20 member countries participate at CERN (European Organization for Nuclear Research) in the Swiss canton of Geneva; about 3.200 employees are working there and more than 10.000 guest scientists from 85 nations carry out experiments in the highly renowned research institution. In 2010 the annual budget of CERN amounted to approximately 850 million Euros. An outstanding project is investigation of the smallest building blocks of matter by means of large-scale particle accelerators. Latest technology and reliable work have top priority here.
After the invitation to tender of the crane refurbishment project in June 2012 and the bidder’s conference that took place afterwards BRUNNHUBER Cranes with company locations in Augsburg and Berlin was awarded the contract and could prevail over the competition. Contracts from CERN are not just sought-after prestige projects for crane manufacturers from all over the world, but first of all technically ambitious tasks requiring the maximum level of know-how and planning competence.
Six weeks of crane reconstruction in underground facility for radiation research
The crane experts from BRUNNHUBER cranes have been on site in total six weeks, from the middle of December until the end of January 2013, to restore the double girder overhead travelling crane completely and to install new tailor-made technology. The confined space required meticulous precision work. Comprehensive safety requirements had to be observed.
The complicated works took place in hall ECN 3 which is a cavern on the French side of CERN. It is the only place where experiments with primary proton radiation of high intensity may be carried out. The hall that is accordingly secured is equipped with valuable measuring technology and there are pipes threaded through it. The double girder OET crane is located in a narrow area of 16 x 100 meters in the hall with total length of 270 m (ECN 3 + TCC 8).
Due to the architectural conditions the BRUNNHUBER experts had to work with millimeter-level accuracy from the beginning. For dismantling of the old trolley they had for example only a space of 100 mm to the top. The component that was to be replaced was disassembled into its constituent parts and removed successively. Only 15-20 mm of space remained on both sides for installation of the new open winch trolley and for lifting it up with the shorter side facing the front by moving it between the endcarriages. Above the beams the trolley frame was turned by 90 degrees and it was positioned with its longitudinal side. With the second hoisting movement the complete hoisting unit consisting of rope drum, hoisting gear and motor was lifted and assembled.
For disassembly and reassembly the crane specialists used a 6 tons spider crane with electrical caterpillar drive. Furthermore two articulated telescopic working platforms were used.
Refurbishment and modernization of the special crane with span of 15,5 m included a capacity increase from 40 to 45 t. Due to the structural conditions of the building an ultra slim design (width 2275 mm, length 3705 mm) of the special open winch trolley was necessary.
In addition to that the crane was equipped with a completely new control technology incl. frequency converters allowing load dependent hoisting speeds from 0,1-10 m per minute (max. weight 10 t) and 0,4-4 m per minute (max. weight 45 t). The existing 2,5 t monorail auxiliary hoist was integrated into the new crane control. A second radio remote control serves as emergency control. A bypass switch was installed allowing movement of the crane in the “safety zone” (detour control) in creep speed mode. The radio remote control now replaces the old pulpit that has also been disassembled on the construction site.
As the crane runways were overlapping, the modernization works included the detour control positioned at one end of the hall and as well an anti-collision device of redundant design in the area of the overlapping crane rails as protection against the neighbored crane.
A new crane platform with foldable, self-locking and electronically monitored ladder as access to the crane from the walkway situated underneath the crane runway was constructed in compliance with the required safety distances and it was installed on site.
In order to replace the old cable carrying system of the crane’s main power supply the existing cables with length of several kilometers had to be cut into segments of 1 meter length for being removed and for being put finally into the container for disposal.
High safety standards for handling with components and for assembly works
After crane refurbishment the safety-oriented crane control system had to work in accordance with category 2 with performance level “D”. For the individual components consistent CE conformity was required. As the crane is located in a controlled area for radiation protection BRUNNHUBER also had to prove certification in compliance with ISO 9001and had to produce evidence of having received the radiation protection admission of the Bavarian Environment Agency (§ 51 Radiological Protection Ordinance) – including person-related radiation passports.
In order to receive the authorization for access to the cavern, among other things the BRUNNHUBER assemblers had to substantiate the respective precautionary medical examination and their professional qualification and they had to pass a special safety instruction and a workshop carried out by CERN rounded off with a test. During the works sometimes the so called „Bio Cell“ (an escape hood) and dosimeters for detection of possible radiation had to on available.
The access to the research cavern was granted via a turnstile sluice with control of persons. Technical equipment and components had to pass the materials sluice for clearance measurement in order to exclude the possibility of exposure to radiation. All works were accompanied by the security staff of the Research Center.
Challenging logistics and successful final reception
Before being able to start working on site the BRUNNHUBER crane experts had to concentrate on exact technical planning and preparative logistics. Different disciplines had to be coordinated; small time slots had to be respected. It simply is a fact that the room for maneuvers in an underground high security area has its particular qualities and challenges. The equipment and components had to be unloaded from overhead via a shaft and then they had to be transported by auxiliary draisine to the spider crane at the place of activities. All planning processes had to fit together smoothly. And this is what happened finally.
With the same success the completely renewed crane passed the final reception test carried out by CERN and the DEKRA expert. He examined the double girder OET crane thoroughly and performed a comprehensive load test. The test load was 49,5 t and exactly this value (110 % of the nominal load) was configured for the overload cut-off. In addition to that a load of 56,5 t was attached in order to measure the deflection of the crane installation at a pre-defined point.
In short: The special crane modernized by BRUNNHUBER passed all tests and could start operation at CERN – where all too often very precious goods are attached to the hook.
BRUNNHUBER and CERN
Between 1998 and 2005 BRUNNHUBER has delivered in total 15 new crane installations to the European research centre – including work underground. In 2003 for example a large double girder OET crane with complete capacity of 280 t (2 open winch trolleys with 140 t capacity each) and lifting height of 100 m was delivered and assembled for a CERN cavern.
At regular intervals, once a year, the Augsburg crane manufacturer is on site for carrying out maintenance works. The BRUNNHUBER experts are also expected to be available in special situations when for example devices with value of millions of Euros are to be transported by crane.