Instrumentation Design

The Institute for Energy Technology has been world leading within design and manufacture of nuclear instrumentation since the early 1960’s for experiments in the Halden Reactor. Today, IFE-Halden has a unique competence in instrumentation used for on-line monitoring of nuclear fuel and material behavior; specially customized instrumentation solutions; and a highly developed program on Generation IV instruments. IFE –Halden has a foresight development program aimed at meeting instrumentation requirements for the long-term future within the nuclear industry.

Eriksen, Knut Waldahl



A variety of different measuring sensors/devices have been designed, qualified and widely used. Normal types of sensors include instruments for measuring temperature, pressure, position/ displacement, diameter, flow, crack-growth, corrosion, ECP, etc. There exists a unique competence in constructing sub-sized and sensitive devices able to withstand rough environments including maintenance by remotely operated equipment.

Several different measurement principles are used (both direct and in-direct measurements). Many of the sensors are non-intrusive. Several different techniques are used in e. g. welding of metal-mantled mineral-insulated signal cables or in fabricating leak-tight sealing systems.

The designers have access to all common design tools, e. g. FEM programs for modelling temperature distributions, stress, fluid fl ow etc. Complex structures and interactions with other components, systems or humans are evaluated by the use of 3-D models or fully interactive virtual reality models. In addition, the designers work very closely with the mechanical workshop, which fabricates prototypes and test units on demand. Qualification of prototypes and sensors normally involves autoclave testing or other types of short or long term testing in a simulated "real" environment.

IFE has a skilled, experienced and dedicated multidisciplinary staff with a genuine interest in getting things to work and solve "impossible" problems in different fields. If something already works - we can often make it even better.

ifeA state of the art workshop is available with access to all types of modern production/ machining equipment such as computerised (CNC) lathes and milling machines (CNC 5-axis milling machines) and equipment for Electrical Discharge Machining. Equipment for welding and heat-treatment of all types of materials is also available. Picture showing a close-up of the 5-axis milling machine.

Electron beam-welding machines are used for both standard and complex high-quality brazing and soldering operations as well as for special heat treatments of materials.

The entire process is guided by an ISO 9000-based quality assurance system. All types of sensors and instruments are included in experiments carried out in the Halden Boiling Water Reactor. Therefore, IFE also has first hand experience of operating in a complex environment, often with remotely operated equipment at tight time schedules. IFE is well positioned to understand the requirements of demanding customers.


At IFE, the designers work very closely with the mechanical workshop, which fabricates prototypes on demand.

Case study: High Resolution Profilometry Gauge

ifeThough IFE designs a wide range of measuring devices, only one device will be described here.

The High Resolution Profilometry Gauge has been developed for performing profilometry and diameter measurements on tubes under high temperature and high pressure conditions. The device has been extensively used in nuclear test reactors, and has also been adopted in several non-nuclear applications.

The High Resolution Profilometry Gauge represents an accurate, reliable and thoroughly tested instrument well suited for operation in demanding environments.

Technical description

The High Resolution Profilometry Gauge is based on the Linear Voltage Differential Transformer principle. A magnetic field is formed within a structure consisting of two primary and two secondary coils, a ferritic core and a moveable ferritic armature. The moveable ferritic armature is connected to a sensor that follows the surface contour to be traced. As the sensor is moving the armature will tilt correspondingly around a hinge point thus changing the size of two small gaps in the magnetic field. These gap changes in the magnetic field will cause the electrical balance between the two coil systems to change accordingly.


The main components of the High Resolution Profilometry Gauge are made from high-grade stainless steels and Inconels. Electron Beam welding is used for all welds. High-temperature mineral insulated cables with Inconel outer sheaths are used as signal cables.

Operating conditions

The maximum operating temperature for the High Resolution Profilometry Gauge is 325° C and the operating pressures are normally in the range 30 to 200 bar.


The accuracy of a High resolution Profilometry Gauge is within +/-1.0 µm. The overall accuracy will depend on the system design (measuring range, guiding systems, drive mechanisms etc). The High Resolution Profilometry Gauge must be connected to a hydraulic or electric positioning system for axial and/or radial gauge movements.


The High Resolution Profilometry Gauge is well suited for long-or short-term measurements of the inner and outer diameters/ surface profiles of tubes/ surfaces exposed to high temperature and pressure conditions.

Operating experiences

High Resolution Profilometry Gauges have been widely used in the experimental programme performed by the Halden Reactor Project in the Boiling Water Reactor during the last 15 years. High Resolution Profilometry Gauges have been delivered to several organisations within the OECD countries.

Life expectancy

The normal lifetime of the instrument is 3-5 years.