On-site interim storage facility Obrigheim (Baden-Wurttemberg)

The following brief description (PDF, 1 MB, file is not barrier-free, in German only) as of April 2008, gives an overview of the planned storage of irradiated fuel at the nuclear power plant site.

Values applied for

Background

On 22 April 2005, the then competent licensing authority, the Federal Office for Radiation Protection (BfS) received an application by Kernkraftwerk Obrigheim GmbH (KWO GmbH) for the storage of spent fuel elements in an on-site interim storage facility at the Obrigheim site. On 1 January 2007, EnBW Kernkraft GmbH (EnKK) superseded KWO GmbH as applicant. On 30 July 2016, the licensing authority changed, as well. Since that date, the Federal Office for the Safety of Nuclear Waste Management (BfE) is responsible for the licensing of interim storage facilities for nuclear fuels and continues the procedures taking place.

The storage of altogether 342 spent fuel elements was applied for which originated from the pressurised water reactor of the Obrigheim nuclear power plant which was already shut down in May 2005.

The fuel elements are currently stored in an already existing external wet storage facility on the site. As the external wet storage facility constrains the planned dismantling works of the Obrigheim nuclear power plant, the applicant intends to operate a separate on-site interim storage facility with dry interim storage of the spent fuel elements on the site of the Obrigheim NPP over a period of 40 years at maximum. The EnKK concept provides for the storage of spent fuel elements in altogether 15 transport and storage casks of the CASTOR® 440/84 type.

On the basis of the enclosure concept for the temporary storage facilities the applicant had initially applied for storing the casks in horizontal positions under single concrete enclosures. Since the concept deviates from the realised storage concepts for the interim storage facilities licensed for 40 years on the other nuclear power plant sites (WTI concept or STEAG concept, respectively) the Federal Ministry for the Environment, Nauture Conservation and Nuclear Safety (BMU) requested the Reactor Safety Commission (RSK) at the end of 2006 to provide a statement on this project. This was done upon an initiative of BfS, previously being competent licence authority. In its statement of 12 April 2007 (in German only), RSK stated that several items of the EnKK application were not in compliance with the Safety Guidelines. With letter of 31 October 2007, EnKK then submitted the amended application dated 22 April 2005, to BfS.

Updated planning concept

It is planned to store the nuclear fuel in a storage hall made of reinforced concrete with a loading and storage area. An operational building is attached to the east side of the storage hall. Furthermore, a separate guardhouse (security centre) together with technical equipment for security services is provided for. The Obrigheim interim storage facility is to be designed for self-sustaining operation and is to be operated in a nearly self-sustained way as soon as it has been commissioned, i.e. independently of the Obrigheim nuclear power plant installations.

Section through the planned on-site interim storage facility Source: EnBW Kernkraft GmbH

The building concept for the storage hall of the Obrigheim on-site interim storage facility was at first oriented at the so-called WTI concept relating to the interim storage facilities in southern Germany. With letter of 6 December 2011 (in German only) the EnKK added further details to the application of 22 April 2005 in terms of construction and plant inspection.

In order to meet new requirements in terms of plant security, it is now planned to store the nuclear fuel in a storage hall (ca. 36.6 m long, ca. 19.7 m wide and ca. 19.0 m high) according to the concept of a so-called STEAG storage facility. As opposed to the WTI concept originally provided for with wall thicknesses of ca. 85 cm for the outer walls and ca. 55 cm for the thickness of the concrete roof of the cask storage hall, wall thicknesses of the outer walls and of the concrete roof were increased to ca. 1.2 m in the current plans for the building. Thus, wall thicknesses in the planned on-site interim storage facility Obrigheim now correspond with the wall thicknesses of the interim storage facilities in Northern Germany which was also constructed according to the so-called STEAG concept.

Alternative storage in the Neckarwestheim on-site interim storage facility

Alternatively, the EnKK submit an application to the BfS for the storage of the 342 spent fuel elements from the Obrigheim NPP in the Neckarwestheim on-site interim storage facility with letter of 10 December 2013. The EnKK concept for the storage of the spent fuel elements in altogether 15 casks of the CASTOR® 440/84 mvK type was maintained. A corresponding licence pursuant fo § 6 AtG was granted on 9 August 2016 by the now competent Federal Office for the Safety of Nuclear Waste Management (BfE).

The Neckarwestheim on-site interim storage facility is situated ca. 40 km from the Obrigheim site. On behalf of the EnKK a transport study was conducted on which transport route (road, rail, river Neckar) to use for the transportation of the CASTOR® casks to the Neckarwestheim on-site interim storage facility. The EnKK has come to the conclusion that transport on an inland vessel on the river Neckar should be prioritised. The so-called "Roll-on/Roll-off procedure" with a transport vehicle should be prioritised for loading/unloading the vessel. On behalf of the EnKK, the NCS GmbH filed a corresponding application to the BfS for a transport licence under § 4 AtG on 27 March 2014. This licensing procedure is still pending and has been continued by the BfE which, since 30 July 2016, has also been responsible for the licensing of nuclear fuel transports.

The application for the storage of the KWO fuel elements in the Neckarwestheim on-site interim storage facility underlines EnKK’s consideration to do without the construction of another interim storage facility and to stop using the Obrigheim site as a nuclear site considerably earlier.