Controls of Feed-Water Temperature to Test Nuclear Elements

Circulation Heater

The Challenge
Inlet temperature of demineralized feed-water must be controlled to properly test heating element. Required temperatures range from not less than room temperature up to 600°F.

The Solution
A specially designed 300 kW, 480 Volt, 3-phase high pressure Chromalox electric circulation heater was built and installed in the process loop.

HEATER CONSTRUCTION: Every part of the heater in contact with water-heating elements, heating chamber, flange and piping, is stainless steel. The heating assembly will withstand 1500 PSI at 600° F. Three banks of elements (100 kW per bank) are mounted through the flange, with wiring inside the top end cap.

ELECTRICAL CONTROLS: Three circuits are used, one for each of three 100 kW banks. One 30-second motor-driven percentage timer controls each of two banks. The third bank is proportionally controlled by a thermocouple. The two timers are easily adjusted by hand to produce the balance of heat required. Three size 4 magnetic contactors are used with the controls. An electronic low-water cutoff prevents elements from energizing unless completely immersed.


  • It quickly delivers, from a cold start, the exact temperature at required pressure.
  • Temperature control is prompt and accurate.
  • Operation is simple. 
  • Because heat is completely contained in a well insulated jacket and piping, little heat escapes to create unpleasant working temperatures in the lab.