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A Rapid-Insertion Control-Absorber Mechanism for Use in Hollow Fuel Elements; Mecanisme d'Insertion Rapide d'Absorbants pour Utilisation dans des Elements Creux; Mekhanizm bystrogo vvoda poglotitelya dlya ispol'zovaniya v polykh toplivnykh ehlementakh; Mecanismo para la Insercion Rapida de Absorbentes en Elementos Combustibles Huecos

Abstract

This report describes the engineering design and performance of a rapid-insertion control absorber mechanism for use within hollow, vertical, fuel elements of the DIDO materials-testing class reactors operating at a thermal flux of 10{sup 14} n/cm{sup 2} s. The initial downward acceleration of the absorber is that of gravity, and the full travel of 161 cm takes 0.4 s. The magnet release time is 5 ms. The absorber weighs 7 kg, has an effective area of 1000 cm{sup 2} of cadmium and controls nearly 3% of reactivity. It can be positioned with an accuracy of 4 x 10{sup -3}cm and withdrawn at speeds of 0.04 cm/s and 0.01 cm/s. The mechanism consists of a vernier stepping-motor which drives a lead-screw and raises or lowers a close-fitting cylindrical shield-plug with an electromagnet at its lower end, which supports a tubular absorber. There are large radial clearances around the absorber, which falls freely when released, except for the viscous drag of the moderator/coolant, until brought to rest by a stop on a central rod passing through the lead-screw to a ring-spring shock-absorber at the top of the mechanism. After release of the absorber, the shield-plug is motored down at fast speed to  More>>
Authors:
King, E. S.F. [1] 
  1. Atomic Energy Research Establishment Harwell, Berks. (United Kingdom)
Publication Date:
Jun 15, 1964
Product Type:
Conference
Resource Relation:
Conference: Symposium on Physics and Material Problems of Reactor Control Rods, Vienna (Austria), 11-15 Nov 1963; Other Information: 5 refs., 7 figs., 3 tabs.; Related Information: In: Physics and Material Problems of Reactor Control Rods. Proceedings of the Symposium on Physics and Material Problems of Reactor Control Rods| 808 p.
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; ACCURACY; ANNULAR FUEL ELEMENTS; CADMIUM; CLOSURES; CONTROL ELEMENTS; DIDO REACTOR; DRAG; ELECTROMAGNETS; FASTENERS; MOTORS; NEUTRON ABSORBERS; REACTIVITY WORTHS; SHIELDS; SHOCK ABSORBERS; SPRINGS
OSTI ID:
22127619
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3032082698
Submitting Site:
INIS
Size:
page(s) 617-629
Announcement Date:
Sep 12, 2013

