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1

FUZZY MODELLING APPLIED TO AN UASB REACTOR  

Microsoft Academic Search

High-rate anaerobic systems, such as the upflow anaerobic sludge blanket (UASB) reactors, are widely used in municipal and industrial wastewater treatment. Even though UASB reactors have several operational advantages, many industries are still reluctant to use them due to the fact that these reactors usually demand constant monitoring of effluent quality, excess sludge discharge and biogas production rate. Otherwise, they

R. M. Borges; C. J. Munaro; R. F. Gonçalves

2

Effect of sponge volume on the performance of down-flow hanging sponge system treating UASB reactor effluent  

Microsoft Academic Search

The performance of down-flow hanging sponge (DHS) system treating UASB reactor effluent at different sponge volume of 38.2,\\u000a 28.7, 19.1 and 9.6% was investigated. The hydraulic retention time (HRT) and flow rate were kept constant at 2.6 h and 0.46 m3\\/day, respectively. The results obtained indicated that reducing the sponge volume of the DHS system from 38.2 to 19.1% significantly\\u000a decreased the

A. Tawfik; A. Ohashi; H. Harada

2010-01-01

3

Anaerobic\\/aerobic treatment of municipal landfill leachate in sequential two-stage up-flow anaerobic sludge blanket reactor (UASB)\\/completely stirred tank reactor (CSTR) systems  

Microsoft Academic Search

The treatability of leachate produced from the lab-scale simulated reactor treating food wastes was investigated in a two-stage sequential up-flow anaerobic sludge blanket reactor (UASB)\\/aerobic completely stirred tank reactor (CSTR). Experiments were performed in two UASB reactors and a CSTR reactor having effective volumes of 2.5 and 9l, respectively. The hydraulic retention times in anaerobic and aerobic stages were 1.25

Osman Nuri A?da?; Delia Teresa Sponza

2005-01-01

4

Effect of sponge volume on the performance of down-flow hanging sponge system treating UASB reactor effluent.  

PubMed

The performance of down-flow hanging sponge (DHS) system treating UASB reactor effluent at different sponge volume of 38.2, 28.7, 19.1 and 9.6% was investigated. The hydraulic retention time (HRT) and flow rate were kept constant at 2.6 h and 0.46 m(3)/day, respectively. The results obtained indicated that reducing the sponge volume of the DHS system from 38.2 to 19.1% significantly decreased the removal efficiency of COD(total) from 80 +/- 8 to 62 +/- 14%; COD(soluble) from 71.2 +/- 10 to 53.7 +/- 18% and COD(particulate) from 86 +/- 10 to 62 +/- 15%. With further reduction of the sponge volume down to 9.6%, the removal efficiency was dropped to 54 +/- 15% for COD(total); 44.1 +/- 14% for COD(soluble) and 42 +/- 12% for COD(particulate). Likewise, the nitrification efficiency and fecal coliform (FC) removal was strongly affected by decreasing the sponge volume of the DHS system, i.e., the nitrification efficiency was dropped by a value of 48.3% when reducing the sponge volume of the DHS system from 38.2 to 19.1%. At sponge volume of 38.2%, the DHS system removes 2.6 +/- 0.3 log(10)/100 ml of FC which is significantly higher than that at sponge volume of 28.7, 19.1 and 9.6%. Accordingly, it is recommended to design and operate such a system at a bulk sponge volume not exceeding 38.2% of the total reactor volume and at an HRT of 2.6 h. PMID:20013130

Tawfik, A; Ohashi, A; Harada, H

2009-12-15

5

Hydrogenated Vegetable Oil Industry Wastewater Treatment using UASB Reactor System with Recourse to Energy Recovery  

Microsoft Academic Search

The investigation was carried out on laboratory scale to assess the feasibility of upflow anaerobic sludge blanket reactor\\u000a system as a pretreatment for hydrogenated vegetable oil industry wastewater with recourse to energy recovery. The reactor\\u000a system operated at 35°C, resulted in COD removal efficiency in the range 98.9–80.1% at organic loading varying in the range\\u000a 1.33–10 kgCOD\\/m3 day. The specific methane

Sunita Shastry; Tapas Nandy; S. R. Wate; S. N. Kaul

2010-01-01

6

Treatment of landfill leachate using sequencing batch and continuous flow upflow anaerobic sludge blanket (UASB) reactors  

Microsoft Academic Search

Treatment of municipal landfill leachate was investigated\\/compared using sequencing batch and continuous flow upflow anaerobic sludge blanket (UASB) reactors. All reactors were operated at organic loading rates (OLRs) between 0.6–19.7 gCOD\\/l d. Performance of the continuous UASB and sequencing batch UASB reactors were very similar at low and intermediate OLRs. Continuous UASB reactors performed more favorably at the higher OLRs

K. J Kennedy; E. M Lentz

2000-01-01

7

UASB reactor hydrodynamics: residence time distribution and proposed modelling tools.  

PubMed

The hydrodynamic behaviour of UASB (Up Flow Anaerobic Sludge Blanket) reactors based on residence time distribution curves allows the implementation of global models, including the kinetic aspects of biological reactions. The most relevant hydrodynamic models proposed in the literature are discussed and compared with the extended tanks in series (ETIS) model. Although derived from the tanks in series model, the ETIS model's parameter is not an integer. The ETIS model can be easily solved in the Laplace domain and applied to a two-stage anaerobic digestion linear model. Experimental data from a 250 m3 UASB reactor treating malting wastewater are used to calibrate and validate the proposed model. PMID:20540420

López, I; Borzacconi, L

2010-05-01

8

Anaerobic biodegradation of aircraft deicing fluid in UASB reactors.  

PubMed

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions (0.8% 1.6% ADF (6000-12,000mg/L COD), 12-56h HRT, and 18-36gVSS/L) were conducted in continuous mode. The development of four empirical models describing process responses (i.e. COD removal efficiency, biomass-specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time, and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass-specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass-specific acetoclastic activity was improved two-fold from 0.23gCOD/gVSS/d for inoculum to a maximum of 0.55gCOD/gVSS/d during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. The predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate is increased. ADF toxicity effects were evident for 1.6% ADF at medium organic loadings (SOLR above 0.5gCOD/gVSS/d). In contrast, good reactor stability and excellent COD removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73gCOD/gVSS/d). PMID:15159155

Tham, P T Pham thi; Kennedy, K J Kevin J

2004-05-01

9

Performance evaluation of an UASB reactor used for combined treatment of domestic sewage and excess aerobic sludge from a trickling filter  

Microsoft Academic Search

This work aimed at evaluating the influence of the excess sludge produced in a trickling filter (TF) on the performance of a UASB reactor used for the combined treatment of domestic sewage and aerobic sludge. During phase 1 of the research, the UASB reactor\\/TF system was fed with domestic sewage pumped directly from the sewer collector of Arrudas stream, in

