PS Magazine - TB 43-PS-588
PS, The Preventative Maintenance Monthly
ISSUE 588
NOVEMBER 2001
If there is no evidence of leaks, check the
MRS for proper illumination. Cover the
MRS’s window and look into the objective
end for illumination from the tritium light
source. If there is no glow, it could mean
the tritium cell is leaking inside the MRS.
Stop and call in your radiation protection
officer (RPO) immediately!
Finally, always wear the latex gloves that
come with the desiccant kit, NSN 1240-01-424-4628, to protect yourself against
potential tritium leaks.
PS 588
NOV 01
13
Frozen Desiccant
1.
Use a
3
∕
8
-in socket-head screw key
to remove both pipe screws on the
barrel of the MRS.
2.
Remove the old O-rings and put
them in a plastic bag.
3.
Unwrap a new desiccant, NSN
6850-01-081-4193, and check its
color. If it’s blue, use it. If it’s some
other color, turn it in and get another.
4.
Push the old desiccant out of the barrel hole by sliding in the new desiccant. Put
the old desiccant in the plastic bag along with the O-rings from the pipe screws.
5.
Install two new O-rings, NSN
5331-00-724-7902, from the desic-
cant kit. Install the screws and torque
‘em between 240-250 lb-in.
6.
Put the latex gloves in the plastic
bag and seal it. Place the bundle into
a second plastic bag and seal it.
7.
Turn the bag in to your RPO for
disposal as radioactive waste.
PS 588
NOV 01
12
M1-Series Tanks…
Watch For
T
he desiccant inside a tank’s muzzle reference sensor (MRS) is there to soak up
moisture, but if it freezes, the MRS window can break. Since the MRS uses radioac-
tive tritium for its light source, cracks are real bad news.
The desiccant is supposed to be changed during semiannual maintenance, but to
prevent freeze cracks, it’s important to check the desiccant for moisture at least
monthly during cold weather.
Before you start, take a look at the MRS window. If you see cracks or excessive
amounts of moisture, double-wrap the MRS in plastic and notify your support.
Look for
illumination
Window
cracked?
Double-wrap MRS
in plastic
Check window
for cracks or
excess moisture
If the
desiccant
needs to be
replaced, do
it like this…
and don’t
forget to
wear
gloves!
Remove both
pipe screws
Put new
packing on
each pipe
screw
hmm…
Add some
desiccant and
call me in
the morning!
…he has
a leaky
muzzle
reference
sensor…
whatta
relief!
thanks,
doc!
y’See,
doc!
he doesn’t
look good.
I’m worried!
I think he’s
gotta cold!
588. 12-13 (C)
9/29/01
4:33 PM
Page 1
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