Micro-Nuclear: No Panacea

By Robert Peltier -- July 16, 2009

As I posted last week, conventionally sized nuclear power (?750–1,250 MW) is dramatically uncompetitive with coal- and gas-fired electricity generation in light of the huge increase in construction costs recently estimated by various utilities. A typical new coal-fired plant may cost on the order of $2,000/MW compared to new nuclear estimated to cost as much as four or five times more. The lower operating costs of nuclear compared to fossil-fired plants cannot erase this capital-cost premium.

Micro-nuclear, with capacity in the 5–100 MW range, while exciting as a new technology, is no panacea. Actual installed costs are yet to be published. But operating cost estimates of less than ten cents a kilowatt-hour have drawn attention to the designs. But are the scale economies in construction, operations, maintenance, and the fuel cycle considered in these preliminary estimates? Small may be beautiful, but a push for decentralizing small nuclear power generators takes our eye off the prize: financing and constructing needed utility-scale nuclear power projects, as well as coal- and gas-fired plants.

Introduction

The resurgence of interest in nuclear power closely followed the introduction of new intrinsically safe Generation III reactor designs such as the Evolutionary Power Reactor (EPR) from AREVA, Westinghouse’s AP-1000, and General Electric’s Enhanced Simplified Boiler Water Reactor or ESBWR. All three are utility-scale designs that range in size up 1,600 MW. The EPR and ESBWR are under active review by U.S. Nuclear Regulatory Commission (NRC) and are expected to be licensed mid-2011 and the end of 2010, respectively. The AP1000 has submitted a design certification amendment that is also scheduled to be completed by the end of 2010.

Perhaps the prime motivator for the nuclear renaissance are the provisions of the Energy Policy Act of 2005 that provide loan guarantees of up 80% of a project’s cost and provides tax credits of 1.8 cents per kilowatt-hour for 6,000 MW from new nuclear power plants for the first eight years of operation—up to about $18 billion in incentives. (Other EPAct incentives are listed in an appendix at the end of the post.) The new NRC combined operating license process also promises to shorten the plant certification process although how much time will be trimmed from this time-intensive process remains to be seen.

There are currently 17 proposals for 26 reactors in licensing hearings before the NRC and more applications are expected. However, the U.S. remains far behind the world in constructing new projects. 45 reactors now under construction world-wide, although 22 of them have encountered delays. The first Generation III+ reactor under construction is AREVA’s EPR at TVO’s Oikiluoto Nuclear Plant in Finland. Also, EDF’s unit 3 at their Flamanville plant in France began construction in 2007 for a scheduled 2012 startup. Two additional EPRs are scheduled to begin construction in China this year.

The technical and financial challenges of building the first of any new complex plant design are many. The price of the first EPR plant is no exception—it has risen from an estimated $4.2 billion to about $8 billion and the in-service date has slipped over 18 months to June 2012. Also, the first two plants using the AP-1000 reactor technology began construction in April with the two-unit Sanmen plant in China. The first reactor is scheduled to begin operation in 2013 and the second in 2014.

Smaller Options

The power industry has been focused on the technology and development schedule of these large, utility-scale projects for the past several years with little attention given to several interesting small reactor designs have been announced and one interesting project is now under construction in Russia.

Design and deployment of very small reactors is not new but a much more technically advanced that the early portable nuclear plants. Perhaps the smallest reactor used in commercial service was the U.S. Army nuclear power program’s PM-2A portable reactor installed underground at Camp Century in northern Greenland. The PM-2A reactor was designed to produce up to 1,560 kW with a portion of the thermal energy produced by the plant used to melt ice for potable water. The plant never produced more that 500kW in actual operation and was disassembled and removed in 1964 signaling the end of the Army’s nuclear program. A history of this interesting program is available here.

Today, several small commercial reactors are in the NRC approval queue. For example, in 2010 the NRC is scheduled to review the design of the International Reactor Innovative and Secure (IRIS), a 335-MWe reactor that has been under development for several years by an international consortium and is thought to be a better fit to meet the power needs of developing countries.

