Dalat Research Reactor Research Articles

Development of 24 and 59 keV Filtered Neutron Beams for Neutron Capture Experiments at Dalat Research Reactor

External filtered neutron beams have been developed at the horizontal radial channels No. 4 of Dalat research reactor. In the material composition of the neutron filters, the primary material components of Iron, Aluminum, Nickel and Vanadium are used to obtain the mono-energetic neutron beams of 24 and 59 keV, with low level of Gamma and slow neutron background. A computer code and Monte-Carlo simulation technique were applied to optimize the filter configurations and to deduce the neutron energy distributions in the filtered beams. A hydrogen-filled proton recoil detector and the activation method with Gold foils were used to measure the neutron energy spectrum and flux of each beam at sample position. The results of experimental neutron fluxes are 6.1 × 105 and 5.3 × 105 n/cm2/s for 24 and 59 keV beams, respectively.

Capture Cross Section Measurements of 185,187Re With Filtered Neutron Beams at the Dalat Research Reactor

Capture Cross Section Measurements of 185,187Re With Filtered Neutron Beams at the Dalat Research Reactor

OPTIMIZATION OF FUEL RELOADING PATTERNS FOR A RESEARCH REACTOR BY SIMULATED ANNEALING

This article presents results obtained from a research into an application of simulated annealing method to the in-core fuel reloading pattern optimization for a research reactor. The decision variable of the optimization problem is a fuel reloading pattern for the next cycle after the present cycle finishes. The objective function maximizes the effective multiplication factor keff at the beginning of cycle while it is established to include an important safety paramater – the power peaking factor, in search process. A procedure for searching the optimal solutions was formed and a computer code was developed in the Fortran language running on PCs. Nuclear safety parameters for the optimization problem are provided from the results of the multigroup neutron diffusion theory computation program CITATION. A sample calculation was performed to find the optimal fuel reloading patterns for the second cycle of the Dalat research reactor and the results are presented in this article.

The application and development of k0-standardization method of neutron activation analysis at Dalat research reactor

In recent years the k0-NAA method has been applied and developed at the 500 kW Dalat research reactor, which includes (1) the establishment of a PC database of k0-NAA-related nuclear parameters, e.g., radionuclide produced, half-lives, k0-factors, Q0, r, Eg, etc; the access to the database is able by a k0-NAA software or by manual; (2) the detection efficiency calibration of gamma spectrometers used in k0-NAA, (3) the determination of reactor neutron spectrum parameters such as a and f factors and neutron fluxes in the irradiation channels, and (4) the validation of the developed k0-NAA procedure by analysing some SRMs, namely Coal Fly Ash (NIST-1633b), Bovine Liver (NIST-1577b) and IAEA-Soil7. The analytical results showed the deviations between experimental and certified values were mostly less than 15% with most Z-scores lower than 2. The k0-NAA procedure established at the Dalat research reactor has been regarded as a reliable standardization method of NAA and as available for practical applications, in particularly for airborne particulate and crude oil samples.