Development of Fundamental Technologies for Retrieval of Fuel Debris - Remote Controlled laser cutting, simulant characterization,
dust and gazes characterization and active trial feasibility study - COMEX NUCLEAIRE – Final Report Summary
Outline of the project
COMEX NUCLEAIRE and CEA proposed to apply to Fuel debris retrieval the LASER technology which is being
used for decommissioning of nuclear facilities and whose encouraging performances were demonstrated in
the tests using simulating fuel debris.
In this project, LASER cutting tests in-air for emerging and non-emerging configurations will be tested. Thesame LASER cutting configurations are proposed under water for different level of water (up to 5m depth).
During LASER cutting sequences, the parameters of the release of cutting (gas composition, chemicalcomposition of dust and water, typical geometry of the particles with the participation of IRSN) will becarefully analyzed. Moreover, a collection loop system for the “big” particles (Ø>10µm) will be implemented
as prototype.

Non-emerging LASER cutting under-water

Project outline and outcome obtained
LASER cutting in air and under water:
Performance assessment of LASER cutting in air emerging and non-emerging configurations and improvement of LASER emerging
cutting test under-water. Feasibility of non-emerging cut under water
Outcome obtained:• Emerging LASER cutting in air (ELC-A) : 100mm cut achieved for Zirconia and 160mm for In-vessel fuel debris Simulant• Emerging LASER cutting under water (ELC-W) : 100mm cut achieved under 17cm of water and 50mm under 5m of water (Zirconia)• Non-Emerging LASER cutting in air (NELC-A): 50mm cut achieved for Zirconia and 40mm for Ex-vessel fuel debris simulant• Non- emerging LASER cutting under water (NELC-W): Feasibility has been confirmed with 4 to 7mm cut achieved, to be continued
further with new parameters to achieve greater cutting performance
Characterization of the samples of water and aerosol after the cutting
Outcome obtained: Main aerosol released are non radioactive elements (Steel and Zircalloy). The main radioactive elements released
have been found to be St, Bs, Ba and Ce (surrogate Pu in the fuel debris simulant). The conversion to radioactivity shows radioactivity
released is of a few 1011Bq for 1 m of laser cut.
Evaluation of the main chemical and physical characteristics of the gas and aerosol released during LASER cutting
Outcome obtained: H2 is the main contributor of the gas released (0.36% vol. max) but far under the below limit of explosivity (4%). In
the size spectrum of the particles emitted during LASER cutting, the main modes measured by IRSN are ~0.2µm for air cutting and~0.4µm for under-water cutting. The aerosol mass concentration and the released quantity during cutting are highly dependent of
cut the fuel debris simulant (Ex-vessel or In-Vessel) and the environment (air or water).
Collection of the “big” particles (Ø>10µm)
Thanks to a nozzle erected close to the cutting area and connected to a collection loop, assessment of the performance of this loop to
recover aerosol and gas during LASER cutting operation.
Outcome obtained: Feasibility has been confirmed, to be continued further to achieve greater collection performance

Development of Fundamental Technologies for Retrieval of Fuel Debris - Remote Controlled laser cutting, simulant characterization,
dust and gazes characterization and active trial feasibility study - COMEX NUCLEAIRE – Final Report Summary
Laser Cutting Summary
NELC-A

ELC-A

ELC – W/A

NELC – W/A

NELC-A on Zirconia

2 Technologies :Emerging Laser Cutting (ELC)
Non-Emerging Laser Cutting (NELC)
2 Environments :In air (A)Underwater (W): shallow depth ordeep water

ELC-W

ELC-A on Simulant

NELC-W

ELC-A performance up to 160mm
ELC-W performance up to 100mm
under 17cm of water and 50mm
under 5m
NELC performance up to 50mm inairCutting Technologies

Deep water cutting configuration

ELC-W on Zirconia

Facility for deep water cutting

ELC-W (5m) on Simulant