ORNL-5388 - the Molten Salt Energy Technologies Web Site

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5-1 5
bypassing the prototype stage and constructing a large power reactor demonstration. Such
a prototype program may also be desirable for the SSCR, particularly if the prototype pro-
gram involved the modification of an existing PWR for spectral-shift control rather than
the construction of a wholly new plant for this purpose.
reactor R&D requirements given for the SSCR in Table 5.1-2 are based on the assumption
that this prototype stage is bypassed. This can be justified on the basis that the SSCR is
rather unique among the various alternatives because of its close relationship to present
PWR technology.
could be designed so that the plant would be operated in either the conventional poison
control mode or in the spectral-shift control mode.
capital investment in the plant and the power output of the plant itself is not at risk.
Likewise, the potential for serious licensing delays is largely mitigated, since the reac-
tor could initially be operated as a poison-controlled PWR and easily reconfigured for
the spectral-shift control once the licensing approvals were obtained.
capital at risk is limited to the additional expenditures required to realize spectral-
shift control, roughly $30 - $60 million for component R&D, plus rental charges on the
heavy water inventory. The additional expenditures for design and licensing, $20 - $50
million, would have also been necessary for the prototype.
However, the estimates of the
In particular, no reactor development would be required and the reactor
As a result, a great majority of the
Consequently, the
The component R&D would consist of a thermal-hydraulic development task; valves and
seal development; development of D20 upgrader technology; and refueling methods development,
design and testing.
from nucleate boiling correlation for the SSCR moderator similar to that which has been
developed for the PWR light-water moderator. The correlations are expected to be very
similar, but tests to demonstrate this assumption for the various mixtures of heavy and
light water will be required.
The thermal-hydraulic tests would be designed to produce a departure
Valves and seal development will be necessary in order to minimize leakage of the
heavy-water mixture; reduction of coolant leakage is important both from an economic
standpoint (because of the cost of D20) and because of the potential radiological hazard
from tritium which is produced in the coolant. Methods of reducing coolant leakage from
valves and seals have been extensively explored as part of the design effort on heavy-
water reactors and utilization of heavy-water reactor experience is assumed. The R&D
program would address the application of the technologies developed for the heavy-water
reactor to the larger size components and higher pressures encountered in the SSCR.
The D20 upgrader employed in the SSCR is identical in concept to the upgraders used
on heavy-water reactors and in the last stage (finishing stage) of D20 production facilities.
The sizing of various components in the upgrader would, however, be somewhat different for
SSCR application because of the range of D20 concentration feeds (resulting from the
changing D20 concentration during a reactor operating cycle), and because of the large
volume of low D20 concentration coolant which must be upgraded toward the end of each
operating cycle. The upgrader R&D program would consider the sizing of the upgrader,