Bern, Cofrentes, cooling water, core meltdown, hazard, Japan, loss of coolant, loss of coolant accident, Mühleberg Nuclear Reactor, NRC, nuclear accident, nuclear energy, nuclear meltdown, nuclear reactor, nuclear reactor pressure vessel shroud cracks, nuclear reactors, nuclear regulatory commission, nuclear safety, reactor pressure vessel, reactor pressure vessel shroud, reactor pressure vessel shroud cracks, risk management, shroud cracks, shroud defects, Spain, Sweden, Switzerland, Taiwan, US, warning
The Mühleberg Nuclear Reactor, near Bern Switzerland, powered down automatically (SCRAM), due to a problem with the water feed system at 11 am on Monday, July 6, 2015. The level of water in the reactor pressure vessel briefly dropped. This was caused by a problem with the water feed system. The reason for the problem is still being analyzed, according to ENSI. http://www.ensi.ch/fr/2015/07/06/centrale-nucleaire-de-muehleberg-arret-automatique-du-reacteur-en-raison-dun-derangement-dans-le-systeme-dalimentation/
Was this somehow caused by the heatwave in Switzerland? Was it caused by Mühleberg’s cracked reactor pressure vessel shroud, whose cracks have been growing since first found in 1990? A pump failure?
Whatever the cause, this incident is a reminder. It is like the banshee keening a warning sign of pending death, while washing the shroud of those about to die. It is the bell tolling a warning – these shroud cracks are so widespread, that the death bell may indeed be tolling for thee.
Mühleberg has had a cracked nuclear reactor shroud since 1990, but many nuclear reactors were found to have cracks in their shrouds in the 1990s. While the French call it an envelope and the Germans call it a coat or cloak, in English it is aptly called shroud.
The nuclear reactor shroud is important for flow of the coolant, but also could cause misalignment, which prevents control rods from being inserted. Thus, cracking could eventually lead to a nuclear meltdown-disaster.
Similarly, the graphite keyway root cracks found at the nuclear reactor near Glasgow Scotland, are a bell of warning: “Serious distortion of the graphite core due to cracking could prevent the insertion of control rods, which are essential for safety and are used to shut down the reactor in an emergency.” http://www.bbc.com/news/science-environment-29481481 “New cracks in Hunterston reactor“, By Rob Broomby, BBC News, 6 October 2014 Hinkley B, Hartlepool and Heysham all have cracks in their graphite, which could prove deadly, and will if they are not shut down in time.
“The U.S. Nuclear Regulatory Commission (NRC) points out in their report that cracks that completely penetrated the shroud affect the flow of water coolant during regular operation, which could lead to a disruption of the coordination of power output and the water flow (NRC, 1996). Also, the NRC warned that significant problems concerning safety could be triggered when the shroud is demolished and separated due to the pipe rupture accident at the main steam pipe or recirculation pipe, which disrupt the function core spray system and control rod drive,” warns the Japanese CNIC. Read the rest and more here: http://www.cnic.jp/english/newsletter/nit92/nit92articles/nit92shroud.html (There is a good image at this link, too.)
According to the NIRS, “The core shroud is a large stainless steel cylinder of circumferentially welded plates surrounding the reactor fuel core. The shroud provides for the core geometry of the fuel bundles. It is integral to providing a refloodable compartment in the event of a loss-of-coolant-accident. Extensive cracking of circumferential welds on the core shroud has been discovered in a growing number of U.S. and foreign BWRs. A lateral shift along circumferential cracks at the welds by as little as 1/8 inch can result in the misalignment of the fuel and the inability to insert the control rods coupled with loss of fuel core cooling capability. This scenario can result in a core melt accident. A German utility operating a GE BWR where extensive core shroud cracking was identified estimated the cost of replacement at $65 million dollars. The Wuergassen reactor, Germany’s oldest boiling water reactor, was closed in 1995 after wary German nuclear regulators rejected a plan to repair rather than replace the reactor’s cracked core shroud.” http://www.nirs.org/factsheets/bwrfact.htm
Some things were written by the US NRC about the Nuclear Shroud problem in the 1990s and as late as 2005. For instance:
“NUREG/CR–6891 ANL–04/20 Crack Growth Rates of Irradiated Austenitic Stainless Steel Weld Heat Affected Zone in BWR Environments Manuscript Completed“: August 2004 Date Published: March 2005 Prepared by O. K. Chopra, B. Alexandreanu, E. E. Gruber, R. S. Daum, and W. J. Shack Argonne National Laboratory” http://www.ipd.anl.gov/anlpubs/2005/03/52654.pdf
There apparently used to be an EU list of cracked nuclear shrouds: http://www.dailykos.com/story/2011/03/15/956586/-Whistleblower-Expose-of-GE-Inspection-Coverup-RARE-EU-Authored-US-BWR-Damage-Report
However, the only list of nuclear reactors with cracked shrouds remaining online appears to be one by the Swiss anti-nuclear group, Fokus Antiatom from 2008.
However, the nuclear shroud cracking problem appears to have been privatized, with the EPRI deleting valuable information and claiming that it is “proprietary information”, even though it deals with public safety! Is this to better shroud it in secrecy? The EPRI is a front group, cloak, for the utilities.
One has to wonder why this document was even published, since almost all of the pages look like this!
“BWRVIP-174NP, Revision 1: BWR Vessel and Internals Project Review of BWR Core Shroud UT Re-Inspection Results for Plants Mitigated with NMCA, OLNC, and HWC EPRI, Palo Alto, CA: 2009. 1019062NP Final Report“, August 2009 ORGANIZATION(S) THAT PREPARED THIS DOCUMENT General Electric Hitachi Nuclear Energy Alliance http://pbadupws.nrc.gov/docs/ML1002/ML100201037.pdf
German wiki on Mühleberg,which is more detailed than the French or English one: https://de.wikipedia.org/wiki/Kernkraftwerk_Mühleberg
See 2002 report in German here: http://static.ensi.ch/1312877809/psu_muehleberg.pdf http://www.ensi.ch/en/dossiers-3/muehleberg-core-shroud/fissures-in-the-muehleberg-core-shroud/
More than anything else, nuclear reactors and nuclear weapons show that we are dangerously connected, and woven into a common tapestry of destiny:
“No man is an island, entire of itself; every man is a piece of the continent, a part of the main. If a clod be washed away by the sea, Europe is the less, as well as if a promontory were, as well as if a manor of thy friend’s or of thine own were: any man’s death diminishes me, because I am involved in mankind, and therefore never send to know for whom the bell tolls; it tolls for thee“. From “Meditation #17 By John Donne From Devotions upon Emergent Occasions (1623), XVII“: https://en.wikisource.org/wiki/Meditation_XVII.
Additional interesting sites-documents re aging of reactors:
There may still be a list at this link, but finding it may take effort: http://safelife.jrc.ec.europa.eu Summary of the problems with aging nuclear reactors, including cracked shrouds: http://www.oeko.de/oekodoc/2217/2014-757-en.pdf