Outage management adapts to COVID-19

The head of the US Nuclear Energy Institute, Maria Korsnick, has written to US Energy Secretary Dan Brouillette urging federal support to ensure that such essential activities can be carried out during the COVID-19 pandemic. US utility Exelon has set up a dedicated website to share information on its ongoing maintenance outage at the Limerick nuclear power plant in Pennsylvania. Meanwhile, South Africa's Eskom and Sweden's Vattenfall have announced changes to outage plans at certain plants.

Nuclear power plants have been designated by the US Department of Homeland Security as critical infrastructure, because continued operation of the power grid is vital to the pandemic response, Korsnick said in her letter. "Our industry has multi-stage plans to continue operations during a pandemic, and our plants have implemented these to the degree required by local conditions. To date, all operating plants are continuing to run reliably, and refuelling operations already underway are moving forward on schedule," she said.

Korsnick called on Brouillette for "urgent support", including ensuring that workers supporting nuclear operations and refuelling outages are included in federal designations of essential workers; allowing such workers to travel to plants; and providing priority access to personal protective equipment used in the course of outages and normal nuclear plant operations.

A nuclear reactor needs to be refuelled once roughly every 18 months or every 2 years, depending on the reactor design. At each refuelling, about one-third of the reactor's oldest fuel bundles are removed to a used fuel pool, the remaining two-thirds are rearranged inside the reactor and fresh fuel is added. In addition to refuelling, tests and inspections of critical safety systems, as well as maintenance work which can only be done when the reactor is not operating, are carried out.

Such an outage typically lasts between two and four weeks, and requires a plant to bring in several hundred specialist workers. Refuelling outages are therefore planned in advance and are scheduled for a period when electricity demand is at its lowest - typically in the spring or the autumn. This spring, 32 nuclear power stations in 21 US states are planning to undergo essential refuelling outages, according to the NEI.

According to US press reports, local communities have expressed concern about the influx of workers as the pandemic is ongoing, with local officials expressing concern about a scheduled outage at Exelon's Limerick nuclear power plant in Pennsylvania.

"We learned of plans to bring approximately 1800 workers into our region from around the United States. We asked Exelon to postpone this refuel until a time when the disease burden from COVID-19 was lower," Valerie Arkoosh, chair of the Montgomery County Board of Commissioners, where Limerick is situated, said in a report by local broadcaster WPVI.

US utility Exelon Generation has set up a dedicated website to provide information on the refuelling outage at Limerick and the measures it has put in place due to COVID-19. The plant is following a "rigorous pandemic preparedness plan" that includes strict governance to prevent and slow the spread of the virus, with all workers undergoing symptom screening and body temperature checks before entry onto the site. "Anyone with symptoms does not enter the site and is advised to consult with a medical professional," it said.

Eskom takes advantage of demand reduction

South African state-owned utility Eskom said it is making use of the significant reduction in electricity demand while the nation is in lockdown due to COVID-19 to increase planned maintenance work, including taking unit 2 at the Koeberg nuclear power plant offline from 3 April. The plant will return to service by 30 April but will be able to restart sooner if need arises, the company said.

Electricity usage in South Africa has dropped by between 7500 MW and 9000 MW since the lockdown came into effect last week, and this has allowed the company to operate without the need to implement loadshedding, it said. It does not expect to implement any loadshedding - planned interruption of supply to certain areas in order to balance supply and demand and avoid a country-wide blackout - while the lockdown is in place, it said.

Swedish unit stays off line

Meanwhile, Sweden's Ringhals unit 1, which is currently in a maintenance outage, will remain off line until after the summer, operator Vattenfall told the Nordpool power exchange. The boiling water reactor was shut down for maintenance on 13 March. Vattenfall on 31 March told Nordpool: "The owners of Ringhals have today decided to instruct Vattenfall AB to review the production optimisation of Ringhals 1. All available fuel will as planned be loaded and the energy content of the core will remain as planned. However date of start will be re-evaluated and optimised in relation to the power market. With current market prices the start of operation will be postponed till after summer."

Ringhals 1 is scheduled to shut permanently by the end of this year. Ringhals unit 2 closed down in December 2019 following a 2015 decision to close the reactors five years earlier than originally planned, for commercial reasons.

Output at Forsmark units 1 and 2 has since 2 April been downrated due to lower electricity demand. According to the company's website, Forsmark 1 was operating at 57% capacity and Forsmark 2 at 54% capacity as of 2pm on 3 April.