Clogged suction strainer

from Wikipedia, the free encyclopedia

The clogging of the suction screen is a safety problem in water-cooled nuclear power plants that was discovered in 1992 .

In that year, the following incident occurred at the Swedish Barsebäck nuclear power plant : Due to a technical malfunction, a single valve opened unintentionally, which is normally used to relieve the pressure in the reactor system. The longer open position led to a certain pressure build-up in the containment , which automatically led to the activation of the containment spray system in order to reduce the pressure. The water jet forces created with the open valve unexpectedly caused the detachment of around 200 kilograms of insulating materials that were structurally adhering to the pipelines. These were rinsed through transfer pipes into the so-called condensation chamber filled with water, where they were also sucked in by the water-sucking pumps of the spray system mentioned. They stuck to the grille that was supposed to protect the suction openings of the pumps against blockages. However, these so-called suction strainers turned out to be much too small to stop the sucked in materials in such a way that there was still enough free suction surface for each pump. The pumps could only suck in too little or no more water, they failed to perform the intended service. However, this had no negative consequences in Barsebäck.

All over the world, however, the specialist committees came to the conclusion that this problem could manifest itself in a more serious emergency cooling case in insufficient core cooling and thus core meltdown . In most places around the world it was decided to a. to massively enlarge the suction strainers in the sumps ( pressurized water reactors ) or in the condensation chambers ( boiling water reactors ) and to make them more closely meshed.

These conversions took place from the 1990s and are z. Partly still going on. The factories ran unnoticed for decades with a deficiency in the emergency cooling system, which could have been disastrous in the event of a major leak in the reactor system. The fact that this never happened suggests a relatively good preventive quality control of the metallurgy of the pipelines.

swell

  • HSK : Experience and research report 2005, chap. Instructive occurrences abroad
  • Advisory Committee on Reactor Safeguards (ACRS, USA): Minutes of a meeting on the problem of sump screen clogging at the Wolf Creek nuclear power plant