Section 3 - Installation
3-25
2.
Select Array spine scan and set scan length for 9.5 inches.
3.
Scan the meter.
4.
Observe the scan to verify that the entire chamber of the meter is included in the scan.
5.
Record the result.
Note:
Array spine scan dose should be less than 200
µ
Gy (20mrad).
6.
Record the highest reading in the service report.
Note:
Enter this information into
The Radiation Measurement Report
(see page 3-28).
CHECK HVPS/S (TANK) FOR RADIATION LEAKAGE
For regulatory and safety reasons, the High Voltage Power Supply/Source (HVPS/S) must be
checked for radiation leakage at installation time or whenever the HVPS/S is replaced.
Theory
Radiation leakage from the HVPS/S results from a defect in the lead liner of the tank or its cover.
If there is a hole in the lead liner, the resulting leakage produce pencil beam. If there is a crack in
the lead liner, the resulting leakage produce a fan beam.
In either case, the initial survey must be taken close to and almost touching the tank with the
survey meter probe. If a leak is found, the meter indicates a spike in the reading. If this occurs,
you must then move the probe one meter (approx. 40”) along the beam from that spot to
determine if the leakage is within acceptable levels.
The Victoreen 450P has a response time of:
Range Time
0-4mR/h 3.3 seconds
0-40mR/h 4.5 seconds
Performing The Procedure
1.
Remove the tank cover and set the X-ray leakage test shield (099-0566) over the
aperture slot.
Figure 3-21. Leakage Test Shield (099-0566)
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