Abstract: An accurate determination of whether the reactivity of individual spent fuel assemblies exceeds a threshold value is made while each assembly is being transferred from the reactor core to the fuel storage rack. The reactivity of each spent assembly is compared with that of a standard assembly by comparing the subcritical multiplication resulting from insertion of a neutron source into the assemblies. The measuring apparatus preferably exteriorly resembles a control element assembly wherein one control element finger containing the neutron source is yoked to another finger containing a neutron detector. The fingers are simultaneously inserted into a standard assembly having a known reactivity and subcritical multiplication, and the resulting flux signal is recorded. Thereafter spent assemblies are sequentially measured to assure that no assembly having a subcritical multiplication greater than that of the standard is ever placed into the storage rack.

Abstract: A first atmospheric bubbling fluidized bed furnace is combined with a second turbulent, circulating fluidized bed furnace to produce heat efficiently from crushed solid fuel. The bed of the second furnace receives the smaller sizes of crushed solid fuel, unreacted limestone from the first bed, and elutriated solids extracted from the flu gases of the first bed. The two-stage combustion of crushed solid fuel provides a system with an efficiency greater than available with use of a single furnace of a fluidized bed.

Abstract: A bi-metallic spacer grid having a Zircaloy perimeter strip consisting of oppositely facing, thin walled metal plates for closely surrounding the array of fuel rods. A rigid, stainless steel cross member extends between internal surfaces of the oppositely facing perimeter plates. In the preferred embodiment, the perimeter plates have cantilevered portions extending above and below the main body of the perimeter strip. The cross members interact with the enlarged portion by urging them outward relative to the perimeter strip as the fuel assembly heats up during operation. The outwardly projecting interface surfaces of each assembly mechanically interact with the interface surfaces of adjacent assemblies providing a mechanical restraint which limits bowing of the assembly. The effectiveness of the spacer grids in limiting bowing is therefore not dependent upon controlling the mechanisms responsible for causing bow.

Abstract: A polyester is formed from a polyol of high molecular weight and a polybasic acid with a reactive acid catalyst to have an effective viscosity and acid number.

Abstract: A structure for impounding liquid is disclosed below the combustion chamber of a steam generator. The structure divides the impounded liquid in two sections, or pools. The first section, or pool, receives the hot residue gravitated from the combustion chamber and absorbs the thermal and mechanical shock of the residue. The second section, or pool, is connected to the first pool through a gate valve and contains a continuous conveyor which transports the cooled residue, received from the first pool, to a point of ultimate disposal.

Abstract: A Kraft pulping process by which spent pulping liquor is burned in a recovery furnace 12 to reduce inactive alkali sulfates therein to active alkali sulfides while producing molten smelt that when added to water forms green liquor and residual dregs bearing catalytic iron. The dregs are separated from the green liquor and divided into first and second portions. The first portion of the dregs is discarded while the second portion of dregs required to maintain a concentration of iron in the smelt at from 0.05% to 5% is recirculated back to the furnace to provide optimum catalytic reduction of alkali sulfates to alkali sulfides. A quantity of alkali metal compounds is added at 24 to the pulping liquor in line 10 to serve as a temperature depressor that, together with the co-addition of said dregs, lowers the temperature of the molten smelt in furnace 12 from approximately 800.degree. C. to a more favorable temperature of about 650.degree. C.

Abstract: A flame scanner has a sensing circuit (10) utilizing a photosensitive device (12) for monitoring and a logic circuit (20) which includes a flame detection circuit (22) and a fault detection circuit (24). The photosensitive device produces a current signal (13) indicative of the intensity of the flame. The current signal is fed to a logarithmic amplifier (14) and converted to a voltage signal (15). The voltage signal (15) powers an LED (18) with its output (4) impinging on the photosensitive device (12). The voltage signal (15) is also transmitted to the flame detection circuit and the fault detection circuit for simultaneous and independent processing. The flame detection circuit continuously processes the signal to determine if a stable flame is present, while the fault detection circuit continuously monitors the integrity of the photosensitive device and its associated sensing circuitry.

Abstract: An entire crude oil stream is preheated by various sources of heat and brought to final temperature by a furnace. At this highest temperature, the stream is flashed into two portions, the heavier portion used only as a source of sensible heat for conservation. The vaporized fractions have their heat recycled into the crude oil stream and are then fractionated to extract a product of desired boiling range, flash point, and vapor pressure. The fractionation column is heated by the heavier, separated portion of the stream and refluxed by heat exchange with the crude oil stream.

Abstract: Apparatus for obtaining complete mixing of char with coal prior to the introduction of the mixture into the combustor (30) of a coal gasifier (10). The coal is carried in one air stream (22), and the char in another air stream (54), to a riffle plate arrangement (26), where the streams of solid are intimately mixed or blended.

Abstract: A control system and method for a nuclear steam supply system for continuously predicting the pending violation of one of the system's design limits. The prediction is made far enough into the future to allow corrective or protective action to be implemented in a timely manner in order to avoid violation of a design limit even on the occurrence of a worst case accident, or, restated, the occurrence of an accident which causes a most rapid approach to the design limit. Various parameters of the nuclear steam supply system are monitored and fed to a calculating mechanism. Samples of these parameters are periodically taken for the periodic detailed calculation of an index representative of the proximity of violation of the appropriate design limit. Continuous readings of these same parameters are taken for the purpose of making continuous updates of the last calculated index.

