ORNL-TM-7207 - the Molten Salt Energy Technologies Web Site

With the different ~Bjectives of nsnproliferating MSRs, the require-
ments for the graphite have diminished from those of the high-performance
breeder.
First, the peak neutron flux in the core can be reduced to
Bevels such that the graphite will last for the lifetime of the reactor
plant, ~eeond, both the low power density ana the pow rate of xenon mass
transfer to the graphite tend to limit the xenon poi~oning effect in tkPs
reactor SO that sealing the graphite may not be necessary. me lessened
gas permeability requirements also mean that the graphite can be irradiated
to higher fluences (Figs. 18 and 19). me lifetime criterion adopted
for the breeder was a damage fluenee of about 3 x 1026 neutrons/&.
0 to 20 30
FLUENCE [neutrons/crn* (E >50 keVB]
Fig. 19, 'Volume changes for monolithic graphites irradiated at 715"6,
nits