PORA tertial report 1/2023

In the first third of 2023, STUK continued to process Posiva's operating licence application material. STUK stated that not all of the material delivered to STUK fulfilled the requirements set for the operating licence application material.

As the processing progresses, STUK will prepare requests for clarification concerning the incomplete materials to Posiva, on the basis of which Posiva must update the materials and resubmit them to STUK for processing. In the first third of the year, STUK sent requests for clarifications on the final safety analysis report and the assessment of the safety case concerning long-term safety.

STUK found shortcomings especially in the system descriptions of the final safety analysis report. In the final safety analysis report, Posiva must present information on nuclear facilities that describes the facilities before the start of nuclear fuel encapsulation. At present, some of the information presented does not describe the final facilities, but rather how they are designed. In addition, STUK observed that the final safety report did not present in sufficient detail all the information that STUK requires to be presented in the final safety report on the basis of the YVL Guides. The requirements set out in the request for clarification relate to the supplementing of these matters.

When inspecting the assessment of the safety case concerning long-term safety prepared by Posiva, STUK made some inspection observations and remarks on the basis of which STUK requires additional information. In the first request for clarification, STUK asks questions concerning, among other things, the initial state after the closure and related deviations as well as the long-term behaviour of the system. STUK has also initiated the preparation of the next request for clarification concerning the safety case in the first third of the year.

During the first third of the year, Posiva was manufacturing, installing and commissioning the systems needed for encapsulation and final disposal. The encapsulation and final disposal facility requires lifting and transfer equipment to transfer spent nuclear fuel and the transfer container or capsule containing spent fuel. STUK has reviewed the construction plans of these lifting and transfer equipment.

STUK also oversees the manufacture of lifting and transfer equipment. STUK has carried out construction inspections for equipment whose manufacture has progressed sufficiently. The inspections verify that the construction has been carried out in accordance with the plans and approved manufacturing methods.

The commissioning of the Posiva nuclear facility involves the testing of systems. With these tests, Posiva ensures that the systems function as planned. Some of the systems are safety-classified, which means that their operation is essential for nuclear and radiation safety. STUK oversees the test runs of such systems, reviews the commissioning testing plans for the systems and monitors test runs on site. During the first third of the year, Posiva carried out the first safety-classified system test run. Plans for the following test runs are being processed by STUK.

STUK carried out two inspections as part of the construction inspection programme, the first of which focused on the management of changes in Posiva's project and organization for operational purposes. Based on the inspection, Posiva's change management procedures appear to be appropriate and mainly meet the relevant safety requirements. The organizational change related to the transition to the operating phase is significant from the point of view of safety, and Posiva will prepare an assessment of the impact of the organizational change on safety. The requirement issued by STUK during the inspection concerns the procedures for the assessment of a future organizational change.

The second inspection of the construction inspection programme focused on the operating instructions of Posiva's nuclear facility, the training of plant operators and the management of human factors. The inspection found that Posiva is still in the process of drafting the operating instructions for the nuclear facility and the procedures necessary for their management.

The inspection showed that the approval procedures for the operators of the Posiva nuclear facility are not fully completed. STUK monitors the development and completion of the approval procedures. The inspection covered the management of human factors in planning as well as the improvement and monitoring of the reliability of human activities. The inspection found that Posiva's plan for integrated system validation does not sufficiently include disturbances and emergencies. During the inspection, STUK made a request to rectify the matter.