STUDY OF DECAY TUBE DISMANTLING

Client:
European Organisation for Nuclear Research, CERN, Geneva

Description:
The CERN Neutrinos to Gran Sasso (CNGS) project is presently in construction phase to study neutrino oscillations in a long base-line experiment. High energy protons are extracted, transported through a 727m long transfer line, particles created are then decayed in a 1km long tube (decay tube) to produce a beam of neutrinos which then travel 730 km through the earth towards a detector at the Gran Sasso laboratory in Italy. Nuclear Technologies were contracted to provide a feasibility study to ascertain the best method of dismantling the underground steel decay tube, which will become radioactive and has to be removed from the underground tunnels at the end of the CNGS operation.

SCOPE OF SERVICE SUPPLIED

• Formulation of workable options for the dismantling of the steel tube, raising of the sections to the surface and transfer to the storage location.

• Preparation of a report including an outline procedure for the above and for each option, a budgetary estimate, feasibility assessment, preliminary safety risk assessment and radiological safety assessment.

• Presentation of all the options that were considered at optioneering workshops, which were attended by stakeholders from CERN. Hi-View, the options ranking software will be operated in the workshop to identify the preferred option.

The final report included a detailed description of the preferred option with detailed dismantling descriptions, detailed costs and programme including safety and waste management requirements and all drawings and schematics.