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At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Fuel strategy for 2 MW SF-TMSR

China has launched a series of projects for developing high performance nuclear energy systems. The 2 MW solid fuel thorium based molten salt reactor (TMSR-SF) is one of these projects, which uses TRISO fuel elements as the fuel carrier and the FLiBe molten salt (2LiF-BeF{sub 2}) as the coolant. TRISO fuel elements have been well developed in respect to manufacturing, testing experiments inside and outside reactors as well as their successful application in HTGRs. The application of LEU (low enriched uranium) spherical TRISO fuel elements in TMSR-SF can be safely conducted through careful control of temperature and power density. Although the soaking of molten salt into graphite has shown no damage to the graphite material as experienced by ORNL group in the sixties last century, the compatibility of FLiBe salt with graphite covering of the fuel elements should be tested before the application. It is expected that TMSR-SF can be an appropriate test reactor for high performance fuel element development. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

U.S. Department of Energy Office of Legacy Management Calibration Facilities - 12103

This paper describes radiometric calibration facilities located in Grand Junction, Colorado, and at three secondary calibration sites. These facilities are available to the public for the calibration of radiometric field instrumentation for in-situ measurements of radium (uranium), thorium, and potassium. Both borehole and hand-held instruments may be calibrated at the facilities. Aircraft or vehicle mounted systems for large area surveys may be calibrated at the Grand Junction Regional Airport facility. These calibration models are recognized internationally as stable, well-characterized radiation sources for calibration. Calibration models built in other countries are referenced to the DOE models, which are also widely used as a standard for calibration within the U.S. Calibration models are used to calibrate radiation detectors used in uranium exploration, remediation, and homeland security. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Formerly Used Sites Remedial Action Program (FUSRAP) W. R. Grace Building 23 Remedial Action-Challenges and Successes - 12247

Monazite sand processing was conducted at the W. R. Grace Curtis Bay Facility (Baltimore, Maryland) from mid-May 1956 through the spring of 1957 under license to the Atomic Energy Commission (AEC), for the extraction of source material in the form of thorium, as well as rare earth elements. The processing was conducted in the southwest quadrant of a ca. 100 year old, five-story, building (Building 23) in the active manufacturing portion of the facility. Building components and equipment in the southwest quadrant of Building 23 exhibited residual radiological activity remaining from the monazite sand processing. U.S. Army Corps of Engineers (USACE) conducted a remedial investigation (RI) and feasibility study (FS) and prepared a Record of Decision (ROD) to address residual radioactivity on building components and equipment in the southwest quadrant of Building 23. The remedy selected for the southwest quadrant of Building 23, which was documented in the ROD (dated May 2005), was identified as 'Alternative 2: Decontamination With Removal to Industrial Use Levels'. The selected remedy provided for either decontaminating or removing areas of radioactivity to meet the RGs. Demonstration of compliance with the selected ARAR was performed using the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) and other appropriate guidance, as well as appropriate dose modeling codes where necessary. USACE-Baltimore District along with its private industry partner worked together under the terms of a 2008 Settlement Agreement to implement the remedial action (RA) for the southwest quadrant of Building 23. The RA was conducted in two phases: Phase 1 was completed to improve the building condition for support of subsequent remedial action and decrease scope uncertainty of the remedial action, and Phase 2 included decontamination and removal activities to meet the RGs and demonstration of compliance with the selected ARAR. Challenges encountered during the RA include: coordination with stakeholders, coordination between multiple RA contractors, addressing unique structural challenges for Building 23, nonradiological hazards associated with the RA, weather issues, and complex final status survey (FSS) coordination. The challenges during the Phase 1 RA were handled successfully. The challenges for the Phase 2 RA, which is anticipated to be complete by late-summer of 2012, have been handled successfully so far. By fall of 2012, USACE is expecting to finalize a robust RA Closure Report, including the Final Status Survey Report, which summarizes the RA activities and documents compliance with the ROD. During the ongoing RA at Building 23, there have been and still are many challenges both technically and from a project management perspective, due in part to the nature and extent of impact at the site (residual radioactivity within an active processing building), dual oversight by the property owner and USACE, and site-specific challenges associated with a complex RA and multiple contractors. Currently, USACE and its industry partner are overseeing the completion of RA field activities. RA closure documentation for the remediation of Building 23 to address residual contamination in building materials will be reviewed/approved by USACE and its industry partner upon completion of the field activities. USACE and its industry partner are working well together, through the Settlement Agreement, to conduct a cost-efficient and effective remedial action to address the legacy issues at Building 23. This cooperative effort has set a firm foundation for achieving a successful RA at the RWDA using a 'forward think' approach, and it is a case study for other sites where an industry partner is involved. The collaborative effort led to implementation of an RA which is acceptable to the site owner, the regulators, and the public, thus allowing USACE to move this project forward successfully in the FUSRAP program. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Successful Implementation of Soil Segregation Technology at the Painesville FUSRAP Site - 12281

