A color guard made up of U.S. Naval Construction Force Reserve members and SRS employees take part in the celebration marking the completion of construction of TEF.

Washington Savannah River Company employees work in the Savannah River Site’s newly consolidated and modernized tritium facility.

A DP engineer, shows Brig. Gen. Ronald J. Haeckel, principal deputy administrator for defense programs for the NNSA, simulated TPBARs in the extraction basket in the Target Rod Prep module.

National Nuclear Security Administration (NNSA) Defense Programs

The NNSA Defense Programs Tritium Facilities located at the Savannah River Site (SRS) provide support to the nation's nuclear defense stockpile missions. In support of the Stockpile Stewardship and Stockpile Evaluation programs, the Tritium Facilities are designed and operated to process tritium, an isotope of hydrogen that is a key component of nuclear weapons. Because tritium decays at the rate of 5.5 percent each year, it must be replenished continually. This task is accomplished either by recycling tritium from existing weapons reservoirs returned from the field or extracting it from commercially-irradiated targets called Tritium Producing Burnable Absorber Rods (TPBARs). All tritium recycling and extraction work is conducted within these facilities at SRS.

Stockpile Stewardship Program

Tritium Recycling
Gases are removed from returned reservoirs (steel containers) using a laser in a secure enclosure. All Tritium gas processes are enclosed in glove boxes with an inert (nitrogen or argon) atmosphere. The inert atmosphere is continuously cycled through strippers to remove tritium, and to maintain the glove box pressure slightly below atmospheric pressure. The glove boxes protect workers from exposure to tritium, and allow most of the tritium to be removed from air effluents, greatly reducing radiological releases to the environment. The unloaded gas contains a mixture of tritium, deuterium, and helium-3, the tritium decay product. Using a diffusion process, the tritium and deuterium are separated from the helium-3 and trace quantities of other non-hydrogen gases. The tritium and deuterium are purified for use in loading new and reclaimed reservoirs.

Separation Enrichment
The component gas stream is pumped through a diffusion process to separate the helium from the hydrogen isotopes. The separated tritium/deuterium gas is transferred to storage beds to await enrichment. The beds occupy about 1/300th of the space required by conventional gas storage tanks.
 
To be useful, the tritium and deuterium must also be separated — a process called enrichment — so they can be mixed in exact proportions. A Thermal Cycling Absorption Process (TCAP) accomplishes this enrichment of the recycled gas. The gas is cycled through a TCAP column using specific operating parameters. The two isotopes are then drawn off separate ends of the column and fed into separate storage beds. Thus, enrichment of both isotopes is accomplished.

Tritium Extraction
Tritium Producing Burnable Absorber Rods (TPBARs) are brought to SRS in a special heavily shielded Nuclear Regulatory Commission-licensed transportation cask on a dedicated trailer. At SRS , the cask is removed from its dedicated trailer with a 125-ton gantry crane, lowered through an opening in the truck bay floor to the cask trolley below, and transferred into the shielded remote handling area. The cask top is removed and the container holding the TPBARs is transferred to an extraction basket. The empty cask is removed from the area via the trolley, loaded back into the specialized trailer, and returned to the supplier.
 
The TPBARs are then breached (cut) in a specially designed, remote-operated module. Next, the extraction basket is transferred to a furnace. The furnace is verified leak-tight and slowly heated. The gas in the TPBARs is transferred via high-efficiency vacuum pumps through uranium beds to calibrated tanks, where gas accountability can be performed. The flow of tritium continues through process systems designed to extract and then separate out any contaminates. Once the gas cleanup is complete, the tritium is transferred via underground transfer lines to the adjacent reservoir loading facility.

Mixing, Loading and Welding
Before loading into the reservoirs, tritium and deuterium are mixed to an exact ratio. Several different types of reservoirs, all requiring different gas proportions, are processed at SRS.
 
Laboratory analysis, using a mass spectrometer (an instrument that measures the mass of atoms and molecules), verifies each tank contains the exact mix for its intended reservoir. The blended isotopes are fed into a mechanical compressor system that compresses the gas mixture to achieve the proper loading pressure.
 
When each reservoir is loaded to the correct pressure, its fill stem is welded closed. This completely seals the gas into the reservoir. The seal weld is inspected using radiography and other nondestructive methods.

Stockpile Surveillance Program
As part of the nuclear weapons stockpile surveillance program, selected gas transfer systems (including reservoirs) are removed from the active stockpile and sent to the Savannah River Site for testing. The tests ensure the tritium gas delivery system will function properly should the weapon be used. In addition to function testing, the reservoirs are subjected to one or more conditioning steps simulating forces that could be experienced during use. These tests, including vibration, acceleration, and dynamic shock, are important to ensure weapons systems reliability.
 
All operational activities performed at the SRS Defense Programs Tritium Facilities ensure the needs of national defense are met by safely recycling, manufacturing, and testing an essential component of our nuclear defense system, while protecting employee safety, public health and the environment.