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Natural abundant Zinc is available in the following
five stable isotopes:
64Zn
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48.06% |
66Zn
|
27.9% |
67Zn
|
4.1% |
68Zn
|
18.8% |
| 70Zn |
0.6% |
|
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These zinc isotopes can be engineered, both in distribution
and in chemical form, to meet the specific needs of customers.
Using the most advanced centrifuge technology in the world;
concentrations can be enriched to exceed 99% or depleted below
1%.
Depleted Zinc Isotopes Usage
Zinc, depleted in the isotope 64Zn, is presently
used as an additive in the cooling water systems of BWR nuclear
reactors worldwide. The majority of U.S. reactors now utilize
depleted zinc oxide (DZO) injections while PWR operators have
started to evaluate the technology. Preliminary results indicate
that depleted zinc acetate may be more advantageous for use
in PWRs.
The addition of 64Zn greatly reduces corrosion
processes, including stress corrosion cracking. Furthermore,
the added zinc reduces the amount of radioactive 60Cobalt
formed because of the irradiation of natural cobalt in the
construction materials of the reactor. 60Co is
a major contributor to radiation build-up in the cooling systems
and therefore causes elevated dose rates of maintenance personnel.
Production of Depleted Zinc Products1
Diethyl zinc gas is depleted in custom-made facilities, which
use advanced gas centrifuges. The use of centrifuges for isotope
separation is a process that takes advantage of the difference
in molecular weight between the various isotopes. A cascade
of centrifuges is required to achieve significant changes
in the enrichment. A single pass through the cascade can provide
enough depletion such that 64Zn (natural abundance
of 48%) is reduced to less than 1%.
The ultracentrifuge consists of a vacuum recipient with a
fast spinning rotor inside. The diethyl zinc gas is fed into
the rotor, where it is accelerated until it has nearly the
same rotational frequency as the rotor itself. The gas molecules
are then subjected to centrifugal forces induced by the centripetal
acceleration. Heavy molecules are subjected to larger forces
than light molecules and will therefore migrate towards the
rotor wall.
The gas is extracted from the centrifuge by a set of gas
extraction scoops; the heavy fraction scoop is located near
the rotor wall, whereas the light scoop is more to the centre
of the rotor.
Product Specification
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64Zn Content <
1% |
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Chemical Purity > 99.8% |
The diethyl zinc produced during the depletion process is
converted by a wet chemical process to the desired chemical
form, such as the oxide, acetate, or any other zinc compound.
The conversion to a powder occurs under strict supervision
of process parameters giving accurate control of particle
size and moisture content. If required, the zinc powder can
be pressed into forms and sintered to high-density pellets.
Please visit the following links for complete chemical and
physical specifications:
Depleted Zinc Oxide Specifications
Depleted Zinc Acetate
Dihydrate Specifications
| Note 1. |
H. Rakhorst in Production of
DZO at Urenco presented at the 15th BWR Chemistry
and materials Workshop, GE Nuclear San Jose Offices, US
June 3-4, 2002. |
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