Trade.Information

Product Name: TRITIUM CONTAMINATION IN PIPES TOOLS and OBJECTS

Product Description

System: Ion Transfer Electret Ion Chamber 
Lab/Field: Field (In situ measurement ) 
Radiation detected : Low energy beta emitters such as tritium inside pipes, on contaminated tools and other irregularly shaped objects. 

Introduction 

Pipes do get contaminated with tritium in pipes used in heavy water reactors and in thermonuclear research programs and at times in handling of tritiated compounds. The beta particles have a very small range in air (3 to 4 mm) and conventional methods of monitoring by locating a windowless gas proportional counters inside the pipes is not practical. The ions produced by the beat radiation are moved out to an electret ion chamber and measured. This method is called as ion transfer method. 
Operation 

This system is a passive integrating detector system for measurement of tritium and other low energy emitters. It consists of a charged Teflon disk(electret), open faced ionization chamber, and electret voltage reader and data logger. When the electret is screwed into the chamber, a static electrostatic field is established and a passive ionization chamber is formed. When the ions are brought into such a chamber by the fast moving air flow through an alpha contaminated pipe, the ions are attracted to the charged surface of the electret, and the electret charge originally present gets reduced. The electret charge is measured before and after the exposure with a portable electret voltage reader, and the rate of change of the charge ( change divided by the time of exposure) is proportional to the beta activity inside the pipe. 

Electret ion chambers(electret +chamber) are inexpensive, simple, passive with no moving parts or electronic components, unaffected by ambient environmental conditions and can be normally used for several measurements before a need for replacement of the electret. 
Specificity/Sensitivity 

This method is a gross beta measurement. The lower limit of detection is a function of deployment time: 2 to 3 million dpm (about 50,000 Bq) 2000 to 3000 dpm (about 50 Bq) can be detected in 15 minutes. Higher levels are measurable in shorter period s, and still lower levels in longer periods. This method is usable for determining the beta contamination inside the pipes. A contamination level of 2200 dpm/cm2 in a pipe, 6 feet long and 2 inch diameter is measurable in 15 minutes. Higher levels are measurable in shorter periods, and still lower levels in longer periods. The limit of detection address the derived limits in DOE facilities and in heavy water reactors. 
Applicability for Site Clean up: 

High contamination levels may be measured with a deployment times of a few minutes. Several electret ion chambers are usable with several pipes at a time and analyzed at a time using one measuring/analyzing equipment. 
The unit is adaptable for measuring contaminated tools, and other irregularly shaped objects. 

Validation and Calibration: It is easy to validate and calibrate using standard tritium sources. 
Cost 
Cost of Equipment: $ 4000 to $ 6000 
Consumable cost of detector per measurement: Under $ 1

Company Details

Rad Elec Inc (REI) was incorporated in 1987 to manufacture and commercialize a product researched and developed under a research contract with NYSERDA (New York Energy Research and Development Authority) during 1986 -1987. The product was based on... more