Proceedings of the U.S. Nuclear Regulatory Commission Tenth Water Reactor Safety Research Information Meeting, held at National Bureau of Standards, Gaithersburg, Maryland, October 12-15, 1982 /

Includes papers describing research sponsored by the Office of Nuclear Regulatory Research, NRC.

Proceedings of the U.S. Nuclear Regulatory Commission Eleventh Water Reactor Safety Research Information Meeting, held at National Bureau of Standards, Gaithersburg, Maryland, October 24-28, 1983 /

Includes bibliographies.

Crystallography of zirconium hydrides in recrystallized Zircaloy-2 fuel cladding lay electron backscatter diffraction

Precipitation morphology and habit planes of the delta-phase Zr hydrides, which were precipitated within the a-phase matrix grains and along the grain boundaries of recrystallized Zircaloy-2 cladding tube, have been examined by electron backscatter diffraction (EBSD). Radially-oriented hydrides, induced by residual tensile stress, precipitated in the outside region of the cladding, and circumferentially-oriented hydrides in the stress-free middle region of the cladding. The most common crystallographic relationship for both types of the hydrides precipitated at the inter- and intra-granular sites was identical at (0001)(alpha) // {111}(delta), with {1017}(alpha) // {111}(delta) being the occasional exception only for the inter-granular radial hydrides. When tensile stress was loaded, the intra-granular hydrides tended to preferentially precipitate in the grains with circumferential basal pole textures. The inter-granular hydrides tended to preferentially precipitate on the grain faces opposite to tensile axis. The change of prioritization in the precipitation sites for the hydrides due to tensile stress could be explained in terms of the relaxation effect of constrained elastic energy on the terminal solid solubility of hydrogen at hydride precipitation.

Anti-nuclear demonstration on Wall street

General note: Title and date provided by Bettye Lane.

Japan´s energy future: Between a return to nuclear energy and a turn to renewables

After the triple disaster of 11 March 2011, Japan is at an energy crossroad. In the short and medium run it depends on fossil fuel imports to ensure its energy security, but the long term will be determined by the decisions taken at present. For Japan energy security is a national security challenge, as stated in its National Security Strategy. The article reviews the Japanese nuclear path, studies the factors shaping the Japanese electricity market and analyzes the current energy situation. Moreover, it also assesses the principles that have marked Japan’s energy policy and the two last Strategic Energy Plans -one prior to Fukushima and the other after it- before tackling the debate on the optimal future energy mix that Japan should adopt to meet its energy security trilemma, marked by its environmental commitment.

Modelado detallado de una central nuclear CANDU con CITVAP.

La línea de cálculo de INVAP consiste principalmente de los códigos CONDOR y CITVAP. Este último es la versión mejorada del código CITATION II que resuelve la ecuación de difusión neutrónica multigrupo por el método de diferencias finitas. CITVAP es ampliamente usado para estudiar reactores de investigación y reactores de potencia tales como PWR, BWR, VVER y últimamente se implemento nuevas funciones para estudiar una central PHWR tipo Atucha. Siguiendo con la línea de reactores PHWR, en este trabajo se estudian las capacidades y deficiencias del código de núcleo CITVAP para modelar una central nuclear tipo CANDU. Se plantean mejoras a realizar para un manejo mas eficiente desde el punto de vista del usuario, tanto de la gestión de combustibles, movimientos de barras de control y zonas líquidas como mejoras en el modelo termohidraulico. La metodología consiste en validar la línea de cálculo de INVAP, contrastando los resultados con el benchmark IAEA-tecdoc-887. El proceso de validación consiste en cálculos de celda en dos y tres dimensiones usando los códigos CONDOR y SERPENT respectivamente, obtención de secciones eficaces macroscópicas en función del quemado y cálculos de núcleo para distintas configuraciones de los dispositivos de control usando un núcleo fresco y una distribución de quemado en equilibrio. Se analizan las dificultades que se presentan al modelar el núcleo con las capacidades actuales del código y se plantean posibles soluciones a implementar. Para un estudio completo de un reactor CANDU, se estudian tres de la características distintivas de este tipo de reactor: la termohidraulica, la gestión de combustibles y los dispositivos de control de reactividad, distribución de potencia y apagado.

