Necsa radioactive waste management plan development

The national radioactive waste management policy and strategy document [3] prescribes the use of a balanced and systematic way of evaluating respec­tive waste management options using a multi-attribute analysis approach such as the BATNEEC process. It was, however, decided to utilize the more recent best practical environmental option (BPEO) and best practicable means (BPM) multi-attribute analysis processes. The BPEO process will be utilized for the selection of the management options whilst the BPM process will be followed for the refinement of design and operational conditions.

BPEO studies are particularly relevant to strategic decision making, involving choices between alternative management options. The fundamen­tal comparison relates to the performance of environmental options, but the process should provide a holistic appraisal, which includes continual improvement, of factors associated with the practicability of implementing strategic alternatives. BPM relates to optimization of the selected option from the perspective of radiological protection, and is concerned with the detailed refinement of design and operation conditions.

The evaluation criteria used for the selection of the BPEO and BPM are as follows:

1. Cost effectiveness

• life cycle cost of waste.

2 Operational feasibility

• existing or new technology

• international best practice

• regulatory constraints and challenges

• ease of operation.

3. Environmental and social acceptability

• public safety impact

• perceived risk and social acceptability

• environmental impact

• continual improvement potential.

4. Safety

• worker safety impact

• public safety impact

• accident risk

• safety impact reduction potential.

The aim of a BPEO study is to ensure that the reasoning behind a strategic decision, involving technical, scientific and more qualitative judgments (including their consistency with the overriding principles of precautionary action and sustainable development), is made visible.

The process to determine the BPEO for each waste or material category is presented schematically in Fig. 20.13 . In instances where management options for certain waste categories exist and those processes are author­ized or in the process of authorization, then that will be regarded as the preferred option (BPEO) for that waste category. It should be noted, however, that the authorization process includes evaluation of options and justification of selected actions.

This process entails the following in sequential order:

1. Identification of the waste or material. This includes radioactive waste or redundant radioactively contaminated materials/equipment for which no further need is foreseen as identified by the generator or waste operator.

2. Categorization/grouping of waste/material according to its possible management option. The categorization allows for grouping together of waste streams or material with the same attributes and that will be managed in the same manner.

3. Following the flow diagram for each waste/material category to find the BPEO and associated BPM.

• Recovery of uranium (source material). Some radioactive waste at Necsa contains uranium that could be recovered for re-use. Due to the high value associated with uranium, especially uranium in its enriched form, it is worthwhile to identify radioactive waste streams with recoverable quantities of uranium. The recovery route will be regarded as the BPEO for that respective waste stream. Different option evaluations will be performed in order to find the BPM for each waste stream in this waste category where recovery processes have to be developed.

• Waste/material clearable. Material or waste that conforms to the criteria for clearance will not be further treated but will be processed to demonstrate compliance with clearance criteria. The clearance route will be regarded as the BPEO for that category. The ‘clearance’ of radioactive material allows for the release of the material from nuclear regulatory control in terms of the compliance with clearance

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levels. If the waste/material is clearable with further treatment, then it will be treated as such. If a treatment process exists, then treatment will be performed. If not, an exercise will be performed to find the BPM for treatment of that category as described previously. Existing treatment processes include chemical decontamination and smelting.

• Waste/material acceptable for re-use or recycling. This step allows for the release of material that does not conform to clearance criteria

but conforms to the criteria for re-use or recycling. If treatment is required to enable release of the material, the same procedure will be followed as described previously to determine the BPM.

• Waste/material acceptable for authorized storage.

• Waste/material acceptable for authorized disposal. This step allows for the release of material that does not conform to clearance criteria or for re-use or recycling but does conform to the criteria for author­ized disposal. If treatment is required to enable authorized disposal of the material, the same procedure will be followed as described previously to determine the BPM.

• BPEO waste management option study (regulated storage or regu­lated disposal). Waste that does not conform to any of the above categories requires an option study to find the BPEO for that waste category. The option study will determine whether the BPEO for a specific waste category will be regulated disposal or regulated storage. Once the BPEO for that waste category has been selected, the waste will be treated in accordance with existing processes or, if such processes do not exist, an option study will be performed to select the BPM.

There are three options when treating radioactive waste, namely volume reduction, removal of radionuclides from the waste and the change of the physical form and/or chemical composition. The nature and composition of the respective waste categories allow in most instances a decision to be taken on the BPM for that waste category. For example, in the case of the compressible waste type, the BPEO would be volume reduction. Different methodologies can, however, be applied in order to reduce the volume of the waste such as com­paction, incineration and segregation. Option studies are subse­quently performed in order to determine which of these methodologies would be the preferred option or for the respective waste category.

4. When the BPM evaluation process indicates the establishment of new facilities or processes or the significant modification of existing facilities or processes, then external regulatory approval is required. This will mainly entail the Environmental Impact Assessment (EIA) process as prescribed by the Environmental Management Act, No. 199 in order to obtain a Record of Decision (RoD) as well as the NNR’s nuclear authorization process.

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