Typically the highest cost component of the radiological soils remediation of Formerly Utilized Sites Remedial Action Program (FUSRAP) sites is the cost to transport and dispose of the excavated soils, typically contaminated with naturally occurring isotopes of uranium, thorium and radium, at an appropriately permitted off-site disposal facility. The heterogeneous nature of the contamination encountered at these sites makes it difficult to accurately delineate the extent of contaminated soil using the limited, discrete sampling data collected during the investigation phases; and difficult to precisely excavate only the contaminated soil that is above the established cleanup limits using standard in-field scanning and guiding methodologies. This usually results in a conservative guided excavation to ensure cleanup criteria are met, with the attendant transportation and disposal costs for the larger volumes of soil excavated. To address this issue during the remediation of the Painesville FUSRAP Site, located in Painesville, Ohio, the Buffalo District of the U.S. Army Corps of Engineers, and its contractor, Safety and Ecology Corporation (SEC), employed automatic soil segregation technology provided by MACTEC (now AMEC) to reduce the potential for transportation and disposal of soils that met the cleanup limits. This waste minimization technology utilized gamma spectroscopy of conveyor-fed soils to automatically segregate the material into above and below criteria discharge piles. Use of the soil segregation system resulted in cost savings through the significant reduction of the volume of excavated soil that required off-site transportation and disposal, and the reduction of the amount of imported clean backfill required via reuse of 'below criteria' segregated soil as place back material in restoring the excavations. Measurements taken by the soil segregation system, as well as results of quality control sampling of segregated soils, confirmed that soils segregated as below criteria for reuse as site fill did meet the Record of Decision cleanup criteria for the site. Automatic soil segregation technology was successfully implemented as part of the 2010 - 2011 remediation effort at the Painesville FUSRAP Site. The Orion ScanSortSM system employed at the site demonstrated the ability to accurately determine the radioactivity concentrations in the processed soil and soil-like material and quickly segregate that material for appropriate final disposition. Data from the soil segregation system and confirmatory QC samples indicated that the segregated 'below criteria' soils met the cleanup criteria in the ROD, and was appropriate for reuse as fill in the excavations. The reduction of the total excavated soil volume requiring off-site disposal by 94% yielded significant project cost savings through reduction of transportation and disposal and backfill procurement costs. Use of automatic soil segregation technology was an efficient and cost-effective method for addressing the radiological contamination at the Painesville Site. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Development of Microwave Technology for TENORM Waste Treatment - 17377

The sludge and scales generated by the oil and gas industry usually contain radionuclides of the thorium and uranium decay chains, the so-called technologically enhanced, naturally occurring radioactive materials (TENORM) waste. The handling of this waste must consider both the radiation risks presented by those radionuclides and its chemical toxicity, due to the decomposition of oil residues, which may generate hydrogen sulfide and other hazardous compounds. In the case of Brazil, Public Law 10.308 limits the management options for radioactive waste generated by offshore oil production rigs to drumming and storage; it prohibits disposal of any radioactive waste in sea-waters, seabed or oceanic islands. This paper describes the results of the work to develop a treatment process using a specially designed microwave oven, which removes simultaneously water and hydrocarbons from the sludge, thus reducing the volume, the chemical toxicity and the chemical reactivity of the waste. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Developments that are making the Versa-Pac Indeed More Versatile (and More Useful to Industry) - 16267

