A loss of offsite power event at a nuclear power plant, also called a LOOP event, is considered a serious safety risk that could put many lives in danger. After the 2012 incident at the Fukushima-Daiichi power plant in Japan, which involved an extended loss of offsite power in the wake of a massive earthquake and subsequent tsunami, the nuclear industry has worked to make power plants even safer and better able to withstand even the most severe accident scenarios involving catastrophic weather or seismological events.
Nuclear facilities must also evaluate their ability to withstand another sort of threat, a threat to the security of the facility in the event of an attack from an outside adversary. Through testing their response force, updating their security technology and analyzing the weaknesses of their overall security system, facilities come to determine whether or not they are able to guard against these sorts of attacks as well.
Now researchers at the Texas A&M Engineering Experiment Station’s Nuclear Security Science and Policy Institute (NSSPI) are asking the question of how to combine these two separate forms of analysis-both safety and security-to get a more complicated picture of what would happen in the case of a combined safety-security threat. Does the security risk rise in the event of a catastrophic failure or LOOP event?
Patrick O’Neal is a NSSPI graduate student working on this problem with Dr. Sunil Chirayath, director of NSSPI and an associate professor in the nuclear engineering department at Texas A&M University. "Currently, when a facility carries out safety and security analyses they are independent of each other; however, safety events make it easier for an adversary to accomplish some nefarious goal and a security event makes ensuring operational safety more difficult. Essentially this research demonstrates a novel, more holistic approach to evaluating the overall vulnerabilities of a facility; an approach that no facility is using currently," O’Neal explains.
He conducted a probabilistic risk assessment for the safety system in question and then combined it with an evaluation of the plant’s physical protection system to find an overall plant vulnerability for different combined safety-security scenarios. This type of work is necessary because safety and security are a topic of such importance for any nuclear facility, yet the manner in which they are investigated creates situations where a facility might be left more vulnerable than it is aware.
According to O’Neal, "A typical nuclear power plant has countless volumes detailing procedures to follow for any sort of safety event, and security professionals have gone to painstaking ends to form detailed plans on how to protect the plant from an outside threat, but very few facilities, if any, have security plans that are formed by safety events and vice versa."
The analysis that O’Neal has done suggests that increased security during a safety-related event is warranted. This realization could be a first step towards developing more informed and responsive safety and security procedures for nuclear facilities.