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High-temperature plumbing and advanced reactors
The use of nuclear fission power and its role in impacting climate change is hotly debated. Fission advocates argue that short-term solutions would involve the rapid deployment of Gen III+ nuclear reactors, like Vogtle-3 and -4, while long-term climate change impact would rely on the creation and implementation of Gen IV reactors, “inherently safe” reactors that use passive laws of physics and chemistry rather than active controls such as valves and pumps to operate safely. While Gen IV reactors vary in many ways, one thing unites nearly all of them: the use of exotic, high-temperature coolants. These fluids, like molten salts and liquid metals, can enable reactor engineers to design much safer nuclear reactors—ultimately because the boiling point of each fluid is extremely high. Fluids that remain liquid over large temperature ranges can provide good heat transfer through many demanding conditions, all with minimal pressurization. Although the most apparent use for these fluids is advanced fission power, they have the potential to be applied to other power generation sources such as fusion, thermal storage, solar, or high-temperature process heat.1–3
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.
