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Deep geologic repository progress—2025 Update
Editor's note: This article has was originally published in November 2023. It has been updated with new information as of June 2025.
Outside my office, there is a display case filled with rock samples from all over the world. It contains a disk of translucent, orange salt from the Waste Isolation Pilot Plant near Carlsbad, N.M.; a core of white-and-bronze gneiss from the site of the future deep geologic repository in Eurajoki, Finland; several angular chunks of fine-grained, gray claystone from the underground research laboratory at Bure, France; and a piece of coarse-grained granite from the underground research tunnel in Daejeon, South Korea.
J.R. Stencel, J.D. Gilbert, O.A. Griesbach, J.M. Greco
Fusion Science and Technology | Volume 14 | Number 2 | September 1988 | Pages 1047-1053
Measurement of Tritium | doi.org/10.13182/FST88-A25276
Articles are hosted by Taylor and Francis Online.
Measurements within the Tokamak Fusion Test Reactor (TFTR) vacuum vessel atmosphere in 1985 indicated low levels of tritium oxide (HTO). From January to July 1987 approximately 3 × 1018 D-D fusion neutrons were produced in TFTR operations. These reactions would be expected to produce a triton for each reaction or 5.4 GBq (145 milliCuries) of tritium. An HTO measurement made of the vessel on 7/10/87, five days after the last pulsing of the machine, but before the machine was let up to air, indicated an HTO level of 1 MBq m−3 (28 µCi m−3) or approximately six times the DOE concentration guide value of 185 kBq m−3 (5 µCi m−3). The ICRP 30 Derived Air Concentration (DAC) limit of 800 kBq m−3 (22 µCi m−3) will become the limit when Draft DOE Order 5480.11 is implemented. A venting program for the vessel was set up with the objective of limiting the internal dose equivalent to personnel working inside the vacuum vessel. An HTO/HT measurement indicated a 57:1 ratio. HTO was detected in Neutral Beam Injectors (NBI). Tritium concentrations were also detected in a roughing pump in oil/water mixtures within the pump reservoirs. The water to oil tritium concentration ratio was 660:1. The graphite indicated an outgassing effect during the activities within the vessel. In addition, the loose powdered graphite with its tritium absorption presented the first known contamination problem for a tokamak operation. Smearable contamination levels up to 600 Bq/100 cm2 (36,000 dpm/100 cm2) were detected inside the vacuum vessel. This paper discusses the measurements, contamination problems, and results of dealing with the first operational health physics tritium-related activity in a fusion energy research tokamak.