Wednesday, March 17, 2010

Small and Modular Reactors

Small and modular nuclear reactors (those with a thermal power output below 200 MWTh) have become of strong interest, both in Canada and worldwide for a number of reasons. In Canada, the interest arises from the following sources:
(i) The need to replace the NRU (National Research Universal) reactor with another multipurpose research reactor, as recommended by the NRCan Expert Review Panel on Medical Isotope Production last year [Recommendation I, p. xi Executive Summary; also on p. 73 of the main body of the report]
(ii) The interest expressed by energy providers (as well as industrial users such as in mining and tar sands extraction) in off-grid electric and/or thermal process power in modular and scalable units - partly from remote siting considerations and also from emissions reduction considerations
(iii) University nuclear reactors for training and research
(iv) Reactors for dedicated medical radioisotope production.

Separately of the off-grid power reactor interest from resource extractive industries, there is also interest in small reactors as a possible solution for developing countries and first-time nuclear countries who have small or under-developed electric grids. They are also an attractive option for small gas- or coal- fired generating units as a direct replacement, where grid and transmission infrastructure already exist, as in rural areas of developed nations.

As well, the lower up-front capital cost of the smaller power reactors is a motivating consideration for the increased interest, as is the potential for upward scalability in total power output by addition of more units in a more graded manner. Given the lower radionuclide inventory as well as some passive safety features in some of the small reactor designs, they become of additional interest from both the safety and the proliferation-resistance standpoints.

Although some reactors have a thermal output as low as 20 KWTh, the 200 MWTh threshold is chosen to define the upper limit of 'small reactors' from the point of view of accumulation of the radionuclide inventory - which is much smaller below a threshold of 200 MWTh. As well, given that some reactors may have passive safety features, the balance of engineered safety requirements that are imposed could be different for smaller reactors than for large reactors. Consequently, it is possible to justify what has come to be called a 'graded approach' in the safety assessment of small reactors - a smaller reactor will have safety requirements commensurate to the relative risk, compared to a larger reactor, and not necessarily identical ones. This graded approach could reflect itself, for example, in the containment structure requirement, or in extent of the exclusion zone, where the regulatory requirement may not necessarily be identical to that for large power reactors.

The Canadian Nuclear Safety Commission (CNSC) is currently in the process of developing regulatory & licensing guides and related requirements for small nuclear reactors based on these considerations, and will be holding appropriate stakeholder consultations, information sessions and technical workshops during the course of this year to disseminate information and solicit feedback before finalizing the requirements.


US Secretary of Energy Steven Chu outlined the interest in small and modular reactors in his Wall Street Journal op-ed on March 23, 2010, a summary of his Congressional testimony of 3-3-2010.
In his 2011 budget request, President Obama requested $39 million for a new program specifically for small modular reactors. Although the Department of Energy has supported advanced reactor technologies for years, this is the first time funding has been requested to help get SMR designs licensed for widespread commercial use.

Right now we are exploring a partnership with industry to obtain design certification from the Nuclear Regulatory Commission for one or two designs. These SMRs are based on proven light-water reactor technologies and could be deployed in about 10 years.

Expanding on the likely advantages of small modular reactors, he said:
Small modular reactors would be less than one-third the size of current plants. They have compact designs and could be made in factories and transported to sites by truck or rail. SMRs would be ready to "plug and play" upon arrival.

If commercially successful, SMRs would significantly expand the options for nuclear power and its applications. Their small size makes them suitable to small electric grids so they are a good option for locations that cannot accommodate large-scale plants. The modular construction process would make them more affordable by reducing capital costs and construction times.

Their size would also increase flexibility for utilities since they could add units as demand changes, or use them for on-site replacement of aging fossil fuel plants. Some of the designs for SMRs use little or no water for cooling, which would reduce their environmental impact. Finally, some advanced concepts could potentially burn used fuel or nuclear waste, eliminating the plutonium that critics say could be used for nuclear weapons.
To achieve this potential, we are bringing together some of our nation's brightest minds to work under one roof in a new research center called the Nuclear Energy Modeling and Simulation Hub.

Update The Consortium for Advanced Simulation of Light Water Reactors (CASL), the Energy Innovation Hub specific to Nuclear Energy, has been formed, with Dr. Douglas B. Kothe as Director. The Core partners are Oak Ridge National Lab (ORNL), Electric Power Research Institute (EPRI), Idaho National Lab (INL), Los Alamos National Lab (LANL), Massachusetts Institute of Technology (MIT), North Carolina State University (NCSU), Sandia National Labs, Tennessee Valley Authority (TVA), University of Michigan, and Westinghouse Electric Company.

The operational structure and mission statement of CASL explicitly incorporates the vision Prof. Chu has articulated, for example, of 'Bell Labs-like institutions which are mission-driven but solve fundamental problems as well'. See here.

In CASL Director Dr. Kothe's words, (CASL):

• Focuses on a single topic, with work spanning the gamut, from basic research through engineering development to partnering with industry in commercialization
• (creates) Large, highly integrated and collaborative creative teams working to solve priority
technology challenges
• Embraces both the goals of understanding and use, without erecting barriers between
basic and applied research
(emphasis added).

