Very high temperature laser heated furnace for Knudsen cell mass spectrometry

Abstract

A very high temperature furnace (up to 3000 degrees C) for the Knudsen cell mass spectrometry (KCMS) based on a laser heating technique has been developed. It is demonstrated that this system overcomes some of the typical technological problems encountered by the standard methods and can be more easily handled in special environments such as gloveboxes or hot cells. This paper describes the laser heated KCMS general design. The technology of the laser furnace along with its advantages, disadvantages, and applications is presented. Mechanical designs, some technical details, and the importance of the temperature control are also discussed.

Helium solubility and behaviour in uranium dioxide

“…Next a Laser Knudsen Cell (LKC) [4], is used to release the helium from the UO 2 sample previously infused by annealing and to measure the helium release profile as a function of the temperature. It is a laser heated furnace (B in Fig.…”

“…The two samples were separately infused in HEIDI, with a helium pressure of 100 MPa, for 1 h, at 1523 and 1743 K respectively. After, the infusion the samples were placed into the LKC, where they were annealed with the following temperature program: 50 K min À1 temperature ramp to1873 K with a plateau of 5 min at 1773 K. The released gas was collected, measured and compared with the signal of a known spike of 4 He, in the Q-GAMES.…”

The dissolution of helium in La-doped UO2 as a surrogate of hypo-stoichiometric UO2

“…Three different UO 2 samples, containing 6, 11, and 22 mol% lanthanum, respectively, were examined. Helium was introduced in the samples by the infusion technique, and its release rate as a function of annealing temperature and quantitative measurements were performed by Laser Knudsen Cell and Quantitative Gas Measurement Systems, respectively [30,31]. Characterization of the samples was performed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).…”

A mass spectrometry method for quantitative and kinetic analysis of gas release from nuclear materials and its application to helium desorption from UO2and fission gas release from irradiated fuel

“…The system is equipped with full-range vacuum gauges (1 × 10 5 to 5 × 10 −8 Pa) (21,22) to assure a full control of the pressure in the HP sample chamber (1) and in the mass spectrometer chamber (7). As the high vacuum gauge is measured with a hot cathode ion gauge, its use is avoided when measuring light gases like helium in order to prevent the dissociation of hydrocarbons and water in the plasma produced by the gauge, that would produce low-mass fragments like hydrogen and deuterium and thus falsify the results.…”

“…The second one is a laser heated Knudsen cell mass spectrometer (LKC-MS) [22] which is used to study the thermal release of gas from infused materials. Since the Knudsen cell technique allows quantitative determination only for condensable vapours, which is not the case of noble gases, the Q-GAMES has been introduced to obtain quantitative and complementary kinetic data on He, Kr, and Xe released during the annealing of samples in the KEMS and LKC-MS.…”