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

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"spent" fuel. If credit were allowed for the residual fissile uranium
in the salt (plutonium presumably would not be recovered), the net U308
requirement would be reduced by almost one-half,
The temporal distribution of fuel requirements in a DMSR is also
significant. The data in Table 17 show that only about 36% of the makeup
fuel is required during the first 15 years of the cycle; the major demand
occurs toward the end-of-life. Thus, if the reactor were operated at a
lower capacitv factor in later years, the U308 requirement could be re-
duced further or the plant calendar lifetime could be extended. The ad-
vantage associated with the time distribution of the makeup fuel require-
ment is partly offset by the large initial fuel loading and the high in-
plant fissile inventory. Therefore, an optimum fuel cycle might coneeiv-
ably balance a Power initial loading (and inventory) having a lower net
conversion ratio against a higher requirement for makeup fuel.
pears to be some latitude for optimization of the fuel cycle in this area.
3.1.6.2 Potential for imDrsvement
*
There ap-
mile the fuel utilization of this conceptual system compares favor-
ably with that of other reactor systems, some further improvements may be
possible. Only a limited range of fuel volume fractions and core zone
sizes has been conside~edl for this core, and other values could lead to
higher performance. However, there appears to be little potential benefit
in using more than two core zones.
The actinide content of the salt is thought to be near optimum for
long-term, high-performance conversion, but, as implied previously, an-
other concentration might be better for the 30-year cycle. Certainly,
some improvement in fuel utilization would come from relaxing the re-
quirement for 2 3 8 ~ content either of the system in operation or of the
makeup material being added. Table 18 shows the approximate effect of
these constraints on 2 3 5 ~ requirements.
fully denature the makeup feed material has only a small effect on the
fuel requirement.
Removing the requirement to
Similarly, increasing the allowed enrichment of 234U
This is frequently done in electric power stations as newer and
dk
cheaper plants are built.