Daher-TLI acquired the assets and employees of Century Industries, a radioactive material packaging manufacturing facility, in 2013. Included in that acquisition was the Versa-Pac Shipping Package. The Versa-Pac is an NRC licensed Type AF packaging (Certificate of Compliance no. USA/9342/AF-96) and was originally designed as a replacement for standard 7A drum-type transportation packaging. It can be used directly or in conjunction with pails, drums or inserts that can be manufactured to accommodate a variety of smaller containers and vessels. The Versa-Pac comes in two sizes, the VP-55 (i.e., 55-gallon drum version) and VP-110 (i.e., 110-gallon drum version). It features a patented design concept in combination with the drum exterior to provide enhanced structural protection to payloads under Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC), per 10CFR71.71 and 10CFR71.73 respectively. Since its introduction in 2010, the Versa-Pac has been utilized mainly as a one-time use package for disposing of radioactive waste. The package is also designed as a reusable package for transporting front-end materials. Discussions with current and prospective clients have resulted in numerous improvements, accomplished and planned, to the package's payload capability through additional engineering analyses and actual design modifications. Revision 10 to the NRC Certificate of Compliance, dated August 6, 2015, introduces an enrichment-loading table that allows shipping larger quantities of U-235 for enrichments less than 100 wt.%. It also authorizes shipment of natural thorium. Other planned and proposed improvements include provisions to transport UF{sub 6} in 1S, 2S, and 5B cylinders, design changes that further increases the amount of U-235 at enrichments less than 100 wt.%, increasing the capacity of the VP-110, developing a lighter 30-gallon version, the VP-30, and introducing content limits specific to uranium-oxides in multiple forms. This paper traces the engineering and design efforts involved in expanding the Versa-Pac's versatility. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Hydrided moderators for nuclear reactors

High temperature moderators for nuclear reactors and processes for their production are disclosed. The moderators include at least one hydrided metal and/or hydride metal allow, such as yttrium hydride, thorium hydride, yttrium-cerium hydride, yttrium-gadolinium hydride, yttrium calcium hydride, cerium hydride, etc. Such metal hydrides and/or hydride alloys may have high thermal stability, a relatively low thermal neutron absorption cross section, the ability to retain hydrogen over a large temperature range, and have good mechanical properties. Such moderators may induce spectral shift in reactors which, in turn, magnifies the Doppler reactivity temperature coefficient. Such moderators to thermalize neutrons may also enhance fuel utilization and cost-effectiveness of the reactor while keeping the core portable.

Dasari, Venkateswara Rao↗
DOE OSTI2025

Undercooling minimization in ultrasound coupled DTA measurements of molten salts

Molten salts are ionic liquids that are used for the electrolytic pyroprocessing of metals and as heat transfer fluids in very high temperature processes. Recently, halide-based molten salt reactors (MSR) have gained momentum for high density and environmentally responsible electricity generation. The function of these reactors and their fuel cycle depend on a knowledge of the halide salt’s thermodynamic properties [1]. Therefore, high accuracy phase equilibria of MSR relevant base halide and actinide containing salts are needed. Modern thermal analysis of the phase transitions of halide salts is usually done during heating at relatively high scan rates with commercial devices. Normally such measurements are adequate for pure or pseudo-binary salts. However, as the number of components in the mixture increases, accurately resolving the liquidus becomes increasingly difficult. Reversing the scanning mode greatly increases the sensitivity of phase transition measurements but can decrease accuracy due to undercooling [2] — a common occurrence in molten halide systems [3]. This work presents the development of a differential thermal analysis (DTA) cell intended for use in radiological gloveboxes. Non-contact ultrasonic agitation of the halide salt is implemented to limit kinetic limitations on crystallization during cooling to minimize undercooling [4]. Measurements on halide salts are also presented to elucidate the effect of non-contact mixing on undercooling. Reference [1] S. Boyd and C. Taylor, “3 - Chemical fundamentals and applications of molten salts,” in Molten Salt Reactors and Thorium Energy, T. J. Dolan, Ed., Woodhead Publishing, 2017, pp. 29–91. doi: 10.1016/B978-0-08-101126-3.00003-8. [2] K. Nitsch, A. Cihlár, and M. Rodová, “Molten state and supercooling of lead halides,” J. Cryst. Growth, vol. 264, no. 1, pp. 492–498, Mar. 2004, doi: 10.1016/j.jcrysgro.2004.01.011. [3] L. Rycerz, “Practical remarks concerning phase diagrams determination on the basis of differential scanning calorimetry measurements,” J. Therm. Anal. Calorim., vol. 113, no. 1, pp. 231–238, Jul. 2013, doi: 10.1007/s10973-013-3097-0. [4] Md. H. Zahir, S. A. Mohamed, R. Saidur, and F. A. Al-Sulaiman, “Supercooling of phase-change materials and the techniques used to mitigate the phenomenon,” Appl. Energy, vol. 240, pp. 793–817, Apr. 2019, doi: 10.1016/j.apenergy.2019.02.045.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2011

