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Book Results of Monte Carlo Calculations of Neutron Spectra and Doses Outside the BDMS Shielding

Download or read book Results of Monte Carlo Calculations of Neutron Spectra and Doses Outside the BDMS Shielding written by and published by . This book was released on 2000 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: A set of Monte Carlo calculations of the neutron dose rates and neutron spectra outside Blend Down Monitoring System (BDMS) shielding were performed with U.S. and Russian neutron fluence-to-dose conversion coefficients. The purpose of these calculations was to facilitate the proper interpretation of the dose rate measurements from rem meters outside the BDMS shielding. An accurate determination of the dose rate is of particular interest so that dose rate can be compared with the applicable regulatory limit. The calculations show that the neutrons outside the BDMS shielding are significantly reduced in energy, i.e. the spectrum is shifted (moderated) towards the lower energies and contains significantly larger amount of neutrons in the energy range below 100 keV. The result of these calculations indicates that the dose measurement for the BDMS neutrons is overestimated from 25% to 55% depending on the location around BDMS when using either Russian or U.S. dose conversion coefficients. For an accurate neutron dose determination the application of an appropriate correcting factor to the neutron dose measurement is necessary.

Book Monte Carlo Calculations of the Penetration of Normally Incident Neutron Beams Through Concrete

Download or read book Monte Carlo Calculations of the Penetration of Normally Incident Neutron Beams Through Concrete written by F. H. Clark and published by . This book was released on 1967 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 05R Monte Carlo code (See ORNL-3622, NASA N65-17892) was adapted to calculate fast-neutron doses within and outside of concrete slab shields. Such calculations were performed for a variety of shield thicknesses (0 to 180 cm) and for various monoenergetic sources from 0.7 to 14 MeV. The concrete chosen is ordinary concrete with approximately 6% water content. Results are plotted as tissue kerma versus penetration distance for each source energy. The source is in each case a broad normally incident beam. (Author).

Book Shielding Calculations for the BDMS UF6 Mass Flow Meter

Download or read book Shielding Calculations for the BDMS UF6 Mass Flow Meter written by and published by . This book was released on 2001 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: We performed Monte Carlo calculations of the neutron and gamma ray spectra and neutron and gamma dose rates outside the shielding of the UF6 mass flowmeter. The UF6 mass flowmeter and the UF6 mass flowmeter are the two main components of the Blend Down Monitoring System (BDMS) equipment. The BDMS equipment is designed to continuously monitor the UF6 enrichment and mass flow rates in processing pipes at uranium facilities. The UF6 mass flowmeter incorporates four 252Cf neutron sources, surrounded by a polyethylene shielding block. The uranium fission products generated by the 252Cf neutrons are detected down the pipe, thus confirming the UF6 mass flow rate. The dose calculations used both U.S. and Russian gamma and neutron fluence-to-dose conversion coefficients. The purpose of these calculations was to facilitate proper interpretation of the neutron dose rate measurements from rem meters (e.g., rem balls) outside of BDMS shielding. An accurate determination of the dose rate is particular interest in that it enables dose rates to be compared with the applicable regulatory limit. The calculations show that neutrons outside of BDMS shielding are significantly reduced in energy, i.e., the spectrum is shifted (i.e., moderated) towards lower energies and contains significantly larger amount of neutrons in the energy range below 100 keV. Results of the calculations indicate that neutron dose rate measurements taken outside of BDMS shielding are overestimated by 25% to 55%, depending on the location around BDMS, when using either Russian or U.S. dose conversion coefficients. For an accurate neutron dose rate evaluation, application of an appropriate correction factor to the neutron dose rate measurements is necessary.

Book Results of the Analysis by Monte Carlo of Fast neutron Shielding Properties of Compound Cubical and Spherical Shields

Download or read book Results of the Analysis by Monte Carlo of Fast neutron Shielding Properties of Compound Cubical and Spherical Shields written by F. H. Clark and published by . This book was released on 1966 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive program of calculations was performed to check certain fast-neutron dose-rate measurements made at Project BREN in 1962. The response characteristic of the modified long counter was computed. Nitrogen and oxygen cross sections were reviewed and used in calculations of the transport in air of neutrons from a Godiva source to a distance of 66 g/sq cm. Transport results obtained by Monte Carlo were compared with those obtained by the moments method. A spectrum at an 80-g/sq cm penetration was determined. The perturbating effect of a structure on the neutron field in its neighborhood was estimated. The effect of variations of the spectrum with penetration distances on doses computed with different weight functions was also examined; the Snyder-Neufeld multicollision physical dose was found to vary with distance in a way markedly different from others examined. Work was also done on importance sampling techniques, especially the exponential transform, and the sampling problem was formulated in a simplified, approximate expression to facilitate statistical interpretations. Finally, a number of shield penetration calculations were performed to compare with the measurements and to determine the effects of shield shape, shield cavity size, and source angular distributions incident on the shields. The agreement between the calculations and the measurements was within the uncertainty in the detector response characteristic. (Author).

Book Monte Carlo Calculations for Shields

Download or read book Monte Carlo Calculations for Shields written by Wendell De Marcus and published by . This book was released on 1948 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Monte Carlo Calculations Using MCNP4B for an Optimal Shielding Design If A14 MeV Neutron Source

Download or read book Monte Carlo Calculations Using MCNP4B for an Optimal Shielding Design If A14 MeV Neutron Source written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The shielding for 14-MeV neutrons from a D-T generator at SLAC needs to be optimized in terms of shield thickness and cost. Shielding calculations were made using the MCNP4B Monte Carlo code and the ENDF/B-VI cross section set. A few materials were studied: iron, borated polyethylene, three types of normal and heavy concrete, and mixtures of iron and borated polyethylene. The effects of shielding geometry (sphere, cube, and the proposed geometry) were also examined. The transmission results of ambient dose equivalents, as well as the attenuation lengths and the average energies, for neutrons and gammas outside the shielding are presented.

Book Monte Carlo Calculations on Intranuclear Cascades

Download or read book Monte Carlo Calculations on Intranuclear Cascades written by Hugo W. Bertini and published by . This book was released on 1963 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Therapeutic Applications of Monte Carlo Calculations in Nuclear Medicine

Download or read book Therapeutic Applications of Monte Carlo Calculations in Nuclear Medicine written by H. Zaidi and published by CRC Press. This book was released on 2002-09-01 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: Therapeutic Applications of Monte Carlo Calculations in Nuclear Medicine examines the applications of Monte Carlo (MC) calculations in therapeutic nuclear medicine, from basic principles to computer implementations of software packages and their applications in radiation dosimetry and treatment planning. With chapters written by recognized authorit

Book Monte Carlo Methods for Shield Computation

Download or read book Monte Carlo Methods for Shield Computation written by Gerald Goertzel and published by . This book was released on 1951 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book COMPARISON OF MONTE CARLO CALCULATIONS WITH MEASUREMENTS OF FAST NEUTRON DOSE TRANSMITTED FROM A BEAM SOURCE THROUGH A SNAP 2 LiH SHIELD

Download or read book COMPARISON OF MONTE CARLO CALCULATIONS WITH MEASUREMENTS OF FAST NEUTRON DOSE TRANSMITTED FROM A BEAM SOURCE THROUGH A SNAP 2 LiH SHIELD written by and published by . This book was released on 1968 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A General Monte Carlo Neutronics Code

Download or read book A General Monte Carlo Neutronics Code written by Robert R. Johnston and published by . This book was released on 1963 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: