The AM3M is a continuous air monitoring system designed to measure the particulate, iodine and noble gas activity in a sample air stream. The font class="thead"> AM3M uses three separate measuring channels arranged in series to perform the measurement. A common vacuum pumping system is used to transport sample gases through the system. Local RM1R display and control units are included for system operation, data concentration and communication. The particulate channel uses a lead shielded moving filter that provides collection of airborne particles using a continuous spool of filter paper. The filter paper deposition provides an even distribution and includes the capability of adjusting the filter paper speed to accommodate applications that deposit higher activities, such as post-accident monitoring and analysis. The particulate channel is equipped with a beta sensitive plastic scintillation detector (model SD201PB) for detection of beta emitting particles. The detector interfaces with a locally mounted spectrum analyzer (model SDA3E) that provides biasing voltage to the detector, analyzes the nuclear pulses for counting, and provides an automatic gain control function. The SDA3E unit communicates with the display and control unit (model RM1R) using Ethernet (TCP/IP), RS232 or RS485 communications for display of the measured activity and for alarm determination.

The exhaust from the particulate channel is plumbed to the inlet of the iodine monitoring channel. The iodine monitoring channel uses a fixed filter lead shielded sampler for collection of the iodine activity. In the iodine channel, a TEDA activated charcoal cartridge or silver zeolite cartridge replaces the particulate fixed filter media. A gamma sensitive scintillation detector (model SD220N) is placed within the lead shielded sampler with the sensitive end exposed to the collection cartridge. The SD220N detects the gamma events and provides the nuclear pulses to an external pulse analyzer unit for pulse analysis and transfer data to the RM1R. The sample
gases, with particulate and iodine activity removed, enter the noble gas sampler for measurement. The noble gas sampler (model GS54) is a lead shielded sampler enclosing a sensitive volume. A SD220N gamma scintillation detector or SD201PB beta scintillation detector is located with the sensitive volume for measurement of noble gas activity. Again, the detector detects the nuclear events, pulses, biasing voltage, and performs gain stabilization. The noble gas sampler includes a vacuum transducer to
automatically correct the measured activity to standard pressure. The vacuum pumping system uses a positive displacement carbon vane pump for transport of sample gases through the monitoring system. A mass flow meter and proportional control
valve allows the sample flow rate to be either manual set to the desired flow or to match the sample flow rate to a stack or vent velocity for representative sampling. The flow rate is provided to the local RM1R electronics for determination of total release and for calculation of concentrations. Alarms are included for annunciation of a low flow condition.