Present indications are that
the principal gearing in nuclear power plants will be in connection with
turbines. Such reduction units should
be far
enough removed from the area of
high radiation that no degradation of the oil
from such a source will occur.
Cox et al.^14 who have
considered this matter state: “Irradiation tests of turbine oils show that
maximum expected radiation doses in
current and projected power plants over a twenty year period does not change the physical
properties of the oil. Oxidation stability and other properties are,
therefore, still of most importance in turbine oil selection”.
Also Okrent^43 in treating design considerations of nuclear powered surface vessels concludes that the reduction gearing in connection with the
turbine presents no problems from
a radiation standpoint. In spite of the
above thoughts, Watson^51
mentions that in nuclear
power generating stations, a
number of applications will be
found where gears should
be run without lubrication. Experiments were, therefore, made
with various materials, run in a dry state, with latter wear. As a result, it is suggested that if loads are not
heavy, spur gears, made of case hardened
En steel, phosphate prior to
coating the flanks with molybdenum
disulfide, can be run continuously, in a dry state, without measurable
wear. Also a worm wheel ,
made from woven
asbestos base with a case
hardened steel worm, is promising
for operation in a dry state.
No doubt, when and if gear oils
with radiation resistance are necessary, suitable fluids will have been
developed. Thus, polybenzenoid compounds containing short alkyd groups show promise
in such applications.
One interested
in this subject might avail himself
of a series of eight
papers devoted to “Non-conventional
Lubricants and Bearing Materials such as Are Used
in Nuclear Engineering”. These
were presented at the Manchester college of Science and Technology on April 12,
1962 by the lubrication and Wear Group of The Institute of Mechanical Engineers
(British).
