TERMIUM Plus^®

Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 DEF

A neutron detector for which the cross-section of the detection reaction varies inversely with neutron speed.  1, record 1, English, - 1%2Fv%20detector

Record number: 1, Textual support number: 1 OBS

v: velocity.  2, record 1, English, - 1%2Fv%20detector

Record number: 1, Textual support number: 2 OBS

1/v detector: term and definition standardized by the International Organization for Standardization (ISO).  3, record 1, English, - 1%2Fv%20detector

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 DEF

Détecteur de neutrons pour lequel la section efficace de la réaction de détection varie [inversement à] la vitesse des neutrons.  1, record 1, French, - d%C3%A9tecteur%20en%201%2Fv

Record number: 1, Textual support number: 1 OBS

v : vitesse.  2, record 1, French, - d%C3%A9tecteur%20en%201%2Fv

Record number: 1, Textual support number: 2 OBS

détecteur en 1/v : terme normalisé par l'Organisation internationale de normalisation (ISO).  3, record 1, French, - d%C3%A9tecteur%20en%201%2Fv

Record 1,  Textual support,  Spanish

Record 3,  Textual support,  English

Record number: 3, Textual support number: 1 CONT

If blanket modules contain lithium, a reaction occurs : the incoming neutron is absorbed by the lithium atom, which recombines into an atom of tritium and an atom of helium. The tritium can be removed from the blanket and recycled into the plasma as fuel. Blankets containing lithium are thus considered "breeding blankets" for tritium. Within the fusion reaction, tritium can be bred indefinitely.  2, record 3, English, - tritium%20breeding%20blanket

Record 3,  Textual support,  French

Record number: 3, Textual support number: 1 DEF

Couverture qui produit du tritium par réaction des neutrons avec le lithium qu'elle contient.  2, record 3, French, - couverture%20tritig%C3%A8ne

Record number: 3, Textual support number: 1 CONT

La présence de lithium dans les modules de couverture déclenche la réaction suivante : le neutron incident est absorbé par l'atome de lithium, lequel se recombine alors en un atome de tritium et un atome d'hélium. On peut extraire le tritium de la couverture puis le recycler dans le plasma et le rendre à sa fonction de combustible. On appelle donc «couvertures tritigènes» les couvertures qui contiennent du lithium. La réaction de fusion permet ainsi de produire du tritium de manière continue.  3, record 3, French, - couverture%20tritig%C3%A8ne

Record number: 3, Textual support number: 1 OBS

couverture tritigène : désignation et définition publiées au Journal officiel de la République française le 2 septembre 2021.  4, record 3, French, - couverture%20tritig%C3%A8ne

Record 3,  Textual support,  Spanish

Record 4,  Textual support,  English

Record number: 4, Textual support number: 1 CONT

Nuclear reactors can be controlled by a mechanical control rod system for a very subtle reason. In a chain reaction there are only fractions of seconds between one fission event and the next one(s), initiated by the former. However, since a small fraction of the neutrons needed to keep the chain going are generated with a delay in the range of ten seconds the necessary response time of the control system is in the range of 0. 1 seconds, thus making mechanical control possible in the first place. For plutonium the delayed neutron fraction is almost a factor of three smaller than for uranium, increasing demands on the control system.  2, record 4, English, - mechanical%20control%20rod

Record 4,  Textual support,  French

Record number: 4, Textual support number: 1 CONT

Cœur du réacteur. [...] Les dispositifs de réglage de la réactivité montés verticalement comprennent [...] les barres de commande mécaniques qui se trouvent normalement à l'extérieur du cœur. Elles sont insérées pour compléter la réactivité négative des barres de commande à eau ordinaire ou on les fait chuter pour effectuer une réduction rapide de la puissance.  1, record 4, French, - barre%20de%20commande%20m%C3%A9canique