Other suppliers have also announced more compact reactors designed for even smaller power applications. For example, Babcock & Wilcox Co. (B&W) recently unveiled the mPower, a modular 125-MW Generation III nuclear reactor that can be scaled to produce up to 750 MW. Others include the South African–developed Pebble Bed Modular Reactor; Toshiba Corp.’s Toshiba 4S reactor, Hyperion Power’s hydride reactor, and NuScale Power’s modular light water reactor. Each of these five designs is explained below:

B&W’s mPower Reactor

The mPower reactor is an advanced light water reactor (ALWR) with passive safety systems, in which the core and helical steam generators are contained within a below-ground containment structure (Figure 1). It uses standard pressurized water reactor (PWR) fuel and is designed to operate on a five-year cycle between refuelings. The reactor is expected to have a 60-year life. B&W calls the design a “true Generation III++ nuclear technology.”

1. Babcock & Wilcox recently introduced their mPower integral modular reactor design that can be scaled from 125MW to 750+ MW. Courtesy: B&W

The reactor was designed to meet the “emerging needs of the commercial nuclear renaissance.” The scalable nature of the nuclear plants built around the mPower reactor could provide “practical” power increments of 125 MW to meet local energy needs within power grid and plant site constraints, B&W said.

B&W, a McDermott International subsidiary, has formed a new business unit, B&W Modular Nuclear Energy, to spearhead the development, licensing, and delivery of the mPower reactor. It has also notified the Nuclear Regulatory Commission (NRC) of its intent to submit an application for design certification of the reactor in 2011.

Hyperion Power Generation: 8 cent/kWh from 30 MW?

Last fall, Hyperion Power Generation, a Santa Fe, N.M., company, launched a publicity campaign for its “hot-tub”-sized 30-MW hydride reactor, a licensed technology developed by Los Alamos National Laboratory. The 10-ton unit, only 5 feet in diameter, is a sealed module with integrated radiation shielding that would be fueled and refueled every five to seven years at the factory (Figure 2).

2. Santa Fe–based Hyperion Power plans to manufacture 4,000 miniature reactors, each with a capacity of 30 MW, after it receives the NRC’s approval. Courtesy: Hyperion Power

The mini-reactor is designed to be transported via ship or truck and be buried — for safety and security reasons — in a concrete vault 10 feet underground. According to the company, the hydride reactor would use uranium hydride, which combines the fissile material with the moderator in the same compartment.

“The mobility of the moderator reverses any overpower excursions,” Hyperion said in an August 2008 fact sheet. “Nuclear reactivity runaway is therefore impossible. Any possibility of a mechanical failure is eliminated by the complete lack of mechanical moving parts.” Hyperion expects that the waste produced by the unit, approximately “the size of a softball,” is a “good candidate for fuel recycling.

Hyperion’s goal is to produce reactors to generate power for less than $0.08 per kWh, and it anticipates that its unit would have four primary uses: to provide off-grid power to military bases; for oil and gas recovery and refining; for remote communities that lack power generation sources; and for back-up power or emergency generation in areas prone to disasters.

Confident that the technology will catch on, Hyperion is looking to build about 4,000 hydride reactors within the first 10 years of production at a cost of between $25 million and $32 million. But first it must receive the NRC’s approval. The company is now preparing to apply for a manufacturing license in September 2009 and hopes to begin production within two to four years. NRC documents indicate, however, that the process could take until 2015.

Toshiba’s 4S Reactor

Hyperion’s hydride reactor isn’t the only serious contender in the micro-nuke race. For the past two years, Toshiba — the Japanese conglomerate that owns Westinghouse — has been working on the 4S (super-safe, small, and simple) reactor, a unit that it claims could produce power for as little as $0.05 per kWh.

The 4S reactor is based on a smaller 10-MW design, the Liquid Metal Cooled Reactor (LMR). That reactor is cooled by liquid sodium instead of water; sodium allows the reactor to run at a higher heat and avoids the use of highly pressurized pipes. The 4S also uses liquid lithium-6 to moderate the reactor instead of conventional control rods. Like the hydride reactor, the 4S is completely sealed and requires no maintenance.

Toshiba has proposed to demonstrate the reactor in the Alaskan village of Galena; if its plans work out, this project could be on-line by 2012. According to the NRC, Toshiba is all set to submit a design approval for the 4S as early as next year. That review should be complete by 2013, the agency expects.

NuScale Power, Inc.

NuScale Power Inc., an Oregon company, is also in the running. Its 45-MW reactor is based on a “multi-application” light water reactor designed by Oregon State University (OSU). The NuScale reactor is a modular unit designed to be built on-site. NuScale estimates that plant construction would take between two and three years. The modular reactor and containment vessel measures about 60 feet in length and 14 feet in diameter. Like other pressurized water reactors, NuScale’s reactor is water-cooled, but it eliminates the many pumps and pipes by working the water through a convection-based “natural circulation system” (Figure 3). The company said that an electrically heated demonstration model one-third the size of NuScale’s reactor at OSU confirmed the effectiveness of the cooling system.

