Metal tritides helium emission

Technical Report · Fri Feb 01 00:00:00 EST 1980

DOI:https://doi.org/10.2172/5551079· OSTI ID:5551079

Beavis, L C

Over the past several years, we have been measuring the release of helium from metal tritides (primarily erbium tritide). We find that qualitatively all tritides of interest to us behave the same. When they are first formed, the helium is released at a low rate that appears to be related to the amount of surface area which has access to the outside of the material (either film or bulk). For example, erbium tritide films initially release about 0.3% of the helium generated. Most tritide films emit helium at about this rate initially. At some later time, which depends upon the amount of helium generated, the parent occluding element and the degree of tritium saturation of the dihydride phase the helium emission changes to a new mode in which it is released at approximately the rate at which it is generated (for example, we measure this value to be approx. = .31 He/Er for ErT/sub 1/./sub 9/ films). If erbium ditritide is saturated beyond 1.9 T/Er, the critical helium/metal ratio decreases. For example, in bulk powders ErT/sub 2/./sub 15/ reaches critical release concentration at approx. = 0.03. Moderate elevation of temperature above room temperature has little impact on the helium release rate. It appears that the process may have approx. = 2 kcal/mol activation energy. The first helium formed is well bound. As the tritide ages, the helium is found in higher energy sites. Similar but less extensive measurements on scandium, titanium, and zirconium tritides are also described. Finally, the thermal desorption of erbium tritides of various ages from 50 days to 3154 days is discussed. Significant helium is desorbed along with the tritium in all but the youngest samples during thermodesorption.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 5551079
• Report Number(s): SAND-79-0645; TRN: 80-008006
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
07 ISOTOPES AND RADIATION SOURCES
HELIUM
DESORPTION
TRITIUM
SORPTIVE PROPERTIES
ERBIUM
SCANDIUM
TITANIUM
ZIRCONIUM
GRAIN SIZE
METALS
NEUTRON SOURCES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CRYOGENIC FLUIDS
CRYSTAL STRUCTURE
ELEMENTS
FLUIDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MICROSTRUCTURE
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
PARTICLE SOURCES
RADIATION SOURCES
RADIOISOTOPES
RARE EARTHS
RARE GASES
SIZE
SURFACE PROPERTIES
TRANSITION ELEMENTS
YEARS LIVING RADIOISOTOPES
360104* - Metals & Alloys- Physical Properties
070200 - Radiation Sources