KORAD - Low and intermediate level waste (LILW) consultation

Case description

Fortum and TVO Nuclear Services (TVONS), drawing on Teollisuuden Voima Oy’s (TVO) experience, were contacted to assist KORAD in the process of drafting a periodic safety review (PSR) for KORAD's low and intermediate level waste (LILW) disposal facility. Both Fortum and TVO own and operate a LILW repository at their respective NPP sites in Loviisa and Olkiluoto. Through the planning, construction and operation of these repositories, both companies have gained extensive experience in the area of radioactive waste management and disposal. Furthermore, Posiva Oy - a nuclear waste management company jointly owned by Fortum and TVO - is preparing for the final disposal of spent nuclear fuel in Olkiluoto, making it the first operator in the world to start final disposal of spent nuclear fuel in a geological repository.

Fortum and TVONS consulted KORAD on two tasks: firstly in drafting a guidance document for the LILW repository PSR, and secondly, drafting a document describing the formulation of the waste acceptance criteria (WAC), defining the requirements the waste packages must meet to be accepted for disposal in the repository. 

 

Our approach

Fortum and TVO both operate NPPs and are responsible for managing their own nuclear waste. This has resulted in strong in-house waste management expertise that is directly applicable to international consultancy assignments. In supporting KORAD, Fortum and TVO shared their experience from operating their own waste management and disposal facilities. Consultation was provided on two topics.

 

Consultation on drafting a PSR

Fortum and TVONS delivered the PSR-related consultation by describing what they had taken into account and done when compiling PSRs for their own LILW repositories. The purpose of a PSR for a disposal facility is to evaluate operational experiences, aging management and effects of aging, new technological developments, as well as compliance with the regulatory requirements.

The consultation emphasized that expert support improves the cost efficiency of the project by ensuring the PSR scope is defined appropriately. Internal personnel should be involved in PSR preparation to support knowledge transfer within the organization. The long-term safety case was highlighted as the central part of the PSR, requiring sufficient schedule and resources. Effective coordination with authorities and external contractors, as well as careful project, budget, and resource planning, were identified as key factors for the successful preparation of the PSR.

 

LILW Waste Acceptance Criteria consultation

The consultation derived from the LILW repository waste acceptance criteria (WAC) definition experience of both companies, and included the description of the inventory of the waste to be disposed of. WAC is usually based on international, mostly IAEA recommendations, however details vary between countries. Nuclide-specific activity limits of waste accepted into a repository are part of the WAC. Meeting the defined WAC, including activity limits, ensures safe disposal, both during the operational and the post-closure phases of the repository.

Some final conclusions Fortum and TVONS drew after analysing their respective WAC, were the differences in activity limits between the two companies. At Fortum, the limits were defined focusing on long-term safety, meanwhile the TVO limits were mostly based on the operational safety considerations (i.e., radiation dose received by personnel, transport safety). This variation can be attributed to the different waste treatment and disposal concepts in the two organisations. TVO solidifies relatively fresh liquid waste, which results in relatively high external dose rates. In the Fortum-operated Loviisa NPP, the liquid waste to be solidified is older and packaged into concrete containers, which reduces the external dose rate.

Nuclear operators are responsible for disposing their own waste in Finland, explaining why the Finnish regulations regarding WAC are not very prescriptive and leave room for deriving the activity limits. In many other countries, the limit derivation is more strictly regulated, as nuclear waste disposal is often carried out in a centralized manner. The differences between Fortum and TVONS activity limit derivation offered KORAD a wider approach to waste criteria management.

 

Value added

Fortum and TVONS provided consultation on drafting PSRs and managing nuclear waste in accordance with WAC. The consultation helped KORAD in structuring its PSR process and formulating WAC based on Finnish experiences and practises.

Safe generation of nuclear power requires a robust and credible plan for managing, storing and disposing of radioactive waste throughout the power plant life cycle and after its closure. KORAD sought for assistance in providing documents for the regulatory and general know-how of safely disposing LILW, and Fortum and TVO were able to contribute to the safe generation of carbon-free nuclear power in South Korea.