Krško completes IAEA review of long-term operation

Krško, a 696 MWe Westinghouse pressurised water reactor, is Slovenia's only nuclear power plant and generates about one-third of its electricity. The plant, which is co-owned by neighbouring Croatia, began commercial operation in 1981, and a 20-year extension to its initial 40-year operational lifetime was confirmed in mid-2015. NEK plans to extend Krško's operations until 2043.

A SALTO peer review is a comprehensive safety review addressing strategy and key elements for the safe long-term operation (LTO) of nuclear power plants. LTO of nuclear power plants is defined as operation beyond an established time frame determined by the licence term, the original plant design, relevant standards, or national regulations.

SALTO missions complement IAEA Operational Safety Review Team (OSART) missions which are designed as a review of programmes and activities essential to operational safety. SALTO peer reviews can be carried out at any time during the lifetime of a nuclear power plant, although according to the IAEA the most suitable time lies within the last 10 years of the plant's originally foreseen operating period. SALTO and OSART reviews are carried out at the request of the IAEA member country in which the review is to take place.

On 4-14 October, a ten-person team - comprising experts from Belgium, Hungary, Pakistan, Spain, Switzerland, the UK and three IAEA staff members - reviewed the Krško plant's preparedness, organisation and programmes for safe LTO.

The team identified good practices and good performances that will be shared with the nuclear industry globally. These included: the plant has a well-structured and comprehensive programme of proactive and reactive activities for the ageing management of the safety related cables; the plant has set up an efficient intranet portal which offers all staff access to relevant management applications, programmes, documents, procedures, data and records; and the plant's Steam Generator Ageing Management Programme demonstrates a strong commitment to excellence and several activities under this programme exceed international safety standards.

The team also provided recommendations to further enhance the preparations for LTO safety, including: the plant should ensure detailed planning for the management of the third periodic safety review to begin in 2022 in support of LTO preparation; the plant should complete the ageing management reviews of structures, systems and components; and the plant should implement effective knowledge management in support of LTO.

"We observed that the operator is implementing preparations for safe LTO in a timely manner," said team leader and IAEA Nuclear Safety Officer Martin Marchena. "A number of ageing management and LTO activities already meet IAEA safety standards. The SALTO team encourages the plant to address the review findings and progress with the implementation of all remaining activities for safe LTO."

Stane Rožman, President of the Krško Management Board, said: "We appreciate the IAEA's support to our plant in ageing management and preparation for safe LTO. The results of this mission will help us to improve our activities for safe LTO and to further align them with IAEA safety standards."

The team provided a draft report to the plant management and to the Slovenian Nuclear Safety Administration (SNSA), the country's nuclear regulatory authority, at the end of the mission. The plant management and SNSA will have an opportunity to make factual comments on the draft. A final report will be submitted to the plant management, SNSA and the Slovenian government within three months.