During rated power operation, an automatic reactor shutdown occurred due to signal of "Neutron Flux High". As a result of investigation, it was estimated that since fastening of the rotation preventing pin had been insufficient, which had been attached at the connecting part of between a valve poppet and a valve stem in one of the 8 main steam isolation valves (MSIVs). This pin was damaged by vibration caused from steam flow and detached pilot- and main poppets plugged the main steam line causing increased reactor pressure which resulted in "Neutron Flux High". There was no release of radioactive materials outside the reactor facility. Also there was no unplanned occupational exposure of employees working under radiation. BASIS FOR RATING: The occurrence probability of detachment of poppet from a main steam isolation valve is considered being the same as inadvertent closure of an MSIV due to malfunction. Then a real initiator of expected frequency can be assumed for this event. Thus rating of this event by INES resulted in a level-0 using the defence-in-depth criterion. DIFFICULTIES IN RATING: Definition of occurrence frequency of an initiator like such a new event was rather difficult.
Everywhere you look, the nuclear industry’s hype machine is in overdrive. Goldman Sachs, Microsoft, and the UK government all tout small modular reactors as the silver bullet for climate change and energy security. Tech billionaires are hiring nuclear veterans. Wall Street is whispering about “round-the-clock power” for artificial intelligence data centers. For those old enough […]
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Big batteries and EVs to the rescue again as faults with new nuclear plant cause chaos on Nordic grids The Finnish nuclear power plant Olkiluoto was finally connected to the grid last year, at an estimated cost of €11 billion compared to the original budget of €3 billion. That cost blowout forced its developer, the […]
A vast subsea nuclear graveyard planned to hold Britain’s burgeoning piles of radioactive waste is set to become the biggest, longest-lasting and most expensive infrastructure project ever undertaken in the UK. The project [UK's nuclear waste dump] is now predicted to take more than 150yrs to complete with lifetime costs of £66bn in today’s money...The […]
Last year, the Dutch Province of Limburg started an alliance in which, besides the local government, research institutes, small nuclear reactor (SMR) developers, utilities, industrial customers and funders cooperated. With this "Limburg SMR alliance" Limburg tried to lead the way towards an SMR in Limburg. The preferred site for a first SMR would be Chemelot, […]