P. P. Pontes; C. A. L. Chernicharo; E. C. Frade; M. T. R. Porto

2003-01-01

10

Feasibility of methanolic waste treatment in UASB reactors  

Microsoft Academic Search

Feasibility of methanolic waste treatment in an upflow anaerobic sludge blanket (UASB) reactor operating continuously for a period of more than 400 days was examined. Optimum pH was found to be between 7.0–7.3. In this pH range, there was no excessive build-up of volatile fatty acids and no upset or reactor failure was observed. Elementary pathways of degradation of methanol

Zafar Iqbal Bhatti; Kenji Furukawa; Masanori Fujita

1996-01-01

11

Maximum COD Loading Capacity in UASB Reactors at 37°C  

Microsoft Academic Search

The maximum capacity chemical oxygen demand (COD) loading in upflow anaerobic sludge blanket (UASB) reactors is evaluated using three 8.5 L reactors and high-strength synthetic wastewaters composed of milk and sucrose at 37~ The study was conducted over a wide-range COD loading rate (18-260 g.L-l.day 1), by varying hydraulic retention time (HRT) (1.8-10 hr) and COD levels in wastewater (6,000-20,000

Herbert H. P. Fang; H. K. Chui

1993-01-01

12

Decolorization of azo dye (Orange II) in a sequential UASB–SBR system  

Microsoft Academic Search

The combination of up-flow anaerobic sludge blanket (UASB) and sequencing batch reactor was chosen as an anaerobic and aerobic system, respectively, in the treatment of Orange II-containing wastewater. The Orange II and COD removal efficiencies were improved in the UASB system when the operating temperature and hydraulic retention time were increased up to 30°C and 48h, respectively. Nearly complete decolorization

Soon-An Ong; Eiichi Toorisaka; Makoto Hirata; Tadashi Hano

2005-01-01

13

Anaerobic decolorization of reactive dyebath effluents by a two-stage UASB system with tapioca as a co-substrate  

Microsoft Academic Search

This study investigates the anaerobic treatability of the reactive dyebath effluents in three different colors, namely, black, red and blue, by using a pilot scale two-phase UASB system which consisted of an acidification tank and a UASB reactor with a hydraulic retention time of about 12 h for each phase. In the first three experiments, the feed wastewater was prepared from

Sopa Chinwetkitvanich; Munsin Tuntoolvest; Thongchai Panswad

2000-01-01

14

Anaerobic biodegradation of aircraft deicing fluid in UASB reactors  

Microsoft Academic Search

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions (0.8% 1.6% ADF (6000–12,000mg\\/L COD), 12–56h HRT, and 18–36gVSS\\/L) were conducted in continuous mode. The development of four empirical models describing process responses (i.e. COD removal

Pham thi Tham; Kevin J. Kennedy

2004-01-01

15

TREATMENT OF METHANOLIC WASTEWATER BY ANAEROBIC DOWN-FLOW HANGING SPONGE (ANDHS) REACTOR AND UASB REACTOR  

NASA Astrophysics Data System (ADS)

Anaerobic down-flow hanging sponge (AnDHS) reactor and UASB reactor were operated at 30℃ for over 400 days in order to investigate the process performance and the sludge characteristics of treating methanolic wastewater (2 gCOD/L). The settings OLR of AnDHS reactor and of UASB reactor were 5.0 -10.0 kgCOD/m3/d and 5.0 kgCOD/m3/d. The average of the COD removal demonstrated by both reactors were over 90% throughout the experiment. From the results of methane producing activities and the PCR-DGGE method, most methanol was directly converted to methane in both reactors. The conversion was carried out by different methanogens: one closely related to Methanomethylovorans hollandica in the AnDHS retainted sludge and the other closely related to Methanosarcinaceae and Metanosarciales in the UASB retainted sludge.

Sumino, Haruhiko; Wada, Keiji; Syutsubo, Kazuaki; Yamaguchi, Takashi; Harada, Hideki; Ohashi, Akiyoshi

16

Performance and behaviour of planted and unplanted units of a horizontal subsurface flow constructed wetland system treating municipal effluent from a UASB reactor.  

PubMed

A system composed of two horizontal subsurface flow constructed wetlands operating in parallel was evaluated for the post-treatment of UASB (upflow anaerobic sludge blanket) reactor effluent, for a population equivalent of 50 inhabitants per unit. One unit was planted with cattail (Typha latifolia) and the other was unplanted. The study was undertaken over a period of 4 years, comprising monitoring of influent and effluent constituents together with a full characterization of the behaviour of the units (tracer studies, mathematical modelling of chemical oxygen demand (COD) decay, characterization of solids in the filter medium). The mean value of the surface hydraulic load was 0.11 m(3)m(-2)d(-1), and the theoretical hydraulic retention time was 1.1 d in each unit. Using tracer tests with (82)Br, dispersion number (d) values of 0.084 and 0.079 for the planted and unplanted units were obtained, indicating low to moderate dispersion. The final effluent had excellent quality in terms of organic matter and suspended solids, but the system showed low capacity for nitrogen removal. Four-year mean effluent concentration values from the planted and unplanted units were, respectively: biochemical oxygen demand (BOD5): 25 and 23 mg L(-1); COD: 50 and 55 mg L(-1); total suspended solids (TSS): 9 and 9 mg L(-1); N-ammonia: 27 and 28 mg L(-1). The COD decay coefficient K for the traditional plug-flow model was 0.81 and 0.84 d(-1) for the planted and unplanted units. Around 80% of the total solids present in the filter medium were inorganic, and most of them were present in the interstices rather than attached to the support medium. As an overall conclusion, horizontal subsurface flow wetlands can be a very suitable post-treatment method for municipal effluents from anaerobic reactors. PMID:24135097

da Costa, Jocilene Ferreira; de Paoli, André Cordeiro; Seidl, Martin; von Sperling, Marcos

2013-01-01

17

Continuous fill intermittent decant type sequencing batch reactor application to upgrade the UASB treated sewage.  

PubMed

The performance of continuous flow intermittent decant type sequencing batch (CFID) reactor treating the effluent of an UASB reactor treating domestic wastewater and operated at 8 h hydraulic retention time (HRT) was investigated. The CFID was operated at three different HRTs (22, 8 and 6 h) and three different dissolved oxygen (DO) patterns (<0.5, 2.5-3.5 and 3.5-4.5 mg/L). The highest effluent quality was observed at the 8 h HRT and 2.5-3.5 mg/L DO concentration. At this operational condition, the average BOD, TSS, ammonia nitrogen and fecal coliform removal efficiencies were 83, 90, 74 and 99 %, respectively. The CFID is a promising post-treatment option for existing UASB systems, with a final effluent quality that comply with receiving water and effluent reuse criteria. PMID:23117522

Khan, Abid Ali; Gaur, Rubia Zahid; Diamantis, Vasileios; Lew, Beni; Mehrotra, Indu; Kazmi, A A

2012-11-02

18

The anaerobic treatment of soft drink wastewater in UASB and hybrid reactors  

Microsoft Academic Search

The anaerobic treatment of soft drink wastewater (SDW) was studied in two laboratory reactors—a 1.8-L UASB reactor and a 3-L\\u000a hybrid reactor-sludge bed containing a layer of polyurethane in the upper part, at 35°C. The highest organic loading rates\\u000a (OLR) achieved were 13 and 16.5 g COD\\/L · D for hybrid and UASB reactors, respectively, with the treatment efficiency of

S. V. Kalyuzhnyi; J. Valadez Saucedo; J. Rodriguez Martinez

1997-01-01

19

Application of neural network for simulation of upflow anaerobic sludge blanket (UASB) reactor performance.  

