AESS Systems Engineering Template: Scenario that follows compels a choice of “Aerospace to Solve Nuclear Power Safety” options. Aerospace to Solve Nuclear Power Safety Views are expressed from author (V. Socci) from open-source information and no implied affiliation is assumed: Compiled for IEEE AESS, 2011
Outline • Background Information • Industry needs and issues • Potential solutions • Recommendations • References
Background • The ongoing nuclear crisis in Japan teaches the world a lesson: • There is no absolute guarantee of safety in developing nuclear energy, no matter how much people rack their brains to ramp up security measures. • Nuclear power plant leaks cannot be contained by frontiers. • No single country can hold the reigns on nuclear safety. • People have to find better ways to maintain the safety of nuclear power plants. • Even the best technology is susceptible to human errors. • Are nuclear crises a result of social issues or technical issues? • Many believe that the Chernobyl nuclear accident was caused by the Soviet Union's social system. • Japan's tragedy shows us that even the country with the most advanced technology in the world can fall victim to a nuclear accident.
Key Facts • Statistics from the International Atomic Energy Agency in January 2011: • There are presently 442 commercial nuclear reactors around the world. • These reactors generate about 16 percent of the world's electricity. • The World Nuclear Association also predicts that there will be one 1,000-megawatt nuclear power plant built every five days by 2015. (source: http://opinion.globaltimes.cn/editorial/2011-04/635446.html) • The world is at risk as experimental nuclear fusion is becoming an unregulated and uncontrolled hobby. See http://www.foxnews.com/scitech/2011/08/02/swedish-man-builds-nuclear-reactor-in-his-kitchen/
Nuclear Power Plants • Nuclear power plants are some of the most sophisticated and complex energy systems ever designed. They cannot be failure proof. • Nuclear failures may occur in a variety of ways: • Instability, uncontrolled power • Loss of coolant, Nuclear meltdown • Nuclear shutdown, grid overload • Nuclear terrorism • Vulnerability to intentional attacks
Reactor Source: http://www.world-nuclear-news.org/uploadedImages/wnn/Images/bwr-cycle.gif
Nuclear Safety Systems • Three primary objectives of nuclear safety systems as defined by the Nuclear Regulatory Commission • shut down the reactor, • maintain it in a shutdown condition, and • prevent the release of radioactive material during events and accidents
Various protective systems • Reactor protection system (RPS) • Control rods • Safety injection / standby liquid control • Essential service water system (ESWS) • Emergency core cooling system (ECCS) • High pressure coolant injection system (HPCI) • Depressurization system (ADS) • Low pressure coolant injection system (LPCI) • Corespray system • Containment spray system • Isolation cooling system
Various protective systems • Emergency electrical systems • Diesel generators • Motor generator flywheels • Batteries • Containment systems • Fuel cladding • Reactor vessel • Primary containment • Secondary containment • Core catching • Non-containable events
Various protective systems • Ventilation and radiation protection • Containment ventilation • Control room ventilation
Solutions to Nuclear Events • New Technologies • The next nuclear plants will have even greater improvements in safety. • Some improvements made are having three sets of emergency diesel generators and associated emergency core cooling systems, having quench tanks above the core that open into it automatically, having a double containment, etc. • Safety risks may be the greatest when nuclear systems are the newest, and operators have less experience with them. • Nuclear engineer David Lochbaum explained that almost all serious nuclear accidents occurred with what was at the time the most recent technology. “The problem with new reactors and accidents is twofold: scenarios arise that are impossible to plan for in simulations; and humans make mistakes". As one director of a U.S. research laboratory put it, "fabrication, construction, operation, and maintenance of new reactors will face a steep learning curve: advanced technologies will have a heightened risk of accidents and mistakes. The technology may be proven, but people are not".
Solutions • Safety Culture • The International Nuclear Safety Advisory Group, defines the term as “the personal dedication and accountability of all individuals engaged in any activity which has a bearing on the safety of nuclear power plants”. The goal is “to design systems that use human capabilities in appropriate ways, that protect systems from human frailties, and that protect humans from hazards associated with the system”. • Safety-critical Design and Operating Procedures • Operating security • The Aerospace Industry is developed around a safety culture and framework. • Robust, fault-tolerant designs • Minimize human error
Solutions • Risk Assessment • The AP1000 has a maximum core damage frequency of 5.09 x 10−7 per plant per year. The Evolutionary Power Reactor (EPR) has a maximum core damage frequency of 4 x 10−7 per plant per year. General Electric has recalculated maximum core damage frequencies per year per plant on the order of 10-5. • Aircraft are designed at failure rates of 10-9. • The Aerospace industry has a history of high reliability, design for system safety, safety-critical operation, and safety/reliability assessment.
Solutions • Standards development • Nuclear risks are an international concern. • Environmental concerns (e.g. probability for earthquake) are difficult to assess. • True nuclear safety requires a multiple-disciplinary approach. • Regulations, inspections, and audits by authorities.
Dialogue and Recommendations • How can IEEE influence/enable a Safety Culture in the nuclear energy industry? • What can aerospace engineering offer for risk assessment of nuclear designs and operation? • Can standards be developed and enhanced?
References • http://opinion.globaltimes.cn/editorial/2011-04/635446.html • Jan Willem Storm van Leeuwen (2008). Nuclear power – the energy balancehttp://www.stormsmith.nl/ • François Diaz Maurin (2011). Fukushima: Consequences of Systemic Problems in Nuclear Plant Design, Economic & Political Weekly (Mumbai) Vol. 46, No. 13, pp.10–12, 26 March, 2011. http://epw.in/epw/uploads/articles/15865.pdf • http://www.world-nuclear-news.org/RS_Insight_to_Fukushima_engineering_challenges_1803112.html • M.V. Ramana. Nuclear Power: Economic, Safety, Health, and Environmental Issues of Near-Term Technologies, Annual Review of Environment and Resources, 2009. 34, pp.139-140. • http://www.ans.org/pubs/magazines/nn/docs/2006-1-3.pdf • Benjamin K. Sovacool. A Critical Evaluation of Nuclear Power and Renewable Electricity in Asia, Journal of Contemporary Asia, Vol. 40, No. 3, August 2010, p. 381.