TREAT F-series LMFBR loss-of-flow experiments

The F-series tests are done to study fuel behavior in an LMFBR LOF accident. These tests are performed in dry (no sodium) capsules to separate out effects of sodium on fuel behavior and, in F3 and subsequent tests, to permit visual observation. Justification for a dry capsule is that the fuel behavior of interest such as fuel-pin breakup and extensive axial motion are assumed to occur after sodium voiding in a LOF accident. Two distinct F-series designs have been subject to TREAT tests. The design used for tests F1 and F2 permitted a study of extensive axial fuel motion and used the fast neutron hodoscope as the principal instrumentation. The second design, used for tests F3 and F4 and to e used for tests F5 and F6, permits a study of fuel pin break-up with high speed photography as the principal instrumentation.