Syntheses and single-crystal structures of CsTh(MoO{sub 4}){sub 2}Cl and Na{sub 4}Th(WO{sub 4}){sub 4}

Colorless crystals of CsTh(MoO{sub 4}){sub 2}Cl and Na{sub 4}Th(WO{sub 4}){sub 4} have been synthesized at 993 K by the solid-state reactions of ThO{sub 2}, MoO{sub 3}, CsCl, and ThCl{sub 4} with Na{sub 2}WO{sub 4}. Both compounds have been characterized by the single-crystal X-ray diffraction. The structure of CsTh(MoO{sub 4}){sub 2}Cl is orthorhombic, consisting of two adjacent [Th(MoO{sub 4}){sub 2}] layers separated by an ionic CsCl sublattice. It can be considered as an insertion compound of Th(MoO{sub 4}){sub 2} and reformulated as Th(MoO{sub 4}){sub 2}.CsCl. The Th atom coordinates to seven monodentate MoO{sub 4} tetrahedra and one Cl atom in a highly distorted square antiprism. Na{sub 4}Th(WO{sub 4}){sub 4} adopts a scheelite superlattice structure. The three-dimensional framework of Na{sub 4}Th(WO{sub 4}){sub 4} is constructed from corner-sharing ThO{sub 8} square antiprisms and WO{sub 4} tetrahedra. The space within the channels is filled by six-coordinate Na ions. Crystal data: CsTh(MoO{sub 4}){sub 2}Cl, monoclinic, P2{sub 1}/c, Z=4, a=10.170(1) A, b=10.030(1) A, c=9.649(1) A, {beta}=95.671(2){sup o}, V=979.5(2) A{sup 3}, R(F)=2.65% for I>2{sigma}(I); Na{sub 4}Th(WO{sub 4}){sub 4}, tetragonal, I4{sub 1}/a, Z=4, a=11.437(1) A, c=11.833(2) A, V=1547.7(4) A{sup 3}, R(F)=3.02% for I>2{sigma}(I). -- Graphical abstract: The two-dimensional layered structure of CsTh(MoO{sub 4}){sub 2}Cl viewed down the b axis. Display Omitted Research highlights: {yields} Syntheses of CsTh(MoO{sub 4}){sub 2}Cl and Na{sub 4}Th(WO{sub 4}){sub 4} from chlorides. {yields} Single-crystal structures of CsTh(MoO{sub 4}){sub 2}Cl and Na{sub 4}Th(WO{sub 4}){sub 4}. {yields} CsTh(MoO{sub 4}){sub 2}Cl can be considered as an inclusion compound composed of covalent [Th(MoO{sub 4}){sub 2}] layer and ionic [CsCl] layers. {yields} Na{sub 4}Th(WO{sub 4}){sub 4} adopts a defect scheelite structure.