3. NuScale Power uses naturally circulated water to cool its mini-pressurized water reactor, eliminating the need for pumps and pipes. Courtesy: NuScale Power

NuScale is prepared to submit an application for design approval to the NRC in 2010. The NRC estimates that its review process will conclude by mid-2013. Because the company employs a familiar technology, according to a February 2008 briefing slide on the NRC’s web site, NuScale could have an advantage over the 4S and hydride reactors. “NRC skill set and tools are lacking for the LMR and hydride reactor,” the agency wrote. “With adequate resources and staff, it will take at least 5 years to develop independent capabilities for LMR.”

Russia’s New Nuclear Navy
According to the Russian nuclear agency RIA Novosti, the state owned nuclear power generating monopoly Rosenergoatom and Sevmash shipyard, located in the Arctic port of Severodvinsk, have signed a contract to built the world’s first floating nuclear power plant (Figure 4). A spokesman for Sevmash shipyards says the first barge will cost about $420 million. Construction of the first barge began in 2007 and is expected to be commissioned in 2011. Five such plants are expected to be operational by 2020.

Sergei Obozov, head of the state-controlled Rosenergoatom consortium in charge of nuclear power plants announced the reactor will provide heating and electricity to Sevmash — was the perfect solution for supplying energy in sparsely-populated regions on Siberia’s northern coast, on the Kamchatka Peninsula and in Russia’s far eastern regions, where there is currently no electricity supply, and that Russian authorities were looking at 11 other possible sites for such reactors. Russia currently has 31 operating reactors at ten separate sites that account for about 17% of the country’s power generation.

Production costs are predicted to be 5 to 6 cents/kWh. If necessary, the plant also will be able to supply heat and desalinate as much as 8.5 million cubic ft of seawater a day. Because the uranium to be used as fuel will be enriched less than 20%, the initiative won’t run afoul of the International Atomic Energy Agency’s non-proliferation rules.

Sergey Kiriyenko, the head of the Federal Agency for Nuclear Power, said that Russia possessed “unique experience … on using small and medium-power nuclear reactors.” When asked about plant safety issues, Kiriyenko denied that the reactor would pose a security or safety risk, saying that the Sevmash plant—the only Russian plant where atomic submarines are manufactured—was sufficiently well guarded. “There will be no floating Chernobyl,” Kiriyenko said, according to ITAR-Tass news agency.

Sevmash hasn’t been too forthcoming with the project specs but sources say each ship will have two small reactors totaling 70MW on a ship about 450 ft long displacing 21,000 tons. Sources say the two KLT-40S reactors are adapted from those already in use on three Russian nuclear-powered icebreakers. Thermal energy will also be delivered up to a distance of 180 miles. The design life-span is 40 year with fuel element replacement every two to three years. The project is said to have a 12 year payback.

4. An artist’s conception of what the world’s first floating nuclear power plant will look like. The first of what may be a series of nuclear barges is under construction at the Sevmash shipyard located on Siberia’s northern coast. Courtesy: Sevmash

(POWER magazine Sr. Staff Writer Sonal Patel also contributed to this post)

Appendix

Nuclear incentives in the Energy Policy Act of 2005 are:

• Extends the Price-Anderson Nuclear Industries Indemnity Act through 2025;
• Authorizes cost-overrun support of up to $2 billion total for up to six new nuclear power plants;
• Authorizes a production tax credit of up to $125 million total per year, estimated at 1.8 US¢/kWh during the first eight years of operation for the first 6.000 MW of capacity; consistent with renewables;
• Authorizes loan guarantees of up to 80% of project cost to be repaid within 30 years or 90% of the project’s life;
• Authorizes $2.95 billion for R&D and the building of an advanced hydrogen cogeneration reactor in Idaho;
• Authorizes ‘standby support’ for new reactor delays that offset the financial impact of delays beyond the industry’s control for the first six reactors, including 100% coverage of the first two plants with up to $500 million each and 50% of the cost of delays for plants three through six with up to $350 million each;
• Allows nuclear plant employees and certain contractors to carry firearms;
• Prohibits the sale, export or transfer of nuclear materials and “sensitive nuclear technology” to any state sponsor of terrorist activities;
• Updates tax treatment of decommissioning funds;
• A provision for the U.S. Department of Energy to report in one year on how to dispose of high-level nuclear waste.