PubMed

Up-flow anaerobic sludge blanket (UASB) reactors are being used with increasing regularity all over the world, especially in India, for a variety of wastewater treatment operations. Consequently, there is a need to develop methodologies enabling one to determine UASB reactor performance, not only for designing more efficient UASB reactors but also for predicting the performance of existing reactors under various conditions of influent wastewater flows and characteristics. This work explores the feasibility of application of an artificial neural network-based model for simulating the performance of an existing UASB reactor. Accordingly, a neural network model was designed and trained to predict the steady-state performance of a UASB reactor treating high-strength (unrefined sugar based) wastewater. The model inputs were organic loading rate, hydraulic retention time, and influent bicarbonate alkalinity. The output variables were one or more of the following, effluent substrate concentration (Se), reactor bicarbonate alkalinity, reactor pH, reactor volatile fatty acid concentration, average gas production rate, and percent methane content of the gas. Training of the neural network model was achieved using a large amount of experimentally obtained reactor performance data from the reactor mentioned above as the training set. Training was followed by validation using independent sets of performance data obtained from the same UASB reactor. Subsequently, simulations were performed using the validated neural network model to determine the impact of changes in parameters like influent chemical oxygen demand (COD) concentration and hydraulic retention time on the reactor performance. Simulation results thus obtained were carefully analyzed based on qualitative understanding of UASB process and were found to provide important insights into key variables that were responsible for influencing the working of the UASB reactor under varying input conditions. PMID:11835141

Sinha, Sucheta; Bose, Purnendu; Jawed, Mohammed; John, Siby; Tare, Vinod

2002-03-30

20

Performance evaluation of an UASB reactor used for combined treatment of domestic sewage and excess aerobic sludge from a trickling filter.  

PubMed

This work aimed at evaluating the influence of the excess sludge produced in a trickling filter (TF) on the performance of a UASB reactor used for the combined treatment of domestic sewage and aerobic sludge. During phase 1 of the research, the UASB reactor/TF system was fed with domestic sewage pumped directly from the sewer collector of Arrudas stream, in Belo Horizonte-Brazil. During phase 2, besides feeding the reactor with domestic sewage, the UASB reactor was also fed with the aerobic sludge from the trickling filter. The UASB reactor, with a volume of 420 litres, was operated at a mean hydraulic detention time of 5.6 hours in both operational phases. After 133 days of continuous monitoring, no detrimental effect was noticed on the performance of the UASB reactor regarding the return of the aerobic sludge produced in the TF. On the contrary, the COD results indicated a higher percentage of compliance with the discharge standards set forth by the Brazilian environmental legislation. During phase 2 of the research, when the UASB reactor was used for combined treatment of domestic sewage and excess aerobic sludge from the TF, the anaerobic effluent presented mean concentrations of 108 mgCOD x L(-1), 57 mgBOD x L(-1) and 18 mgTSS x L(-1). PMID:14640222

Pontes, P P; Chernicharo, C A L; Frade, E C; Porto, M T R

2003-01-01

21

Anaerobic biodegradation of linear alkylbenzene sulfonate (LAS) in upflow anaerobic sludge blanket (UASB) reactors  

Microsoft Academic Search

The anaerobic biodegradation of Linear Alkylbenzene Sulfonate (LAS) was studied in Upflow Anaerobic Sludge Blanket Reactors (UASB). One reactor was fed with easily degradable substrates and commercial LAS solution during a period of 3 months (Reactor 1), meanwhile a second reactor was fed with a commercial LAS solution without co-substrate (Reactor 2) during 4 months. Both reactors were operated with

José L. Sanz; Elayne Culubret; Juan de Ferrer; Alfonso Moreno; José L. Berna

2003-01-01

22

Use of the UASB reactor for the anaerobic treatment of stillage from sugar cane molasses  

SciTech Connect

The feasibility of applying the UASB concept for the anaerobic treatment of stillage of distilleries in the sugar producing area of Argentina was subject to study. Results obtained in a 100-l UASB reactor treating stillages with COD values between 35 and 100 g COD/l are presented. Loading rates of up to 24 g COD/l/day, were applied with an average COD removal of 75% and a biogas production of more than 9 l/l/day, with an average methane content of 58%. The settling velocity distribution of sludge particles would indicate a good formation of biomass pellets. System interruptions of months without feed and at ambient temperature (20-24/sup 0/C) were well tolerated.

Sanchez Riera, F.; Cordoba, P.; Sineriz, F.

1985-12-01

23

Comparative performance of UASB and anaerobic hybrid reactors for the treatment of complex phenolic wastewater.  

PubMed

The performance of an upflow anaerobic sludge blanket (UASB) reactor and an anaerobic hybrid reactor (AHR) was investigated for the treatment of simulated coal wastewater containing toxic phenolics at different hydraulic retention times (0.75-0.33d). Fast start-up and granulation of biomass could be achieved in an AHR (45d) than UASB (58d) reactor. Reduction of HRT from 1.5 to 0.33d resulted in a decline in phenolics removal efficiency from 99% to 77% in AHR and 95% to 68% in UASB reactor respectively. AHR could withstand 2.5 times the selected phenolics loading compared to UASB reactor that could not withstand even 1.2 times the selected phenolics loading. Residence time distribution (RTD) study revealed a plug flow regime in the AHR and completely mixed regime in UASB reactor respectively. Energy economics of the reactors revealed that 12,159MJd(-1) more energy can be generated using AHR than UASB reactor. PMID:22940341

Ramakrishnan, Anushuya; Surampalli, Rao Y

2012-07-27

24

Biodegradation of aircraft deicing fluid in an upflow anaerobic sludge blanket (UASB) reactor  

Microsoft Academic Search

Dilute aircraft deicing fluid (ADF) wastewater (5, 10 and 20 g chemical oxygen demand (COD)\\/L) can be successfully treated in Upflow Anaerobic Sludge Blanket (UASB) reactors at volumetric organic loading rates as high as 10 g COD\\/L\\/d, with COD removal efficiencies between 85 and 98 percent. UASB reactors in this study treating ADF solutions of 20 g COD\\/L at OLR

C. Darlington; K. J. Kennedy

1998-01-01

25

Anaerobic treatment of natural tannin extracts in UASB reactors.  

