Argonne National Laboratory Reports

The Mk-IIC Integral Loop was modified to provide an in-pile experimental apparatus that would simulate the subassembly coolant flow rate and inlet pressure head of the Fast Test Reactor (FTR). There were two main design changes. First, the safety dump tanks were removed from the Mk-IIC loop and replaced by a second annular linear induction pump (ALIP). Second, a flow restricting orifice was sized so that the hydraulic requirements of prototypical test-section coolant velocity and pressure head would be achieved. The resulting redesigned loop was used for the in-pile TREAT transient over-power Test H6, which investigated fuel sweep-out and coolability following fuel-pin failure under hydraulic conditions typical of the FTR. The procedure reported here will help in the design of advanced TREAT vehicles such as the Mk-III loop