Radiological characterization requirements

1. The applicable radionuclides to be expected in a waste drum shall be provided for each drum.

2. Waste drums shall be radiologically characterized, reporting the activ­ity of all nuclides present in the waste.

3. Radiological characterization of waste drums can be carried out by non-destructive assaying (NDA) such as a drum scanner (Fig. 20.10) or radiochemical analysis of representative sample/s taken from the drum.

4. If use of statistical sampling is considered (e. g., limited number of drums analysed from a whole population), the suggested method shall be documented, justified and presented to PDO for approval, before any such sampling and analysis would be accepted.

5. NLM has a NNR-authorized radiological characterization (NDA) method for waste drums containing gamma-emitting nuclides and waste density of less than 1 g/cc in 100-210 L plastic or metal drums.

6. Waste from generators that could be characterized by this authorized method can be accepted without the need to provide evidence of radiological characterization.

7. The characterization of any waste drum containing a mixture of gamma — and non-gamma-emitting nuclides, or pure non-gamma — emitting nuclides, or density more than 1 g/cc lies with the waste.

8. When analyses are to be based on analysis of a representative sample taken from the waste, the analysis shall be performed by an accredited laboratory and method, and samples taken according to an approved sampling plan. This plan shall provide evidence that the prescribed sampling method ensures representative sampling. Evidence of at least the following shall be provided with each waste drum:

• sample and waste mass

• traceability to calibrated scales used

• activity calculation sheet

• laboratory analysis report

• reference to approved characterization procedure.

9. Evidence of the approved characterization method shall be provided to PDO, and where applicable a copy of the approved sampling plan.

image221

20.10 Non-destructive assaying at Necsa [1].

10. When none of the methods described is possible, generators could still apply to PDO for acceptance of the waste by submitting a motivation for acceptance of a best estimate of the activity in the waste package based on knowledge of the waste producing process. A formal request shall be provided where at least the following shall be provided in a report:

• unique identifiers of waste drums (numbers)

• detailed description of waste and container

• quantities, number of drums and weight

• reasons why characterization (sampling/analysis, etc.) is not possible

• detailed description of the assumptions made and justifications for the expected nuclide-specific activity in each drum

• nuclide-specify activity estimations for each drum.

Добавить комментарий

Ваш e-mail не будет опубликован. Обязательные поля помечены *