Mirion Technologies DMC-2000 User manual

Radiation. Safety.
Using Telemetry for Diving
Applications

Introduction
•Training this year is broken up into smaller modules. This allows more flexibility for the
customer to determine attend only the training needed.
•While the time for each class is more limited, if you have specific issues, problems or
applications you need to work out ,let me know and we’ll see if we can work it in as part of
the class.
•We hope that you will enjoy this class, have some fun, and maybe even learn something.

Agenda
•Introduction
•Equipment
•Passive
•Active
•Dosimeter Transmission
•Testing
•Setup
•Monitoring

Radiation. Safety.
Introduction
•Diving -We receive a lot of calls on Diving operations,
normally because it is an infrequent task (except at
Oconee) and personnel are not familiar with the set up of
the equipment, or they don’t have all of the correct
equipment for the job.
•Because many times diving is an emergency task during an
outage and becomes critical path, spare equipment is
highly recommended.
•Also, it is very important to assemble and test all of the
equipment as it will be used prior to placing it onto the
diver and into the water.
•Before we assemble and test the dive equipment, we need
to discuss first what equipment is typically used.
•We have two different types of antenna systems for
underwater work: a Passive system and an Active system.
How each site plans on utilizing the equipment will help
determine what type of equipment is best to use.

Radiation. Safety.
Equipment –Passive Antenna System
Passive Antenna System –This can be used in two ways
•With the repeater: In this scenario you have two radios in the repeater instead of one
-and they are connected by an internal serial cable. One radio is connected to the
remote underwater antenna and the other has an external antenna that broadcasts
the signal out to be picked up by a local or system Base Station
•Direct to base station: Instead of connecting to the repeater, the antenna can be
connected directly to a Base for local monitoring with a serial cable or for system
monitoring. This method is the simplest with the least points of failure for critical
activities –but it is limited to one diver at a time (or one diver per base).
•When using the 300’ antenna, there is a supplied amplifier that should be used. Be
sure to power the amplifier with the provided 15V power supply (you do not need to
use this for the 100’ antenna).
•Drawbacks with this system include: the coax cable can be more easily damaged and is
difficult to repair for U/W use. Also there is additional signal loss (especially with the
longer cable lengths). Finally, when multiple divers are in the water, the repeaters can
feed back on each other causing crosstalk interference and loss of data so you need
separation distance.

Radiation. Safety.
Equipment –Active Antenna System
Active Antenna System
•The active system must be used with the active repeater, and cannot be
mixed with the passive system.
•In this system, one of the repeater radios is actually incased in epoxy in the
paddle to use underwater. This provides much better coverage than the
passive system since the radio is actually on the diver instead of just the
antenna. Thus, there is no signal loss through the cables. The underwater
radio is connected to the topside radio by a standard underwater AMP cable
which carries serial data.
•Drawbacks with this system include the fact that it cannot be used directly
with a Base, and will feed back into itself when out of the water. It is also
more difficult to test since you cannot easily isolate the active antenna.
•One of the keys to using the Active system is to be able to test both
components. We have created a procedure to do this which we will go
through at part of this application.

Radiation. Safety.
Equipment – Dosimeter Transmission
iMUX -Typically most plants use an iMUX.The reason for this is that it ensures better
coverage for multiple dosimeters since the iMUX can be placed close to the antenna
regardless of where the dosimeters are placed on the diver.
•ALWAYS use new Alkaline batteries in the iMUX for each dive. Also place new
batteries in the dosimeters to be used at the start of the job, and ensure the battery
cover is torqued correctly on the dosimeter. Weak batteries and poor contact in a
DMC can cause the dosimeter to loose contact due to flexing under pressure at
certain depths.
•The drawbacks for using an iMUX are that it is a little bulky, and the connection to
the dosimeters are some times difficult to keep secure. Also, no enhanced alarms.
iPAM TX / DMC-3000 Transmitter -It is possible to use iPAM’s/3k Tx instead of an iMUX in
certain scenarios. This can work with a limited number of dosimeters kept in relatively
close proximity but will typically not maintain as continuously strong a contact as with an
iMUX.You can use an iPAM in addition to an iMUX for an enhanced alarm if needed.
Using an active antenna will improve the coverage for this methodology.
•The drawbacks as noted include: the coverage, each dosimeter is more bulky, and
the system is more susceptible to moisture / water intrusion

Radiation. Safety.
Testing –Dive Equipment
•iMux –This is pretty easy. Connect all dosimeters to the adapters, plug the
adapters into the iMux, power the iMux and see if all the lights blink correctly.
Then look you your telemetry software and verify all the dosimeters are being
received.
•Active System –See Mirion Testing Procedure 12-00256 Handout
•Passive System
•Repeater –In general you can perform a similar test to the above
procedure to verify the repeater works, simply change the channel of
Radio 1 of the repeater and the channel of an iPAM. This isolates the set
so the base cannot see them directly, only through the repeater.
•Base - A lot of plants connect the Passive antenna directly to a base and
do not use the repeater. In this case the base is easily tested with or
without the dive antenna so the real focus is the antenna.

Radiation. Safety.
Testing –Dive Equipment
•Passive System
•Antenna -The easiest way to check operability of the passive dive antenna
is to place in a coil and read the resistance across the center pin and shield.
It should read ~1.1k Ohms. While reading the resistance, flex and stress
the cable and look for changes in the reading to verify there are no breaks.
However, for additional assurance, you can also try to shield the antenna
and transmitter (you can use an iPam). Basically wrap the antenna paddle
and an iPAM in several layers of foil, sealing well up the cable. Disconnect
the antenna from the base and move the shielded paddle far enough away
from the base that you no longer receive the iPAM. Then connect the
antenna to the base and verify you can no receive the iPam.
•Another indication of a problem with the passive antenna is the light on
the amplifier blinks out after being turned on.