Nature and Quantity of Waste Assessments

Client:
UK NIREX Ltd

Description:
The role of UK Nirex Ltd (Nirex) is to provide the UK with environmentally sound options for the disposal of radioactive waste generated by the nation’s commercial, medical, research and defence activities. Encapsulation of some such waste in standard grout formulations presents uncertainties in long-term product performance as a result of continuous waste-matrix interactions.

Alternative grouts, including Calcium Sulphoaluminate based cements, are being considered by some waste producers in order to address these issues. This document presents a proposal for a study to establish what is known relating to Calcium Sulphoaluminate cements in terms of waste compatibility and product quality consistent with Nirex disposal criteria.

Scope of service supplied

Nuclear Technologies undertook a literature review to collate information available on Calcium Sulphoaluminate cements. The information was assessed to determine the suitability for encapsulation of wastes in these cements against the following criteria:

• Immobilisation of radionuclides;

• Mechanical and physical properties;

• Chemical containment;

• Wasteform degradation/passivity;

• Fire and impact performance;

• Gas generation;

• Process product envelope;

• Post closure issues e.g. interactions with disposal facility backfill.

The assessment focused on those areas where it was judged that the most challenging issues would be raised by the proposed wasteform. Where there was insufficient information available it was highlighted and recommendations for any potential future experimental work programmes were made.