PubMed

Tannin extracts are substances commonly used in leather production processes. Since most of the steps of tannery manufacturing processes are carried out in aqueous environments, the presence of these compounds in the wastewaters is important. The aim of this work is to study the feasibility of the anaerobic degradation of three natural tannin extracts in three Upflow Anaerobic Sludge Blanket (UASB) reactors, which were fed with increasing concentrations of two condensed (quebracho and wattle) and one hydrolysable tannin extract (chestnut). Concentrations of applied extracts were 100, 200, 400, 800 and 1,000 mg/l, and 5 g/l of glucose was used as cosubstrate. Reactors were operated during 210 days and their performance was evaluated from the values of total and soluble COD, total and intermediate alkalinity, volatile fatty acids, pH and UV absorption at 280 nm. COD removal efficiencies higher than 85% were achieved in all cases. However, tannin extract removal efficiencies (based on UV-280 nm absorption measurements) were significantly lower, around 20% for condensed extracts and 60% for the hydrolysable one, when the reactors operated with the highest tannin extract concentration. The operation of the reactors was stable, commonly with alkalinity ratios below 0.30. Mass balances carried out indicate that most of the COD removal efficiencies are due to the removal of the readily biodegradable organic matter (glucose), whereas the tannin extracts are hardly anaerobically biodegradable, especially condensed extracts (wattle and quebracho). PMID:14640213

López-Fluza, J; Omil, F; Méndez, R

2003-01-01

26

Use of UASB reactors for brackish aquaculture sludge digestion under different conditions.  

PubMed

Treatment and disposal of high volume of salty waste production in recirculating aquaculture systems (RASs) is a major challenge and the sludge is often a source of environmental pollution and salinization of receiving soils and water bodies. Anaerobic digestion is an efficient mean for the treatment of wastes of different origins and might serve a useful tool for the reduction of salty aquaculture discharge load. Use of an upflow anaerobic sludge blanket (UASB) reactor for digestion of brackish aquaculture sludge from RASs under different C:N ratios, temperatures, and hydraulic retention times demonstrated high removal efficiencies of over 92% as volatile solids (VS), 98% as chemical oxygen demand and 81% as total suspended solids in all reactors. Methane production topped 7.1 mL/gVS d and was limited by low C:N ratio but was not influenced by temperature fluctuations. The treated liquid effluent from all reactors was of sufficient quality for reuse in the RAS, leading to significant water recycling and saving rates. UASB may be an attractive solution for brackish sludge management in RASs. PMID:23528783

Mirzoyan, Natella; Gross, Amit

2013-03-13

27

Treatment of textile dyeing wastewater using two-phase pilot plant UASB reactor with sago wastewater as co-substrate  

Microsoft Academic Search

Textile dyeing industry is considered as one of the largest generators of toxic chemical wastewater in India. Wastewaters from textile dyeing industries were studied for the decolourization and removal of degradable organics with tapioca sago wastewater as a co-substrate in a pilot scale two-phase Upflow Anaerobic Sludge Blanket (UASB) reactor. The UASB reactor was inoculated with seed sludge from the

M. Senthilkumar; G. Gnanapragasam; V. Arutchelvan; S. Nagarajan

2011-01-01

28

Peptidolytic Microbial Community of Methanogenic Reactors from two Modified Uasbs of Brewery Industries  

PubMed Central

We studied the peptide-degrading anaerobic communities of methanogenic reactors from two mesophilic full-scale modified upflow anaerobic sludge blanket (UASB) reactors treating brewery wastewater in Colombia. Most probable number (MPN) counts varied between 7.1 x 108 and 6.6 × 109 bacteria/g volatile suspended solids VSS (Methanogenic Reactor 1) and 7.2 × 106 and 6.4 × 107 bacteria/g (VSS) (Methanogenic Reactor 2). Metabolites detected in the highest positive MPN dilutions in both reactors were mostly acetate, propionate, isovalerate and, in some cases, negligible concentrations of butyrate. Using the highest positive dilutions of MPN counts, 50 dominant strains were isolated from both reactors, and 12 strains were selected for sequencing their 16S rRNA gene based on their phenotypic characteristics. The small-subunit rRNA gene sequences indicated that these strains were affiliated to the families Propionibacteriaceae, Clostridiaceae and Syntrophomonadaceae in the low G + C gram-positive group and Desulfovibrio spp. in the class ?-Proteobacteria. The main metabolites detected in the highest positive dilutions of MPN and the presence of Syntrophomonadaceae indicate the effect of the syntrophic associations on the bioconversion of these substrates in methanogenic reactors. Additionally, the potential utilization of external electron acceptors for the complete degradation of amino acids by Clostridium strains confirms the relevance of these acceptors in the transformation of peptides and amino acids in these systems.

Diaz, C.; Baena, S.; Patel, B.K.C.; Fardeau, M.L.

2010-01-01

29

Effect of extracellular enzyme activity on digestion performance of mesophilic UASB reactor treating high-strength municipal wastewater  

Microsoft Academic Search

Effect of extracellular enzyme activity on digestion performance of up-flow anaerobic sludge blanket (UASB) reactor was investigated\\u000a for enhancement of anaerobic treatability of municipal wastewater. Two identical UASB reactors (9 L), namely Reactor-A (without\\u000a enzyme addition) and Reactor-B (with enzyme addition), were simultaneously operated at mesophilic conditions (32 ± 2 °C) with\\u000a a hydraulic retention time of 24 h. Preliminary test results showed that the

F. Ilter Turkdogan-Aydinol; Kaan Yetilmezsoy; Sezen Comez

2011-01-01

30

Study on the treatment of tannery wastewater with high pollution load by UASB reactor  

Microsoft Academic Search

The pollution load of the tannery wastewater was higher than before with the strict environmental protection laws and implying of water-saving process, and aerobic treatment of tannery wastewater was no longer suitable for treating tannery wastewater with high pollution load. In this paper, the UASB9' up flow anaerobic sludge blanket9' reactor be used to treat the tannery wastewater with high

Xingyuan Ma; Qi Liu; Jun Ma

2011-01-01

31

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor  

Microsoft Academic Search

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30°C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of

Tarek A. Elmitwalli; Ralf Otterpohl

2007-01-01

32

Performance of an on-site UASB reactor treating leachate at low temperature  

Microsoft Academic Search

A pilot-scale UASB reactor was used to study treatment of municipal landfill leachate (COD 1.5–3.2gl?1) at low temperatures (13–23°C) and in on-site conditions for 226days. The reactor was successfully operated by decreasing the process temperature as leachate temperature decreased in winter. Despite changes in leachate quality, 65–75% COD and up to 95% BOD7 removals were achieved at 18–23°C with organic

Riitta H. Kettunen; Jukka A. Rintala

1998-01-01

33

Enhanced granulation in UASB reactor treating low-strength wastewater by natural polymers.  

