Twenty years of dry interim storage of spent nuclear fuel (SNF) in Germany- History and developments - 15575

Conference · Wed Jul 01 00:00:00 EDT 2015

OSTI ID:22824440

Gastl, Christoph; Palmes, Julia ^[1]

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1. Federal Office of Radiation Protection (Germany)

According to article 6 of the German Atomic Energy Act, storage of nuclear fuel requires a license granted by the competent authority in this field, which is the Federal Office of Radiation Protection. In 1983 a license to store spent nuclear fuel (SNF) and later expanded for vitrified high level waste (HAW) for the interim storage facility in Gorleben was granted. Dry Interim storage at the NPP sites in its actual form started in 2002 in the interim storage facility next to the NPP Lingen. Since this time each NPP erected its own storage facility and three central storage facilities have been built. All of these facilities use dry storage in metallic casks. The actual storage licenses for SNF and the HAW (which is stored in Gorleben and Rubenow) are limited to 40 years starting with the first cask emplacement. As no opening of the cask is intended during the storage period the condition of the inventory and the cask before loading has to be known in detail. This requires for instance detailed knowledge of the history of the SNF loaded as well as supervision of the manufacturing process of the cask. Within the last twenty years several mishaps influenced the regulatory point of view. During a loading campaign in a boiling water reactor traces of pool water remained in the gasket slot and during the drying procedure crystalline boron salts prevented the required tightness. After that event a long-term experiment was started and is still going on which studies the effects of water and minor damages to the gasket. As well changes in the loading procedure have been introduced. The pressure switch used to monitor the pressure in the space between primary and secondary lid has a self surveillance function. This indicated a malfunction 23 times in the last twenty years. Examinations of all events indicated no systematic failure, but a weak point seems to be the plug-in connection. The manufacturer introduced some modifications to improve the system. Introduction of FEM methods in safety analysis to amend the existing methods of testing allowed a new view on and in the cask safety analysis. Progress in this field is closely connected to the available computing capacity and stipulates experts to ongoing improvement. After expiring of the storage license which will be the case for the first cask loaded in 1992 and stored in Ahaus 2032 an extension or a new license can only be granted if the at this time relevant requirements are met. This will require detailed knowledge about the happenings and accidents during the previous storage period. All experience of the periodic safety assessment (PSA) which started in 2013 and accompanying experiments conducted till now and during the licensed storage time will be needed. (authors)

• Research Organization: WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
• OSTI ID: 22824440
• Report Number(s): INIS-US-19-WM-15575; TRN: US19V1012069486
• Resource Relation: Conference: WM2015: Annual Waste Management Symposium, Phoenix, AZ (United States), 15-19 Mar 2015; Other Information: Country of input: France; 2 refs.; available online at: http://archive.wmsym.org/2015/index.html
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ATOMIC ENERGY ACT
BORON
DRY STORAGE
FAILURES
FEDERAL REPUBLIC OF GERMANY
GASKETS
GORLEBEN SALT DOME
HIGH-LEVEL RADIOACTIVE WASTES
INVENTORIES
LICENSES
LINGEN REACTOR
MONITORING
PRESSURE MEASUREMENT
RADIATION PROTECTION
RADIOACTIVE WASTE STORAGE
RISK ASSESSMENT
SAFETY ANALYSIS
SPENT FUEL CASKS
SPENT FUELS
STORAGE FACILITIES
VITRIFICATION