Abstract: A flow monitoring system which utilizes the decay of a measurable parameter of the flowing fluid by measuring the magnitude of the parameter at two spaced points along the flow of the fluid. Accurate measurements are enabled by the elimination of detector identity and calibration problems by repeatedly translating one detector between first and second positions external to the fluid conduit along the flow path of said fluid. This translation is preferably accomplished by a pendulum device with the detector positioned at the end of the pendulum.

Abstract: A shock buffer is provided for the gradual deceleration of a rapidly descending control element assembly in a nuclear reactor. The interactive buffer components are associated respectively with the movable control element assembly and part of the upper guide structure independent of and spaced from the fuel assemblies of the reactor.Preferably, the buffer is of the piston and cylinder type, with a piston extending upward from a tube sheet of the upper guide structure and a cylinder opening downward and carried by the control element assembly near its upper end. The cylinder descends about the buffer piston near the lower extent of control element assembly travel. Liquid naturally occupying the buffer cylinder, as the reactor coolant at the ambient pressure within the reactor, provides hydraulic decelerating forces on the control element assembly when relative insertion of the piston in the cylinder occurs.

Abstract: An apparatus for the safe storage of a plurality of fissionable masses including an array of discrete neutron absorbing shields which utilizes the principle of the neutron trap to reduce the multiplication factor of the storage array to a subcritical value when immersed in a neutron moderating medium. Each discrete neutron absorbing shield is spaced such that the encircled fissionable mass is spaced from the next adjacent neutron absorbing shield by a distance determined by the enrichment of the fissonable masses and attenuation of the moderating medium.

Abstract: A process for making an adjustable split door frame is disclosed, the process comprising the steps of cladding the front surface of the board with vinyl, grooving a plurality of parallel grooves of various shapes in the back surface of the board down to but not through the vinyl, folding and gluing the board along the grooves, inserting a support member and attaching a hard board to the back surface of the resulting door frame. In addition, a second board is clad, grooved and folded in a similar manner to provide the other half of the split adjustable door frame.

Abstract: A system is provided for the relief of excess pressure from the region above the nuclear reactor core to the cold leg on the occurrence of a loss of coolant accident. This system includes a series of passages connecting the annulus surrounding the exterior of the core barrel with the interior of the outlet nozzle or with the plenum above the reactor core. A flow blocking obstruction, such as a seal band, is held in a flow blocking position by the differential pressure experienced during normal operation of the reactor between the exterior of the core barrel and the exit region of the reactor core. Reversal of the differential pressure, which may be expected upon the occurrence of a loss of coolant accident, removes the flow blocking obstruction to permit the relief of excess pressure which may result at the outlet end of the reactor core.

Abstract: An actuator comprises a piston and cylinder in which the piston is biased axially inwardly of the end of the cylinder to an intermediate position by two bias members respectively on axially opposite sides of the piston. Limit means associated with each respective bias member serve to coact between the respective bias member and the cylinder to limit the inward travel of the respective bias member in the cylinder to establish a constant position at which the piston receives no net biasing force from the two bias members. Each limit means may comprise a flanged cup which moves with the inner end of the bias member and a stop surface in the cylinder for engaging the cup flange to limit its inward movement, and thus the inward movement of the bias member.

Abstract: An improved surface traversing apparatus is provided in which one anchor or group of anchors is connected with one base, another anchor or group of anchors is connected with another base, each anchor group is movable en bloc transversely of its respective base for lateral movement across the surface of a member to be traversed, and the two bases are movable relative to one another in a direction which moves one finger group alternately toward and away from engagement with a member engaged by the other finger group. The anchors may be selectively expandable fingers which are longitudinally insertable into and retractable from openings in a steam generator tube sheet to provide the engagement therewith.

Abstract: An improved surface traversing apparatus has an anchor finger selectively movable laterally of another anchor finger into near or substantial alignment with an opening in a member for insertion thereinto and includes one or more of the fingers being mounted to a base portion of the platform by a mounting arrangement which allows one finger to be deflected laterally relative to another finger such that the finger being inserted may deflect into exact alignment with the receiving opening by lateral engagement with the sidewall of the opening. Each finger is resiliently mounted to a connecting member which is, in turn, connected to the base portion of the platform. The resilient mount for each finger normally centers the finger and allows both pivotal and translatory displacement of the finger relative to the connecting member.

Abstract: A system is provided which prevents the operation of a nuclear reactor in a region of a prohibited reactor power distribution. The method of operation includes inhibiting the insertion of control rods into the reactor on the basis of a power dependent control rod insertion limit and further overriding the control of the reactor by rapidly reducing reactor power when reactor power increases to a reactor power which exceeds by a predetermined margin the limit set by the power dependent control rod insertion limit.

Abstract: An apparatus for the safe storage of a plurality of fissionable masses including an array of discrete neutron absorbing shields which utilizes the principle of the neutron trap to reduce the multiplication factor of the storage array to a subcritical value when immersed in a neutron moderating medium. Each discrete neutron absorbing shield is designed to perimetrically encircle each of the stored fissionable masses. Each shield is spaced such that the encircled fissionable mass is spaced from the next adjacent neutron absorbing shield by a distance determined by the enrichment of the fissionable masses and attenuation of the moderating medium.

