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STEEL CUTTING USING LINEAR-SHAPED CHARGES

Objective

Various types of cutting charges already exist, but mainly for cutting of few millimetres thick material.

The research work will therefore focus on the development of a high performance cutting charge minimizing the damages to surrounding structures for the dismantling of thick-walled steel components (ranging between 10 to 250 mm thickness), eg, pipes, reactor pressure vessels. The work will include studies and experiments at small and large scale, as well as a study to eliminate or minimize undesired secondary effects caused by the projection of splinters at high speed.

Specific data will be produced on costs, work time and secondary waste arisings from the application of this steel cutting technique.

It is expected that the project will result in an economical and dose-rate tolerant cutting technique particularly suitable for dismantling work in inaccessible places.
Various types of cutting charges already exist, but mainly for cutting material of a few millimetres thickness. The research work therefore focuses on the development of a high performance cutting charge, minimising the damage to surrounding structures, for the dismantling of thick walled steel components (ranging between 10 to 250 mm thickness), eg pipes, reactor pressure vessel.

The first phase of the work programme, determination of basic charge parameters has been completed. A first batch of 8 charges, differing in the manufacture of the confinement (cold formed or machined), was manufactured and fired against targets at different stand offs (charge to target distance). During 4 tests pressure transducers and accelerometers were also employed. Another batch of 18 charges was manufactured and tested against steel blocks at a fixed stand off. These charges differed in:
quantity of explosives;
liner geometry;
initiation;
wave shaping.
A charge was fired without target in order to better study its jet by means of X-rays. The analysis of the experimental data was completed, the configuration which gives the best performances was determined and suggestions for a further optimization were given. The second phase of the work programme, optimisation of the cutting charges, started and the preliminary theoretical studies were completed. An analytical computer code for the study of the effects of asymmetries on the jet from a linear shaped charge was developed and the programme for the firing tests of the second phase was defined.
WORK PROGRAMME

1. Determination of basic charge parameters

1.1. Theoretical assessment to characterize high performance cutting charges.
1.2. Manufacture of charges and execution of tests.
1.3. Analyses of the experimental data compared with the theoretical results, conclusions on first phase.

2. Optimization of the cutting charges

2.1. Theoretical assessment to optimize important parameters.
2.2. Manufacture of charges and execution of tests with measurements of blast effects in the air, of ground vibrations, photographs from an ultra-rapid framing camera and of flash X-ray tubes.
2.3. Analyses of the experimental data with a view to specify high-performance charges.

3.High-performance cutting charges specifications and tests.

3.1. Theoretical assessment of the final configuration of high-performance cutting charges and specification of 8 tests (in order to determine the scaling law).
3.2. Manufacture of charges and execution of large-scale tests in special areas allowing large amounts of explosives.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Oto Melara SpA
Address
Via Valdilocchi 15
19100 La Spezia
Italy