PubMed

Reetha (Sapindus trifoliata) seed extract and Chitosan were used as additives in the sludge bed of a UASB reactor treating low strength wastewater to enhance granulation. Five parallel laboratory scale UASB reactors were operated for 250 days with synthetic wastewater feed containing COD in the range of 600-800 mg/L. The reactors were seeded with spent sludge from a full-scale 5MLD UASB treatment plant at Jajmau, Kanpur, India. The seed sludge contained little or no granules. Different additives in the five reactors were as follows: control with no additive, cationic part of Reetha extract as additive, anionic part of Reetha extract as additive, bulk Reetha extract as additive and Chitosan as additive. The granulation rapidly increased in all the reactors beyond the 90th day of operation. The mean granule sizes as well as the fraction of granular sludge (particle size > or = 100 microm) were more in the presence of some of the additives compared to the control reactor. Chitosan significantly enhanced granulation followed by the cationic and anionic fractions of the Reetha extract. The bulk Reetha extract did not show enhancement of granulation. The ESEM/EDAX results showed that the bigger granules (3-4 mm) had porous structure and appeared as conglomerates of smaller granules. PMID:15537012

Tiwari, M K; Guha, S; Harendranath, C S

2004-01-01

34

Development of empirical models for performance evaluation of UASB reactors treating poultry manure wastewater under different operational conditions  

Microsoft Academic Search

A nonlinear modeling study was carried out to evaluate the performance of UASB reactors treating poultry manure wastewater under different organic and hydraulic loading conditions. Two identical pilot scale up-flow anaerobic sludge blanket (UASB) reactors (15.7L) were run at mesophilic conditions (30–35°C) in a temperature-controlled environment with three hydraulic retention times (?) of 15.7, 12 and 8.0 days. Imposed volumetric

Kaan Yetilmezsoy; Suleyman Sakar

2008-01-01

35

Bicarbonate dosing: a tool to performance recovery of a thermophilic methanol-fed UASB reactor.  

PubMed

The thermophilic-anaerobic treatment of methanol-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor, was found to be quite sensitive to pH shocks, both acid and alkaline. The results of the recovery experiments of sludge exposed to an alkaline shock, indicated that the addition or deprivation of sodium bicarbonate (NaHCO3) in the medium, plays an important role in the competition of methanogens and (homo)acetogens for methanol. In addition, caution has to be taken when using NaHCO3 for buffering methanol-containing wastewaters, since its introduction in the system will favour (homo)acetogenesis when proper conditions are not established. Based on these results, a recovery strategy for methanogenesis was proposed where bicarbonate is supplied stepwise, and the reactor is operated in a batch mode. This strategy was found to be appropriate, i.e. the results revealed that the recovery of methanogenesis on methanol from a reactor upset or complete failure caused by pH shock is possible, even in systems where (homo)acetogens are outcompeting methanogens. The time and the number of feedings required will depend on the degree of deterioration of the sludge. PMID:14640205

Paulo, P L; van Lier, J B; Lettinga, G

2003-01-01

36

Using a UASB reactor for thickening and digestion of discharged sludge from submerged aerated biofilters.  

PubMed

Results from one year of experimental monitoring the wastewater treatment plant of UFES (Federal University of Espírito Santo) treating a residential urban area of city of Vitoria ES, Brazil, have shown a good performance by a UASB reactor as a part of domestic sewage treatment and also performing aerobic sludge thickening and digestion. The total solids concentration around 6% was obtained in main sludge blanket at bottom of reactor despite a high daily aerobic sludge load discharged from four aerobic submerged biofilters containing 0.4% TS and 80% of VS/TS. Similar values were found in another experimental period when the reactor was fed only with raw domestic sewage. The average removal efficiency of organic matter and suspended solids observed for domestic sewage treatment are around 63% of SS and 64% COD. These results were obtained in the UASB reactor working with or without aerobic sludge recycling, with constant or variable load and hydraulic detention time (HDT) less than 6 hours. A proposed mass balance allows a theoretical assessment of aerobic sludge digestion and accumulation into UASB reactor. PMID:12188562

Franci Gonçalves, R; Veronez, F A; Kissling, C M S; Cassini, S T A

2002-01-01

37

Biological hydrogen production in a UASB reactor with granules. II: Reactor performance in 3-year operation.  

PubMed

The experiment was conducted to evaluate the performance of an upflow anaerobic sludge blanket (UASB) with granules for H(2) production from a sucrose-rich synthetic wastewater at various substrate concentrations (5.33-28.07 g-COD/L) and hydraulic retention times (HRTs) (3-30 h) for over 3 years. The kinetics of H(2) production was evaluated, and the sludge yield and endogenous decay coefficient of the H(2)-producing granules were estimated to be 0.334 g-VSS/g-COD and 0.004/h, respectively. Based on Gibbs free energy calculations, the formation thermodynamics of caproate, an important aqueous product, were analyzed. Experimental results show that the H(2) partial pressure in biogas decreased with increasing substrate concentration, but was not sensitive to the variation of HRT in a range of 6-22 h. The H(2) production rate increased with increasing substrate concentration, but decreased with increasing HRT. The H(2) yield was in the range of 0.49-1.44 mol-H(2)/mol-glucose. Acetate, butyrate, caporate, and ethanol were the main aqueous products in the reactor, and their concentrations were dependent on both substrate concentration and HRT. An elevated substrate concentration resulted in a shift of fermentation from butyrate- to caporate-type in the reactor and the formation of caproate was dependent on the H(2) partial pressure. The 3-year experimental results demonstrate that H(2) could be produced continuously and stably from the acidogenic-granule-based UASB reactor. PMID:16615161

Yu, Han-Qing; Mu, Yang

2006-08-01

38

Effect of sulfate on anaerobic degradation of benzoate in UASB reactors  

SciTech Connect

Anaerobic processes have been widely used for the treatment of various high-strength industrial wastewaters. However, application has been limited for the treatment of sulfate-rich industrial wastewaters, such as those from the petrochemical, and mining industries. Wastewaters containing benzoate and sulfate were treated in two upflow anaerobic sludge blanket (UASB) reactors at 34--37 C for 320 d. The sulfate concentration was increased stepwise in Reactor-A up to 7,500 mg/L, and was kept mostly constant at 3,000 mg/L in Reactor-B. Both reactors removed over 98% of organic chemical-oxygen demand (COD) for sulfate up to 6,000 mg/L, despite the fact that the mixed liquor contained up to 769 mg S/L of total sulfides and up to 234 mg S/L of dissolved H{sub 2}S. Sulfate0reducing efficiency decreased with the increase in sulfate concentration, but increased with time at each sulfate concentration. Reactor-B consistently reduced 89% of sulfate. However, both organic COD removal and sulfate-reducing efficiencies of Reactor-A dropped drastically at 7,500 mg SO{sub 4}{sup {minus}2}/L, and showed no sign of recovery after 50 d. The system failure was likely due to the increased sulfate, instead of sulfide, toxicity. From the COD balance, 93.4% of COD removed was converted to methane instead of sulfides, with a net sludge yield of 0.047 g volatile suspended solids (VSS)/g COD. The sulfur balance was over 97%.

