DIGITAL DEVICES | UPGRADING AND UPRATING Undetected changes in components is just one of several
concerns that nuclear plant operators have to consider around the growth of low-cost frequent-use EDDs and other technologies. The NRC says, “new failure modes may increase the consequences of a malfunction or failure or create the possibility for an accident type different than any previously evaluated”. This may arise in the case of aftermarket parts, special
manufacturing, repair or new build, equivalency, reverse engineering or a design change. “Left undetected, undeclared digital content could find its way into, and become a de facto change to, the plant’s licensing basis.” The NRC considered whether EDDs could increase a
nuclear plant’s vulnerability to common cause failure (CCF). EDDs have that potential, it concluded, and a solution may not be straightforward. CCFs are typically avoided by having different channels. However, if there are common components like valve controllers that all have the same EDDs, with the same software triggers, this may cause CCF concerns. But placing valve controllers for different valves on a rack could cause a CCF because of their physical location. “Thus, while one problem may be solved the solution could create other problems,” it said. In its report the US NRC noted that the supply chain
represents a “significant cyber-attack pathway for digital assets and systems,” and generally that the increasing use of EDDs, increasingly likely to be from vendors outside the nuclear industry, will increase cyber security vulnerabilities and concerns. So too will the use of wireless technologies. These
“advance the capabilities of EDD significantly” and beyond their analog counterparts, but they raise both cybersecurity concerns and issues over electromagnetic interference Cybersecurity is naturally top of a list of concerns for the
nuclear industry and for the energy industry as a whole. New research published by risk management and quality assurance provider DNV suggests that the industry is not becoming complacent (see box two).
Look carefully The US NRC noted that the nuclear industry remains cautious over the use of EDDs and its comment that “the presence of new and potentially unknown failure modes in digital systems and components translates into a slower rate of incorporating digital systems into nuclear power plants compared to the process industries” would no doubt be equally applied to other new digital technologies. So would the NRC’s view that software failures will be a
major threat for reliability. It advises that changes should be considered very carefully if they will increase complexity – even if they are useful functions such as automated self- testing. It says, “self-diagnostics can add a lot of benefit by identifying errors and deviating performance; however, self-diagnostics add complexity, may have untested steps, and may falsely increase confidence in a device.” Nevertheless, the US regulator highlights the opportunities presented by EDDs and associated technologies. For
example: ● Embedded digital capabilities will enable new types of components that are not feasible without the high- speed data acquisition and processing capabilities supplied by the on-board electronics and advances in instrumentation and control (I&C) systems and components.
● Emerging applications of autonomous control allow for reactor components that operate in extreme environments – the NRC’s example is replacing mechanical bearings with magnetic bearings that can allow a pump to be made from materials that can operate above 650°C.
● Allowing for a shift away from a centralised control architecture that requires exceptional operator knowledge of the power plant and that involves costly and difficult design of the operational and safety systems. The NRC says: “localised control through the use of EDDs could allow designs to be simplified and could streamline operation of complex systems while improving modularity similar to object-oriented control architectures.”
Overall, the opportunity is for a nuclear industry – and an electricity industry – that is better equipped for the future. New embedded technologies, ‘as a service’ offering capabilities such as data storage and analytics, and new parties that specialise in these technologies, can help the nuclear industry reduce costs and improve its offering – provided they are carefully incorporated. ■
1 Devices to watch The US NRC identifies 18 types of components with EDDs that may contain
digital content. They are: ● Chart (data) recorders ● Priority logic modules ● Circuit breakers ● Pumps ● Diesel generators ● Radiation monitors ● Flowmeters ● Relays, time-delay relays ● Gas analysers ● Temperature transmitters ● Level meters ● Uninterruptible power supplies ● Motor control centers ● Valve actuators ● Power supplies ● Valves ● Pressure transmitters ● Voltage regulators
2 Rising concerns over cyber security
DNV recently released The Cyber Priority, a research survey exploring attitudes to the state of cyber security in the energy sector. The test and verification company spoke to more than 940 energy professionals around the world working in the power, renewables, and oil and gas sectors. It revealed that a majority regard cyber-attacks as a major vulnerability. The respondents thought that within the next two years a cyber- attack on the industry is likely to cause operational shutdowns (85%), damage to energy assets and critical infrastructure (84%), environmental harm (74%) or loss of life (57%). DNV said that concern about the threats has grown following Russia’s invasion of Ukraine, with 67% of interviewees saying that recent cyber-attacks on the industry have driven their organisations to make major changes to their security strategies and systems. ■
www.neimagazine.com | June 2022 | 37
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