Safety for nuclear energy

Nuclear energy might be the source of all evils for environmental activists, but for many countries around the world it is a key option to meet the targets set by the Paris Agreement on Climate Change.

These countries (which include most members of the European Union, China and the US) have opted for a mix of nuclear energy and renewables to reduce greenhouse gases (GHGs) which are emitted by fossil-fuel generated energies. According to the International Energy Agency (IEA), nuclear power has avoided about 55 Gigatonnes (Gt) of CO2 emissions over the past 50 years, nearly equal to two years of global energy-related CO2 emissions.

Since the Fukushima nuclear disaster in 2011, however, concerns about the safety of nuclear energy have risen and some nations have opted to denuclearize, either temporarily (Japan) or permanently (Switzerland, Germany…). Safety is therefore THE prime concern for governments and the nuclear industry to ensure nuclear energy remains one of the options on the table for reducing GHG emissions. Nuclear power plants (NPPs) must be able to demonstrate that they deliver energy safely, securely and efficiently, now more than ever before. 

IEC expertise on safety

IEC cooperates with the International Atomic Energy Agency (IAEA), a UN agency that works to promote the safe, secure and peaceful use of nuclear technologies and which sets global safety standards for nuclear energy. Experts from IEC Technical Committee 45 take part in the technical working group on nuclear power plant instrumentation and control (TWG-NPPIC), which was founded by the IAEA in 1971 to give advice on and promote research into nuclear plant technology, notably human system interfaces. 

IEC TC 45, and more specifically one of its subcommittees, SC 45A, publishes international standards covering the entire lifecycle of the electrical and electronic control systems of nuclear power plants, from conception, through design, manufacture, test, installation, operation, maintenance, repair, modernization and decommissioning.

Aside from the radioactive elements, there are many combustible sources within a nuclear power plant. A control, pump and turbine room are composed of complex networks of mechanics and electronics that demand their own safety standards. The loss of any of those peripherals following a fire, for example, could affect the safety of personnel, in addition to potentially impacting energy production.

It is therefore of the utmost importance that they are designed and built in compliance with the very strict requirements enunciated in standards and specifications, most notably in IEC International Standards developed by IEC Technical Committee 31: Equipment for explosive (Ex) atmospheres.

Through its conformity assessment work, IEC has a solution for all sectors of industry that are operating in hazardous environments. One of the four IEC Conformity Assessment (CA) Systems, IECEx, provides testing and certification for all types of Ex equipment and related services, as well as personnel competence.

Machine learning could help

Statistical analysis and machine learning can be used to reduce the uncertainty in predicting a hazard event in NPPs. This can be achieved by running a series of simulations that provide variations on hazard event conditions, conducting statistics on existing data and simulation results to identify key parameters that most significantly affect the hazard level as well as using deep learning models and statistics to identify how to lower the hazard uncertainty. These tools can supply a more complete approach for risk reduction.

IEC and ISO develop publications and international standards for information and communication technologies through their joint technical committee (ISO/IEC JTC 1) with  subcommittees (SCs) covering 22 different areas. SC 42 covers artificial intelligence and publishes several standards dealing with big data and how to use it.

Mitigating the risk of a cyber attack

The main systems within a nuclear power plant fall broadly into two categories. Primary systems control the reactor itself and, when needed, shut it down and maintain it in a safe condition to protect it. Secondary systems control the power generation equipment. Many of these systems, built years ago, are still based on analogue equipment that is not connected to a network. While these systems have problems of their own, they are not susceptible to cyber attacks.

However, less recent NPPs are being gradually brought up to date through the installation of digital equipment which will affect both systems, while new NPPs are designed with digital primary and secondary systems. The increased use of digital technology, which goes hand in hand with the automatization of the electricity grid, makes NPPs more vulnerable to cyber criminals. This increasing threat is taken very seriously by nations and the nuclear industry itself. IEC TC 45 issued its first standard addressing cyber security issues in August 2014. It recently published a completely revised second edition of IEC 62645. The publication was developed “to prevent and/or minimize the impact of attacks against I&C programmable digital systems on nuclear safety and plant performance. It covers programme level, architectural level and system level requirements.”

On a broader level, IEC 62443, published by IEC TC 65, can be applied to any industrial environment, including critical infrastructure facilities, such as power utilities or nuclear plants, as well as in the health and transport sectors.  The new edition of IEC 62645 proposes a table of high-level correspondence between the IEC 62443 series and IEC 62645, listing dozens of subclauses related to the context of the organization, lifecycle implementation for I&C programmable digital system security and security controls.

Where we stand

According to the IEA, in 2019, 5,5 GW of additional nuclear capacity were connected to the grid and 9,4 GW were permanently shut down, bringing global capacity to 443 GW. New projects were launched (about 5,2 GW), and refurbishments are under way in many countries to ensure the long-term operations of the existing fleet. This is not enough to meet the IEA’s own sustainable development scenario. While the cost of nuclear energy has always been an issue, increased concerns over safety have slowed down its expansion. Working with the industry, the IEC is helping to promote safety and security in every area of generation, production and transmission of nuclear energy, thereby reassuring governments and regulators that it can be used as part of the energy mix for reducing GHGs.