Abstract: A vertical shell-and-tube steam generator (10) which has a plurality of U-shaped tubes (60,62) through which the heating fluid flows, vaporizing fluid flowing on the outside of the tubes. A plurality of separators (26) are located above the tubes to remove liquid from the generated vapor. Orifices are located in some of the separator inlets (22) located above the hot leg region (60) of the U-tubes reducing the problem of overloading of these separators (26) by accomplishing a more uniform flow distribution of vapor from the areas above both the hot (60) and cold (62) legs of the U-tubes.

Abstract: A method and apparatus for making metal tubes (12) by centrifugally casting muffs (12) in a rotating mold (10), the inner diameter of which is tapered, having a smaller diameter at the pouring end (14) and a larger diameter at the non-pouring end. The outer diameter of the resulting muff is then machined (30) to form a cylindrical member of uniform diameter along its entire length. The inner diameter is also machined (28) smooth, and the finished muff is then reduced (32,34) in diameter and wall thickness to make a long tube (12).

Abstract: Furnace performance is controlled during start-up or very low load operation at a time when the minimum air flow required to be supplied to the furnace is significantly greater than that required to burn the fuel being supplied to the furnace. Decreased furnace heat absorption is accomplished by supplying a larger quantity of the air immediately adjacent the fuel input location for the purpose of diluting the combustion gases and immediately decreasing their temperature level. Increased furnace heat absorption is obtained by introducing a greater portion of the air flow into the furnace at a location remote from the fuel being burned so that the gases at the fuel location remain at a high temperature, and transfer heat to the walls, before being diluted by the incoming air.

Abstract: A tubular member of the type, primarily intended for utilization in a boiler, and having rifling, i.e., ribbing, provided on the internal surfaces thereof that is operable for purposes of effecting the disruption of the internal flow of the fluid passing therethrough. The ribbing with which the subject tubular member is provided embodies a configuration that is preselected so that the ribbing is operative to enable accurate and precise control to be exercised through the use thereof over the movement of the fluid flowing through the tubular member. Consideration is given to the following factors, among others, in establishing the design criteria that, in turn, determines the configuration that the ribbing embodies in a given tubular member; namely, the type of fluid; the fluid pressure; the fluid flow rate; the internal dimensions of the tubular member; the temperature gradient within the tubular member wall, both circumferentially and longitudinally, etc.

Abstract: An improved guide tube post which decreases the flow induced vibration of a cylindrical control rod suspended therethrough. The inner wall of the post, near where it exits into a diffuser region, is provided with a polygonal cross section. When, due to random fluctuation, the rod assumes an eccentric position near the wall of the post, the polygonal post geometry provides a relatively large angle between the post wall and the surface of the rod near the wall. It has been found that if this angle is too small, strong secondary flows develop along the length of the control rod and interact with other vortices in the diffuser region, to produce the vibration driving force. The polygonal cross section in the post modifies the secondary flow to reduce the intensity of the interaction with the diffuser vortices.

Abstract: A machine for smoothly and controllably winding or unwinding a stiff in-core-instrument tube onto and off of a reel during ythe refueling of a nuclear reactor. The machine includes a frame (33) and a circular reel (32) having a substantially continuous helical groove (44) extending around the circumference of the reel. The groove is adapted to receive the tube (14). A plurality of cam rollers (52) are carried by the frame and closely spaced around the circumference of the reel. The rollers keep the tube in the groove whereby the tube may be more easily wound onto or off of the reel. In the preferred embodiment, the reel carries a disposable cartridge (46) in which the grooves are formed.

Abstract: A method of providing tubes of the type intended primarily for use in boilers with a variably rifled interior surface. The function of the latter surface is to create turbulence within the tube operative to break up the laminar flow of the water or steam flowing therethrough so as to thereby promote more efficient heat transfer during steam generation and so as to minimize the susceptibility of the tube to overheat due to the effects of nucleate boiling.

Abstract: A control rod having a spring device on its lower end for eliminating oscillatory contact of the rod against its adjacent guide tube wall. The base of the device is connected to the lower tip of the rod. A plurality of elongated extensions are cantilevered downward from the base. Each extension has a shoulder for contacting the guide tube, and the plurality of shoulders as a group has a transverse dimension that is preset to be larger than the inner diameter of the guide tube such that an interference fit is obtained when the control rod is inserted in the tube. The elongated extensions form an open-ended, substantially hollow member through which most of the liquid coolant flows, and the spaces between adjacent extensions allow the flow to bypass the shoulders without experiencing a significant pressure drop.

Abstract: The vertical fuel pipe of a fluidized bed extends up through the perforated support structure of the bed to discharge granulated solid fuel into the expanded bed. A cap, as a deflecting structure, is supported above the discharge of the fuel pipe and is shaped and arranged to divert the carrier fluid and granulated fuel into the combusting bed. The diverter structure is spaced above the end of the fuel pipe and provided with a configuration on its underside to form a venturi section which generates a low pressure in the stream into which the granules of solid fuel are drawn to lengthen their residence time in the combustion zone of the bed adjacent the fuel pipe.

Abstract: The temperature of the flue gas entering a spray dryer SO.sub.2 absorption chamber (26) is increased so as to maintain the temperature of the flue gas leaving the spray dryer SO.sub.2 absorption chamber (26) at a preselected temperature above the adiabatic saturation temperature of the flue gas so as to permit greater amounts of sulfur oxide absorbent slurry (36) to be sprayed into the flue gas, thereby allowing the treatment of flue gas containing high levels of sulfur oxide.