Fang, H.H.P.; Liu, Y.; Chen, T. [Univ. of Hong Kong (Hong Kong)

1997-04-01

39

Effect of sulfate on anaerobic degradation of benzoate in UASB reactors  

Microsoft Academic Search

Anaerobic processes have been widely used for the treatment of various high-strength industrial wastewaters. However, application has been limited for the treatment of sulfate-rich industrial wastewaters, such as those from the petrochemical, and mining industries. Wastewaters containing benzoate and sulfate were treated in two upflow anaerobic sludge blanket (UASB) reactors at 34--37 C for 320 d. The sulfate concentration was

Herbert H. P. Fang; Yan Liu; Tong Chen

1997-01-01

40

Bicarbonate dosing: a tool to performance recovery of a thermophilic methanol-fed UASB reactor  

Microsoft Academic Search

The thermophilic-anaerobic treatment of methanol-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor, was found to be quite sensitive to pH shocks, both acid and alkaline. The results of the recovery experiments of sludge exposed to an alkaline shock, indicated that the addition or deprivation of sodium bicarbonate (NaHCO3) in the medium, plays an important role in the competition

P. L. Paulo; Lier van J. B; G. Lettinga

2003-01-01

41

Different types of sludge granules in UASB reactors treating acidified wastewaters  

Microsoft Academic Search

The influence of a high energy substrate, i.e. sucrose, on the granular sludge yield and the development of different types of granular sludge was investigated by using Upflow Anaerobic Sludge Bed (UASB) reactors fed with synthetic wastewater. The feed COD was a mixture of volatile fatty acids (VFA) i.e., 20, 40, and 40% of the COD as C2-, C3-, and

Jullapong Thaveesri; Daniele Daffonchio; Bart Liessens; Willy Verstraete

1995-01-01

42

Kinetic analysis of anaerobic digestion of cattail by rumen microbes in a modified UASB reactor  

Microsoft Academic Search

The kinetics of anaerobic digestion of cattail by rumen microbes in a modified upflow anaerobic sludge blanket (UASB) reactor was systematically analyzed in this study. The Monod and first-order equations were combined to develop kinetic models to describe the substrate degradation, microbial growth and product formation. At an influent cattail concentration (volatile solids) of 12.1g\\/L, hydraulic retention time of 0.75

Zhen-Hu Hu; Han-Qing Yu; Zheng-Bo Yue; Hideki Harada; Yu-You Li

2007-01-01

43

Methane production by treating vinasses from hydrous ethanol using a modified UASB reactor  

PubMed Central

Background A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. Results The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. Conclusions The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production. Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production.

2012-01-01

44

Performance evaluation and kinetic modeling of the start-up of a UASB reactor treating municipal wastewater at low temperature.  

PubMed

A kinetic modeling-based study was carried out to evaluate the start-up performance of a 10-L up-flow anaerobic sludge blanket (UASB) reactor treating municipal wastewater under different organic and hydraulic loading conditions. The reactor was operated for 105 days (around 4 months) below 20 °C and with three different hydraulic retention times of 24, 12 and 5 h. Imposed volumetric organic loading rates (OLR) ranged from 0.57 (±0.05) to 11.78 (±0.85) kg TCOD/m(3)-day. Although relatively high incoming volumetric OLR values were employed to the system, the UASB reactor demonstrated a favorable performance on the anaerobic treatability of municipal wastewater, and no process failure was recorded in the start-up stage. On the basis of experimental results, the modified Stover-Kincannon model was successfully applied to define the start-up kinetics with a very high value of the correlation coefficient (R = 0.9729). Maximum substrate utilization rate constant and saturation constant of the modified Stover-Kincannon model were determined as U (max) = 1.996 g/L-day and K (B) = 1.536 g/L-day, respectively. PMID:20683617

Turkdogan-Aydinol, F Ilter; Yetilmezsoy, Kaan; Comez, Sezen; Bayhan, Hurrem

2010-08-04

45

Effect of non-feeding period length on the intermittent operation of UASB reactors treating dairy effluents.  

PubMed

Recent environmental concerns have prompted a re-evaluation of conventional management strategies and refueled the search of innovative waste management practices. In this sense, the anaerobic digestion of both fat and the remaining complex organic matter present in dairy wastewaters is attractive, although the continuous operation of high rate anaerobic processes treating this type of wastewaters causes the failure of the process. This work accesses the influence of non-feeding period length on the intermittent operation of mesophilic UASB reactors treating dairy wastewater, in order to allow the biological degradation to catch up with adsorption phenomenon. During the experiments, two UASB reactors were subject to three organic loading rates, ranging from 6 to 12 g(COD) x L(-1) x d(-1), with the same daily load applied to both reactors, each one with a different non-feeding period. Both reactors showed good COD removal efficiencies (87-92%). A material balance for COD in the reactors during the feeding and non-feeding periods showed the importance of the feedless period, which allowed the biomass to degrade substrate that was accumulated during the feeding period. The reactor with the longest non-feeding period had a better performance, which resulted in a higher methane production and adsorption capacity for the same organic load applied with a consequent less accumulation of substrate into the biomass. In addition, both reactors had a stable operation for the organic load of 12 g(COD) x L(-1) x d(-1), which is higher than the maximum applicable load reported in literature for continuous systems (3-6 g(COD) x L(-1) x d(-1)). PMID:16900520

Coelho, N M; Rodrigues, A A; Arroja, L M; Capela, I F

2007-02-01

46

Achieving the nitrite pathway using FA inhibition and process control in UASB-SBR system removing nitrogen from landfill leachate  

Microsoft Academic Search

An up-flow sludge blanket (UASB) and sequencing batch reactor (SBR) system was introduced to remove organics and nitrogen\\u000a from landfill leachate. The synergetic effect of free ammonia (FA) inhibition and process control was used to achieve the\\u000a nitrite pathway in the SBR. In previous research, inhibition of FA on nitrite oxidizing bacteria (NOB) activity has been revealed\\u000a and the process

HongWei Sun; Qing Yang; GuoRi Dong; HongXun Hou; ShuJun Zhang; YingYing Yang; YongZhen Peng

2010-01-01

47

Post-treatment of UASB effluent in an expanded granular sludge bed reactor type using flocculent sludge  

Microsoft Academic Search

The performance of an EGSB (expanded granular sludge bed) reactor type using flocculent sludge was evaluated for the post-treatment of effluent from UASB reactor treating domestic sewage. A pilot-scale 157.5-L EGSB reactor was monitored during a 331-day period. The original concept of the EGSB reactor was based on granular sludge use and by applying of high upflow liquid velocities (Vup).

M. T. Kato; L. Florencio; R. F. M. Arantes

2003-01-01

48

Methane production in an UASB reactor operated under periodic mesophilic-thermophilic conditions.  

PubMed

Methane production was studied in a laboratory-scale 10 L anaerobic upflow sludge bed (UASB) reactor with periodic variations of the reactor temperature. On a daily basis the temperature was varied between 35 and 45 degrees C or 35 and 55 degrees C with a heating period of 6 h. Each temperature increase was accompanied by an increase in methane production and a decrease in the concentration of soluble organic matter in the effluent. In comparison to a reactor operated at 35 degrees C, a net increase in methane production of up to 22% was observed. Batch activity tests demonstrated a tolerance of mesophilic methanogenic populations to short-term, 2-6 h, temperature increases, although activity of acetoclastic methanogens decreased after 6 h exposure to a temperature of 55 degrees C. 16S sequencing of DGGE bands revealed proliferation of temperature-tolerant Methanospirillum hungatii sp. in the reactor. PMID:18383125

Bourque, J-S; Guiot, S R; Tartakovsky, B

2008-08-15

49

Effect of corrosion of steel elements on the treatment of dairy wastewater in a UASB reactor.  

