The first tritium experiment in the JET machine was carried out in November 1991. A number of different regulatory approvals were required in order to proceed with the experiment. These included radioactive discharge authorisation, approval of the safety justification and endorsement of the arrangements for accounting for tritium. Preparation for the full D-T phase of JET planned for 1996 was under way prior to the experiment and has continued subsequently. Up to 90g of tritium will be used in the full D-T phase and JET has obtained authorisation for holding this amount on site and for related radioactive discharges. Safety submissions for tritium operation of the JET machine and tritium plant have been made. The paper highlights the regulatory issues involved in determining the appropriate site inventory limit. It emphasises the importance of establishing a well-founded justification in the case for radioactive discharge authorisations and the necessity of matching the form of the compliance monitoring employed to the predicted mix of nuclides discharged. The accident analysis criteria and routine dose limits used at JET are discussed in relation to the tightening of regulatory requirements, together with QA and design standards.