36 MATERIALS SCIENCE↗
DOE OSTI2010

Preliminary Results on Direct Observation of True Ternary fission in the reaction {sup 232}Th+d (10 MeV)

Results of the first direct observation of the true ternary fission of {sup 234}Pa* nucleus are presented. The yield of the effect depending of the experimental geometry is about 10{sup -5}/binary fission. Mass of the lightest fragment in the triplet lies mainly in the range of (20 divide 40) a.m.u. Connection between the effect and known heavy ion or lead radioactivity is discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Toward a new description of triaxial nuclei

The liquid drop Hamiltonian is amended with a potential which allows us to separate, in the intrinsic frame, the equations for {beta} and {gamma} coordinates. The Schroedinger equation for {beta} is that for a sextic oscillator plus a centrifugal term, while that for {gamma} is just the equation for the Mathieu function. The total energy has a compact form. The operator for the electric quadrupole transitions is considered in the intrinsic frame and involves two parameters accompanying the harmonic and anharmonic components. The parameters determining the energies as well as those defining the transition operator are to be determined by a fitting procedure. Applications refer to five isotopes: {sup 188}Os, {sup 190}Os, {sup 192}Os, {sup 228}Th, and {sup 230}Th. Results are in good agreement with the corresponding experimental data. Results are also compared with those obtained within the coherent state model. A possible connection between the two formalisms is pointed out.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Determination of the half-life of the ground state of {sup 229}Th by using {sup 232}U and {sup 233}U decay series

The half-life of the ground state of {sup 229}Th ({sup 229}Th{sup g}) has become an important factor in nuclear technology, for example, in the geological disposal of nuclear spent fuel. However, the values reported in two previous studies are not in agreement. This study reevaluates the half-life of {sup 229}Th{sup g} by using a simple and reliable method. The {sup 232}U/{sup 233}U activity ratio of a {sup 232,233}U sample was measured by high-resolution {alpha}-particle spectrometry. Next, the {sup 228}Th/{sup 229}Th{sup g} activity ratio of the Th sample, which was grown from the {sup 232,233}U sample, was also measured. The half-life of {sup 229}Th{sup g} was calculated from these activity ratios, the growth time, and the half-lives of {sup 232}U, {sup 233}U, and {sup 228}Th. From the results of these five measurements, the half-life of {sup 229}Th{sup g} is determined to be 7932 {+-} 55 yr at a confidence level of 2{sigma}.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Air and radon pathways screenings methodologies for the next revision of the E-area PA

The strategic plan for the next E-Area Low-Level Waste Facility Performance Assessment includes recommended changes to the screening criteria used to reduce the number of radioisotopes that are to be considered in the air and radon pathways incorporated into the GoldSim® atmospheric release model (ARM). For the air pathway, a revised screening methodology was developed based on refinement of previous E-Area PA screening approaches and consideration of the strategic plan recommendations. The revised methodology has three sequential screening steps for each radioisotope: (1) volatility test using the Periodic Table of the Elements, (2) stability test based on half-life, and (3) stability test based on volatility as measured by the Henry’s Law constant for the assumed dominant gaseous species or vapor pressure in the case of tritiated water. Of the 1252 radioisotopes listed in the International Commission on Radiological Protection Publication 107, only the 10 that satisfied all three steps of the revised screening methodology will be included in the ARM. They are: Ar-37, Ar-39, Ar-42, C-14, H-3, Hg-194, Hg-203, Kr-81, Kr-85, and Xe-127. For the radon pathway, a revised screening methodology was developed that also has three sequential steps: (1) identify all decay chains that terminate at Rn-222, (2) screen out parents that decay through U-238 because of its 4.5-billion-year primordial half-life, and (3) eliminate remaining parents whose half-life is shorter than one day. Of the 86 possible decay chains leading to Rn-222, six decay chains consist of 15 unique radioisotopes that will be incorporated into the ARM. The 15 radioisotopes are: U-238, Th-234, Pa-234m, Pu-238, U-234, Th-230, Ra-226, Cf-246, Cm-242, Am-242m, Am-242, Np-238, Np-234, Pa-230, and Rn-222.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

Treatment of HER2-Expressing Breast Cancer and Ovarian Cancer Cells With Alpha Particle-Emitting {sup 227}Th-Trastuzumab

