Client: RWE AG
Location: Mülheim-Kärlich NPP, Rhineland-Palatinate
Structure: Natural draft cooling tower, height: 162 m
Project time frame: as of 2004
The dismantling of the 162-meter-high cooling tower of the former Mülheim-Kärlich nuclear power plant is a special project in our company history so far.
The plant is located north of the city of Koblenz and is being dismantled as of summer 2004.
As ARGE Rückbau Kühlturm Mülheim-Kärlich, the company Mittelsdorf Erdbau-Abbruch-Recycling began the selective dismantling of the natural draft cooling tower in early 2017, together with long-term business partner MB Schornstein- und Betonabbruch GmbH & Co. KG.
This project also formed the basis for the merger of the two companies into MB Spezialabbruch GmbH & Co.KG.
The dismantling of the cooling tower presented a new technical challenge. Due to the immediate vicinity of plant components that are under nuclear supervision and the close proximity to high-frequency Deutsche Bahn railroad tracks, there was also a heightened need for safety. Taking this into account, we cooperated with our project partners to develop special selective demolition technology which renders the use of explosives obsolete. Instead, specially designed demolition equipment was used. This technology is unique in the world and ensures a high level of efficiency and safety in the dismantling of cooling towers.
The demolition of the cooling tower at the Mülheim-Kärlich nuclear power plant was carried out in two phases.
Phase 1: Dismantling via RDB 100
Our specially developed and patented special demolition device, the RDB 100, was used in the first dismantling section. This was the first time that the “M A M A © ” process developed by us was used as a dismantling method for natural draft cooling towers. In this context, the abbreviation MAMA stands for: M aschinelles, Automatisiertes, Mannloses, Abbruch-Verfahren (machine-based, automated, unmanned, demolition process).
The goal of the first demolition phase was to reduce the cooling tower from its original height of 162 m to a height of approx. 80 m.
To accomplish this, a special, redundantly designed height access system was first installed on the outer shell of the cooling tower to ensure safe access for the operating personnel. Then our special demolition equipment was positioned on the edge segment of the cooling tower using a lifting construction specially developed for this purpose.
The machine was operated remotely via radio. The operators were standing on the corresponding working platforms. With the attachment connected to the boom of the machine, the successive dismantling of the cooling tower edge segment began.
The RDB 100 has a special design that allows it to move safely along the cooling tower wall, which is comparatively very narrow at approx. 16 cm.
Phase 2: Conventional demolition with remote controlled demolition equipment
The goal of the second demolition phase was the controlled collapse by targeted compression failure of the load-bearing column structure of the remaining approx. 80-meter-high residual structure. To accomplish this, the cooling tower shell was first prepared by creating slots in the geometry and position specified by the structural engineer using a special sawing technique. Remote-controlled, specially designed demolition equipment was then used, which, equipped with chisels and demolition shears, demolished 16 of the total of 72 supports at the bottom of the cooling tower in a predefined sequence. These measures eventually weakened the structure of the cooling tower to such an extent that a targeted structural failure occurred in a precisely pre-planned manner.
Even during this phase of the demolition, the safety of the operating personnel and the project participants was ensured thanks to our innovative procedure and parallel process scenarios that were considered and implemented, as it was completely unnecessary for people to remain in the safety area.
Controlled collapse of the cooling tower from different angles