NIF is capable of fielding tritium-containing targets on both cryoTARPOS and TARPOS. Due to differences in hardware systems associated with each positioner, different limits on the packaging and quantity of tritium allowed apply to the two positioners.
TARPOS can only accept targets containing integral tritium inventories, and a limited quantity of tritium (currently limited to <100 mCi per target).
CryoTARPOS (90-015) is set up to accommodate fuel (including various mixtures of THD) in small pressure vessels known as reservoirs. These reservoirs are configured to be mounted directly on the target positioner nose cone or outside the target positioner vessel in a specially designed glove box. Maximum tritium inventory is limited by various facility safety bases and environmental limits. Typical targets contain up to about 20 Ci of tritium; targets containing up to about 60 Ci of tritium currently may be accommodated for special applications. Reservoirs are filled at the LLNL tritium facility to fuel specifications provided by experimenters. These mixes must meet both tritium facility and NIF limits and be compatible with NIF system capabilities.
For both cryoTARPOS and TARPOS, the mix and pedigree of fusionable-gas fills (including T, D, and 3He) and the target design are controlled to manage the potential neutron yields for a given shot and help determine facility safety setup considerations. Due to the presence of tritium (and potentially other radioisotopes), targets and equipment installed or connected to the target positioners are considered radiologically contaminated until proven otherwise (if possible).