[en] Most current adjustment procedures, including LSL, can adjust only one spectrum with dosimetry located at the point of the input spectrum. Many radiation experiments have dosimetry at more than one location, and fluence or damage exposure values are desired for locations other than those covered by dosimetry. Thus, the use of single-spectrum dosimetry to these experiments causes considerable loss of information and introduces large uncertainties. Two extensions of the LSL code to cover multiple-spectra adjustment are discussed. Each extension has different restrictions and covers a different range of applications

[en] This report describes the GAMLIB 1-5 library, which is used in the calculation of the activity of radionuclides present in the gamma-ray spectra of irradiated neutron fluence detectors. The library contains all constants needed to calculate the activity for reactions normally applied in neutron fluence determinations, performed in irradiation experiments in the HFR. It also contains the nuclide constants for the activity calculation of gamma-ray measurements of U and Pu samples. The library consists of two kinds of tables, the first containing gamma-ray energies and gamma-ray emission probabilities with their uncertainties and the nuclide code, the other the nuclide code, decay constant, gamma -ray energies and gamma-ray emission probabilities. No cross-section data are stored in this library. All the relevant dat of the Nuclear Data Guide (Dordrecht, Kluwer 1989) have been used as base for this library. Other data have been obtained from recent literature. This library comprises 155 nuclides and 1115 gamma-ray energies. (author). 9 refs

[en] An innovative MCNP-based fluence computational package MF3D is developed and validated for accurate, BWR, three-dimensional, continuous-energy, neutron and gamma fluence computation. MF3D's applications include: 1) fluence computations for plant surveillance and life extension, 2) thermal neutron fluence and associated helium-production computations, 3) steel and sapphire dpa radiation damage calculations, 4) benchmark for conventional fast-neutron fluence computer programs such as DORT, and 5) radiolysis modeling for water chemistry analysis. MF3D is employed to compute neutron and gamma fluxes at locations of interest at various exposure points of operational cycles. Finally, the neutron and gamma fluxes at various exposure points of the cycles are integrated over time in order to obtain the neutron and gamma fluence at various locations of interest. MF3D was validated by benchmarking against BWR activation wire measurements at selected locations between the shroud and the reactor pressure vessel of a BWR4 operated by BKW in Switzerland. The innovative MF3D computational package has been developed and validated in good agreement with the measurements and is a useful tool for computing accurate BWR fluence, dpa radiation damage and helium production and for benchmarking existing, less precise methodologies. (author)

[en] This report describes the dosimetry systems for neutron fluence and dose measurements used by the study group from the Boris Kidric Institute and the final results obtained at the Viper reactor. Methods used for gamma dose measurements have been described earlier

[en] The vessel metal radiation embrittlement and the prediction of the reactor lifetime depend on the estimation of RPV neutron fluence. The RPV neutron fluence in Kozloduy NPP Units 5 and 6 is being evaluated after every cycle taking into account the loading patterns and cycle operation regimes. The neutron fluence verification is based on comparison of calculated and measured induced activity values of the detectors irradiated in the cavity behind the vessel during the cycle. Special device for positioning of the detectors behind reactor pressure vessel was used. Wire activation detectors from copper and iron - two in horizontal direction and two in vertical one, and three sets of foil detectors from iron, copper and niobium for absolute measurement have been fasten onto the device. Result from the verification of neutron fluence on the WWER-1000 RPV at Kozloduy NPP Unit 6 after cycle 2 are presented. The data analysis shows that the fluence was determined with an error below 9%. (author)

[en] In this paper, the author reports some main methods to determine the nuclear parameters of material irradiation in testing reactor (nuclear power, burn-up, fluxes, fluences, ...). The different methods (theoretical or experimental) are reviewed: neutronics measurements and calculations, gamma scanning, thermal balance, ... The required accuracies are reviewed: they are of 3-5% on flux, fluences, nuclear power, burn-up, conversion factor, ... These required accuracies are compared with the real accuracies available which are at the present time of order of 5-20% on these parameters

[en] Neutron sources using the Be(d,n) and Li(d,n) reactions will be employed for much of the irradiation testing of candidate fusion reactor materials for the next several years. Passive dosimetry, particularly helium accumulation neutron dosimetry in combination with radiometric dosimetry, provides the most accurate characterization of the neutron fluence for the large flux and energy spectrum gradients found in the limited irradiation volumes. This application of the helium accumulation dosimetry method is discussed, and results using this method to characterize accurately a Be(d,n) neutron field are presented

[en] Accurate monoenergetic neutron fluence rates are required for energy response study of neutron area monitors and dosimeters. Absolute measurement of monoenergetic neutron fluence rates at neutron energies above 1 MeV can be done by observing recoil proton scattered at forward angles from hydrogenous radiator. Any charged particle detector can be used to detect the recoil protons. Such a radiator-collimator-detector system is called as telescope. The Proton Recoil Telescope (PRT) efficiency can be computed precisely provided the absolute value of the n-p elastic scattering cross section is well known. This work describes the absolute measurement of 14 MeV neutron fluence rate from D-T neutron generator using proton recoil neutron telescope

[en] The knowledge of neutron spectra is necessary for the interpretation of the irradiations of materials. Because of the spectrum variations it is necessary to determine the damage cross sections for the comparison between the different irradiations. At Melusine, the neutron fluences were measured by the ⁶³Cu(n,α) reaction in the case of irradiations of reactor vessel steels. Neutron spectra were studied experimentally by In, Ni, Al activation detectors, and theoretically by the two-dimensional transport codes ANISN-DOT III. The response of the different damage functions were calculated from these spectra. Results point out a great sensitivity of the spectral indices and damage response to the irradiation device structures

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