Combustion Engineering, Inc.

Joseph M Burger

Frank Bevilacqua

A liquid level sensing apparatus (32) senses the level of liquid surrounding the apparatus. A plurality of axially spaced sensors (36) are enclosed in a separator tube (86). The separator tube (86) tends to collapse the level of a two-phase fluid within the separator tube into essentially a liquid phase and a gaseous phase where the collapsed level bears a relationship to the coolant inventory outside the separator tube. The level of the liquid phase is sensed by level sensing apparatus (32). The separator tube (86) contains inlet-outlet ports (90,92) near the top and bottom thereof to equalize the liquid level inside and outside the separator tube (86) when the level fluctuates or the water within the separator tube (86) flashes to steam. Each sensor (36) is comprised of a heater (64), a heated thermocouple junction (68) and an unheated thermocouple junction (66) within an elongated heat conductive housing (62). The heated portion of housing (62) is enclosed in a splash guard (72) with inlet-outlet ports ( 78,82) near the top and bottom to equalize the liquid level inside and outside the splash guard (72) and to eliminate the spurious indications of liquid level change which may arise if water droplets contact the housing (62) in the region of the heater. To prevent steam bubbles entrained in a two-phase fluid cross flow from entering the lateral inlet-outlet ports (90,92) of the separator tube (86), the separator tube (86) is enclosed in support tube (100) which may in turn be enclosed in an otherwise unused control element assembly shroud (110). The lateral inlet-outlet ports (90,92) of separator tube (86) are axially offset from lateral inlet-outlet ports (102) of support tube 100 at least where support tube 100 is subjected to cross flow. The shroud (110) is open on the bottom and has lateral inlet-outlet ports (112) to facilitate liquid level fluctuations to equalize inside and outside shroud (110). An alternate embodiment permits the measurement of more than one liquid level.

Heated junction thermocouple level measurement apparatus

A nuclear fuel assembly grid (12) having four substantially solid perimeter plates (28) forming a rigid quadrangle (20) surrounding the fuel elements (36) and having stop surfaces (32) formed on the internal surfaces thereof for contacting each adjacent fuel element. A plurality of interlaced strips (24) are attached to and extend from each plate to the oppositely facing plate, forming a lattice of regularly spaced openings (16) through which the fuel elements traverse the grid. These strips are of two types, the first consisting of two perpendicular center strips (44,44') that divide the grid into four symmetric quadrants, each center strip having a spring tab (48') projecting into each opening (16') contiguous to the center strip. The second type of interlaced strip consists of the remainder of the strips (52), half of which are oriented parallel to one center strip and the other half are oriented parallel to other center strip. The second type, or interior, strips have a generally undulating bent stop surface (50) such that one bend (56) projects into each adjacent contiguous opening on the side of the interior strip facing the respective parallel center strip. Each interior strip also has a spring tab (48') projecting into each adjacent contiguous opening on the side of the interior strip opposite the respective parallel center strip.

Spacer grid for nuclear fuel assembly

A core shroud including flexible panels sealingly attached to the inner surface of the shroud at an elevation opposite the fuel assembly grids nearest the core midplane. Each panel forms the outer wall of a deformable chamber which is pressurized through a conduit carried by the shroud. One end of the conduit is in fluid communication with the reactor coolant at a high pressure location remote from the panels, producing a pressure differential across the panel which urges the panel against the adjacent grid to prevent core bowing.

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Granby, CT, United States of America

Joseph M Burger