ENSI subsumes events and findings under the term incidents. Both incidents with implications for nuclear safety (art. 21 para. 1 NEO and art. 38 para. 3 let. a and c NEO) as well as incidents of public interest (Art. 38 para. 3 let. b NEO) must be reported. The latter includes incidents on the site of the nuclear plant that are perceptible from outside of the plant regardless of whether they are significant in terms of nuclear safety.
Events in Swiss Nuclear Power Plants
As a measure following on from the reactor accident at Fukushima, Japan, ENSI ruled on 1 April 2011 that the Swiss nuclear power plant operators must furnish proof of their ability to control a very unlikely extreme flood, and must do so by the end of June 2011. In order to provide this proof, the […]
A faulty resistor on an electronic card led to the failure of a module in the turbine control system. As a result, the control dampers on the low pressure turbines closed slowly. According to its design, the plant reacted by shutting down the turbines and automatically reducing the reactor power to 67% by inserting control […]
During a function test on the high pressure core spray (CS) system, a thin jet of water was detected. This jet emerged from a weld seam on a small-bore pipe leading to a safety valve. The function test was interrupted, and the affected section of the small-bore pipe was replaced within the permissible time for […]
A few days ago, Leibstadt Nuclear Power Plant (KKL) informed the Swiss Federal Nuclear Safety Inspectorate (ENSI) that some fuel elements do not fulfil the requirements of the applicable specifications. Accordingly, KKL decided to replace them for safety reasons. The safety of man and the environment was ensured at all times.
An inspection of fuel elements in Leibstadt NPP revealed that critical boiling states – so-called dryouts – had systematically occurred over several cycles.