71 per cent of the total installed nuclear power capacity worldwide (Table 2.4). As of the last update (2003), the countries with significant waste arisings that are not included are Canada, China, India, the Russian Federation, the ROK and the UK.

From this table, it can be seen that, based on the IAEA classification, worldwide 76 per cent of the arisings are L/ILW-SL, 23 per cent L/ILW-LL and 1 per cent HLW.

2.7. Inventories

2.7.1. Inventory types

As mentioned in the introduction, an inventory is one of the basic requirements for any national radioactive waste management programme. Depending on the maturity of the programme, an inventory can be purely a model of the expected wastes or can, if sufficient knowledge exists, be based on real waste data. However, it is important to understand the differences between the two types of inventories.

The first type of inventory can be termed as a model (reference) inventory and is essentially a simplification of the multitude of different waste types produced in any nuclear programme to allow the performance of an efficient safety analysis. The basis of this type of inventory is the grouping and summarising of the characteristics of similar wastes, e.g., same type of cemented waste from different nuclear power plants, etc. This can, at the beginning of a disposal programme, be a pure model but, as more wastes are characterised or produced (e.g., decommissioning), becomes less of a model and reflects more precisely the real waste. However, the final inventory for repository closure safety assessments will be a simplification of the individual waste package inventory described below.

The second type of inventory records the individual waste package properties, e.g., activity content, dose rates, etc., and is used to ensure that the waste meets repository acceptance criteria and that a detailed record exists of what has been placed in a repository. This is particularly important for ‘‘problematic’’ wastes, as it allows emplacement of specific wastes in tightly defined areas of a repository (see Chapter 5 for further details).

2.7.2. Types of data recorded

The types of data recorded in a waste inventory (e.g., Alder and McGinnes, 1994; McGinnes, 2002) can, as was noted in the introduction, be broken down into three areas: radiological, chemical and physical.