Record 4,  Textual support,  Spanish

Record 5,  Textual support,  English

Record number: 5, Textual support number: 1 CONT

The alpha-neutron reaction, which occurs when alpha particles emitted from plutonium-238 interact with atoms of naturally occurring oxygen, results in a high neutron emission rate from plutonium oxide, and may cause a high neutron exposure to workers. To reduce this exposure, an oxygen exchange process would be used to replace the higher cross-section oxygen isotopes(oxygen-17 and oxygen-18) with oxygen-16, which has a very small cross section for the alpha-neutron reaction.  2, record 5, English, - alpha%2Dneutron%20reaction

Record number: 5, Textual support number: 1 OBS

alpha-neutron reaction : term extracted from the “Glossaire de l'énergie nucléaire” and reproduced with permission of the Organisation for Economic Co-operation and Development.  3, record 5, English, - alpha%2Dneutron%20reaction

Record 5,  Textual support,  French

Record number: 5, Textual support number: 1 CONT

Le plutonium selon sa forme physico-chimique, est aussi un émetteur de neutrons (fissions spontanées, réactions alpha-neutron) [...]  2, record 5, French, - r%C3%A9action%20alpha%2Dneutron

Record number: 5, Textual support number: 1 OBS

réaction alpha-neutron : terme extrait du «Glossaire de l’énergie nucléaire» et reproduit avec l’autorisation de l’Organisation de coopération et de développement économiques.  3, record 5, French, - r%C3%A9action%20alpha%2Dneutron

Record 5,  Textual support,  Spanish

Record 6,  Textual support,  English

Record number: 6, Textual support number: 1 DEF

The average number of neutrons with the velocity and position of type B which must be added to a critical system to keep the chain reaction rate constant after removal of a neutron with the velocity and position of type A.  1, record 6, English, - relative%20importance

Record number: 6, Textual support number: 1 OBS

relative importance: term and definition standardized by ISO.  2, record 6, English, - relative%20importance

Record 6,  Textual support,  French

Record number: 6, Textual support number: 1 DEF

Nombre moyen de neutrons ayant la vitesse et la position de B qui doivent être ajoutés à un système critique pour maintenir constant le taux de réaction en chaîne après suppression d'un neutron ayant la position et la vitesse de A.  1, record 6, French, - importance%20relative

Record number: 6, Textual support number: 1 OBS

importance relative : terme et définition normalisés par l'ISO.  2, record 6, French, - importance%20relative

Record 6,  Textual support,  Spanish

Record 7,  Textual support,  English

Record number: 7, Textual support number: 1 DEF

A neutron detector for which the cross-section of the detection reaction varies inversely with neutron speed.  1, record 7, English, - 1%2Fv%20detector

Record number: 7, Textual support number: 1 OBS

1/v detector: term standardized by ISO.  2, record 7, English, - 1%2Fv%20detector

Record 7,  Textual support,  French

Record number: 7, Textual support number: 1 DEF

Détecteur de neutrons pour lequel la section efficace de la réaction de détection varie comme l'inverse de la vitesse des neutrons.  1, record 7, French, - d%C3%A9tecteur%20en%201%2Fv

Record number: 7, Textual support number: 1 OBS

détecteur en 1/v : terme et définition normalisés par l'ISO.  2, record 7, French, - d%C3%A9tecteur%20en%201%2Fv

Record 7,  Textual support,  Spanish

Record 8,  Textual support,  English

Record number: 8, Textual support number: 1 DEF

In a nuclear reactor, the situation where the rate of the fission chain reaction is increasing, i. e. when more than one neutron from each fission is causing a further fission(the reproduction factor is more than 1.)  2, record 8, English, - divergence

Record number: 8, Textual support number: 1 OBS

divergence: term standardized by ISO in 1997.  3, record 8, English, - divergence

Record 8,  Textual support,  French

Record number: 8, Textual support number: 1 DEF

Dans un réacteur nucléaire, processus de démarrage au cours duquel le facteur de multiplication effectif k_ef croît jusqu'à la valeur 1.  2, record 8, French, - divergence

Record number: 8, Textual support number: 1 OBS

divergence : terme normalisé par l'ISO en 1997.  3, record 8, French, - divergence