PubMed

Experiments were performed in parallel using two laboratory upflow anaerobic sludge blanket (UASB) reactors. One of the two reactors was packed with spiral elements made of steel wire with 48% iron content in order to examine the influence of the steel elements on the chemical oxygen demand (COD) and efficiency of phosphorus removal from synthetically prepared dairy wastewater. A strong relationship was found between anaerobic corrosion and efficiency of phosphorus removal. Phosphorus removal in the reactor packed with steel elements was between 16.4% and 64.4% higher than without the steel elements present. The anaerobic corrosion process improved COD removal efficiency by 1.0-3.1%, which was statistically significant. When steel elements were present the methane content of the biogas was increased by 6.7%. Increasing the organic loading rate had a strong effect on the anaerobic efficiency of the dairy wastewater treatment. PMID:20540419

J?drzejewska Cici?ska, M; Krzemieniewski, M

2010-05-01

50

Behavior of an Up-flow Anaerobic Sludge Bed (UASB) reactor at extreme salinity.  

PubMed

High salinity is one of the most well known inhibitors and salt concentrations above 1% are reported as highly saline. Salt may be found in the main collectors of municipal sewer systems which carry the risk of seawater infiltration and where domestic wastewaters are treated with landfill leachates such cases in Istanbul. Discharging of leachates into sewerage would also result in additional ammonium loads in Municipal Treatment Plants (MTPs). In this study, synthetic wastewater was fed to a lab-scale Upflow Anaerobic Sludge Bed (UASB) reactor operated at a constant hydraulic retention time (HRT) of 1 day. The salt concentration was increased artificially whereas the ammonium concentration was fixed at 1000 mg/l throughout the study. Results indicated no significant inhibition up to 2% salinity + 1000 mg/l NH4 and TOC removals could reach up to 88%. Besides, effective total biogas productions having methane content of 84% could be achieved. It is obvious that anaerobic microorganisms (especially methanogens) could well adapt to high salinity ratios. No inhibition at high ammonium concentration might have been attributed to the fact that the pH in the system was not high enough for the formation of free ammonia. Investigation of the combined effect of high salinity and ammonium was carried on by increasing the salinity to 3% in the study. Results indicated that TOC removals decreased to around 56% and 3% salinity caused . a sharp decrease both in organic material removal and total biogas production. Thus the critical salinity level was determined as 3% for the methanogens in the mesophilic anaerobic digesters. PMID:16114624

Gomec, C Y; Gonuldinc, S; Eldem, N; Ozturk, I

2005-01-01

51

Organics, sulfates and ammonia removal from acrylic fiber manufacturing wastewater using a combined Fenton-UASB (2 phase)SBR system  

Microsoft Academic Search

A combined Fenton-UASB (2 phase)-SBR system was employed to treat acrylic fiber manufacturing wastewater. The Chemical Oxygen Demand (COD) removal and effluent Biochemical Oxygen Demand (BOD) to COD were 65.5% and 0.529%, respectively, with the optimal Fenton conditions: ferrous was 300mg\\/L; hydrogen peroxide was 500mg\\/L; pH was 3.0; reaction time was 2.0h. In two-phase UASB reactor, mesophilic operation (35±0.5°C) was

Jin Li; Zhaokun Luan; Lian Yu; Zhongguang Ji

2011-01-01

52

Methanogenic community change in a full-scale UASB reactor operated at a low F\\/M ratio  

Microsoft Academic Search

A full-scale upflow anaerobic sludge blanket (UASB) reactor was investigated in terms of archaeal composition, acetoclastic methanogenic capacity and performance over a 2-year period. Performance of the reactor in terms of COD removal efficiency varied between 60% and 80% at organic loading rates (OLRs) in the range of 2.5–12 kg COD md. The reactor had been operated under a F\\/M

M. Kolukirik; O. Ince; B. Kasapgil Ince

2007-01-01

53

Mesophilic biomethanation and treatment of poultry waste-water using pilot scale UASB reactor.  

PubMed

The feasibility of applying the up-flow anaerobic sludge blanket (UASB) treatment for poultry waste (faeces) water was examined. A continuous-flow UASB pilot scale reactor of 3.50 L capacity using mixed culture was operated for 95 days to assess the treatability of poultry waste-water and its methane production. The maximum chemical oxygen demand (COD) removed was found to be 78% when organic loading rate (OLR) was 2.9 kg COD m(-3) day(-1) at hydraulic retention times (HRT) of 13.2 hr. The average biogas recovery was 0.26 m3 CH4 kg COD with an average methane content of 57% at mean temperature of 30 degrees C. Data indicate more rapid methanogenesis with higher loading rates and shorter hydraulic retention times. At feed concentration of 4.8 kg COD m(-3) day(-1), anaerobic digestion was severely retarded at all hydraulic retention time tested. This complication in the reactor operations may be linked to build-up of colloidal solids often associated with poultry waste water and ammonia toxicity. Isolates from granular sludge and effluent were found to be facultative anaerobes most of which were Pseudomonas genera. PMID:12180651

Atuanya, Ernest I; Aigbirior, Moses

2002-07-01

54

A novel process using enhanced acidification and a UASB reactor for biomethanation of vegetable market waste.  

PubMed

The processing of solid vegetable market waste was attempted in a two-stage digester. Initially, for the hydrolysis and acidification of waste, enhanced extraction process was carried out by continuous sprinkling of water over the bed of waste in a mild steel 100 1 solid bed digester. The leachate obtained after completion of acidification phase was further treated in 24.6 1 UASB reactor for biogas production. The effect of waste-liquid ratio, dilution and sprinkling rate on the digestion of waste were studied. A high strength leachate, with a COD of 25,298 mg l(-1) and total volatile fatty acids concentration of 11.3 g l(-1), was obtained as a result of hydrolysis and acidification in a very short retention time of 40 h. The COD reduction of 94% was achieved during UASB reactor operation at organic loading rate of 19.6 kg COD m day(-3). A minimum hydraulic retention time of 16 h was achieved. PMID:11720263

Rajeshwari, K V; Lata, K; Pant, D C; Kishore, V V

2001-08-01

55

Anaerobic degradation of aircraft deicing fluid (ADF) in upflow anaerobic sludge blanket (UASB) reactors and the fate of ADF additives  

Microsoft Academic Search

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions were conducted in continuous mode. The development of four empirical models describing process responses (i.e., chemical oxygen demand (COD) removal efficiency, biomass specific acetoclastic activity, methane

Thi Tham Pham

2002-01-01

56

Treatment of a low concentration industrial chemicals mixture in an UASB reactor.  

