U.S. Nuclear Regulatory Commission is preparing for SMR applications
•Has identified several generic issues in four primary categories:
•Is aggressively working many of these issues with focus on LWR-based designs
•Expect non-LWR designs to require more review time, although some licensing experience exists
•Strong interest in SMRs has emerged in the United States
•All sectors are actively engaged:
–U.S. Department of Energy
–U.S. Nuclear Regulatory Commission
–SMR vendors and suppliers
•First potential deployment could be as early as 2020
The B and W mPower is a proposed 125 MW modular,, advanced light water nuclear reactor. The reactor is to be built by Babcock & Wilcox Co. in North America, and shipped by rail to generating sites. The reactor’s power output is approximately 125 MWe, or approximately 10% of a typical reactor. The reactor’s design includes an underground containment facility that would store all of the spent fuel the reactor would use during its expected 60 year operating lifetime. Babcock & Wilcox is planning to apply to the Nuclear Regulatory Commission for design certification by 2013, and plans to deploy the first unit by 2020 at the Tennessee Valley Authority’s Clinch River Site.
Fluor, the largest publicly traded engineering-and-construction firm in the U.S., purchased a majority stake in NuScale, which is based in Corvallis, Ore., for $30 million in October, 2011. The company estimates in 2010 that overnight capital cost for a 12-module, 540 MWe NuScale plant is about $4000 per kilowatt.
Another full-size HTR design is the Antares reactor being put forward by Areva. It is based on the GT-MHR and has also involved Fuji. Reference design is 600 MWt with prismatic block fuel like the GT-MHR. Target core outlet temperature is 1000°C for a very high temperature reactor (VHTR) version, or up to 850°C for the HTR version. It uses an indirect cycle, possibly with a helium-nitrogen mix in the secondary system, removing the possibility of contaminating the generation or hydrogen production plant with radionuclides from the reactor core.
In February 2010, General Atomics announced a modified version of its GT-MHR design – the Energy Multiplier Module (EM2). The EM2 is a 500 MWt, 240 MWe helium-cooled fast-neutron HTR operating at 850°C and fuelled with 20 tonnes of used PWR fuel or depleted uranium, plus 22 tonnes of low-enriched uranium (~12% U-235) as starter. Used fuel from this is processed to remove fission products (about 4 tonnes) and the balance is recycled as fuel for subsequent rounds, each time topped up with 4 tonnes of further used PWR fuel. (The means of reprocessing to remove fission products is not specified.) Each refuelling cycle may be as long as 30 years. With repeated recycling the amount of original natural uranium (before use by PWR) used goes up from 0.5% to 50% at about cycle 12. High-level wastes are about 4% of those from PWR on open fuel cycle. A 48% thermal efficiency is claimed, using Brayton cycle. EM2 would also be suitable for process heat applications. The main pressure vessel can be trucked or railed to the site, and installed below ground level.
The company anticipates a 12-year development and licensing period, which is in line with the 80 MWt experimental technology demonstration gas-cooled fast reactor (GFR) in the Generation IV program
Holtec International in February 2011 said it had set up a subsidiary – SMR LLC – to commercialize a 140 MWe reactor concept called Holtec Inherently Safe Modular Underground Reactor (HI-SMUR 140). This is a pressurised water reactor with external steam generator, using fuel similar to that in larger PWRs. It has full passive cooling in operation and after shutdown. The whole reactor system will be installed below ground level. A 24-month construction period is envisaged for each unit. Holtec expects to submit an application for design certification to NRC by the end of 2012. The Shaw Group is providing engineering support for the design.
World SMR projects
I think the most likely world SMR projects that will actually get built are the ones being built in China (the first HTR-PM is already under construction), China CAP100, Korea SMART, and the Russian SVBR 100. The national programs seem to have more certain funding, licensing and support.
