Shortly before 0300 EST, on 30 January 1996, operators at the Wolf Creek Generating Station received indication of decreasing water levels in the Circulating (CW) and Service (SW) Water pump intake structure and started both Essential Service Water (ESW) pumps. The decrease in water level was caused by the formation of ice on the intake travelling screens. At 0437 operators manually tripped the reactor from 80% power in anticipation of the need to trip the CW pumps. Following reactor trip, five control rods failed to fully insert, (10 to 29 cm out). This failure to fully insert did not directly affect the event, but it did complicate the operator's response. Decay heat was removed through the steam generators using the atmospheric relief valves with feed from the Auxiliary Feedwater pumps. At 0614 the turbine-driven Auxiliary Feedwater pump was secured and declared inoperable due to a shaft gland leak. At 0847 the "A" ESW pump was secured due to low ESW pump intake level caused by the formation of "Frazil" ice below the surface of the water on the intake trash rack. Although the "B" ESW train remained in operation throughout the event, there were several occasions when the "B" ESW pump intake water level decreased to a level that threatened to render this pump inoperable as well. Justification: the manual reactor trip and loss of the Main Condenser following the imminent loss of the Circulating Water pumps resulted in initiation of the safety related Auxiliary Feedwater System. Core cooling with the Motor-driven Auxiliary Feedwater pumps (after the turbine-driven auxiliary feedwater pump was declared inoperable) was dependent upon either the ESW system (provides emergency diesel generator cooling) or offsite power. Offsite power remained available through the event. The "B" ESW train and one SW pump remained in operation throughout the event. The SW pump could also have been used to supply ESW loads. In addition, the plant had sufficient make-up inventory and a diesel driven fire pump that could have been used to feed the steam generators if necessary. Based on Severity Classificaiton Criteria for Degradation of Defense in Depth with an initiator (Table II), this event would be rated a level 1/2. However, there are additional factors that were considered. Taken together, these additional factors justify rating the event as a level 2. The first addional factor was the common cause failure potential introduced by the "frazil" ice phenomena. The second factor was that a control room operator did not align the ESW system in accordance with the operating procedure which resulted in a decrease in flow through the ESW pump intake structure warming lines. The decrease in warming flow was a contributor to the loss of the "A" ESW train and the potential loss of the "B" ESW train due to "frazil" ice buildup on the trash racks early that morning. On-site and off-site impact criteria were not relevant for this event.
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, […]
From the IPFM: During a visit to the Civaux nuclear power plant on 18 March 2024, France's Minister of the Armed Forces unveiled a plan to use the plant to produce tritium for the French nuclear weapons program. Civaux is a civilian power plant that belongs to and is operated by Electricité de France. According […]
An analysis by the Norwegian NGO Bellona of transborder trade operations with the customs code 840130 (irradiated fuel assemblies or fuel elements) show a more than twofold increase of import to EU countries of fresh nuclear fuel in cash terms – from 280 million Euros in 2022 to 686 million Euros in 2023. In physical […]
The French government has said it is "seriously" studying the option of building a plant to convert and enrich reprocessed uranium to cut its reliance on Russia following the invasion of Ukraine. The only plant in the world that currently converts reprocessed uranium for use in nuclear power plants is in Russia. "The option of […]