FUNCTIONAL USES OF TEMPERATURE DETECTORS
Temperature Detectors
FUNCTIONAL USES OF TEMPERATURE DETECTORS
Temperature sensing devices, such as RTDs and thermocouples, provide necessary
temperature indications for the safe and continued operation of the DOE facility
fluid systems. These temperature indications may include:
Reactor hot and cold leg temperatures
Pressurizer temperature
Purification demineralizer inlet temperature
Cooling water to and from various components
Secondary feed temperature
EO 1.6
STATE the three basic functions of temperature
detectors.
EO 1.7
DESCRIBE the two alternate methods of determining
temperature when the normal temperature sensing
devices are inoperable.
EO 1.8
STATE the two environmental concerns which can
affect the accuracy and reliability of temperature
detection instrumentation.
Functions of Temperature Detectors
Although the temperatures that are monitored vary slightly depending on the details of facility
design, temperature detectors are used to provide three basic functions: indication, alarm, and
control. The temperatures monitored may normally be displayed in a central location, such as
a control room, and may have audible and visual alarms associated with them when specified
preset limits are exceeded. These temperatures may have control functions associated with them
so that equipment is started or stopped to support a given temperature condition or so that a
protective action occurs.
Detector Problems
In the event that key temperature sensing instruments become inoperative, there are several
alternate methods that may be used. Some applications utilize installed spare temperature
detectors or dual-element RTDs. The dual-element RTD has two sensing elements of which only
one is normally connected. If the operating element becomes faulty, the second element may be
used to provide temperature indication. If an installed spare is not utilized, a contact pyrometer
(portable thermocouple) may be used to obtain temperature readings on those pieces of equipment
or systems that are accessible.
IC-01
Page 8
Rev. 0
