[en] To support the recovery operation at TMI-2, this work was performed to evaluate the capability of high/ultrahigh-pressure water to remove loose fuel debris and tightly bonded radioactive cesium from both smooth and threaded sections of leadscrew removed from the TMI-2 reactor. The loose debris flushing was conducted at eight locations on a rotating leadscrew section using a 5000 psi water jet, and stand-off distances of 6, 12, 24, and 48 inches. Cesium removal studies were conducted at seven locations on rotating and translating leadscrew sections using water jet pressures of 5000 to 35,000 psi, stand-off distances of 1, 2.25, and 6 inches, and traverse rates of 19 and 37 in./min. Decontamination factors for loose debris removal were 1.1 and 2.0 on the smooth and threaded leadscrew sections, respectively. The low decontamination factors reflected the relatively small amount of loose debris present on the leadscrew sections. Loss of debris presumably occurred during handling and packaging. For the cesium removal work, decontamination factors increased with increasing pressure and stand-off distance, and decreased with increasing traverse rate. The maximum decontamination factor of 144 was obtained at a pressure of 35,000 psi, stand-off distance of 6 in., and traverse rate of 37 in./min