic Energy Agency conferences. Financing discussions involved stakeholders from Export–Import Bank of the United States, national ministries such as Ministerio de Industria-level bodies in potential host states, and corporate investors including Toshiba Corporation and Mitsubishi Heavy Industries. Technical milestones were reported alongside demonstration discussions involving utilities like EDF and national programs in Poland and Romania.

Regulatory Approval and Licensing

Licensing efforts engaged regulatory authorities including the U.S. Nuclear Regulatory Commission, the Nuclear Regulatory Authority of Japan, and European national regulators coordinated through Euratom frameworks. Safety case development followed guidance from International Atomic Energy Agency safety standards and harmonization efforts by World Nuclear Association working groups. Vendor design certification pathways referenced precedents set by AP1000 and EPR reviews, and interactions included review teams from Sandia National Laboratories and Lawrence Livermore National Laboratory supporting probabilistic and severe-accident analyses.

Deployment Plans and Operational Projects

Deployment proposals targeted markets in Central and Eastern Europe, Latin America, and Asia with outreach to utilities such as Eren, CEZ Group, and state entities akin to Rosatom partners. Project planning scenarios explored coupling to industrial heat users in petrochemical complexes like those operated by Shell and Saudi Aramco, and integration with grids managed by operators such as ENTSO-E and ISO New England. Site selection considered examples from Hinkley Point and Vogtle Electric Generating Plant project management practices, and project finance models paralleled arrangements used by Exelon and Talen Energy.

Economic and Proliferation Considerations

Economic assessments compared levelized costs with large reactors like EPR and small modular concepts from NuScale Power and market entrants such as TerraPower, considering capital cost drivers documented by World Bank and International Monetary Fund analyses. Proliferation risk analyses addressed safeguards by International Atomic Energy Agency and export controls under regimes including the Nuclear Suppliers Group and bilateral agreements such as 123 Agreement (United States)-style arrangements. Decommissioning lessons referenced experiences at Shoreham Nuclear Power Plant and Forrestal-era naval reactor retirements and cost estimates informed by Nuclear Energy Agency reports.

Category:Pressurized water reactors Category:Small modular reactors