The Säteilyturvakeskus (STUK) — Radiation and Nuclear Safety Authority — is the Finnish regulatory authority for nuclear safety, radiation protection, and the use of ionising and non-ionising radiation. It reports to the Ministry of Social Affairs and Health.

Mandate

STUK regulates and supervises:

  • Operating nuclear power reactors at Loviisa (units 1-2) and Olkiluoto (units 1-2, plus OL3 commissioned 2023).
  • The Onkalo deep geological repository for spent fuel, operated by Posiva — the world's first repository to enter regulatory approval and construction.
  • Industrial, medical and research uses of radiation, including dental and veterinary radiography.
  • Natural radiation, particularly radon in homes, drinking water and workplaces.
  • Emergency preparedness and environmental monitoring.

Legal framework

The principal statutes are the Nuclear Energy Act (990/1987 as amended) for nuclear facilities, and the Radiation Act (859/2018) for radiation protection. Implementing regulations are issued by the Government and by the Ministry, with technical detail set out in STUK's own regulatory guides.

STUK's regulatory rules are consolidated in the STUKLEX online publication system. The YVL Guides series provides the binding technical requirements for nuclear-power-plant safety, divided into A (general management), B (plant and systems), C (radiation safety, environment and emergency), D (nuclear materials), and E (structural mechanical).

Onkalo and waste

STUK's technical work on Onkalo has been pivotal internationally. The licence decisions on Posiva's construction (2015) and operating licence (under review) have been closely watched and frequently cited. The Finnish approach uses the KBS-3 method — three engineered barriers (copper canister, bentonite buffer, crystalline bedrock) — shared with the Swedish SKB programme.

International cooperation

Nordic cooperation with SSM (Sweden), DSA (Norway), the Danish authority and Geislavarnir (Iceland) is institutionalised through joint reports and exercises. STUK is active in IAEA, NEA and WENRA.

STUK is widely regarded as a rigorous and transparent regulator with deep technical staff capacity. Its inspectorate culture and openness on YVL drafting have influenced regulator-development programmes elsewhere.