Construction of a larger version of the HTR-10, China’s HTR-PM, was approved in principle in November 2005, with construction start in mid 2011. This was to be a single 200 MWe (450 MWt) unit but will now have twin reactors, each of 250 MWt driving a single 210 MWe steam turbine. The fuel is 9% enriched (520,000 elements) giving 80 GWd/t discharge burn-up. Core outlet temperature is 750ºC. The size was reduced to 250 MWt from earlier 458 MWt modules in order to retain the same core configuration as the prototype HTR-10 and avoid moving to an annular design like South Africa’s PBMR. This 210 MWe Shidaowan demonstration plant at Rongcheng in Shandong province is to pave the way for an 18-unit (3x6x210MWe) full-scale power plant on the same site, also using the steam cycle. Plant life is envisaged as 60 years with 85% load factor.
China Huaneng Group, one of China’s major generators, is the lead organization involved in the demonstration unit with 47.5% share; China Nuclear Engineering & Construction (CNEC) will have a 32.5% stake and Tsinghua University’s INET 20% – it being the main R&D contributor. Projected cost is US$ 430 million (but later units falling to US$1500/kW with generating cost about 5 ¢/kWh). Start-up was scheduled for 2013, now 2015 [It is already under construction]. The HTR-PM rationale is both eventually to replace conventional reactor technology for power, and also to provide for future hydrogen production. INET is in charge of R and D, and is aiming to increase the size of the 250 MWt module and also utilize thorium in the fuel. Eventually a series of HTRs, possibly with Brayton cycle directly driving the gas turbines, would be factory-built and widely installed throughout China.
CAP 100 or ACP100
This is a 100 to 150 MWe PWR being promoted by China National Nuclear Corporation (CNNC), which aims to begin construction of a two-module demonstration plant by 2015. It involves a joint venture of three companies for the pilot plant: CNNC as owner and operator, the Nuclear Power Institute of China as the reactor designer and China Nuclear Engineering Group being responsible for plant construction. No location for the pilot plant has been decided. The CAP-100/ ACP100 is designed for electricity, heat or desalination. This may be the technology envisaged for Zhangzhou in Fujian, announced in November 2011 to be built by CNNC New Energy Corporation, a joint venture of CNNC (51%) and China Guodian Corp.
On a larger scale, South Korea’s SMART (System-integrated Modular Advanced Reactor) is a 330 MWt pressurised water reactor with integral steam generators and advanced safety features. It is designed by the Korea Atomic Energy Research Institute (KAERI) for generating electricity (up to 100 MWe) and/or thermal applications such as seawater desalination. Design life is 60 years, with a three-year refuelling cycle. While the basic design is complete, the absence of any orders for an initial reference unit has stalled development. KAERI is proceeding with licensing the design by 2012, with a view to then building a 90 MWe demonstration plant to operate from 2017. A single unit can produce 90 MWe plus 40,000 m3/day of desalinated water.
A smaller and newer Russian design is the Lead-Bismuth Fast Reactor (SVBR) of 75-100 MWe, from Gidropress. This is an integral design, with the steam generators sitting in the same Pb-Bi pool at 440-495°C as the reactor core. It is designed to be able to use a wide variety of fuels, though the reference model uses uranium enriched to 16.5%. With U-Pu MOX fuel it would operate in closed cycle. Refuelling interval is 7-8 years. The SVBR-100 unit of 260-280 MWt would be factory-made and shipped as a 4.5m diameter, 7.5m high module, then installed in a tank of water which gives passive heat removal and shielding. A power station with 16 such modules is expected to supply electricity at lower cost than any other new Russian technology as well as achieving inherent safety and high proliferation resistance. (Russia built seven Alfa-class submarines, each powered by a compact 155 MWt Pb-Bi cooled reactor, essentially an SVBR, and 70 reactor-years operational experience was acquired with these.)
In December 2009, AKME-Engineering, a 50-50 joint venture, was set up by Rosatom and the En+ Group (a subsidiary of Basic Element Group) to develop and build a pilot SVBR unit14. En+ is an associate of EuroSibEnergo and a 53.8% owner of Rusal, which has been in discussion with Rosatom regarding a Far East nuclear power plant and Phase II of the Balakovo nuclear plant. The plan is to complete the design development by 2017 and put on line a 100 MWe pilot facility by 2020, with total investment by Russkiye Mashiny of RUR16 billion ($585 million).