Record 8,  Textual support,  Spanish

Record 10,  Textual support,  English

Record number: 10, Textual support number: 1 CONT

Computational capability has been developed to calculate sensitivity coefficients of generalized responses with respect to cross-section data in the SCALE code system. The focus of this paper is the implementation of generalized perturbation theory(GPT) for one-dimensional and two-dimensional deterministic neutron transport calculations. GPT is briefly summarized for computing sensitivity coefficients for reaction rate ratio responses within the existing framework of the TSUNAMI sensitivity and uncertainty(S/U) analysis code package in SCALE. GPT provides the capability to analyze generalized responses related to reactor analysis, such as homogenized cross-sections, relative powers, and conversion ratios, as well as measured experimental parameters.  1, record 10, English, - generalized%20perturbation%20theory

Record number: 10, Textual support number: 1 OBS

The SCALE code system includes a sensitivity and uncertainty (S/U) analysis code package called TSUNAMI. TSUNAMI originally focused on keff responses for criticality safety analysis and included the capability to compute sensitivity coefficients using forward and adjoint solutions from three-dimensional Monte Carlo or one-dimensional (1D) discrete ordinates eigenvalue calculations.  1, record 10, English, - generalized%20perturbation%20theory

Record 10,  Textual support,  French

Record number: 10, Textual support number: 1 CONT

Méthode GPT. Au milieu des années 1960, Usachev, Lewins et Gandini généralisèrent la théorie des perturbations à toute sorte d’observable, paramètre physique pouvant être mesuré (et/ou calculé), qui peut être représenté sous la forme d’un rapport de quantités intégrales, linéaires du flux et/ou du flux adjoint. Pour reconstruire la valeur d’un observable d’un système multiplicateur dans des conditions perturbées, la théorie généralisée des perturbations […] fait appel à une fonction particulière, dite fonction importance généralisée, qui est la solution unique de l’équation du bilan adjointe du système à laquelle on ajoute un terme inhomogène, appelé source généralisée. Ce terme, qui est strictement orthogonal au mode fondamental, contient, au premier ordre, l’information sur la nature de la perturbation et son impact sur le flux.  1, record 10, French, - th%C3%A9orie%20g%C3%A9n%C3%A9ralis%C3%A9e%20des%20perturbations

Record 10,  Textual support,  Spanish

Record 11,  Textual support,  English

Record number: 11, Textual support number: 1 CONT

A third type of neutron-induced nuclear reaction is fission. Typically, fission occurs following the absorption of a slow neutron by several of the very heavy elements.  1, record 11, English, - neutron%2Dinduced%20nuclear%20reaction

Record 11,  Textual support,  French

Record 11,  Textual support,  Spanish

Record 12,  Textual support,  English

Record number: 12, Textual support number: 1 CONT

Spatial homogenization can be performed using [a] criterion of reaction rate conservation, using the spatial neutron flux distribution for weighting … a simple flux and volume weighting procedure is valid when there is no leakage from the region, which is homogenized. In general, averaged cross sections homogenized by the simple flux and volume weighting satisfy the condition of average reaction rate conservation, but do not reproduce the partial neutron currents on the region boundaries.  1, record 12, English, - %20flux%20and%20volume%20weighting

Record 12,  Textual support,  French

Record number: 12, Textual support number: 1 CONT

Pondération par les flux et les volumes. En ce qui concerne l’homogénéisation, on est amené à pondérer les flux par les volumes pour respecter les flux moyens, et à pondérer les sections efficaces par les produits des flux par les volumes pour respecter les taux de réaction. En ce qui concerne la condensation, les règles sont les mêmes en remplaçant «volumes» par «intervalles de léthargie».  1, record 12, French, - pond%C3%A9ration%20par%20les%20flux%20et%20les%20volumes

Record 12,  Textual support,  Spanish

Record 13,  Textual support,  English

Record number: 13, Textual support number: 1 DEF

A structure in which a fission chain reaction can be maintained and controlled. It usually contains a fuel, coolant, moderator, and control absorbers and is most often surrounded by a concrete biological shield to absorb neutron and gamma ray emission.  2, record 13, English, - nuclear%20fission%20reactor