Purpose: To evaluate the cytotoxic effects of low-dose-rate alpha particle-emitting radioimmunoconjugate {sup 227}Th-p-isothiocyanato-benzyl-DOTA-trastuzumab ({sup 227}Th-trastuzumab [where DOTA is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]) internalized by breast and ovarian cancer cell lines in order to assess the potential of {sup 227}Th-trastuzumab as a therapeutic agent against metastatic cancers that overexpress the HER2 oncogene. Methods and Materials: Clonogenic survival and cell growth rates of breast cancer cells treated with {sup 227}Th-trastuzumab were compared with rates of cells treated with nonbinding {sup 227}Th-rituximab, cold trastuzumab, and X-radiation. Cell growth experiments were also performed with ovarian cancer cells. Cell-associated radioactivity was measured at several time points, and the mean radiation dose to cells was calculated. Results: SKBR-3 cells got 50% of the mean absorbed radiation dose from internalized activity and 50% from cell surface-bound activity, while BT-474 and SKOV-3 cells got 75% radiation dose from internalized activity and 25% from cell surface-bound activity. Incubation of breast cancer cells with 2.5 kBq/ml {sup 227}Th-trastuzumab for 1 h at 4{sup o}C, followed by washing, resulted in mean absorbed radiation doses of 2 to 2.5 Gy. A dose-dependent inhibition of cell growth and an increase in apoptosis were induced in all cell lines. Conclusions: Clinically relevant activity concentrations of {sup 227}Th-trastuzumab induced a specific cytotoxic effect in three HER2-expressing cell lines. The cytotoxic effect of {sup 227}Th-trastuzumab was higher than that of single-dose X-radiation (relative biological effectiveness = 1.2). These results warrant further studies of treatment of breast cancer and ovarian cancer with {sup 227}Th-trastuzumab.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2010

Fission rate and transient time of highly excited nuclei in multi-dimensional stochastic calculations

The influence of the dynamical model dimensionality in use on the fission rates studied within the stochastic approach to fission dynamics [1]. Time dependence of the fission rate was calculated with the use of multidimensional Langevin equation. Particle evaporation was not taken into account. One-, two- and three-dimensional cases were considered on the basis of the left bracec, h, alpharight brace-parametrization of the nuclear surface shape. Calculations were performed for the large number of compound nuclei with Z{sup 2}/A parameter in the range 20<Z{sup 2}/A<40 and excitation energy 200 MeV. A considerable increase of the stationary fission rate in the transition from one-dimensional to three-dimensional case was revealed [2]. This increase is about two times for the nuclei around {sup 224}Th and about 10{sup 2} for the light nuclei near the Businaro-Gallone point. The influence of the dissipation mechanism on the transient time is studied for multidimensional systems. It was shown that the ratios of the stationary fission rates obtained in the calculations with the different dimensionalities: R{sup 3D}{sub st}/R{sup 1D}{sub st} and R{sup 2D}{sub st}/R{sup 1D}{sub st} remain almost the same for different dissipation mechanisms. Thus we conclude that the fission rate is mostly determined by the structure of the potential energy surface of the system. For one-body dissipation mechanism it was shown that the transient time tau{sub tr} is about 5 or 6 times greater at k{sub s} = 1.0 than at k{sub s} = 0.25. Two-body dissipation mechanism leads to the smaller tau{sub tr} values in comparison with the one-body dissipation mechanism at k{sub s} = 0.25. The transient time does not change significantly in the dynamical calculations with the different dimensionality. We also compared the dynamically calculated stationary fission rate to the Kramers rate.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2010

Absorbed Gamma-Ray Doses due to Natural Radionuclides in Building Materials

This work is devoted to the application of high-resolution gamma-ray spectrometry in the study of the effective dose coming from naturally occurring radionuclides, namely {sup 40}K, {sup 232}Th and {sup 238}U, present in building materials such as sand, cement, and granitic gravel. Four models were applied to estimate the effective dose and the hazard indices. The maximum estimated effective dose coming from the three reference rooms considered is 0.90(45) mSv/yr, and maximum internal hazard index is 0.77(24), both for the compact clay brick reference room. The principal gamma radiation sources are cement, sand and bricks.

61 RADIATION PROTECTION AND DOSIMETRY↗