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THE CHARACTERIZATION AND DETERMINATION OF RADIOACTIVE WASTE FROM DECOMMISSIONING

Objective

The objective of this laboratory-scale experimental investigation is to develop the "fingerprint" method for the characterization of waste arising from decommissioning projects to the point where it could be used more extensively after its initial limited application.

The "fingerprint" method relies on the ability to carry out comprehensive analysis, for all of a specified range of radionuclides on a statistically justified set of samples. In order to achieve this, development of several aspects, related particularly to the difficulty of measuring some specific electron capture and low energy beta-emitting nuclides, is required.

It is expected that the establishment of accurate fingerprints, when coupled with simple measurement of the total activity, will enable correct sentencing of waste and thus minimize the cost of the disposal of the waste arising from the decommissioning of radiochemical laboratories or reactor facilities.

Collaboration is envisaged with TUV Sudwest, FRG (contract No. FI2D0033), both on the development of radiochemical methods and on the assessment of measurement techniques.
The objective of this laboratory scale experimental investigation is to develop the fingerprint method for the characterisation of waste arising from decommissioning projects to the point where it could be used more extensively after its initial limited application. The fingerprint method relies on the ability to carry out comprehensive analysis, for all of a specified range of radionuclides on a statistically justified set of samples. In order to achieve this, development of several aspects, related particularly to the difficulty of measuring some specific electron capture and low energy beta emitting nuclides, is required.

The work carried out has been concerned with the development of methods for the dissolution of concrete, procedures to separate chemically and radiochemically pure calcium-41, iron-55, nickel-63, tritium and carbon-14 and methods for counting the separated products. The methods developed have been used successfully on concrete from the Windscale advanced gas cooled reactor (WAGR) for which a good correlation has been found between these difficult to measure nuclides and the more easily measured gamma emitting nuclides europium-152, cobalt-60, barium-133 and caesium-134.
WORK PROGRAMME

1. Acquisition of contaminated material and fabrication of simulants.

2. Development of methods for the removal of radioactive contaminants to solution.

2.1. Survey on existing methods for removal of radioactivity from contaminated materials.
2.2. Leaching experiments.
2.3. Investigation on microwave dissolution techniques.
2.4. Investigation on electrolysis for the recovery of tritium.

3. Development of preconcentration, separation and analysis methods.

3.1. Selection and commissioning of slow injection analysis.
3.2. Development of methods for iron, nickel and uranium.
3.3. Development of method for iodine.
3.4. Development of method for calcium.
3.5. Investigation on combustion techniques for the recovery of carbon and hydrogen.

4.Development of counting methods for the difficult-to-measure nuclides.

4.1. Development of liquid scintillation.
4.2. Development of gas proportional counting.
4.3. Development of x-ray counting.

5. Statistical assessment to characterize the waste and satisfy the quality assurance standards.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

United Kingdom Atomic Energy Authority (UKAEA)
Address
Harwell Laboratory
OX11 0RA Didcot
United Kingdom

Participants (1)

Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek
Netherlands
Address
Stieltjesweg 1 155
2600 AD Delft