ORNL-1771 - Oak Ridge National Laboratory

ANP QUARTERLY PROGRESS REPORT
10-2 10.‘
4400 K, which is in the blue region,
7.2 x lO-’lumen = 1,8 x 10-7wat~ ofvisible light.
The amount of air glow can then be characterized
as the fraction of energy transformed into visible
I ight:
/=
watts of visible light ii) tube
watts of energy dissipated in tube by gamma radiotian
1.9 x
- - - - 6 x for atmospheric pressure.
3.2 x 10-2
This experimental valus nf light yield is in disa-
5
yreament with the theoretical estimates of Welton
(0.0.5) and of Fcaulkner6 (2 x In neither of
these calculations was the effect of pressure
considered.
172
1
PRESSURE (cm Hg)
Fig. 13.6. Variation of Glow with Pressure.
ORNL-LR-DWG 2659
EQUIVALENT ALTITUDE (ft)
60,000 40,000 20,000 0
10 1 0‘
The value of L may be used to calculate the
light emission from a typical nuclear-powered
aircraft. For a reactor power of 200 Mw and a
reactor shield of 147 cm of water (similar to the
shield design of the 1950 ANP Shielding Board’),
the BSF measurements indicate that the gamma-ray
dose just outside the edge of the shield would be
1.36 x lo6 r/hr with ri relaxation length of 22 cm.
The dose integrated over spoce outside the shield
is 1.2 x 10’’ (r.cm3)/hr. Multiplying this by L,
the luminosity would be 75 lumens, which would
have roughly the equivalent brightness to the eye
of CI 10-w (+7 w) incandescent light if the aircraft
were far enough away to appear CIS o point source
. .. . . . . . . . . . . . . . . . . . . .-
7Report v/ the Shielding Board /or the Aircralt Nuclear
Propulszon Program, ANP-53 (act. 16, 1950).