Tritium behavior in ITER beryllium

Technical Report · Mon Oct 01 00:00:00 EDT 1990

DOI:https://doi.org/10.2172/6308279· OSTI ID:6308279

Longhurst, G R

The beryllium neutron multiplier in the ITER breeding blanket will generate tritium through transmutations. That tritium constitutes a safety hazard. Experiments evaluating tritium storage and release mechanisms have shown that most of the tritium comes out in a burst during thermal ramping. A small fraction of retained tritium is released by thermally activated processes. Analysis of recent experimental data shows that most of the tritium resides in helium bubbles. That tritium is released when the bubbles undergo swelling sufficient to develop porosity that connects with the surface. That appears to occur when swelling reaches about 10--15%. Other tritium appears to be stored chemically at oxide inclusions, probably as Be(OT){sub 2}. That component is released by thermal activation. There is considerable variation in published values for tritium diffusion through the beryllium and solubility in it. Data from experiments using highly irradiated beryllium from the Idaho National Engineering Laboratory showed diffusivity generally in line with the most commonly accepted values for fully dense material. Lower density material, planned for use in the ITER blanket may have very short diffusion times because of the open structure. The beryllium multiplier of the ITER breeding blanket was analyzed for tritium release characteristics using temperature and helium production figures at the midplane generated in support of the ITER Summer Workshop, 1990 in Garching. Ordinary operation, either in Physics or Technology phases, should not result in the release of tritium trapped in the helium bubbles. Temperature excursions above 600{degree}C result in large-scale release of that tritium. 29 refs., 10 figs., 3 tabs.

• Research Organization: EG and G Idaho, Inc., Idaho Falls, ID (United States)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC07-76ID01570
• OSTI ID: 6308279
• Report Number(s): EGG-FSP-9304; ON: DE91006067; TRN: 91-001914
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BERYLLIUM
TRANSMUTATION
BREEDING BLANKETS
TRITIUM RECOVERY
DIFFUSION
ITER TOKAMAK
NEUTRON FLUENCE
NEUTRON REACTIONS
SWELLING
TEMPERATURE DEPENDENCE
TRITIUM
ALKALINE EARTH METALS
BARYON REACTIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CLOSED PLASMA DEVICES
ELEMENTS
HADRON REACTIONS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
METALS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
ODD-EVEN NUCLEI
RADIOISOTOPES
REACTOR COMPONENTS
RECOVERY
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
YEARS LIVING RADIOISOTOPES
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