Record number: 13, Textual support number: 1 CONT

The nuclear fission reactor is possible because more neutrons are produced in fission than are needed to initiate it.  3, record 13, English, - nuclear%20fission%20reactor

Record 13,  Textual support,  French

Record number: 13, Textual support number: 1 DEF

Dispositif dans lequel une réaction de fission nucléaire en chaîne peut être entretenue et dirigée.  2, record 13, French, - r%C3%A9acteur%20%C3%A0%20fission%20nucl%C3%A9aire

Record number: 13, Textual support number: 1 CONT

Dans le réacteur à fission nucléaire, on utilise, pour contrôler la réaction de fission nucléaire en chaîne, des barres contenant un absorbant énergique de neutrons.  3, record 13, French, - r%C3%A9acteur%20%C3%A0%20fission%20nucl%C3%A9aire

Record 13,  Textual support,  Spanish

Record 14,  Textual support,  English

Record number: 14, Textual support number: 1 CONT

[Nuclear Gas Turbines] Fuel type... The fuel load is contained in a ’cartridge’ co(nuclear grade) vessel filled with fuel elements to be described further on. This cartridge is placed in a thick walled graphite vessel that is a fixed part of the reactor system; this vessel acts as a neutron reflector enabling the sustaining of the chain reaction.  1, record 14, English, - cartridge

Record 14,  Textual support,  French

Record number: 14, Textual support number: 1 CONT

Cartouche d'éléments du combustible graphite.  1, record 14, French, - cartouche

Record 14,  Textual support,  Spanish

Record 15,  Textual support,  English

Record number: 15, Textual support number: 1 CONT

... to make a chain reaction, the initiating neutron disappears and must be replaced by new ones.  1, record 15, English, - initiating%20neutron

Record 15,  Textual support,  French

Record 15,  Textual support,  Spanish

Record 16,  Textual support,  English

Record number: 16, Textual support number: 1 DEF

A ratio of the tritium produced by nuclear reaction between neutron and lithium in a blanket to that consumed by the DT [deuterium] reaction in a fusion reactor.  1, record 16, English, - tritium%20breeding%20ratio

Record number: 16, Textual support number: 1 OBS

Future fusion blankets are required to supply tritium as a fuel by themselves.  1, record 16, English, - tritium%20breeding%20ratio

Record 16,  Textual support,  French

Record number: 16, Textual support number: 1 DEF

[...] rapport du nombre d'atomes de tritium produit dans la couverture au nombre d'atomes de tritium consommé par les réactions de fusion.  1, record 16, French, - TBR

Record 16,  Textual support,  Spanish

Record 17,  Textual support,  English

Record number: 17, Textual support number: 1 CONT

A second cooling funtion is provided for safety reasons, to deal with the possibility of a loss of primary coolant circuit function during operation of the reactor. A breach in the primary coolant circuit, for example, could allow the core to overheat, resulting in damage to the nuclear fuel. A pressurizer arrangement injects additional coolant into the circuit to maintain operational pressure and to replace coolant that may be lost through a minor breach or leak in the coolant circuit. Various techniques are known for cooling the reactor core in the event of a major breach such as the rupture of a conduit in the primary coolant circuit. Neutron absorbing control rods can be inserted into the fuel array quickly to damp the nuclear reaction, for example when the sensed coolant pressure drops.  1, record 17, English, - major%20breach

Record 17,  Textual support,  French

Record number: 17, Textual support number: 1 CONT

Grosse brèche. Ce type d'accident de perte de réfrigérant primaire (APRP) est supposé initié par la rupture franche et complète d'une branche froide du circuit primaire (dite rupture guillotine). Le fluide s'écoule alors par les deux tronçons ouverts. La décompression est rapide : l'écoulement est homogène et les phénomènes gravitaires ne jouent qu'un rôle marginal.  1, record 17, French, - grosse%20br%C3%A8che

Record 17,  Textual support,  Spanish

Record 18,  Textual support,  English

Record number: 18, Textual support number: 1 CONT

absorption :Neutron-nuclear absorption reactions involve the absorption of a neutron by a nucleus and the release of energy. Fission is a type of neutron absorption reaction.  1, record 18, English, - neutron%20absorption%20reaction

