gs Of. es 
} : e ( 
gs (Nominal 100 ohms) 
a _ Stackpole © Reactor up 4 
: 4 X Reactor down FIG. 2. Effect of in-pile irradiation on JAN RC-20- 
ue type carbon composition resistors having nominal 
resistances of 100 and 10° ohms. Recovery during 
S reactor down time is indicated for the high-resist- 
~8 ance elements. Irradiations were with fluxes-of 9.6 
X 10!” thermal neutrons/cm?/sec, 10° fast neutrons/ 
3 “10 cm?/sec, and 2 X 10! gammas/cm?/sec 
3 "1003 
E g : 
ae 2 1009- (MEPCO) 
ee 09 wx x 
= 1.004 grr 
& 
= 
= i 
« : . 
- 1009 tIRC) - : 
x @ x 2 0 Bw @ > ® © Xo x 
1.004 : 
10 es 4 fo} ! 2 3 4 5 6 7 8 9 10 
0 2 2 e es \ Integrated. Thermal—Neutron Flux (10%n/em?) 
* Integrated Thermal—Neutron Flux (10!7n/em®) Ce oe 
FIG. 3. Graphs demonstrate relative stability of 
wire-wound resistors to pile irradiation. Each point 
represents the average value for four resistors of 
large potential gradients may be pro- vosuuliael 10,000-ohm value. Thermal flux 6.23 X 101! 
duced by charge displacement through n/cm?/sec 
Compton collisions (3, 8, 9). 
Figure 1 shows insulation resistance i 
during irradiation. 25 Centralsb ceramic 
fe ° 00:0 0-0 O26 2° rok ee 
i Aerovox Hi Q ceramic 
= 9 oo 0 love} Lele) igo x 
Z Erie ceramic e ‘ : } 
re Ore 620-22 ore) 0 0 20 x ' 
; Corn@i ~Oubilier mica 
ae ome .9 *%* 00 0 0 0nMO 
Resistors 
a wo 
Resistors may suffer for a variety of 
reasons: The alternate paths afforded 
by ionization may reduce the effective 
value of large resistances subjected to 
high potentials. The breakdown of 
bonding and impregnating materials 
may also permit parallel conduction 
paths. The basic resistance material 
may also suffer. 
ba) 
oS = 
a wn 
w 
Je-(10® farads )->| fk —-(10-® forads)—-——>{_ ke —— (10°* tareds) —>} 
; a 
wo 
, eepscdaee eb pe ) . : 
Figures 2 and 3 exhibit some in-pile ‘eg |. 48 : . 
data on resistors. It is immediately £ 49 ; ‘ 
apparent that the resistance of a com- 3 pape ; Vice) mice: 
ppare at the star , 3 XO@ y op WB 00 < 90 
ponent to nuclear radiation varies 48 A cee ° 
markedly with the manufacturer. The : 
; y “ seh pid hili 50 Aerovox mica — 
increase of the rate effect’ with large : x 0M@0 00 4% 000 °o 0 pO 
resistance values is expected. The as - : 
initial change of resistance on insertion 
into the reactor results from a tem- 33 
° O Reactor up 
perature change from 20 to 50° C. i X Reactor down Hi Q Aerovox ceromic 
Wire-wound power resistors showed 3 : 
practically no radiation damage. 
Capacitors 
Mica, ceramic, electrolytic, and oil eto | 2 3 4 66 7 G2 oO cl 
capacitors were tested. Electrolytic 
capacitors failed in about one-tenth of 
the standard exposure time (1018 FIG. 4. Mica and ceramic capacitors show different stability under reactor 
2). 7; . irradiation. Top three charts are for CK60Y821Z ceramics. Next three are for 
n/em z oil capacitors enlarged ove Oe CM61C473J micas. Bottom chart is for CK61Y152Z ceramics. Each point is an 
gas evolution and developed leaks; and average for four capacitors. Thermal fluxes were 7 X 10!! n/cm?/sec for first 
mica and ceramic capacitors showed three charts, 6 X 101! n/cm?/sec for others 
integroted Thermal—Neutron Flux (10'7n/em?) A 
| 
93 
