SNLL Tritium Research Laboratory

DOE-HDBK-1129-99

Tritium facility utilities such as chilled water, compressed air, gas supplies, ventilation, floor drains,

sink drains, storm drains, and stacks should not be shared with other non-tritium areas. Sharing

these systems spreads tritium contamination to other areas, complicates day-to-day management

of the facility, and impacts the transition process if the facility is transitioned to other use. The use

of hazardous materials should be reduced or eliminated in the initial design stages of the facility,

as it will likely lead to the generation of mixed wastes and increased D&D costs.

4.6.1 SNLL Tritium Research Laboratory

Tritium operations have been terminated at the TRL, and the facility has been transitioned to other

use. The problems encountered during transition of the TRL should serve as an example for

facility designers of the future. The TRL was designed beginning in 1972 specifically to handle

tritium, and a few changes to the initial design would have resulted in significant cost and

timesaving during the transition process.

The tritium removal system in the central glovebox had a supply and return manifold fabricated

of six-inch diameter stainless steel pipe. The associated vacuum pump effluent manifold

consisted of an all welded two-inch diameter pipe. These manifolds were approximately 200

feet long and extended down the central corridor of the building. The manifolds extended into

each room from the corridor and were of all welded construction. During the transition process,

special tooling had to be purchased to cut the six-inch and two-inch diameter pipe into sections

small enough to be disposed of as solid waste.

Designing the system to include flanges and isolation valves at specific locations would have

resulted in some cost savings during facility dismantlement and transition. However, since too

many valves and flanges can increase the potential for leaks during operation, the installation

points should be placed only at strategic locations.

The floor covering installed in the TRL consisted of 12-inch tiles glued to the concrete floor.

Both the floor tile and the adhesive contained asbestos that had to be removed during

transition of the facility. Additionally, tritium-contaminated liquids were spilled on the floor

during operation and leaked through the tile into the concrete below. The use of adhesives

made of non-hazardous materials would have resulted in significant cost saving.

Princeton University Plasma Physics Laboratory has suggested that sealing the concrete with a

thick, hard finish epoxy paint prior to installation of any floor covering would mitigate the impact

of tritiated liquid spills, although even epoxy will experience tritium permeation.

The TRL was equipped with a recirculating chilled water system. The water-to-gas heat

exchangers used the chilled water to cool the glovebox and vacuum effluent tritium removal

system gases, vacuum furnace heat exchangers, glovebox temperature control systems, and

in a variety of other tritium-related tasks. After a few months of operation, tritium

contamination was found in the chilled water. In order to control the buildup of tritium in this

system, the contaminated water was periodically drained from the system and replaced with

uncontaminated water.

If the initial design had used water-to-water heat exchangers as barriers, the volume of

contaminated water would have been minimized. If double-walled, gas-flushed, water-to-gas

heat exchangers had been used, the contamination would have been significantly lower.