Facts

Parties and procedural history: Axpo Power AG operates the Beznau nuclear power plant (KKB) with two reactor units. Following the accident in Fukushima in March 2011, the Swiss Federal Nuclear Safety Inspectorate (ENSI) required the operator to review the design of the KKB. The subject of the deterministic safety proof was whether, in the event of a 10'000-year earthquake and its combination with earthquake-induced flooding, core cooling and the safety of the fuel element storage pools remain assured with single-failure tolerance and whether radiation exposure does not exceed the dose limit of 100 mSv.

Administrative act: Axpo Power AG submitted the safety proof on 30 March 2012. On 7 July 2012 ENSI drafted a file note stating that the proof had been fully provided and that no immediate provisional shutdown was indicated. On 13 July 2012 ENSI published an article in which it described the 10'000-year earthquake as 'the most extreme earthquake that must be considered' and assigned it to incident category 3 with a limit of 100 mSv. On 19 August 2015 the applicants, residents in emergency planning zone 1, requested the issuance of a ruling on factual acts. By ruling of 27 February 2017, ENSI determined that the acceptance of the deterministic proof was lawful.

Prior instance: The applicants appealed to the Federal Administrative Court, which by judgment of 22 January 2019 (A-1969/2017) dismissed the appeal insofar as it was admissible, imposed the procedural costs on the applicants and set a party compensation of CHF 60'000.-- in favour of Axpo Power AG. The prior instance based its non-entry on the request for immediate provisional shutdown on a lack of current legal interest in protection, alternatively on a substantive dismissal.

Before the Federal Supreme Court: The applicants requested annulment and a finding that the conduct of ENSI was unlawful, an order for provisional shutdown, and alternatively a new comprehensive deterministic proof for a 10'000-year (and slightly more frequent) earthquake with a dose limit of 1 mSv. Axpo Power AG and ENSI requested dismissal. The Federal Administrative Court and the DETEC waived submission of observations.

Points at issue: (1) standing and current legal interest in protection; (2) subject matter of the dispute and specificity of the requests; (3) applicable intertemporal law (old law at the time of the factual act or new law as of 1 February 2019); (4) dose limit for incidents resulting from a 10'000-year earthquake (1 mSv under Art. 94 para. 4 old RPO 2005 or 100 mSv under Art. 94 para. 5 old RPO 2005); (5) ENSI's duty to demand a proof for incident category 2; (6) requirements for immediate provisional shutdown under Art. 3 AusserbetriebnahmeV; (7) consequences as to costs and compensation, taking into account the Aarhus Convention.

Standing and legal interest in protection: Standing to appeal was affirmed, as a majority of the appellants live in emergency planning zone 1. The current practical interest was affirmed despite alleged retrofits, since the newly required incident analyses had not yet been submitted to and reviewed by ENSI. With regard to the request for shutdown there is a formal denial of justice (Art. 29 para. 1 Cst.), so that standing exists independently of the legal interest in protection.

Subject matter and specificity: New requests are inadmissible (Art. 99 para. 2 FSCA). The request for a declaration relating to Art. 123 para. 2 lit. c and d RPO corresponds in substance to the request before the prior instance and is admissible. Requests no. 3, 5 and 6, as well as the request for future abstention, were not assessed for lack of specificity (Art. 42 FSCA).

Considerations

Applicable law: The Federal Supreme Court holds that, in the absence of transitional provisions, the law in force at the time the factual act or ruling was issued is in principle decisive (issuance of the ruling on 27 February 2017). The amendments to the ordinances as of 1 February 2019 contain no transitional provisions. For the question of the lawfulness of the 2012 safety proof, the law valid when the ruling was issued is therefore decisive; the new requirements are relevant only for a proof that may newly be requested. Whether the new ordinance law conflicts with higher-ranking law is not examined.

Interpretation of the dose limit: The wording of Art. 94 paras. 4 and 5 old RPO 2005 is unclear, as incidents with a frequency of 10-4 per year cannot be clearly assigned either to para. 4 or to para. 5. The historical element indicates that the 10'000-year earthquake has always been assigned to the highest incident category (category 3), and that the ordinance-maker did not intend a reclassification through codification. Teleologically, the graduation of dose limits according to frequency is justified, whereby rarer events justify a higher radiation exposure. Systematically, Art. 94 para. 5 old RPO without assignment of the 10'000-year earthquake to category 3 would have no practical scope of application, as rarer earthquakes were not known. The 10'000-year earthquake is therefore to be assigned to incident category 3 with a limit of 100 mSv.

Fulfilment of the proof and duty to a second proof: The determined dose values were above 1 mSv but below 100 mSv, so that ENSI correctly considered the proof for category 3 to have been provided. Nevertheless, under the principle of the covering spectrum (Art. 1 lit. e Hazard Assumptions Ordinance), ENSI should also have required a safety proof for an earthquake with a frequency representative of incident category 2 and the limit of 1 mSv. A proof for category 3 is not readily conclusive as to compliance with the lower limit of category 2. The omission constitutes an exercise of technical discretion contrary to federal law, as ENSI insufficiently performed its supervisory duty under Art. 70 para. 1 lit. a NEA.

Provisional shutdown: Under Art. 3 Shutdown Ordinance, immediate provisional…