A second Energy Innovation Hub also announced is the Joint Center for Artificial Photosynthesis (JCAP), a partnership between Caltech and Lawrence Berkeley Laboratory:

JCAP research will be directed at the discovery of the functional components necessary to assemble a complete artificial photosynthetic system: light absorbers, catalysts, molecular linkers, and separation membranes. The Hub will then integrate those components into an operational solar fuel system and develop scale-up strategies to move from the laboratory toward commercial viability. The ultimate objective is to drive the field of solar fuels from fundamental research, where it has resided for decades, into applied research and technology development, thereby setting the stage for the creation of a direct solar fuels industry.

Saturday, March 13, 2010

CNSC Presentations at NRC-RIC 2010

Two senior officials of the Canadian Nuclear Safety Commission (CNSC) made presentations at the US Nuclear Regulatory Commission Regulatory Information Conference 2010 (NRC-RIC 2010) last week. The President of the CNSC, Dr. Michael Binder, spoke at NRC-RIC-2010 on A Canadian Regulator's Perspective on International Cooperation. He noted that there were now 48 CANDU-type power reactors in 7 different countries (plus 3 reactors under construction - 1 in Argentina and 2 in India). Emphasizing that national regulators have responsibilities toward customer countries, which he considered an international extension of Canada's safety mandate, he outlined the three phases of Canada's current engagement with the regulatory mechanism in a customer country: (i) With the national regulating agency in the buyer country (ii) On-site, at the end-use location of Canadian-origin technology (e.g. at the site of a CANDU reactor). (iii) Training of regulators as well as interactions at the university level. As the Nuclear Renaissance unfolds, he also indicated that the pattern of Canadian inernational regulatory engagement might move beyond bilateral engagements and evolve to encompass more multilateral mechanisms such as the Multinational Design Evaluation Program (MDEP), with greater harmonization of codes and standards and perhaps including a code of conduct for vendors of nuclear technology.

The Vice President of the CNSC's Technical Services Branch, Terry Jamieson took the theme of International Cooperation in Nuclear Regulation forward, speaking on the MDEP's Role in Converging Codes and Standards. He outlined the efforts of the Codes and Standards Working Group (CSWG) of the MDEP, and indicated that the present focus of the group was on the pressure boundary components. Although different countries had their own codes and standards regarding pressure boundary components, the American Society of Mechanical Engineers (ASME) codes were used as a basis for comparison, focusing first on Class I Pressure Vessels. The objective was to eventually evolve a harmonized set of standards (since full convergence was not found feasible). Next steps will focus on codes for Class I piping, pumps and valves, and later on codes for components beyond those at the pressure boundary.

Saturday, March 6, 2010

Nuclear Regulatory Commission Regulatory Information Conference NRC-RIC-2010

The US Nuclear Regulatory Commission (NRC) will be holding its annual Regulatory Information Conference (NRC-RIC) from March 9 to March 11, 2010. The conference will bring together a variety of stakeholders in the nuclear sector with regulators and technical specialists, both from the NRC and from US national laboratories. While most attendees will be from within the US, there will also be a large number of attendees from other countries, including Canada, who will share their own experiences and provide their own insights into nuclear regulatory affairs.

Apart from plenary sessions addressed by NRC Chairman and Commissioners, there will also be technical sessions on a number of cutting-edge issues at the interface of regulation and technology. These include a session on Materials Degradation at the Containment and Reactor Coolant System Pressure Boundary [Audio], which will discuss probabilistic analysis tools for carrying out the assessment of materials degradation at the pressure boundary, incorporating insights from investigations of the Pressurized Thermal Shock phenomenon. This is expected to contribute, for example, to better understanding of the probability of leak before rupture of piping systems. There are also at least two technical sessions on international issues: one on International Coordination between countries pursuing New Nuclear Power, another on International Cooperation on New Reactors [including the activities of the Multinational Design Evaluation Program (MDEP)]. Another session is devoted to discussing regulatory applications of International Experience in Operating Nuclear Reactors.

A technical session on Regulatory and Policy Issues for Small Modular Reactors should prove particularly interesting - since there is now great interest in the possibility of constructing small and modular reactors (including for isotope production; research; and local, off-grid power or heat applications). [Audio of event].

A separate session discussing the interest in Small and Modular Reactors will also be held [Audio].There will also be a session devoted to new developments in Probabilistic Risk Analysis (PRA) for nuclear power plants, including a talk on peer review of the US NRC's SPAR (Standardized Plant Analysis Risk) model. [Audio]

There is also a session on technical, policy and R&D issues related to the licensing of the Next Generation Nuclear Plant (NGNP), a gas-cooled reactor currently under development. [Session; Audio]. This includes a talk on the US NRC's efforts to develop an evaluation model(EM) for the NGNP. Other sessions of interest include a poster session on Central and Eastern US Seismic Source Characterization (SSC) model development, which may have implications for characterizing seismic sources in Canada as well.

Overall, the conferences promises to be quite interesting indeed.

The US NRC published a Commission Paper (SECY-10-0034) on Potential Policy, Licensing, and Key Technical Issues for Small Modular Nuclear Reactor Designs on 3-28-2010.