Citation Formats

King, E. S.F. A Rapid-Insertion Control-Absorber Mechanism for Use in Hollow Fuel Elements; Mecanisme d'Insertion Rapide d'Absorbants pour Utilisation dans des Elements Creux; Mekhanizm bystrogo vvoda poglotitelya dlya ispol'zovaniya v polykh toplivnykh ehlementakh; Mecanismo para la Insercion Rapida de Absorbentes en Elementos Combustibles Huecos. IAEA: N. p., 1964. Web.
King, E. S.F. A Rapid-Insertion Control-Absorber Mechanism for Use in Hollow Fuel Elements; Mecanisme d'Insertion Rapide d'Absorbants pour Utilisation dans des Elements Creux; Mekhanizm bystrogo vvoda poglotitelya dlya ispol'zovaniya v polykh toplivnykh ehlementakh; Mecanismo para la Insercion Rapida de Absorbentes en Elementos Combustibles Huecos. IAEA.
King, E. S.F. 1964. "A Rapid-Insertion Control-Absorber Mechanism for Use in Hollow Fuel Elements; Mecanisme d'Insertion Rapide d'Absorbants pour Utilisation dans des Elements Creux; Mekhanizm bystrogo vvoda poglotitelya dlya ispol'zovaniya v polykh toplivnykh ehlementakh; Mecanismo para la Insercion Rapida de Absorbentes en Elementos Combustibles Huecos." IAEA.
@misc{etde_22127619,
title = {A Rapid-Insertion Control-Absorber Mechanism for Use in Hollow Fuel Elements; Mecanisme d'Insertion Rapide d'Absorbants pour Utilisation dans des Elements Creux; Mekhanizm bystrogo vvoda poglotitelya dlya ispol'zovaniya v polykh toplivnykh ehlementakh; Mecanismo para la Insercion Rapida de Absorbentes en Elementos Combustibles Huecos}
author = {King, E. S.F.}
abstractNote = {This report describes the engineering design and performance of a rapid-insertion control absorber mechanism for use within hollow, vertical, fuel elements of the DIDO materials-testing class reactors operating at a thermal flux of 10{sup 14} n/cm{sup 2} s. The initial downward acceleration of the absorber is that of gravity, and the full travel of 161 cm takes 0.4 s. The magnet release time is 5 ms. The absorber weighs 7 kg, has an effective area of 1000 cm{sup 2} of cadmium and controls nearly 3% of reactivity. It can be positioned with an accuracy of 4 x 10{sup -3}cm and withdrawn at speeds of 0.04 cm/s and 0.01 cm/s. The mechanism consists of a vernier stepping-motor which drives a lead-screw and raises or lowers a close-fitting cylindrical shield-plug with an electromagnet at its lower end, which supports a tubular absorber. There are large radial clearances around the absorber, which falls freely when released, except for the viscous drag of the moderator/coolant, until brought to rest by a stop on a central rod passing through the lead-screw to a ring-spring shock-absorber at the top of the mechanism. After release of the absorber, the shield-plug is motored down at fast speed to engage the absorber again. The size of the absorber system is within the overall dimensions of the fuel element and may be removed from the reactor together with the fuel element or separately by means of the fuel-unloading flask. (author) [French] L'auteur indique les caracteristiques techniques et les performances d'un mecanisme d'insertion rapide d'absorbants destine a etre utilise dans des elements creux et verticaux de reacteurs d'essai de materiaux du type DIDO, de flux thermique egal a 10{sup 14} n/cm{sup 2} s. L'acceleration initiale est celle de la pesanteur; le temps de parcours (61 cm) est de 0,4 s. L'aimant se declenche en 5 ms. L'absorbant pese 7 kg; sa surface efficace est de 1000 cm{sup 2} de cadmium et il compense environ 3% de reactivite. Sa position peut etre reglee avec une precision de 4 x 10{sup -3}cm et on peut le retirer a des vitesses de 0,04 cm/s'et 0,01 cm/s. Le mecanisme est constitue par un moteur a vernier qui entraihe une vis sans fin et eleve ou abaisse un obturateur cylindrique adapte a la protection a sa base d'un electro-aimant qui soutient un tube absorbant. Il y a un espace important autour du tube absorbant, qui tombe en chute libre (il rencontre seulement la resistance visqueuse du ralen- tisseur/refroidisseur) jusqu'a ce qu'il soit arrete dans sa chute par une barre centrale passant a travers la vis sans fin et aboutissant a un amortisseur a ressort circulaire situe au sommet du mecanisme. Apres la chute du tube absorbant, le moteur fait descendre rapidement l'obturateur dans lequel on engage de nouveau le tube. La dimension du mecanisme est comprise dans les dimensions d'ensemble de l'element et on peut le sortir du reacteur en meme temps que l'element ou separement, au moyen de la bouteille de dechargement du combustible [Spanish] El autor describe las caracteristicas tecnicas y funcionales de un mecanismo de mando para absorbentes de control, de insercion rapida, aplicable a los elementos combustibles huecos, verticales, de los reactores de ensayo de materiales de tipo DIDO, cuyo flujo termico es de 10{sup 14} n/cm{sup 2} s. La aceleracion descendente inicial del absorbente es la debida a la gravedad y la carrera total, de 61 cm, se cumple en 0,4 s. El intervalo de disparo del iman es de 5 ms. El absorbente pesa 7 kg, tiene una superficie efectiva de 1000 cm{sup 2} de Cd y una capacidad de regulacion del 3% de la reactividad. Su posicion puede fijarse con una precision de 4 x 10{sup -3}cm y la velocidad de extraccion varia entre 0,04 cm/s y 0,01 cm/s. El mecanismo consta de un motor de avance a vernier que acciona un tornillo de guia y puede elevar o bajar un obturador blindado cilindrico de ajuste estricto que lleva un electroiman en el extremo inferior y sostiene el absorbente tubular. La luz radial alrededor del absorbente es grande, de modo que este ultimo cae libremente cuando se suelta, venciendo solamente la resistencia debida a la viscosidad del moderador refrigerante, siendo detenido por un tope situado en una barra central que corre a lo largo del tomillo-guia hasta un amortiguador de muelle anular situado en la parte superior del mecanismo. Despues de soltar el absorbente, el obturador es desplazado hacia abajo por el motor, a toda velocidad, para volver a enganchar el absorbente. El dispositivo cabe en el elemento combustible y puede ser extraido del reactor junto con dicho elemento o separadamente, por medio de la caja de descarga de combustible. (author) [Russian] V nastojashhem doklade opisyvaetsja tehnicheskij proekt i harakteristika mehanizma s bystro vvodimym poglotitelem dlja ispol'zovanija vnutri polyh vertikal'nyh Toplivnyh jelementov reaktorov, prednaznachennyh dlja ispytanija materialov, tipa DIDO s potokom teplovyh nejtronov 10{sup 14} n/cm{sup 2}/sek. Pervonachal'noe uskorenie vvodimogo poglotitelja proishodit za schet sily tjazhesti, i polnyj vvod sterzhnja na 61 sm zanimaet 0,4 sek. Na otdeljonie ot magnita uhodit 5 millisekund. Poglotitel' vesit 7 kg, jeffektivnaja ploshhad' kadmija sostavljaet. 1000 cm{sup 2} , i on kontroliruet pochti 3% reaktivnosti. On mozhet byt' ustanovlen na mesto s. tochnost'ju do 4 x 10{sup -3}cm i izvlechen so skorost'ju 0,04 sm/sek i 0,01 sm/sek. Mehanizm sostoit iz stupenchatogo noniusnogo motora, kotoryj privodit v dvizhenie hodovoj vint i podnimaet ili opuskaet plotno prignannuju cilindricheskuju zashhitnuju probku, na nizhnem konce kotoroj nahoditsja jelektromagnit; podderzhivajushhij trubchatyj poglotitel'. Vokrug poglotitelja imjojutsja bol'shie radial'nye zazory, i pri osvobozhdenii poglotitelja on svobodno padaet, hotja ostaetsja vjazkoe trenie zamedlitelja/ohladitelja do ego ostanovki stoporom central'nogo sterzhnja, prohodjashhim cherez hodovoj vint k amortizirujushhemu ustrojstvu s kol'cevoj pruzhinoj, nahodjashhemusja v verhnej chasti mehanizma. Posle osvobozhdenija poglotitelja motor ochen' bystro opuskaet vniz zashhitnuju probku dlja novogo zahvata poglotitelja. Razmer poglotitel'noj sistemy sovpadaet s obshhimi razmerami toplivnogo jelementa, i ona mozhet byt' izvlechena iz reaktora vmeste s toplinym jelementom ili otdel'no s pomoshh'ju kontejnera dlja vygruzki topliva. (author)}
place = {IAEA}
year = {1964}
month = {Jun}
}