Fork Detectors (IAEA) B2102 Series

ANTECH B2102 Series Fork Detectors are routinely used as inspection tools, for safeguards purposes, and to conduct non-destructive measurements to determine the radiation from reactor pond fuel rod assemblies while stored underwater.

Fork Detectors are used to measure neutron and gamma radiation activity from spent fuel assemblies. They are supplied in three different configurations:

  • BWR used to measure Boiling Water Reactor fuel rods
  • PWR used to measure Pressurised Water Reactor fuel rods
  • VVER used to measure VVWR fuel rods (currently used in Russia and the Ukraine)

The difference between the different types of unit is the inner distance between the tines of the detector head; the VVER option has the largest detector head and the BWR has the smallest. All other components are identical. The detectors are designed to be portable and easy to assemble to facilitate transportation between sites and quick set-up.

Detector efficiencies of 2-4% (typical) are attainable, depending on the detector type and geometry.

B2102 Fork Detector Datasheet


B2102 Series Fork Detectors are manufactured to meet the IAEA’s requirements. Each unit consists of a detector head with integral electronics, a set of connection pipes with associated interconnect clamps, O-ring seals, interconnect cables and a mechanism for attaching the detector assembly to the pond gantry side rails.

There are three output signals: two from the neutron detectors which are combined as a single output from the two fission chambers in each tine of the detector head, and one from the two ion chambers which is combined as a single output. These three output signals are fed into the counting electronics, such as a MiniGrand or MicroMesskanal.

Each detector can be supplied tested with nuclear sources (optional) and are delivered with full documentation and test records including a leak test report, Certificate of Conformance and manufacturers test records for preamplifier and ³He tubes.

Features & Benefits


  • High density polyethylene detector head – PWR, BWR and VVER fuel configuration – to be specified by customer
  • All external components manufactured from polished stainless steel and polyethylene
  • Rugged cable construction with extra strain relief for connectors
  • Water tight detector head and pipe assemblies (IP68)
  • Supplied with 11000 mm (433.07 in) of extension pipes, connecting flanges, clamps and ‘O’ ring seals
  • Mounting bracket for securing to gantry surrounding fuel pond
  • Reusable and decontaminable shipping containers for the detector body, other components and pipe sections
  • An essential spares and maintenance kit


  • Can be supplied as a system with all commercially available neutron counting shift registers
  • Designed for ease of decontamination
  • Easily assembled and dismantled for transportation between facilities
  • Highly reliable detector electronics
  • Components leak tested prior to delivery
  • Detector head and extension pipes supplied in reusable type transportation containers
  • IAEA configuration
  • 2 input/1 output OR box
  • BWR, PWR and VVER detector components to a common design, apart from polyethylene detector head, enabling substitution of detector head geometries
Model B2102-BWR Model B2012-PWR Model B2012-VVER
Configuration BWR PWR VVER
Dimensions between tines (W x D) 165 mm x 195 mm 235 mm x 245 mm 430 mm x 425 mm
Neutron detectors 4 x RS-P6-0805-110 Fission Chambers with 127 mm (5 in) active length (or equivalent)
Gamma detectors 2 x LND Model 52113 Ion Chambers with 127 mm (5 in) active length
Preamplifier PDT 210A (or equivalent)
Extensions pipes 5 x 2000 mm (78.8 in); 1 x 1000 mm (39.37 in) length, lifting pipe
Cables RG174 (or equivalent) multicore cable assemblies under a single common cover
Nucleonics Fully compatible with MiniGrand, Grand and MicroMessKanal counting electronics