SAFETY & SECURITY |
New uses for old information
Anders Riber Marklund says the ability to process existing safety assessment results with observations during an incident can strengthen emergency preparedness and response
Anders Riber Marklund
Nuclear safety & licensing principal consultant at Vysus Group
NUCLEAR POWER IS BECOMING PREVALENT in discussions on how to limit global warming. It was notable that the International Atomic Energy Agency (IAEA) appeared during COP26, and just this year there have been announcements on nuclear new-build plans from China and France, and a funding pledge of £1.7bn from the UK government. But as nuclear technology becomes more important the stakes rise. Risk assessment becomes still more important — but how do we avoid becoming slow to respond to the market, as the sheer volume of research, lessons learned and documentation accumulates? How can we use existing information in new applications? Major nuclear accidents such as those at Fukushima in
Japan, Chernobyl in Ukraine and Three Mile Island in the USA are extremely important in learning lessons, not only on how to improve risk assessment and safe design, but also on how to enhance defence in depth, all the way to enhanced emergency preparedness and response (EP&R) protocols. IAEA safety standards point out the importance of being
able to classify emergencies and define intervention levels based on observed conditions. Does this mean that all safety assessments performed prior to an incident are ignored during an event, or can we still make use of their information? How much of the vast amount of information produced by regular safety assessments made in normal operation can be put to efficient use in EP&R and how much will be thrown away, due to organisational or regulatory requirements or simply lack of time and resources in an accident situation?
Right: The Three Mile Island accident acts as a reminder that vital information needed to implement emergency protocols is not always available during an event Photo credit: George Sheldon/
Shutterstock.com
Far right: At Fukushima loss of on-site and offsite power made emergency response efforts more difficult Photo credit: Tepco
36 | January 2022 |
www.neimagazine.com The Fukushima and Three Mile Island accidents act as
reminders that vital information needed to implement emergency protocols is not always available during an event in time to take action. This may come down to unforeseen events or sudden situational changes, as well as inaccuracies in a site’s initial safety assessment under ‘normal’ working conditions. The Three Mile Island incident illustrates this. Together, inadequate communication systems and data delayed as a result of misconceptions about the site characteristics, deprived management teams of critical information. This shaped the response to the incident. At Fukushima, parts of the emergency response plan
relied on making dose projections, but the relevant system was unavailable due to the AC power loss. Once these limits are understood, the ability to process
available information and make a risk-informed call becomes an altogether different challenge. A decade ago, our nuclear safety and licensing team was
asked how to use probabilistic risk assessments (PRAs), to create a tool for source term estimation. The tool would be used during the early stages of a nuclear accident, when information is both scarce and contradictory, and it would have low requirements on hardware, to make it robust during potentially challenging conditions. PRAs have been successfully used within the nuclear
sector since the 1970s. Complex level 1 & 2 PSA models and documentation have been developed for several plants, to complement the traditional deterministic design basis. The importance of this development can be illustrated
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