Record 18,  Textual support,  French

Record 18,  Textual support,  Spanish

Record 19,  Textual support,  English

Record number: 19, Textual support number: 1 CONT

... a typical capture reaction [involves] a neutron being captured by the isotope boron-10. This [initiates] a nuclear reaction that [produces] a characteristic gamma ray which [can] be detected by... gamma radiation detection methods...  1, record 19, English, - capture%20reaction

Record 19,  Textual support,  French

Record number: 19, Textual support number: 1 OBS

Dans certains cas, les neutrons peuvent être capturées et induire une réaction nucléaire. Cette probabilité d'interaction s'exprime par une section efficace de capture [...] propre à chaque élément et fonction de l'énergie.  1, record 19, French, - r%C3%A9action%20de%20capture

Record 19,  Textual support,  Spanish

Record 20,  Textual support,  English

Record number: 20, Textual support number: 1 CONT

Fission chambers... [These] counters [are] designed for the detection of neutrons by their interaction with a solid fissile material... Neutrons cause fission of the fissile material and the high energy ionising products of that reaction result, usually, in the output of pulses from the chamber. These chambers are known as pulse fission chambers since the rate of pulse output is proportional to the rate of fission reactions and, therefore, to the neutron flux.  1, record 20, English, - pulse%20fission%20chamber

Record 20,  Textual support,  French

Record number: 20, Textual support number: 1 CONT

Chambres à fission, en régime d'impulsions. Elles ont une sensibilité faible (comprise entre 0,1 et 4 cps/nv) et délivrent des impulsions de très faible amplitude. Leur intérêt réside dans la très faible influençabilité vis-à-vis des gamma. Elles peuvent supporter jusqu'à 10₄ Gy/h.  1, record 20, French, - chambre%20%C3%A0%20fission%20en%20r%C3%A9gime%20d%27impulsions

Record number: 20, Textual support number: 1 OBS

Gy=gray (the unit of absorbed dose of radiation).  2, record 20, French, - chambre%20%C3%A0%20fission%20en%20r%C3%A9gime%20d%27impulsions

Record 20,  Textual support,  Spanish

Record 21,  Textual support,  English

Record number: 21, Textual support number: 1 DEF

A self-contained device designed to respond to excessive temperature or neutron flux density in a reactor and to act to reduce the reaction rate to a safe level.  1, record 21, English, - reactor%20safety%20fuse

Record number: 21, Textual support number: 1 OBS

The device may or may not contain stored energy to facilitate its operation.  1, record 21, English, - reactor%20safety%20fuse

Record 21,  Textual support,  French

Record number: 21, Textual support number: 1 DEF

Dispositif autonome destiné à intervenir lors d'une élévation excessive de la température ou de la densité de flux de neutrons dans un réacteur en agissant de façon à ramener le taux de réaction à un niveau assurant la sécurité.  1, record 21, French, - fusible%20de%20s%C3%A9curit%C3%A9%20d%27un%20r%C3%A9acteur

Record number: 21, Textual support number: 1 OBS

Ce dispositif peut contenir ou ne pas contenir de l'énergie emmagasinée en vue d'en faciliter le fonctionnement.  1, record 21, French, - fusible%20de%20s%C3%A9curit%C3%A9%20d%27un%20r%C3%A9acteur

Record 21,  Textual support,  Spanish

Record 29,  Textual support,  English

Record number: 29, Textual support number: 1 OBS

The resonance integral in which the cross section is replaced by an effective cross section and which gives the true reaction rate when the flux density does not vary inversely as the neutron energy.  1, record 29, English, - effective%20resonance%20integral

Record 29,  Textual support,  French

Record number: 29, Textual support number: 1 OBS

Intégrale de résonance dans laquelle la section efficace est remplacée par une section efficace effective, et qui donne le vrai taux de réaction lorsque la densité de flux neutronique varie autrement que selon la loi de l'inverse de l'énergie des neutrons.  1, record 29, French, - int%C3%A9grale%20effective%20de%20r%C3%A9sonance

Record 29,  Textual support,  Spanish