[en] The Callan-Symanzik equation is utilized within the framework of Gribov's Reggeon field theory to prove that a bare Pomeron of unit intercept necessarily restricts the renormalized Pomeron to satisfy the same condition, i.e., α/sub renorm./ (0) = 1, at a nontrivial fixed point β(g*) = 0 of the Callan-Symanzik equation. The proof of this assertion does not depend on the validity of the epsilon expansion (epsilon = 4-D). (U.S.)

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[en] This report describes the preirradiation thermal analysis of the HRB-22 capsule designed for irradiation in the removable beryllium (RB) position of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). CACA-2 a heavy isotope and fission product concentration calculational code for experimental irradiation capsules was used to determine time dependent fission power for the fuel compacts. The Heat Engineering and Transfer in Nine Geometries (HEATING) computer code, version 7.2, was used to solve the steady-state heat conduction problem. The diameters of the graphite fuel body that contains the compacts and the primary pressure vessel were selected such that the requirements of running the compacts at an average temperature of < 1,250 C and not exceeding a maximum fuel temperature of 1,350 C was met throughout the four cycles of irradiation

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[en] Recent R and D studies on Nuclear Analytical Chemistry utilizing techniques like Neutron Activation Analysis (NAA), Prompt Gamma-ray NAA (PGNAA), Particle Induced Gamma Ray and X-Ray Emission (PICE/PIXE) for compositional analysis of materials have been summarized. The work includes developments and applications of (i) single comparator NAA, called as k₀-NAA, (ii) k₀-based internal monostandard NAA (IM-NAA), (iii) k₀-based prompt gamma ray NAA (PGNAA) and (iv) instrumental NAA using thermal and epithermal neutrons and (v) PIGE and PIXE methods using proton beam for low Z and medium Z elements, respectively. (author)

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[en] Nuclear analytical techniques (NATs), utilizing neutron and proton based nuclear reactions and subsequent measurement of gamma rays, are capable of chemical characterization of various materials at major to trace concentration levels. The present article deals with the recent developments and applications of conventional and k0-based internal monostandard (i) neutron activation analysis (NAA) and (ii) prompt gamma ray NAA (PGNAA) methods as well as (iii) in situ current normalized particle induced gamma ray emission (PIGE). The materials that have been analyzed by NAA and PGNAA include (i) nuclear reactor structural materials like zircaloys, stainless steels, Ni alloys, high purity aluminium and graphite and (ii) uranium oxide, U-Th mixed oxides, uranium ores and minerals. Internal monostandard NAA (IM-NAA) method with in situ detection efficiency was used to analyze large and non-standard geometry samples and standard-less compositional characterization was carried out for zircaloys and stainless steels. PIGE methods using proton beams were standardized for quantification of low Z elements (Li to Ti) and applied for compositional analysis of borosilicate glass and lithium titanate (Li₂TiO₃) samples and quantification of total B and its isotopic composition of B (¹⁰B/¹¹B) in boron based neutron absorbers like B₄C. (author)

[en] Prompt gamma ray neutron activation analysis methodologies were standardized using a reflected neutron beam and Compton suppressed γ-ray spectrometer to quantify boron from trace to major concentrations. Neutron self-shielding correction factors for higher boron contents (0.2-10 mg) in samples were obtained from the sensitivity of chlorine by irradiating KCl with and without boron. This method was validated by determining boron concentrations in six boron compounds and applied to three borosilicate glass samples with boron contents in the range of 1-10 mg. Low concentrations of boron (10-58 mg kg^-1) were also determined in two samples and five reference materials from NIST and IAEA. (author)