Electric Heaters in the Nuclear Power Industry

The concept of Immersion Heater is quite simple. Just as the word suggests, it is a heating device that works submerged in water or various kinds of fluid. However, its application is far more complicated than what its function suggests. A simple immersion heater can be used for merely heating up a pool. But the real benefit of immersion heater technology is in its application in the nuclear power industry. The flanged heaters manufactured by WATTCO™ are notable examples of how immersion heaters can be used in such a complicated setting as in maintaining pressurized water reactors in the nuclear power facilities.

Use of Immersion Heater in Nuclear Reactors

One of the key aspects of nuclear power generation is to maintain pressurized water reactors at a constant level. This allows steam generation to power up the turbine for power generation. This is a concept somewhat similar to the steam engine of old locomotives. The primary coolant keeps the nuclear reactor from overheating must maintain 321˚C in order to preserve its liquid state. The coolant is designed to circulate through the loop built into the reactor just like the radiator in an automobile. Moreover, the loop must maintain the high pressure at 2250 psi in order to keep its circulation flowing.

This is achievable by connecting another pressurized tank externally to the reactor equipped with an immersion heater. The goal is to control the temperature of the water in the external tank so that the overall pressure of the water reactors may be maintained at an optimal level. For example, WATTCO™ flanged immersion heaters inserted at the bottom of the tank will heat up the water in the tank so that the combination of water/steam can be controlled at a level required to maintain the reactor.

As the world becomes more conscious of eco-friendly energy alternatives, the demand for cleaner nuclear power generation is increasing. The advantage of an immersion heater is that it is an electric heater. Electricity leaves no environmental residue as opposed to other types of heating units that burn into the atmosphere.

Flanged Immersion Heater

The best immersion type of heaters for nuclear water reactors is the Flanged Heater. It is specifically designed as such that is useful in a pressurized situations, easy to install, and more manageable than other comparable heaters. While it can be used for many different types of liquid heating, this particular product is a water-based heating unit with alloy compositions such as Incoloy® and Inconel® featuring heavy walled sheaths against radiation.

The flanged immersion heaters by WATTCO™ come in a variety of sizes ranging from 2” to 42”. The standard flange ratings are given at 150lbs, 300lbs, and 600lbs. Its apparatus consists of bent tubular elements are brazed or welded onto a flange.  Several matching flanges can be mounted on a nozzle or the tank wall.

Flange Heater Thermoregulation

These heaters are controlled thermostatically by thermocouple devices encased in a terminal box. Besides a standard terminal box option, WATTCO™ also offers water-proof as well as explosion-proof terminal boxes that can be particularly useful for nuclear reactor applications. Digitally controlling temperature, the use of RTD (Resistance Temperature Detectors) allows greater flexibility over the high-temperature situation such as in nuclear water reactors.

The applications of flanged immersion heaters are very wide because of their immersion in most water-based chemicals, such as petroleum. It uses a direct heat approach on the medium with a digital controller to monitor the temperature. The use of a high limit sensor will prevent the liquid medium from overheating. In order to probe the temperature, a thermo-well is often incorporated within the bundle of elements allowing a probe to relay temperature readings to a digital controller.

Despite its portability, flanged heaters are widely used in the industry for heating up volumes of liquid in a fixed gas/liquid controlling. The advantage of a flanged heater is that, unlike other immersion heaters, it can be used to heat up water as opposed to oil. It operates by starting to heat up instantly. The unit maintains the convection current in a uniform direction around the liquid medium until the heat transfer reaches its preset temperature.

Circulation/Inline Immersion Heaters

A more common application for the industrial type of immersion heater is the Circulation Heater, also known as Inline Heater. The names stem respectively from its function and its shape. The main function of this type of heater is to circulate the fluid while maintaining the flow rate. The concept is to transfer the heat from electric power to the fluid. Thus achieving target viscosity for the liquidity to pipe through more easily.

The basic construction of a circulation heater is an inline heater covered by an anti-corrosion metallic vessel chamber. It is a closed chamber with circulation pipes going around, equipped with a pump to carry the fluid. The tank is insulated to prevent heat loss. The chamber features a drain valve to facilitate easy cleaning and maintenance of the system. The flange rating is 150lbs up to 1200lbs.

Immersion Heater Solution by WATTCO™

Specs are typically similar among immersion heaters whether they are circulation/inline or flanged. However, WATTCO™ provides a custom solution to numerous situations for a specified purpose. For example, there was a case involving an advanced gas-cooled nuclear energy consortium, which had required to heat up carbon dioxide/graphite as a cooling agent in the nuclear reactor with a temperature setting at 279˚C for a prolonged period of time. The solution provided was a 12” 2000# psi Stainless Steel 316 circulation heater with thermocouples at exit ports as well as an accurate SCR digital controller.

The benefits reaped by the solution are such that the safety requirements in a highly sensitive environment were satisfied without undermining the specified heat control on the elevated temperature level. An added bonus was that it came with a very low maintenance requirement in addition to a simple installation procedure.

As a recognized manufacturing company of industrial heaters, WATTCO™ is more than just a product manufacturer. We are a solution provider for the oil and gas industries as well as renewable energy, HVAC and government agencies.