Application of Waste Package Specifications for Low Heat Generating Waste

The Waste Package Specifications (WPS) set out the requirements for safe packaging of LHGW to ensure safety during interim storage, transport and geological disposal. This considers the physical and chemical properties of the waste and the container used to package it. LHGW is a Nuclear Waste Services term to categorise waste that does not generate significant heat from its radioactive decay but has enough radioactivity to require protective measures. These measures are necessary to prevent harmful exposure to people and the environment. LHGW typically arises from the operation and decommissioning of nuclear reactors and other nuclear facilities. LHGW makes up by far the largest quantity of radioactive waste by volume.

There are many types of waste with varying physical, chemical and radiation properties. These will impact the choice of waste container and whether the waste will require conditioning to prevent the potential release of hazardous substances. More challenging wastes will need the wasteform to contribute a significant part of the package safety performance, while other wastes will place most reliance on the container. The relative performance of the waste container and the wasteform determines the position of the package within the wasteform/waste diagram.

The WPS consider three categories of waste package:

Unshielded waste packages

These are usually made with thin-walled (a few millimetres thick) metal waste containers. These waste containers provide little shielding from the radioactive waste within the package and so they require remote handling. They will need to be transported in separate transport containers that provide the necessary radiation shielding and containment performance.

Shielded waste packages

These are typically manufactured using reinforced concrete waste containers or metal-walled containers incorporating concrete shielding. Such packages do not require remote handling. These packages can be transported without additional protection.

Robust shielded waste packages

These are typically made using thick-walled (50 millimetres or thicker) cast iron containers. These waste containers aim to provide enough radiation shielding so that remote handling or additional protection during transport is not required. Despite this, it is currently planned for these waste packages to be handled remotely.

See next: Application of Waste Package Specifications for Low Heat Generating Waste: Standardised Waste Container Designs