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You searched for subject:(Short lived Products). Showing records 1 – 2 of 2 total matches.

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EPFL

1. Kröhnert, Hanna. Fission Rates Measured Using High-Energy Gamma-Rays from Short Half-Life Fission Products in Fresh and Spent Nuclear Fuel.

Degree: 2011, EPFL

In recent years, higher discharge burn-ups and initial fuel enrichments have led to more and more heterogeneous core configurations in light water reactors (LWRs), especially at the beginning of cycle when fresh fuel assemblies are loaded next to highly burnt ones. As this trend is expected to continue in the future, the Paul Scherrer Institute has, in collaboration with the Swiss Association of Nuclear Utilities, swissnuclear, launched the experimental programme [email protected] The [email protected] programme aims to better characterise interfaces between burnt and fresh UO2 fuel assemblies in modern LWRs. Thereby, a novel experimental database is to be made available for enabling the validation of neutronics calculations of strongly heterogeneous LWR core configurations. During the programme, mixed fresh and highly burnt UO2 fuel lattices will be investigated in the zero-power research reactor PROTEUS. One of the main types of investigations will be to irradiate the fuel in PROTEUS and measure the resulting fission rate distributions across the interface between fresh and burnt fuel zones. The measurement of fission rates in burnt fuel re-irradiated in a zero-power reactor requires, however, the development of new experimental techniques which are able to discriminate against the high intrinsic activity of the fuel. The principal goal of the present research work has been to develop such a new measurement technique. The selected approach is based on the detection of high-energy gamma-ray lines above the intrinsic background (i.e. above 2200 keV), which are emitted by short-lived fission products freshly created in the fuel. The fission products 88Kr, 142La, 138Cs, 84Br, 89Rb, 95Y, 90mRb and 90Rb, with half-lives between 2.6 min and 2.8 h, have been identified as potential candidates. During the present research work, the gamma-ray activity of short-lived fission products has, for the first time, been measured and quantitatively evaluated for re-irradiated burnt UO2 fuel samples with burn-ups of about 36 and 46GWd/t. Based on experiments carried out with these fuel samples in a reference test lattice of the PROTEUS reactor, fresh-to-burnt-fuel fission rate ratios could be determined. The 1σ uncertainties on the derived fission rate ratios are 1.7 to 3.4% and are mainly due to the statistical uncertainties. Calculated values of the fission rate ratios, as obtained using the Monte Carlo code MCNPX, have been shown to agree with the experimental results within these uncertainties. In deriving fresh-to-burnt-fuel fission rate ratios,142La and 138Cs have emerged as the preferred fission products. Their fission yields for the main fissile isotope (235U, 239Pu and 241Pu) are similar, which makes them relatively insensitive to the exact composition… Advisors/Committee Members: Chawla, Rakesh.

Subjects/Keywords: light water reactors (LWRs); burnt fuel; power distributions; fission rates; zero-power research reactors; [email protected]; gamma-ray spectrometry; high-energy gamma-rays; short-lived fission products

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kröhnert, H. (2011). Fission Rates Measured Using High-Energy Gamma-Rays from Short Half-Life Fission Products in Fresh and Spent Nuclear Fuel. (Thesis). EPFL. Retrieved from http://infoscience.epfl.ch/record/154773

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Kröhnert, Hanna. “Fission Rates Measured Using High-Energy Gamma-Rays from Short Half-Life Fission Products in Fresh and Spent Nuclear Fuel.” 2011. Thesis, EPFL. Accessed August 22, 2019. http://infoscience.epfl.ch/record/154773.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Kröhnert, Hanna. “Fission Rates Measured Using High-Energy Gamma-Rays from Short Half-Life Fission Products in Fresh and Spent Nuclear Fuel.” 2011. Web. 22 Aug 2019.

Vancouver:

Kröhnert H. Fission Rates Measured Using High-Energy Gamma-Rays from Short Half-Life Fission Products in Fresh and Spent Nuclear Fuel. [Internet] [Thesis]. EPFL; 2011. [cited 2019 Aug 22]. Available from: http://infoscience.epfl.ch/record/154773.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kröhnert H. Fission Rates Measured Using High-Energy Gamma-Rays from Short Half-Life Fission Products in Fresh and Spent Nuclear Fuel. [Thesis]. EPFL; 2011. Available from: http://infoscience.epfl.ch/record/154773

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


The Ohio State University

2. Garcia-Dastugue, Sebastian Javier. Dynamic time-based postponement: conceptual development and empirical test.

Degree: PhD, Business Administration, 2003, The Ohio State University

The purpose of this research was to present the conceptual development of dynamic time-based postponement and empirically test it in the context of short-lived products in a supply chain formed by independent firms. Postponement, the deliberate delay of activities, is used to reduce manufacturing and logistics costs while maintaining or increasing product availability. Postponement as described here is time-based because only the time when activities are performed is changed, not the design of the product, the manufacturing process, or the supply chain network. It is dynamic because it represents a method for capturing a number of managerial objectives that change within a short time horizon. The following are the major conclusions of this research: 1. Adapting inventory policies across a supply chain, from speculation to postponement, in short periods results in cost savings to the supply chain while allowing managers to comply with strategic objectives such as meeting strict customer service levels. In this research setting, implementing dynamic time-based postponement resulted in a cost savings of between 5.3 and 6.9 million annually while improving product availability from approximately 92% to 99.5%. 2. Confidentiality remains the biggest hurdle to achieve integration in the supply chain. Despite the closeness of the relationships among the members of the supply chain, there was reluctancy to share cost data. Suppliers felt they were at risk of giving away information that could be used to negotiate better deals. 3. Dynamic time-based postponement represents true implementation of collaborative replenishment because it’s a method for managing the product flow throughout the life cycle of a product across the supply chain. There are three differentiating aspects of this dissertation. First, this is supply chain management research; that is, research that views a supply chain formed by independent organizations holistically and that extends a dyad. Second, postponement is viewed as a dynamic approach based on managers’ willingness to coordinate activities beyond a single firm. Third, in this research, it is recognized that postponement can be implemented by changing the time in which activities are performed, without changing the design of the product, the manufacturing process or the supply chain network. Advisors/Committee Members: Lambert, Douglas (Advisor).

Subjects/Keywords: Postponement; Speculation; Dynamic Time-based Postponement; Inventory Management; Promotions; Limited-Time Offers; Supply Chain Management; Demand Management; Product Life Cycle; Short-lived Products; Seasonal Products; Logistics; Optimization; Empirical

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Garcia-Dastugue, S. J. (2003). Dynamic time-based postponement: conceptual development and empirical test. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1061377587

Chicago Manual of Style (16th Edition):

Garcia-Dastugue, Sebastian Javier. “Dynamic time-based postponement: conceptual development and empirical test.” 2003. Doctoral Dissertation, The Ohio State University. Accessed August 22, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1061377587.

MLA Handbook (7th Edition):

Garcia-Dastugue, Sebastian Javier. “Dynamic time-based postponement: conceptual development and empirical test.” 2003. Web. 22 Aug 2019.

Vancouver:

Garcia-Dastugue SJ. Dynamic time-based postponement: conceptual development and empirical test. [Internet] [Doctoral dissertation]. The Ohio State University; 2003. [cited 2019 Aug 22]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1061377587.

Council of Science Editors:

Garcia-Dastugue SJ. Dynamic time-based postponement: conceptual development and empirical test. [Doctoral Dissertation]. The Ohio State University; 2003. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1061377587

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