Prior to the event the plant was operating stable at 100% power, generator output was 647MWe. All operating parameters were stable and inside the normal operating range. All safety and other significant components were operable; all Protection and Control systems were in function. In progress was a surveillance test according to procedure SMI-4.050, Surveillance Actuation Logic Test SSPS Train B. According to this procedure Reactor Bypass Trip Breaker B was closed. After the simulated signal for Pressurizer High Pressure Trip, Reactor Trip Breaker B opened as it was expected. According to the procedure the breaker was closed again. A few minutes later, the operator noticed indication on the MCB, that the Reactor Trip Breaker B is opened again. As the Reactor Bypass Trip Breaker B was still closed there was no automatic reactor trip. The test was stopped. The breaker was closed manually, and Main Control Room crew decided to perform retest of the breaker. The simulation of the reactor trip signal was performed once more, but the breaker did not open.Further analysis discovered damage to the Undervoltage Card (UV Card) of the Reactor Trip Breaker train B. After precise checking of the UV Card it was found out that the output transistor, which controls current through the undervoltage coil was damaged. A short circuit between the base and collector was found, while the emitter was disconnected. Short-circuited transistor caused the resistor, which is connected to the emitter side of the transistor to burn up, so undervoltage coil stay energized, which caused malfunction of the Reactor Trip Breaker. After the UV card was replaced the test was successfully repeated
.JUSTIFICATION OF RATING Section IV-3.2.1.3(b) Events without a real initiator (New Draft Manual). Assuming that the defect had led to an initiator this would be the reactor trip. Safety functions Within Operational Limits and Conditions. Level 0.
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 […]
Kernenergie en veiligheid: A wargame sought to test if a major radiological release that would prompt the evacuation of millions of civilians in South Korea could distract key US allies from assisting and rebuffing an all-out military invasion of Taiwan. The short answer was yes. The game originally presumed that China, wanting to keep the […]
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, […]
