32 research outputs found
Next generation system modeling of NTR systems
The topics are presented in viewgraph form and include the following: nuclear thermal rocket (NTR) modeling challenges; current approaches; shortcomings of current analysis method; future needs; and present steps to these goals
Recommended from our members
Safety issues in fabricating mixed oxide fuel using surplus weapons plutonium
This paper presents an assessment of the safety issues and implications of fabricating mixed oxide (MOX) fuel using surplus weapons plutonium. The basis for this assessment is the research done at Los Alamos National Laboratory (LANL) in identifying and resolving the technical issues surrounding the production of PuO{sub 2} feed, removal of gallium from the PuO{sub 2} feed, the fabrication of test fuel, and the work done at the LANL plutonium processing facility. The use of plutonium in MOX fuel has been successfully demonstrated in Europe, where the experience has been almost exclusively with plutonium separated from commercial spent nuclear fuel. This experience in safely operating MOX fuel fabrication facilities directly applies to the fabrication and irradiation of MOX fuel made from surplus weapons plutonium. Consequently, this paper focuses on the technical difference between plutonium from surplus weapons, and light-water reactor recycled plutonium. Preliminary assessments and research lead to the conclusion that no new process or product safety concerns will arise from using surplus weapons plutonium in MOX fuel
Recommended from our members
Preliminary lifetime predictions for 304 stainless steel as the LANL ABC blanket material
The prediction of materials lifetime in the preconceptual Los Alamos National Laboratory (LANL) Accelerator-Based Conversion of Plutonium (ABC) is of utmost interest. Because Hastelloy N showed good corrosion resistance to the Oak Ridge National Laboratory Molten Salt Reactor Experiment fuel salt that is similar to the LANL ABC fuel salt, Hastelloy N was originally proposed for the LANL ABC blanket material. In this paper, the possibility of using 304 stainless steel as a replacement for the Hastelloy N is investigated in terms of corrosion issues and fluence-limit considerations. An attempt is made, based on the previous Fast Flux Test Facility design data, to predict the preliminary lifetime estimate of the 304 stainless steel used in the blanket region of the LANL ABC
Recommended from our members
Nuclear fuels technologies Fiscal year 1997 research and development test plan
This document details the research and development (R&D) activities that will be conducted in fiscal year 1997 (FY97) by the Nuclear Fuels Technologies project team for the Department of Energy Office of Fissile Materials Disposition. This work is a continuation and extension of experimental activities that have been conducted in support of the disposition program with regard to using weapons-plutonium in the fabrication of mixed-oxide (MOX) nuclear fuel for reactor-based disposition. The purpose of this work is to identify and if possible, resolve, technical issues associated with applying the large experience base (existing mainly in Europe) of making MOX fuel with recycled reactor-grade plutonium to the fabrication of MOX using weapons-grade plutonium. Therefore, the projects are designed to fill one or more of three needs: (1) To provide potential fabricators a technical basis upon which to evaluate the uncertainties and technical risks associated with MOX fabrication using weapons-plutonium; (2) To provide the fabricator ultimately selected for the disposition mission with a technical basis upon which to build, thereby reducing the amount of development and time required for implementation of the MOX disposition option; and (3) To identify to DOE technical issues that it is unlikely the fabricator will address (e.g., gallium removal), and to resolve these issues or provide a clear path forward for doing so. Because of the volatile nature of the disposition program, all work described within this plan is intended to be completed this fiscal year with its culmination being one of two goals: (1) a summary of the technical results sufficient to hand over to commercial MOX fabricators for their use in planning activities; or (2) an estimate with regard to cost and schedule for follow-on activities to completely resolve the issue as well as sufficient technical supporting information in order for DOE to make well-informed decisions in this regard. 2 figs., 10 tabs
Recommended from our members
Nuclear fuels technologies Fiscal Year 1996 research and development test results
During fiscal year 1996, the Department of Energy`s Office of Fissile Materials Disposition (OFMD) funded Los Alamos National Laboratory (LANL) to investigate issues associated with the fabrication of plutonium from dismantled weapons into mixed-oxide (MOX) nuclear fuel for disposition in nuclear power reactors. These issues can be divided into two main categories: issues associated with the fact that the plutonium from dismantled weapons contains gallium, and issues associated with the unique characteristics of the PuO[sub 2] produced by the dry conversion process that OFMD is proposing to convert the weapons material. Initial descriptions of the experimental work performed in fiscal year 1996 to address these issues can be found in Nuclear Fuels Technologies Fiscal Year 1996 Research and Development Test Matrices. However, in some instances the change in programmatic emphasis towards the Parallex program either altered the manner in which some of these experiments were performed (i.e., the work was done as part of the Parallex fabrication development and not as individual separate-effects tests as originally envisioned) or delayed the experiments into Fiscal Year 1997. This report reviews the experiments that were conducted and presents the results
Recommended from our members
