The Consortium for Advanced Simulation of Light Water Reactors

The Consortium for Advanced Simulation of Light Water Reactors (CASL), the US Department of Energy's (US DOE) Energy Innovation Hub specific to Nuclear Energy, has been formed, headquartered at the Oak Ridge National Laboratory (ORNL) with Dr. Douglas B. Kothe as Director of CASL.

The basic mission of the CASL is to create a virtual reactor (VR) to computationally model and predictively simulate the operation of light water reactors, with a view to (i) decreasing overall capital and operating costs associated with LWRs (ii) decreasing spent nuclear fuel volume generated by LWRs (iii) improving nuclear safety performance, especially by developing computational tools which better predict ageing, degradation and failure of LWR materials and components. The objective is both to impact the sustainability program for current generation light water reactors, as well as to impact the design of future generation nuclear reactors.

The Core partners in CASL 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 US Secretary of Energy Dr. 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).

Link

To develop the VR, CASL has been organized into five technical focus areas (FAs) to perform the necessary work ranging from basic science, model development, and software engineering, to applications:

Advanced Modeling Applications (AMA) – The primary interface of the CASL VR with the applications related to existing physical reactors, the challenge problems, and full-scale validation. In addition, AMA will provide the necessary direction to the VR development by developing the set of functional requirements, prioritizing the modeling needs, and performing assessments of capability.

Virtual Reactor Integration (VRI) – Develops the CASL VR tools integrating the models, methods, and data developed by other Focus Areas within a software framework. VRI will collaborate with AMA to deliver usable tools for performing the analyses, guided by the functional requirements developed by AMA.

Models and Numerical Methods (MNM) – Advances existing and develops new fundamental modeling capabilities for nuclear analysis and associated integration with solver environments utilizing large-scale parallel systems. The primary mission of MNM is to deliver radiation transport and T-H components that meet the rigorous physical model and numerical algorithm requirements of the VR. MNM will collaborate closely with MPO for sub-grid material and chemistry models and will connect to VRI for integration and development of the CASL VR.

Materials Performance and Optimization (MPO) – Develops improved materials performance models for fuels, cladding, and structural materials to provide better prediction of fuel and material failure. The science work performed by MPO will provide the means to reduce the reliance on empirical correlations and to enable the use of an expanded range of materials and fuel forms.

Validation and Uncertainty Quantification (VUQ) – The quantification of uncertainties and associated validation of the VR models and integrated system are essential to the application of modeling and simulation to reactor applications. Improvements in the determination of operating and safety margins will directly contribute to the ability to uprate reactors and extend their lifetimes. The methods proposed under VUQ will significantly advance the state of the art of nuclear analysis and support the transition from integral experiments to the integration of small-scale separate-effect experiments

The European PERFECT Project shares many of the goals of the CASL, in developing 'virtual reactors', though the PERFECT project aims to develop 2, one each for the reactor pressure vessel and the internal structures. The first will concentrate on modeling irradiation degradation, while the second will concentrate on the corrosion faced by internal structures.

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.

Postscript
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.