Environmental Engineering Reference
In-Depth Information
and takes a very long time and therefore should be avoided if at all feasible.
The effects of soil and groundwater on buried cabling and the miles of bur-
ied piping on any nuclear plant site are also at issue (INL, 2009).
Another issue that arises comes from the use of secondary sources of
water. For instance, so-called gray water (sewage that has been through a
waste treatment plant) has been used and is being looked at as cooling water
to reduce overall water use by large power plants. This water has the poten-
tial for higher and different salt concentrations than drinking water sources
and can therefore cause unexpected corrosion or SCC issues (EPRI, 2007).
Corrosion and decay of materials in the spent fuel pools, such as the boron
containing structures that allow tighter packing of the spent fuel but which
suffered unexpected degradation, also needs to be considered.
Outside of the nuclear plant itself but within the nuclear cycle, materials
issues arise in such varied areas as zirconium metal production (the graphite
receptors, ceramic gas injection nozzles, and ceramic linings in the chlorina-
tion of either ZrO
2
or zircon sand); the manufacture of nuclear fuel due to
the common handling of mixtures of HF and nitric acid for UO
2
dissolution;
solvent extraction systems; and incineration of radioactive waste materials.
For the most part, material issues have been solved in other portions of the
cycle, but the ones listed above continue to be very resistant to reasonable
materials solutions.
In summary, the issues outside of the nuclear island that require research
and development are:
The effects on cable insulation decay of temperature and radiation
inside the containment and due to groundwater or soil for buried cable
outside the containment.
Methods to monitor and repair buried piping and cabling.
Understanding of the interaction between older materials used in the
initial construction of the plant and newer materials that may be used to
repair or upgrade current plant systems including spent fuel pools.
Components in the zirconium conversion from oxide or silicates to
chlorides.
Systems that handle mixed HF and HNO
3
in the UO
2
fuel manufacture
area.
Development of phenomenological understanding of the behavior of
these materials in their respective environments that can be used to pre-
dict their behavior over time.
9.6 References
Boiling Water Reactor (BWR) Systems ( 2012 ), Rep. U.S. NRC. Web. 17 May 2012.
< http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf >.
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