Accelerator-based conversion (ABC) of weapons plutonium: Plant layout study and related design issues
In preparation for and in support of a detailed R and D Plan for the Accelerator-Based Conversion (ABC) of weapons plutonium, an ABC Plant Layout Study was conducted at the level of a pre-conceptual engineering design. The plant layout is based on an adaptation of the Molten-Salt Breeder Reactor (MSBR) detailed conceptual design that was completed in the early 1070s. Although the ABC Plant Layout Study included the Accelerator Equipment as an essential element, the engineering assessment focused primarily on the Target; Primary System (blanket and all systems containing plutonium-bearing fuel salt); the Heat-Removal System (secondary-coolant-salt and supercritical-steam systems); Chemical Processing; Operation and Maintenance; Containment and Safety; and Instrumentation and Control systems. Although constrained primarily to a reflection of an accelerator-driven (subcritical) variant of MSBR system, unique features and added flexibilities of the ABC suggest improved or alternative approaches to each of the above-listed subsystems; these, along with the key technical issues in need of resolution through a detailed R&D plan for ABC are described on the bases of the ``strawman`` or ``point-of-departure`` plant layout that resulted from this study
Recommended from our members
Cylindrical TEMP optimization: Final report
This report consists of vugraphs of a presentation on the thermoelectric-electromagnetic pump. Topics covered are: modeling methodology; summary of rectangular TEMP results; cylindrical TEMP optimization task; optimization approach; optimization results; discussion of cylindrical optimization; and thoughts on future work
Recommended from our members
Enhancements to transmutation system performance through use of an accelerator/fluid fuel combination
The destruction of plutonium and other long-lived radionuclides in high-level nuclear waste is receiving considerable international technical interest and effort. At Los Alamos, accelerator-based concepts are under investigation which achieve high burnups of plutonium and other actinides and which simultaneously transmute key long-lived fission products. This paper describes quantitative enhancements brought through use of an accelerator-driven/fluid fuel subcritical blanket. Results are described covering robust response to reactivity insertions, increased neutron economy for transmutation of long-lived fission products using thermal neutrons, and reduced frequencies required for fuel cleanup
Quality assessment of commercial wholegrain flours produced from spelt wheat, common wheat and rye, and of spontaneous sourdough prepared with them
Celem pracy była próba wyprodukowania zakwasów spontanicznych z całoziarnowej mąki z pszenicy zwyczajnej, pszenicy orkisz oraz z mąki żytniej. W badanych mąkach oznaczono zawartość: wody, popiołu, wybranych składników mineralnych, białka ogółem, tłuszczu surowego, błonnika pokarmowego, wybranych mikotoksyn oraz fosforanów mio-inozytolu. Oznaczono ponadto kwasowość tłuszczową, kwasowość potencjalną, liczbę opadania (LO) oraz ilość glutenu i indeks glutenowy. Ze wszystkich całoziarnowych mąk sporządzono zakwasy, które kontrolowano przez 4 dni poprzez oznaczanie kwasowości czynnej (pH) i kwasowości potencjalnej.
Całoziarnowe mąki z pszenicy orkisz odznaczały się większą zawartością białka, związków tłuszczowych i związków mineralnych, ale mniejszą zawartością błonnika całkowitego w porównaniu z mąkami uzyskanymi z pszenicy zwyczajnej i żyta. Wszystkie mąki całoziarnowe (z wyjątkiem orkiszowej MO1) charakteryzowały się podobną zawartością fosforanów mio-inozytolu w formie IP⁶ i IP², jedynie mąka żytnia odznaczała się dodatkowo formami IP⁵ i IP³. W żadnej z badanych mąk pszennych nie oznaczono zawartości mikotoksyn, tj. DON i zearalenonu, z wyjątkiem mąki z pszenicy orkisz MO1, w której zidentyfikowano śladowe jego ilości. Zakwasy otrzymane z mąk całoziarnowych z pszenicy orkisz po 72 h fermentacji w temp. 30 ºC charakteryzowały się większą kwasowością w porównaniu z zakwasami z mąki z pszenicy zwyczajnej, a bardziej zbliżoną do zakwasów żytnich. Zatem wszystkie otrzymane zakwasy można stosować do produkcji chlebów ze 100-procentowej mąki całoziarnowej z żyta, pszenicy orkisz i pszenicy zwyczajnej, w miejsce stosowanego dotychczas w praktyce zakwasu żytniego.The objective of the study was an attempt to produce spontaneous sourdoughs from wholegrain flours made from common wheat, spelt wheat, and rye. In the flours analyzed, the following was determined: water content, ash, selected mineral components, total protein, raw fat, dietary fibre, selected mycotoxins, and myo-inositol phosphates. Moreover, there were determined fat acidity, potential acidity, falling number as well as the content of gluten and gluten index. Using every type of the wholegrain flours tested, sourdoughs were produced; they were, further, monitored for 4 days by determining the active acidity (pH) and titratable acidity.
In comparison to flours made from common wheat and rye, the wholegrain spelt wheat flours were distinguished by higher contents of protein, fat, and mineral compounds; however, they had less total fibre. All the wholegrain flours (except MO1 spelt flour) were characterized by a similar content of myoinositol phosphates in the form of IP⁶ and IP², but only the rye flour was additionally distinguished by the IP⁵ and IP³ forms. Mycotoxins, i.e. DON and zearalenone, were not found in any wheat flours except for the MO1 spelt flour, in which trace amounts of zearalenone were identified. Sourdoughs produced from the wholegrain spelt flour after the 72 h fermentation at 30 ºC were characterized by a greater acidity compared to those produced from the wheat flour and their acidity was more similar to that of the rye sourdoughs. Thus, all the types of sourdough obtained can be used to produce bread from 100 % wholegrain flour made from rye, spelt, and common wheat