Modelado detallado de una central nuclear CANDU con CITVAP.

La línea de cálculo de INVAP consiste principalmente de los códigos CONDOR y CITVAP. Este último es la versión mejorada del código CITATION II que resuelve la ecuación de difusión neutrónica multigrupo por el método de diferencias finitas. CITVAP es ampliamente usado para estudiar reactores de investigación y reactores de potencia tales como PWR, BWR, VVER y últimamente se implemento nuevas funciones para estudiar una central PHWR tipo Atucha. Siguiendo con la línea de reactores PHWR, en este trabajo se estudian las capacidades y deficiencias del código de núcleo CITVAP para modelar una central nuclear tipo CANDU. Se plantean mejoras a realizar para un manejo mas eficiente desde el punto de vista del usuario, tanto de la gestión de combustibles, movimientos de barras de control y zonas líquidas como mejoras en el modelo termohidraulico. La metodología consiste en validar la línea de cálculo de INVAP, contrastando los resultados con el benchmark IAEA-tecdoc-887. El proceso de validación consiste en cálculos de celda en dos y tres dimensiones usando los códigos CONDOR y SERPENT respectivamente, obtención de secciones eficaces macroscópicas en función del quemado y cálculos de núcleo para distintas configuraciones de los dispositivos de control usando un núcleo fresco y una distribución de quemado en equilibrio. Se analizan las dificultades que se presentan al modelar el núcleo con las capacidades actuales del código y se plantean posibles soluciones a implementar. Para un estudio completo de un reactor CANDU, se estudian tres de la características distintivas de este tipo de reactor: la termohidraulica, la gestión de combustibles y los dispositivos de control de reactividad, distribución de potencia y apagado.

Fuel let-down heat exchanger.

"Work performed under contract no. W-7405-Eng.-26."

Conceptual design of the integral measurement system of the radiation dose of the fuel elements for the ALFRED reactor.

Conceptual design of the integral measurement system of the radiation dose of the fuel elements for the ALFRED reactor.

Emergent Antiferromagnetism Out Of The Hidden-order" State In Uru2si2: High Magnetic Field Nuclear Magnetic Resonance To 40 T."

Very high field (29)Si-NMR measurements using a fully (29)Si-enriched URu(2)Si(2) single crystal were carried out in order to microscopically investigate the hidden order (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the (29)Si shift, (29)K(c). Moreover, a strong enhancement of (29)K(c) develops near a critical field H(c) ≃ 35.6 T, and the ^{29}Si-NMR signal disappears suddenly at H(c), indicating the total suppression of the HO state. Nevertheless, a weak and shifted (29)Si-NMR signal reappears for fields higher than H(c) at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.

Observation Of D0 Meson Nuclear Modifications In Au+au Collisions At Sqrt[s(nn)] = 200 Gev.

We report the first measurement of charmed-hadron (D(0)) production via the hadronic decay channel (D(0) → K(-) + π(+)) in Au+Au collisions at sqrt[s(NN)] = 200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, N(bin), from p+p to central Au+Au collisions. The D(0) meson yields in central Au + Au collisions are strongly suppressed compared to those in p+p scaled by N(bin), for transverse momenta p(T) > 3 GeV/c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate p(T) is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.

Espectroscopia de Ressonância Magnética Nuclear de 13C no estudo de rotas biossintéticas de produtos naturais

During the last five decades, as a result of an interaction between natural product chemistry, synthetic organic chemistry, molecular biology and spectroscopy, scientists reached an extraordinary level of comprehension about the natural processes by which living organisms build up complex molecules. In this context, 13C nuclear magnetic resonance spectroscopy, allied with isotopic labeling, played a determinant role. Nowadays, the widespread use of modern NMR techniques allows an even more detailed picture of the biochemical steps by accurate manipulation of the atomic nuclei. This article focuses on the development of such techniques and their impact on biosynthetic studies.