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85748 Garching

Removal of the Cold Source

  • For the upcoming work, the water in the reactor pool is lowered to the working platform.
    © FRM II / TUM

  • An employee aligns the central mast, the first component of the so-called assembly-disassembly device, with the help of the crane above the reactor pool.
    © FRM II / TUM

  • Radiation protection staff help put on and take off protective equipment for work in the reactor pool.
    © FRM II / TUM

  • The central mast is slowly lowered into the pool. FRM II employees control the millimeter-precision positioning below directly from the reactor pool.
    © FRM II / TUM

  • The central mast is mounted at the designated position on the central channel.
    © FRM II / TUM

  • Another component, the so-called guide carriage, serves as a guide aid during the extraction of the Cold Source.
    © FRM II / TUM

  • The guide aid is lowered into the reactor pool and mounted.
    © FRM II / TUM

  • An employee attaches the horizontal stabilization to the central mast and the guide aid.
    © FRM II / TUM

  • Final visual inspections as well as control measurements on the installed assembly-disassembly device confirm the correct installation.
    © FRM II / TUM

  • This is followed by a test run: The dummy (blind plug of the Cold Source) is attached to the carriage adapter and brought into position over the guide rods.
    © FRM II / TUM

  • The dummy slides with the carriage along the guide rods to the flange of the Cold Source in a controlled manner. The position is determined and successfully checked by laser measurements.
    © FRM II / TUM

  • Test run successfully completed! For further work, the reactor pool is filled with water to shield the radiation.
    © FRM II / TUM

  • The sled adapter is now lowered via the guide rods into the reactor pool up to the flange of the Cold Source and bolted to the in-pile part of the Cold Source.
    © FRM II / TUM

  • The use of a special radiation-resistant underwater camera allows permanent monitoring of all work steps.
    © FRM II / TUM

  • With the help of a manually operated chain hoist, the in-pile part is lifted the first 50 cm to overcome the particularly critical area (because it is very narrow) of the jet pipe noses.
    © FRM II / TUM

  • The in-pile part is lifted another 5 meters along the fixture, using the overhead crane.
    © FRM II / TUM

  • The opening of the Cold Source is closed with a lid for self-protection.
    © FRM II / TUM

  • For transport to the storage position, the separation gate between the reactor and storage pool was opened. The transport of the in-pile part of the Cold Source to the storage pool took place completely under water.
    © FRM II / TUM

A unit of equipment for cooling down neutrons – known as the Cold Source – is defective and currently unavailable. Since repair is not possible, the so-called in-pile part which is the heart of the Cold Source, must be completely replaced.

After weeks of meticulous preparation, work is underway to remove the defective in-pile part of the Cold Source from the moderator tank. The in-pile part of the Cold Source is pulled out of the moderator tank and placed in the designated position in the storage pool.

Expansion of the Cold Source
Expansion of the Cold Source

For the upcoming work, the water in the reactor pool is lowered to the working platform.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

An employee aligns the central mast, the first component of the so-called assembly-disassembly device, with the help of the crane above the reactor pool.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

Radiation protection staff help put on and take off protective equipment for work in the reactor pool.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The central mast is slowly lowered into the pool. FRM II employees control the millimeter-precision positioning below directly from the reactor pool.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The central mast is mounted at the designated position on the central channel.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

Another component, the so-called guide carriage, serves as a guide aid during the extraction of the Cold Source.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The guide aid is lowered into the reactor pool and mounted.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

An employee attaches the horizontal stabilization to the central mast and the guide aid.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

Final visual inspections as well as control measurements on the installed assembly-disassembly device confirm the correct installation.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

This is followed by a test run: The dummy (blind plug of the Cold Source) is attached to the carriage adapter and brought into position over the guide rods.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The dummy slides with the carriage along the guide rods to the flange of the Cold Source in a controlled manner. The position is determined and successfully checked by laser measurements.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

Test run successfully completed!
For further work, the reactor pool is filled with water to shield the radiation.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The sled adapter is now lowered via the guide rods into the reactor pool up to the flange of the Cold Source and bolted to the in-pile part of the Cold Source.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The use of a special radiation-resistant underwater camera allows permanent monitoring of all work steps.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

With the help of a manually operated chain hoist, the in-pile part is lifted the first 50 cm to overcome the particularly critical area (because it is very narrow) of the jet pipe noses.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The in-pile part is lifted another 5 meters along the fixture, using the overhead crane.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

The opening of the Cold Source is closed with a lid for self-protection.

© FRM II / TUM
Expansion of the Cold Source
Expansion of the Cold Source

For transport to the storage position, the separation gate between the reactor and storage pool was opened. The transport of the in-pile part of the Cold Source to the storage pool took place completely under water.

© FRM II / TUM

Further informationen about the Cold Source:
https://www.frm2.tum.de/en/frm2/secondary-sources/cold-source/

Story on the diagnosis of the defect of the Cold Neutron Source:
https://mlz-garching.de/englisch/news-und-press/from-behind-the-sciences/the-cool-guy.html

What “Running without Cold Source” means:
https://mlz-garching.de/aktuelles-und-presse/broschueren-und-filme/newsletter/newsletter-ii-2021.html#running_without_cold_source

Anke Görg

Press and
public relations
FRM II

MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Hereon> Helmholtz-Zentrum Hereon
Forschungszentrum Jülich> Forschungszentrum Jülich

MLZ is a member of:

LENS> LENSERF-AISBL> ERF-AISBL

MLZ on social media: