Inspections at the Loviisa nuclear power plant

STUK carries out inspections to oversee the operation and use of the Loviisa nuclear power plant. The periodic inspection programme covers safety management, main operational processes, procedures and technical acceptability of systems.

STUK draws up a plan for the inspection, setting out the subject of the inspection and any preparatory actions required of the licence holder. The result of the inspection and the resulting requirements are set out in the inspection report.

Periodic inspections

Below are summaries of the inspections carried out by STUK in year 2025 in accordance with the periodic inspection programme for the Loviisa nuclear power plant.

Realisation of undefined OLC repair times, 22 January 2025

The inspection assessed the monitoring and implementation of work that requires operational limits at the Loviisa nuclear power plant. The inspection focussed especially on so-called X work, referring to work for which no limit period has been specified in the Operational Limits and Conditions (OLC).

The inspection found that Fortum has comprehensive procedures for monitoring X work. The work and their risk significance are regularly assessed in various meetings and reports. In the job management system, the X work classification is also used for work not within the scope of OLC. In STUK’s view, it would be better to restrict X work to only refer to work requiring operational limits specified in the OLC and establish another classification for non-OLC work. STUK presented an observation on the subject in the inspection report.

Based on the indicators presented by Fortum, the duration of work requiring operational limits in accordance with the permitted 3-day repair period has been significantly reduced in recent years. However, there are no corresponding indicators for other limit categories, which makes it difficult to monitor their duration. STUK estimates that creating such indicators could further improve operations and ensure the coverage of positive development.

In assessing the risk caused by work that requires operational limits, Fortum uses different priority measures to prioritise critical work. X work is monitored in the same way as other work requiring operational limits, and the risk analysis covers their effects. STUK estimates that a more detailed analysis of the distribution of X work into different systems could help further develop practices.

The inspection did not result in any requirements presented by STUK.

Chemistry, 12–14 March 2025

The inspection focused on monitoring the water chemistry conditions and activity levels of the primary and secondary circuits of units 1 and 2 of the Loviisa nuclear power plant. The inspection supervised the appropriateness of the laboratory equipment and facilities used for monitoring. The inspection included a verification of sampling at the plant and reviewed the chemistry organisation.

Based on the inspection, the chemistry organisation is able to adequately respond to the plant’s analysis needs and required development tasks. The laboratory located in the controlled area has been extended, but the deployment of the facilities is still ongoing. STUK made an observation regarding the qualification requirements of the substitute in charge of the safety function of the chemistry area described in the plant’s rules of procedure, taking into account in particular water chemistry control competence.

The inspection did not result in any requirements presented by STUK.