Belgium’s Federal Agency for Nuclear Control (FANC – Federaal Agentschap voor Nucleaire Controle) has submitted its expectations regarding nuclear safety to ENGIE Electrabel for extension of the operating period of the reactors at unit 4 of the Doel NPP and unit 3 at the Tihange NPP. In June the federal government and owner/operator ENGIE Electrabel had concluded an agreement on the extension.

In order to guarantee the nuclear energy supply also during the winters 2025-2026 and 2026-2027, the necessary improvement works may be carried out in a staggered manner, of course without compromising nuclear safety, FANC said.

In February, an analysis by grid operator Elia showed that an energy shortage could occur as early as the winter of 2025-2026 which could only be met with nuclear capacity. “In this difficult context, at the request of the government, FANC has proposed the necessary amendments to the Royal Decree on the safety regulations for nuclear installations to allow the extension of Doel 4 and Tihange 3, the regulator noted. “The necessary safety improvements may be spread over time and must all be implemented by 2028. In this way it is also possible to use Doel 4 and Tihange 3 in the winter 2025-2026.”

FANC also sent a 20-page note to ENGIE Electrabel detailing its expectations with regard to safety for the operating extension.

One example of a safety improvement is the automatic detection of toxic gases in the emergency plan infrastructure. “There is manual detection, but because the concentrations of gases can differ from location to location, an automatic detection system offers more guarantees,” FANC said.

Another example is the replacement of the seals on the pumps of the primary cooling system. “The current seals work by means of water injection, which requires an electrical supply. Should the electricity fail completely and the water injection stop, the seals could degrade and the primary cooling system could leak. In the meantime, there are 'passive' seals that do not degrade in the event of a loss of electrical power.”

“With this note, FANC defines in an autonomous way the elements to be addressed to prepare and justify the long-term operation of the reactors Doel 4 and Tihange 3,” the note concludes. “In order to maintain the safety level of nuclear reactors, it is essential that a number of preconditions are met and that ageing management programmes are implemented efficiently. Thanks to an additional inspection and test programme, the conformity of the installations can also be ensured and any problems can be detected.”

It specifies: “Actions related to the degradation of safety, or intended to demonstrate that the safety level is maintained, addressing non-conformities to the current reference system, must be carried out before restarting the installation in the context of a new operating period. The normally planned tests and inspections, in particular the 10-year tests, must be carried out as planned.” , Additional tests and inspections intended to demonstrate the proper functioning of the installations on a larger scale “must be carried out as early as possible during the 10-year shutdown so that their results can be taken into account and the resulting improvements deemed necessary can be implemented.”

Finally, the remaining actions, whether they are actions to comply with new draft regulatory requirements, or improvements to bring them into line with the new practices, norms and standards, “should be carried out no later than three years after the 40th anniversary of Doel 4 and Tihange 3, except in the case of duly justified exceptions.”

FANC said ENGIE Electrabel is now further developing the concrete action plans and associated timing. FANC will have to approve them and will ensure that priority is given to the activities most important for nuclear safety.

If, due to force majeure, a certain action point cannot be carried out within the set time frame, ENGIE Electrabel must justify this to FANC which must then approve the adapted planning. For example, this could occur if the order for a part was placed on time, but the supplier was unable to deliver on time.

“When Doel 4 and Tihange 3 can be used effectively for electricity production, it will also depend on factors other than nuclear safety alone, such as the delivery of the nuclear fuel and the amendment of the law on nuclear phase-out,” FANC said.

Meanwhile, ENGIE Electrabel has signed a framework agreement with the Belgian government establishing the conditions for the continuation of negotiations between the with a view to reaching a final and legally binding agreement – the transaction document – in October 2023. This confirms the terms of an interim agreement signed in June which includes a lump sum of €15bn ($16.6bn) for waste management “and establishes the Flex LTO [long-term operation] scenario as the base case for further negotiations” on extended operation of the two plants.

Electrabel says this scenario is subject to certain unavoidable conditions to ensure nuclear safety:

  • The on-time delivery of nuclear fuel by the manufacturer;
  • Improvements to plant design, based on the nuclear safety requirements recently transmitted to ENGIE Electrabel by FANC;
  • Qualification of equipment important for safety to ensure correct operation in all conditions. FANC must approve the condition of the facilities before each restart;
  • Certain work to ensure the operational safety of the existing facilities must be carried out within 2-4 months in the case of a Flex LTO;
  • The availability of highly specialised personnel and partner companies must be ensured, taking into account the tight schedule, which is even tighter in the case of a Flex LTO.

“If all these conditions are met, ENGIE Electrabel currently sees no major obstacles to a restart in November 2025.

Image: Tihange nuclear power plant