Measuring Total Tritium (Ci or Bq) Emissions From Stacks and Effluents
Overhoff manufactures instrumentation designed specifically for measuring and recording the total tritium concentration discharged out a stack or other effluent. Our stack monitors include a touch-screen HMI display, which computes the total amount of tritium released in Ci or Bq by multiplying the measured tritium concentration per cubic meter by the stack flow rate. The stack flow rate can be entered manually in the software (static), or a dynamic real-time flow rate can be used by integrating with the output from a flow rate sensor installed in the stack (typically via 4-20mA).
Tritium is typically measured using either dual 2L (MDA: 1 μCi/m3 or 0.04 MBq/m3) or quad 2L (MDA: 0.5 μCi/m3 or 0.02 MBq/m3) ionization chamber assemblies which both provide dynamic gamma compensation. Quad 2L ionization chambers arranged in a cruciform geometry provide the best sensitivity, stability, and omnidirectional gamma compensation for applications that require extra sensitivity and stability due to external gamma fields. If needed, a pump system is provided which includes a filter, pump, and flowmeter.
These monitors include audible and visual alarm indicators, with two tritium level alarms (alert and high level), malfunction alarm (power supply failure or electrometer failure), low flow alarm, latching and non-latching alarm modes, and up to three alarm relays (2 level alarm relays and 1 malfunction alarm relay). Data output to a remote computer or control system is available via RS-232 (max. distance 50 ft.), RS-485 (max. distance 500 ft.), Ethernet, or 4-20mA log.
Available measurement ranges:
Standard Range: 0.1 to 1,999.9 μCi/m3 or 1 to 19,999 μCi/m3
Wide Range: 1 to 1,999,999 μCi/m3 if tritium surface contamination is not a concern*
*If you want to cover a wide measurement range but expect high tritium concentrations in normal use, we offer a dual-chamber system with automatic solenoid valve control to direct the sample to the appropriate chamber. Dual or quad 2L ionization chambers are used for low level measurement, and when the tritium concentration rises past a certain level, the sample is automatically redirected to a single 50mL chamber with wire-grid electrodes to reduce tritium surface contamination. This method ensures that the low level chamber is never contaminated by high concentrations of tritium to retain its integrity. Contact us for more details.
Overhoff real-time stack monitors include:
Model Triathalon-H3: Compact, lightweight stack monitor with color touch-screen display and NEMA-4X wall-mount enclosure with lock and key. A desiccant dryer column allows the user to measure either total tritium (HT + HTO) or HTO only. Includes two tritium level alarms (alert and high), malfunction alarm, and low flow alarm, in addition to a totalizer for computing total tritium release. Note that audible alarm is not provided due to enclosure housing, but can be added on externally if desired.
Model 321-Totalizer: Similar to above unit, but housed in a table-top / 19” rack-mount enclosure. Standard range.
Model 421-Totalizer: Includes an extra wide measurement range to measure all the way from 1 to 1,999,999 μCi/m3.
Model 593 and Model 593.2: Ultra-sensitive, gas proportional counting systems for measuring tritium levels down to 0.01 μCi/m3 (1 kBq/m3) with 0.003 μCi/m3 (0.1 kBq/m3) resolution.
Note we also offer passive stack (air) samplers: