Electricity and Control January-February 2025

Safety of plant, equipment + people Site safety assessments for nuclear power stations Eskom’s Koeberg nuclear power station was recently licensed to operate its Unit 1 for another 20 years. SRK Consulting played a role in assessing site safety and updating the site investigation reports to prepare the Site Safety Report required by the National Nuclear Regulator in support of the licensing application. A ccording to Derry Holmes, Principal Consultant at SRK Consulting, these studies were part of a range of updates undertaken by SRK, which are required to be conducted every five to ten years. The work related to Eskom’s Duynefontyn site, where Koeberg is located. exposed to radiological impact – through proximity, the food chain, water or other channels. The regulator is then in a position to ensure that the plant will continue to operate safely at that geographic location.

While this work considers the potential radiological impacts of the plant on its surroundings, the site safety investigation also considers the impacts of the surroundings on the plant and its safe operation. “These aspects include the geology and geohydrology of the ground on which the plant is built, as well as seismic risks to the integrity of the operation,” Holmes says. “This extends as far as identifying air traffic routes, considering the potential for aircraft-related accidents. The big question to answer with all this data is whether the environment poses a risk to site safety for the duration of the plant’s operational lifecycle.” Many moving parts In the face of identified risks, the studies also consider whether there are any impediments to creating an effective emergency plan – so that people can be evacuated from the area in the event of an incident. This includes considering the existing transportation infrastructure, as well as likely future scenarios taking account of forecast economic growth and urbanisation. “The planning of nuclear power stations requires the gathering of considerable data and intensive engagement with stakeholders, including local government, is essential,” Holmes says. “The planners need to understand the spatial development frameworks of municipalities or metros and there must be agreement between parties about what happens in the future.” This is because the power station must be able to make reasonable forecasts of where infrastructural and urban development is likely to take place in the coming decades. And it needs to stay abreast of changing plans – if the local government changes its plans, for example, in a way that could have an unexpected impact on the power station. SRK has been involved in site safety assessments and monitoring of sites for planned nuclear power plants for over 18 years, Holmes says. Its work includes geohydrological water monitoring where the levels and quality of water are checked in dedicated boreholes, as well as meteorological monitoring of factors like temperature, wind, solar radiation and rainfall. The ecological aspects of an SSR can also benefit from information originally gathered for a project’s Environmental Impact Assessment (EIA). “While the EIA assesses how the power station might impact the ecology, the SSR assesses how the ecological environment may affect the running of the plant,” Holmes highlights. □

“Our work for Eskom included addressing comments by the National Nuclear Regulator (NNR) on the previous version of the Duynefontyn Site Safety Report (SSR), as part of the long term operational licence application for Koeberg,” Holmes says. Koeberg’s Unit 1 is one of around 120 reactors worldwide that continue to operate safely beyond their initial 40-year life. (Eskom’s application to extend the operating licence for Unit 2 at Koeberg, following extensive, recently completed upgrades, is currently with the NNR, awaiting a decision.) Stringent standards Nuclear projects are governed by strict local and international quality and safety standards, requiring a wide variety of aspects to be monitored, analysed and reported. SRK’s work included technical studies in the fields of hydrology, geohydrology,

geotechnology, and meteorology. It also looked at land, water and sea use, ecology, demography, water supply, as well as transport routes, and nearby industrial and military facilities. “Much of the work is conducted by our in-house

SRK Consulting was involved in assessing site safety for Eskom’s Koeberg nuclear power station to support the licensing of Unit 1 for

professionals in specific disciplines, and other aspects are contracted out to specialist associates,” Holmes says. “Town planners, for instance, conduct the investigations on demography, land use, water use, adjacent sea use, and nearby transportation, industrial and military facilities.” He explains that the whole life of the nuclear plant must be considered, so it is important to be able to forecast population growth and movement over this expected lifespan. “One of the reasons why this data is relevant is because of the plant’s potential radiological impact,” he notes. “In addition, for purposes of emergency planning – such as determining an appropriate transport model for evacuation – planners need to know how many people are likely to be in the area in future decades.” Safe operation Using the concept of ‘pathways to humans’, the specialists must consider all the possible ways that people can be

continuing operation.

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26 Electricity + Control JAN-FEB 2025