Abstract: A method is disclosed for welding one or more fins or longitudinally extended plate like members to tubes or pipes by means of radio frequency resistance heating. A V-gap necessary for the high frequency welding technique is created by deforming the tube to produce an out of round or ovular shape. The welding is accomplished as the out of round tube or pipe is deformed back to a round shape while at the same time bringing the fin or plate like member into contact with the tube or pipe.

Abstract: A reactor trip on turbine trip inhibit control system for a nuclear power generating system which utilizes steam bypass valves. The control system inhibits a normally automatic reactor trip on turbine trip when the bypass valves have the capability of bypassing enough steam to prevent reactor trip limits from being reached and/or to prevent opening of the secondary safety pressure valves. The control system generates a bypass valve capability signal which is continuously compared with the reactor power. If the capability is greater than the reactor power, then an inhibit signal is generated which prevents a turbine trip signal from tripping the nuclear reactor.

Abstract: A reactor trip on turbine trip inhibit control system for a nuclear power generating system which utilizes steam bypass valves. The control system inhibits a normally automatic reactor trip on turbine trip when the bypass valves have the capability of bypassing enough steam to prevent reactor trip limits from being reached and/or to prevent opening of the secondary safety pressure valves. The control system generates a bypass valve capability signal which is continuously compared with the reactor power. If the capability is greater than the reactor power, then an inhibit signal is generated which prevents a turbine trip signal from tripping the nuclear reactor.

Abstract: A process for making an adjustable split door frame is disclosed, the process comprising the steps of cladding the front surface of the board with vinyl, grooving a plurality of parallel grooves of various shapes in the back surface of the board down to but not through the vinyl, folding and gluing the board along the grooves, inserting a support member and attaching a hard board to the back surface of the resulting door frame. In addition, a second board is clad, grooved and folded in a similar manner to provide the other half of the split adjustable door frame.

Abstract: A method for operating a nuclear reactor or any other machine or industrial process where it is of importance to terminate operation when a given parameter deviates from a variable operating value by more than a given amount regardless of the rate at which the deviation occurs. A variable setpoint is continuously generated from the past history of the operating parameter by adding the current value to a predetermined excursion margin whenever this causes the variable setpoint to decrease. The setpoint remains constant whenever the operating parameter is increasing so that a system trip is initiated whenever the setpoint is exceeded. The variable setpoint is permitted to increase to within the excursion margin of the operating parameter only when independent authorization is given indicating that the increase is legitimate.

Abstract: Apparatus and method are provided for a nuclear stream supply system for adequately controlling the chemistry of the secondary coolant. The invention includes means for the addition of volatile chemicals, a full flow condensate demineralizer, continuous blowdown capability, radiation detection means, a condensate demineralizer bypass line, and an auxiliary demineralizer sized to handle full blowdown flow. The auxiliary demineralizer is cut into the system and the steam generator feedwater flow is bypassed around the full flow condensate demineralizer whenever radioactivity is detected in the secondary coolant.

Abstract: An emergency core cooling system for a nuclear reactor in which an emergency cooling injection manifold is integrally formed with the guide structure which guides control elements into the reactor core. The guide structure comprises two vertically spaced plates each of which substantially overlies the entire core and which are interconnected by a control element guidance means. A third plate is supported in vertical spaced relationship from one of the plates of the guide structure to define the manifold therebetween. Means are provided for substantially sealing the plenum from the main coolant flow path of the reactor. Means are also provided for introducing emergency coolant into the injection manifold and for dispersing coolant fluid therein into the core in the event of a loss of coolant accident.

Abstract: A releasable locking device for urging limited relative rotation about a longitudinal axis between a first and second object threadably coupled together so as to maintain a tight connection of the coupled objects. The locking device comprises a brake plate which is supported with respect to the second object so as not to move rotationally relative thereto, a locking plate supported with respect to the first object so as not to move rotationally relative thereto, and a biasing means. The brake plate and locking plate are each positioned laterally adjacent to the first object and each have longitudinally extending complimentary ratchet teeth having inclined surfaces on their mutually facing, surfaces, the inclined surfaces of ratchet teeth of the brake plate being adapted to mate with the inclined surfaces of ratchet teeth of the locking plate.

Abstract: A spent fuel assembly handling tube closure valve is provided which assures minimal or zero leakage of trapped liquid metal coolant from the handling tube. One sealing surface of the closure valve is spherical while the other is conical. The spherical-conical combination enables an adequate seal even when the valve cap is misaligned. A further safeguard against leakage is made possible by a sacrificial inert gas system utilizing the diving bell principle. A metered gas supply system supplies additional sacrificial gas should a leak develop. A high-low level mutual inductance probe operates as a leak detector allowing the timely addition of greater quantities of sacrificial gas.

Abstract: A double-sided rack and pinion control element drive mechanism for a nuclear reactor is disclosed wherein scram release is accomplished by the dual action of withdrawing the pinion from its engagement with the rack while at the same time rotating the pinion in a direction consistent with the movement of the rack and the control rod in their downward travel. The pinion is withdrawn from engagement with the rack while remaining in engagement with its stationary driving means. The continuing engagement with the stationary driving means causes the pinion to rotate when the pinion is caused to move away from the rack during disengagement.