Practice + Operations
A Laser Guided
Oil Setting Tool
Lew Beck, Duke Energy, Oconee Nuclear Station
In the past, the nuclear power industry has experienced
equipment failures due to improperly set oilers. There was
never a precision tool available to help ensure the level was
being properly set on a typical oiler . . . until now.
The nuclear power industry has long realized the
importance and benefit of lessons learned from operating experience (OE) that continually helps improve
the nuclear safety, performance, and reliability of its plants.
This awareness comes from openly sharing operating experience and knowledge between all the nuclear sites.
A few years ago, I attended a presentation at a pump
conference that discussed the problem of accurately being
able to set the oil level on pumps that use a typical style constant level oiler. Shortly after the conference, I was reviewing OE notices and saw that a control rod drive pump at a
nuclear site had experienced a catastrophic failure due to an
improperly set oiler. OE data also revealed where a nuclear
plant had discovered after inspection that over 30 percent of
the oilers were improperly set.
This sequence of events caught my attention because
here at the Oconee Nuclear Station we use constant level
oilers. We recognize the importance of being able to correctly
set and accurately maintain the oiler’s oil level on a pump or
other piece of rotating equipment.
Proper oil level is essential for the life of both the lubricant and the equipment. If a critically low oil level condition exists, the rotating equipment bearings will not receive
enough lubricant necessary to maintain proper film strength,
which results in surface contact and eventual failure. Without
enough oil to prevent excess friction, thermal runaway can
quickly occur and lead to a rapid catastrophic failure.
Churning of the oil will also occur if a critically high oil
level condition exists. This accelerates the oxidation rate as a
result of excess air and elevated temperatures. Too much oil
will also lead to oil leaks and can affect the proper operation
of oil rings and flingers.
This critical oil level range – between the low and high
level – can be extremely narrow for rotating equipment with
small bearings. In smaller equipment, setting the oil level so
that it is accurately maintained within its critically low and
This photo from one
nuclear plant shows
the control rod drives
and reactor closure.
high level range becomes even more imperative. (Note: The
equipment manufacturer should always be consulted for the
recommended oil level.)
The industry OE data I reviewed not only exposed that
equipment failures had happened due to improperly set
oilers, but that users could also easily set a constant level oiler
incorrectly by using conventional setup techniques. The typical method for setting an oiler involves using a straightedge
and level and transposing the mark from the oil sump to the
oiler, thus placing a mark on the oiler that corresponds to a
mark on the oil sump.
The accuracy of this method depends entirely upon the
experience of the user and how accurately they can visually
sight the scale between the oil sump and the oiler – which
becomes more difficult as the distance between the two
points of reference increases. The greater the distance the
oiler is from the housing, the easier it is to make a mistake
