Alexander Glaser and M.V. Ramana focus on how nuclear power potentially fits into a modern low-carbon energy system, with an emphasis on accident risks and new technologies. Their research project draws on expertise from the fields of computing, engineering, and policy to evaluate a range of possible alternative energy futures.
Impacts of accidents on nuclear energy’s future
Though prospects for a worldwide large-scale expansion of nuclear power have diminished following the March 2011 nuclear accident in Fukushima, Japan, some countries continue to construct nuclear reactors and a number of countries are proceeding with plans to acquire their first nuclear power plants. The International Atomic Energy Agency counts 29 countries as considering or planning for nuclear power. Proposals for including nuclear power in a nation’s energy supply mix often rely on climate change mitigation arguments.
An important focus during the past year of the Re-engineering the Nuclear Future project led by Alexander Glaser and M. V. Ramana has been to explore better ways of characterizing nuclear power in the integrated assessment models that combine detailed models of economy, energy and climate to project the climate implications of energy policies. Such models often project a need for a five to ten-fold increase in the deployment of nuclear power globally—in part because of the assumption that nuclear energy offers lower cost electricity than renewables. However, these models do not account for the potential costs and policy impacts of catastrophic nuclear accidents. The experience following the Chernobyl and Fukushima accidents suggests that reactions to severe accidents can be varied, widespread, and significant in magnitude. Further, resulting changes in safety regulations will usually translate into higher costs for nuclear power.
Glaser and Ramana worked with Shoibal Chakravarty, who developed a dynamic programming approach to include the impact of accidents on the likely deployment of nuclear power over the next few decades. Preliminary results indicate that if the probability of a Fukushima-scale accident is on the order of one in 100,000 reactor years, the role of nuclear power would be significantly smaller by the end of the century than projected with the same model when the possibility of accidents is ignored. The empirical record of accidents so far suggests an accident probability greater than one in ten thousand years, although the industry claims calculated probabilities for the latest generation of reactors lower than once in a million years. The researchers propose to explore other factors, such as the linkage with nuclear weapons proliferation, that might significantly affect the role that nuclear power could potentially play in climate mitigation.
Regulatory challenges for small modular reactors
Ramana and Glaser also continued to examine the challenges associated with a new generation of small modular reactors (SMRs) with power outputs of 100 to 300 MWe that have been proposed as a potential solution to many of the problems confronting the expansion of nuclear power. Because of their many novel features, it is critical that national nuclear regulators follow careful and thorough licensing procedures to ensure safety. The researchers find that in many cases SMR designers have argued that their reactor designs are already so safe that regulatory authorities should permit existing licensing requirements for nuclear reactors to be eased. One focus has been to allow reactors to be deployed without a sizeable zone where emergency plans for evacuating the population are put in place. This raises the concern that the safety enhancements promised in SMR designs could be offset by a simultaneous relaxation of licensing requirements leading to an overall higher risk or impacts of severe accidents to the populations living in the vicinity of reactors. Future plans include the analysis of potential accident scenarios and their radiological impact to see if such a relaxation of the emergency planning zone rules is justified.