Freeze Protection & Heat Trace

Question 0

Which systems have freeze protection?

Answer 0

Systems with outdoor interfaces.

CH, NC, WC, CM, CW, PW, SC, CT, TB, DS, and DW

Question 1

What supplies power to the freeze protection (QJ) system?

Answer 1

NH and QA (lighting) for only the water rec panel

Question 2

What is heat trace power stepped down to from NH?

Answer 2

120VAC by a transformer located next to the control panel.

Question 3

What does the white indicating light on the freeze protection panel indicate?

Answer 3

It indicates that the circuit is energized.

Question 4

Which panel is the safety related panel for freeze protection?

Answer 4

QJN-C05 is in the CST pump room. It has a push button that clears the main control room alarm.

Question 5

Where are the freeze protection heaters located on the equipment?

Answer 5

On instrument lines and pipes under the insulation.

Question 6

What does it mean that the freeze protection lines are self regulating?

Answer 6

They respond to temperature variations anywhere along the heater length to protect against overheating even when the heater is overlapped.

Question 7

What is the neutral wire for on freeze protection?

Answer 7

Provides electrical path for monitoring the continuity of the heater along its length.

Question 8

What is the ambient fixed set point for the freeze protection panel thermostats?

Answer 8

40F (below energizes the heater and above deenergizes the heaters)

Question 9

What freeze protection indications will cause an alarm in the control room?

Answer 9

Line thermostats will send an alarm if the temperature drops to 35F.
If CST piping heaters are energized there will be an alarm in the control room.

Question 10

What is the normal condition of the freeze protection system?

Answer 10

Automatic standby mode.

Question 11

What is the purpose of the heat trace (QM) system?

Answer 11

Maintain given temperatures associated with special processes. Heat control is maintained to prevent precipitation of concentrated material in the fluids.

Question 12

What systems/components have heat trace?

Answer 12

Boric acid batching tank
RMWT piping
HUT piping
RWT piping
RU- 141/143 piping
Hydrogen analyzers and PASS piping
Solid Radwaste system
LRS evaporator
BAC

Question 13

What can be found on the modular solid state controllers mounted on the heat trace control panel?

Answer 13

Controller set point indication on a calibrated dial
Deviation meter 
High alarm light
Low alarm light
Heater on light

Question 14

What heat tracing alarms are in the control room?

Answer 14

A trouble alarm is registered in the control room for any alarm signal in a local panel including panel power failure.

Question 15

What type of cabling is used for systems requiring temperatures above 200F?

Answer 15

Mineral insulation cables which are series connected resistive elements embedded in mineral insulation within stainless steel jackets.

Question 16

Where is heat tracing for the H2 analyzer system powered from?

Answer 16

PH (class MCCs)

Question 17

What has to be checked to verify a low temperature alarm?

Answer 17

Determination should be made to see if it’s due to system flow (acceptable) or heater malfunction.

Question 18

What happens if the H2 monitor heat trace system becomes inoperable?

Answer 18

The H2 monitor system will have to be declared inoperable. If two channels are inoperable, then the unit may have to be shut down due to tech specs.