The shutdown at BESSY II: busy activity in the ring

Preparing the Undulator "castling": Next year, the undulator will be set up in a different location. So that it then goes quickly, the wiring is now being done.

Preparing the Undulator "castling": Next year, the undulator will be set up in a different location. So that it then goes quickly, the wiring is now being done. © HZB/M. Setzpfand

Long planned: To ensure that the various tasks in the shutdown do not interfere with each other, Christian Jung and his team coordinate the work.

Long planned: To ensure that the various tasks in the shutdown do not interfere with each other, Christian Jung and his team coordinate the work. © HZB/M. Setzpfand

Newly installed: A new supply line, the "Multiple Helium Transfer Line (MTL)".

Newly installed: A new supply line, the "Multiple Helium Transfer Line (MTL)". © HZB/M. Setzpfand

The storage ring BESSY II is down for nine weeks this year while urgent maintenance is being performed and new components are being installed. That sounds like a lot of down time, but there is a long list of work to be done. There is much going on behind the scenes to ensure that BESSY II will be available as reliably as ever for our guest researchers.

All this activity didn’t suddenly start on the 20th of July, the first day of the shutdown. Much of the planning for the current projects goes back many years. The current shutdown is a time, among other things, for renewing and expanding the components of the cooling water system – an extremely urgent matter that we can really literally feel at the moment, seeing as summers in Berlin are getting hotter. This is not just a bother for us humans; it is pushing the BESSY II cooling system to its limits.

When it was commissioned in 1998, BESSY II only needed two cooling towers. A third was added in 2010 – and we are now constructing the fourth! “This will increase our cooling capacity by 650 kW, which is a good 30 percent,” explains Bernhard Nonn, who is coordinating the work in this project. But the new cooling tower is by no means the end of the story: “We also need larger pumps, larger pipelines, and new, modern instrumentation for the cooling water system to run reliably. There have been considerable technological advances in these components in recent years, so it is worthwhile replacing them now,” says Nonn. The experts have already installed the new components and are now getting ready to bring the system online.

The fourth cooling tower is due at the beginning of September

The new cooling tower is expected be here in the first week of September. “Constructing a cooling tower doesn’t sound like a big deal. But there is an immense amount of logistics behind it,” explains Christian Jung, who is coordinating the various works during the shutdown together with Ingo Müller. Part of the problem is that the cooling towers are located in the inner yard in the centre of the ring-shaped building. Getting the fourth tower in there will require a crane with a 90 metre boom. “We have never needed a crane that big before,” Müller says. For the crane to have enough room to manoeuvre, it will first be necessary to clear the site of various recycling presses and other components.

In his office, Christian Jung points to a colourful schedule with a long list of items. This has all of the work planned for the shutdown entered into it, some of which has already been completed.  Six additional large monitors were installed in the control room, for example. This makes it easier for the operators and employees on hall duty to maintain an overview of the various process parameters. “So, there are more degrees of freedom in what they can display now,” Ingo Müller explains. In passing, he mentions that an air conditioning system had to be added here as well. As is typical, there is more logistics involved in the process than can be seen at first glance.

Newly installed: The "Multiple Helium Transfer Line"

Good progress has been made in another project that has required strong nerves on the part of the colleagues: in the winter, a cryogenic system (coldbox) was installed in the experimental hall for cooling the superconducting cavities – for which the roof of the BESSY II hall even had to be opened. The system is now being connected to the supply box during this shutdown. This means laying a massive pipe beneath the hall ceiling, which the experts elegantly call a “Multiple Helium-Transfer Line (MTL)”. In it, there are six different lines for cooling with helium to different temperature levels. Why has this required strong nerves? “Because the line had to be installed so close under the ceiling, we couldn’t use the ceiling crane. So we had to work with the side crane, which wasn’t what we had originally planned. It took a lot of sweat, but everything went smoothly thanks to the professionals on site,” Christian Jung says with satisfaction.

Ingo Müller’s telephone rings: the people to build the radiation protection labyrinth are here. He jumps up and calls on his way out: “Sorry, I have to go do this.” In the future, components for the superconducting cavities will be tested here – and it requires a certain type of shielding. “That’s just another one of the many projects that the HZB colleagues are getting done during this shutdown,” Christian Jung says before listing off many other items.

Planning a shutdown is like putting together a mosaic

Shutdown at BESSY II – above all, that means extremely tightly synchronised and coordinated work. So that the users lose as little time as possible, the shutdown window has been kept to the absolute minimum. Christian Jung and Ingo Müller have to think through every detail and to weigh up alternatives before a solution can be found that satisfies everyone. Any seemingly innocuous task can still turn out to be highly complex in the course of planning – and that means one thing above all else: communicate, communicate, communicate. With many employees from different departments and external companies involved in all the simultaneous jobs during the shutdown, plans have be drawn up well in advance. And all individual projects must fit together to form a whole. “What we are doing is nothing other than piecing together a mosaic. To make sure things go smoothly during the shutdown, we first have to think about how best we can arrange the pieces of the mosaic so that all we have to do then is pick them out,” says Christian Jung.

And how is COVID-19 affecting the work?

“We have high safety regulations. Among other things, people are wearing mouth and nose masks in the hall and we are keeping an attendance record at the gate,” says Jung. COVID-19 has also led to a time delay because a company has taken longer to complete the work than planned. “It is inconvenient, but the extension of the shutdown to nine weeks was unavoidable. So we are bringing some tasks forward that would have otherwise been done next year. That way we will be able to offer as much measurement time as possible in 2021.” 

And yet the situation makes Christian Jung pensive: “We suddenly have much more uncertainty in our planning. Can we be sure that a highly specialized company that we need for working in the ring will still be around next year?” For planners who are used to getting everything finalised early, the frustration is real. But when situations like these arise, a different strength starts to shine: the experienced teams know very well that, at some point, they will have to face unplanned challenges, and that they will be able to overcome them with swiftness and creativity.

Text: Silvia Zerbe