Analysis of Hydrocarbons of the JET Divertor Cryogenic Pump at the End of the Carbon Wall Campaign Using a Micro Gas Chromatograph

et al. 2016

A small amount of tritium is produced by deuterium-deuterium reactions in the core plasma during deuterium plasma experiments conducted in the Large Helical Device (LHD). From the viewpoints of tritium safety handling and public acceptance, any waste gas streams arising from the vacuum vessel of the LHD and Neutral Beam Injection (NBI) system will be treated by an exhaust detritiation system (EDS). The exhaust gas stream produced during the 18th cycle of LHD plasma experiments was observed to design the EDS. The rough pumping gas streams from the LHD and NBIs produced a high flow rate of 300 Nm 3 /h. The vacuum exhaust gas stream from the LHD had a high hydrogen concentration more than 7% and a flow rate of less than 5 Nm 3 /h during plasma experiments. The regeneration gas stream of the cryopump systems had a flow rate of more than 5 Nm 3 /h. Based on these observations, the proposed EDS utilizes two types of tritium recovery system. One comprises two types of catalyst and dual absorbent beds. Other comprises an oxidation catalyst and polymer membrane system.

Section: Ms System In the Edsmentioning

confidence: 99%

Observations of the Gas Stream from the Large Helical Device for the Design of an Exhaust Detritiation System

et al. 2016

“…alytical techniques. Typical analytical techniques include gas chromatography (GC) and use of a residual gas analyzer (RGA) with a quadrupole mass spectrometer [8][9][10][11][12]. A GC system would not be the preferred analytical technique to detect ammonia owing to its high polarity and corrosive attributes, although ammonia has been detected by this method [10].…”

Section: Introductionmentioning

confidence: 99%

Detection of Ammonia and Deuterated Hydrocarbons in Exhaust Gas by Infrared Absorption Spectroscopy during Wall Conditioning

et al. 2021

To detect ammonia and deuterated hydrocarbons in exhaust gas from the Large Helical Device (LHD), infrared absorption spectrometry, FTIR with a long optical path gas cell, was applied. Ammonia (NH 3 ) and deuterated hydrocarbons (C x H y D z ) could be detected during the first operations of wall baking at 368 K and the D 2 glow discharge conducted after vacuum vessel closure. The concentration of ammonia increased with increasing baking temperature, and deuterated ammonia was not detected. Thus, the ammonia, which likely originated from sweat of workers produced during vacuum vessel maintenance activities, was released from the vacuum vessel wall. Hydrocarbons were likely produced by chemical sputtering of carbon tiles and were deuterated by a hydrogen isotope exchange reaction due to D 2 glow discharge, while H 2 O was released from the vacuum vessel during wall baking. It was confirmed that ammonia and various types of deuterated hydrocarbons could be measured discriminately by an FTIR spectroscopy system using a long optical path gas cell.

“…Understanding the behavior of hydrogen isotopes in fusion test devices is an important issue from the viewpoints of radiation safety, development of the fuel cycle process and for tritium removal systems. To observe the behavior of hydrogen in the exhaust gas from the fusion test devices, various types of analytical gas instruments have been applied [1][2][3][4][5][6][7][8][9][10]. One type of conventional gas analysis instrument is a gas chromatograph (GC), which uses a thermal conductivity detector (TCD) and a flame ionization detector.…”

Section: Introductionmentioning

confidence: 99%

“…Residual gas analyses are also performed using high-resolution quadrupole mass spectrometry and threshold ionization mass spectrometry. These systems have been applied for gas analyses by teams operating in the JT-60U [1][2][3]7], JET [4][5][6]8], AUG [9], and EAST [10] experiments. The purpose of a gas analysis instrument is to determine the concentrations of hydrogen isotope gases (Q 2 , Q = H, D, T) and impurities including noble gases, air components, and hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of Hydrocarbons in the Exhaust Gas of a Fusion Test Device Using Infrared Absorption Spectroscopy

2020

To investigate the behavior of hydrogen isotopes in a large fusion test device, a new technique using infrared absorption spectroscopy is applied for the monitoring of hydrocarbons in exhaust gas. Fourier transform infrared (FT-IR) spectroscopy combined with a gas cell, which has an optical path length of 16 m, was installed at the plasma exhaust line. In this configuration, the detection limit of CH 4 , C 2 H 6 , C 2 H 4 , and CO is at the level of sub-ppm. The exhaust gas observations were conducted during hydrogen glow discharge and during the regeneration operation of cryosorption pumps during the hydrogen plasma phase. As a result, hydrocarbons and carbon monoxide were detected in the exhaust gas, and the exhaust behavior and the ratio of gas components were determined. It is also demonstrated that light and the heavy hydrocarbons can be discriminated by the FT-IR system. Our infrared absorption spectroscopy study provides positive prospects for its application to exhaust gas analyses.