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[en] The SVP program intended for determining optimum characteristics of a cylindrical multiplying unit with a central multilayer highly screened rod containing several burnable absorbers is described. The program consists of the SVP main program in which initial data input and call for the selected optimization subprogram are oraganised, F subprogram where alterated variables are identified, the MARS subprogram is called minimized functional restriction system and restriction performing conditions are formed; the MARS subprogram, where at the specified vector of independent variables the burnup in a multiplying unit with a rod, is calculated; two optimization programs, PB2 and PB2A: the first program solves the problem of nonlinear programming with the restrictions of the first series, the second one with those of the first and second series; a set of accessory subprograms organizing non-format data input search scale adjustment, random numbers and print selection. The program is written in FORTRAN-DUBNA language for the BESM computer. Varied parameters can be rod dimensions, of its zones and multiplying unit, composition of the specified chemical elements of all rod zones and that of the multiplying unit. The type of the minimized functional, composition of restrictions system and that of the varied vector is not determinated and is determined by the considered statement of optimization problem. The program is constructed in such a manner as to pass easily from one problem to the other
[en] This invention relates to improvements made to nuclear reactor fuel assemblies, particularly to the procedures and appliances for removably setting up, in the cross-bracing of fuel assemblies, rods of neutron absorbing burnable substances also called 'poisons'
[fr]La presente invention concerne des perfectionnements apportes aux ensembles de combustible de reacteur nucleaire, et plus particulierement, des procedes et appareils en vue de monter de facon amovible dans les croisillons d'ensembles combustibles des barreaux de substances consommables d'absorption de neutrons, substances appelees aussi 'poisons'
[en] Purpose: To increase the charging fuel quantity and at the same time increase the degree of burn-up by inserting a control rod, which has a cladding tube filled with a moderator and burnable poison, into the fuel assembly. Constitution: A control rod, which has a cladding tube filled with burnable poison such as gadolinium, gadolinium compounds, boron, boron compounds and so forth and a moderator such as light water, heavy water, beryllium, beryllium compounds, carbon and carbon compounds, is inserted in lieu of a suitable number of fuel pins into the fuel assembly. Since the burnable poison is charged into the cladding tube without mixing it with the moderator, it is possible to increase the charging quantity of the burnable poison compared to the former system where fuel is mixed with the burnable poison. Thus, the effect of increasing the reactivity is increased, so that it is possible to increase the charging quantity of fuel and the degree of burn-up to that extent. (Horiuchi, T.)
[en] The main object of this invention is to provide a burnable poison rod for nuclear reactors that, at the end of its useful life, is not capable or not very capable of capturing neutrons, so that the useful life of the core is increased
[fr]La presente invention a pour objet principal de fournir une barre de poison combustible pour reacteurs nucleaires, qui, a la fin de sa vie utile, n'est pas ou tres peu capable de capturer des neutrons, de telle sorte que la duree de vie utile du coeur est augmentee
[en] Object: To determine rate of change in reactivity using the integrating power and core flow rate as parameters, to detect the reactivity with high accuracy. Structure: By start signals from an input processor started periodically by means of a timer to incorporate integrating power and core flow rate, a minimum involution operator calculates and outputs a flow rate - reactivity gradient, a secondary operator calculates and outputs a reactivity - flow rate gradient, a reactivity coefficient deciding device decides the reaction coefficient, and a reactivity counter calculates and outputs a changed portion of reactivity. (Kawakami, Y.)
[en] An elongated nuclear reactivity control member, a releasable latching structure useful for releasably attaching the control member at an end to a top nozzle adapter plate of a nuclear fuel assembly is described comprising: (a) a mounting body including an inner plug portion attached to the end of the control member and an outer end portion disposed axially outward from the inner plug portion and the end of the member; and (b) a spring latch disposed about the mounting body and being attached to the outer end portion. The spring latch has at least one latch finger extending toward the inner plug portion of the body and is movable toward and away from the body between an outer latching position in which the finger is adapted to engage a fuel assembly top nozzle adapter plate and retain the elongated member in a stationary relationship with respect to the adapter plate and an inner unlatching position in which the finger is adapted to disengage from the adapter plate and allow removal of the member from the adapter plate