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DEVELOPMENT OF A ROBOTIC SYSTEM (TRR) FOR THE REMOVAL OF TUBES FROM A LATINA STEAM GENERATOR, WITH SUBSEQUENT MELTING AND RADIOLOGICAL CHARACTERIZATION

Objective

The work is related to the design, manufacturing and testing of a Robotic system to Retrieve Tubes (TRR) from a steam generator of Latina Magnox Power Plant owned by ENEL. The retrieved material will be characterized radiochemically, melted and characterized again with a view to reuse.

The use of TRR will allow the reduction from 40 mSv to about 2 mSv of the radiation dose to workforce and a significant cost reduction mainly due to the reuse of obtained material.

The objective of the proposed project is the detailed study of a dismantling technique based on a robotic system and characterization of the material obtained after melting. The Magnox steam generators are the largest contaminated plant items although activity levels are low.

The results of the work should strengthen the cost-effectiveness of reusing material from decommissioning. Moreover, it will allow detailed information to be obtained about the radiological aspects of this technique and be applicable to other Magnox or gas/graphite type reactors.
A robotic system for the removal of tubes from a Latina steam generator has been designed. Definition of functional requirements of the system was made for lay out, technological and safety related aspects, allowing the development of the conceptual design and the progress of design activities up to the constructive assembly and subassembly drawings.

A preliminary activity of qualification tests, in particular to define the essential parameters of the cutting operation, has been carried out, providing useful information for detailed design and elements for a more accurate time estimate.

The system is composed of 2 parts: the tube cutting and retrieval device; the contamination containment system.
The cutting and retrieval device operates inside the steam generator and the contaminated area is isolated from the external environment by means of a confined working cabin; the cutting system is remotely controlled by a console located outside the confined cabin. A visual and instrumental monitoring system allows the operator to survey the various working phases which are executed in a semiautomatic mode. The architecture of the control system has been defined on the basis of the operative sequence enabling software development and hardware definition.
WORK PROGRAMME

1. System requirements definition and studies (ANSALDO with ENEL support)

1.1. Analysis of the robotic system (TRR) layout and of the environmental and radiological conditions (in cooperation with ENEL)
1.2. Functional requirements definition of the TRR
1.3. TRR design at system level (Two TRR designs will be investigated)

2. Mock-up design and manufacturing (ANSALDO)

2.1. Design of a SG tube nest mock-up based on real geometric requirements
2.2. Mock-up manufacturing and installation in the Ansaldo testing facility

3. TRR design and manufacturing (ANSALDO)

3.1. TRR detailed design based on 1 and control system design (Hardware and Software)
3.2. Mechanical part manufacturing, commercial part purchasing and assembly and integration of all parts.

4. Testing of the TRR on the mock-up (ANSALDO)

5. Site preparation (ANSALDO with ENEL support)

6. TRR operation and material transportation (ANSALDO + ENEL & SIEMP. support)

6.1. TRR installation on the SG made available by ENEL
6.2. Tube cutting and removal; charging of cut material in the transport containers
6.3. Chemical and radiological characterization - Transportation to Siempelkamp, Krefeld

7. Restoration of the site

8. Radiochemical analysis (SIEMPELKAMP)

9. Melting (SIEMPELKAMP)

10. Radiochemical analysis (SIEMPELKAMP)

11. Generation of specific data

Coordinator

Ansaldo SpA - Un'Azienda Finmeccanica
Address
Corso Perrone 25
16161 Genova
Italy

Participants (3)

CISE - Centro Informazioni Studi ed Esperienze SpA
Italy
Address
Via Reggio Emilia 39
20090 Segrate Milano
National Nuclear Corporation Ltd
United Kingdom
Address
Chelford Road
WA16 8QZ Knutsford
SIEMPELKAMP NUKLEAR- UND UMWELTTECHNIK GMBH & CO.
Germany
Address
45,Siempelkampstra?e 45
47803 Krefeld