PubMed

A wastewater containing a mixture of methanol, isopropyl alcohol, ethylene glycol, acetic anhydride, methyl, ethyl and isopropyl acetate, acrylic acid, butyl and methyl acrylate, o, m and p-xylene and styrene was fed to an UASB reactor. Isopropanol addition diminished the removal efficiency to 60% and required a long adaptation time for its total mineralization. When acrylic acid was added to the mixture, the removal dropped to 83% and recovered after 40 days. As for the rest of the substrates, p-m-o-xylene addition had no effect on reactor performance, although in batch assays it showed low mineralization. Also the effect of volumetric organic load on removal efficiency was followed up. After diminishing the HRT to 4 and 3 h yielding 4.8 and 6.5 gCOD L(-1) d(-1), removal efficiencies decreased to 79 and 74% respectively. PMID:16180454

Castilla, P; Leyva, A; Garcia, U; Monroy, O; Meraz, M

2005-01-01

57

Performance of anammox UASB reactor treating low strength wastewater under moderate and low temperatures.  

PubMed

An integrated approach to enhance and maintain high anammox activity and abundance in an upflow anaerobic sludge blanket (UASB) treating low strength wastewater under moderate and low temperatures was developed. A quantitative PCR assay showed the abandance of anammox bacteria to be 1.68±0.08×10(9) copies/ml in mixed liquor when the temperature was 30 °C and was maintained at the level of 1.93±0.41×10(9) copies/ml in mixed liquor at 16 °C. A nitrogen removal rate (NRR) of up to 5.72 kg N/m3/d was achieved with a hydraulic retention time (HRT) of 0.12 h at 30 °C, while nitrite and ammonium removal efficiencies were 94.35% and 92.81%, respectively. NRR decreased with a decrease in temperature and was maintained at 2.28 kg N/m3/d with an HRT of 0.28 h when at 16 °C, while nitrite and ammonium removal efficiencies were 92.31% and 78.45%, respectively. The emission rate of the greenhouse gas N2O was below 0.006% of the NRR in the anammox UASB reactor treating low strength wastewater. PMID:23313946

Ma, Bin; Peng, Yongzhen; Zhang, Shujun; Wang, Junmin; Gan, Yiping; Chang, Jiang; Wang, Shuying; Wang, Shanyun; Zhu, Guibing

2012-11-21

58

Performance evaluation and kinetic modeling of the start-up of a UASB reactor treating municipal wastewater at low temperature  

Microsoft Academic Search

A kinetic modeling-based study was carried out to evaluate the start-up performance of a 10-L up-flow anaerobic sludge blanket\\u000a (UASB) reactor treating municipal wastewater under different organic and hydraulic loading conditions. The reactor was operated\\u000a for 105 days (around 4 months) below 20 °C and with three different hydraulic retention times of 24, 12 and 5 h. Imposed volumetric\\u000a organic loading rates (OLR) ranged

F. Ilter Turkdogan-Aydinol; Kaan Yetilmezsoy; Sezen Comez; Hurrem Bayhan

2011-01-01

59

Evaluation of performance and microbial community in a two-stage UASB reactor pretreating acrylic fiber manufacturing wastewater  

Microsoft Academic Search

A two-stage UASB reactor was employed to pretreat acrylic fiber manufacturing wastewater. Mesophilic operation (35±0.5°C) was performed with hydraulic retention time (HRT) varied between 28 and 40h. Mixed liquor suspended solids (MLSS) in the reactor was maintained about 8000mg\\/L. The results showed COD and sulfate removal could be kept at 51% and 75%, respectively, when the HRT was no less

Jin Li; Jun Wang; Zhaokun Luan; Yanqin Deng; Lin Chen

2011-01-01

60

Prospects for a self-sustainable sewage treatment system: a case study on full-scale UASB system in India's Yamuna River Basin.  

PubMed

The government of India decided to launch a project to implement 16 full-scale Upflow Anaerobic Sludge Blanket (UASB) reactors (with a total capacity of 598,000 m(3)/d) in the Yamuna River basin under its Yamuna Action Plan (YAP). A polishing pond called the Final Polishing Unit (FPU) was utilized for post-treatment. This paper evaluates the sewage treatment efficiency of the combined system of full-scale UASB reactors and polishing ponds under Indian climatic conditions. Results have shown that the effluent from the sewage treatment plants (STPs) investigated failed to comply with applicable discharge standards in terms of BOD, SS, and fecal coliform removal. Therefore, it is proposed that such proper operation and maintenance as removing excess sludge and scum be conducted in order to increase treatment efficiency. Moreover, trained and experienced workers are also required to operate and maintain the systems, along with a scientific approach. PMID:16338055

Sato, Nobuyuki; Okubo, Tsutomu; Onodera, Takashi; Ohashi, Akiyoshi; Harada, Hideki

2005-12-09

61

Prospects for a self-sustainable sewage treatment system: A case study on full-scale UASB system in India's Yamuna River Basin  

Microsoft Academic Search

The government of India decided to launch a project to implement 16 full-scale Upflow Anaerobic Sludge Blanket (UASB) reactors (with a total capacity of 598,000m3\\/d) in the Yamuna River basin under its Yamuna Action Plan (YAP). A polishing pond called the Final Polishing Unit (FPU) was utilized for post-treatment. This paper evaluates the sewage treatment efficiency of the combined system

Nobuyuki Sato; Tsutomu Okubo; Takashi Onodera; Akiyoshi Ohashi; Hideki Harada

2006-01-01

62

Anaerobic degradation of aircraft deicing fluid (ADF) in upflow anaerobic sludge blanket (UASB) reactors and the fate of ADF additives  

NASA Astrophysics Data System (ADS)

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions were conducted in continuous mode. The development of four empirical models describing process responses (i.e., chemical oxygen demand (COD) removal efficiency, biomass specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time (HRT), and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass specific acetoclastic activity was improved by almost two-fold during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. Predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate (OLR) was increased. ADF toxicity effects were evident for 1.6% ADF at medium specific organic loadings (SOLR above 0.5 g COD/g VSS/d). In contrast, good reactor stability and excellent removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73 g COD/g VSS/d). Acclimation to ADF resulted in an initial reduction in the biomass settling velocity. The fate of ADF additives was also investigated. There was minimal sorption of benzotriazole (BT), 5-methyl-1 H-benzotriazole (MeBT), and 5,6-dimethyl-1 H-benzotriazole (DiMeBT) to anaerobic granules. A higher sorption capacity was measured for NP. Active transport may be one of the mechanisms for NP sorption. Ethylene glycol degradation experiments indicated that BT, MeBT, DiMeBT, and the nonionic surfactant Tergitol NP-4 had no significant effects on acidogenesis and methanogenesis at the concentration levels studied. A significant inhibition of acetoclastic activity was observed for NP at 100 mg/L, with acetic acid consumption rate at 38% of that for controls. No evidence for anaerobic degradation of benzotriazole and its derivatives was observed; however, both batch and continuous experiments suggested that anaerobic degradation of NP occurred. Kinetic analysis of operational data obtained for the anaerobic treatment of ADF in UASB reactors indicated that the substrate utilization rate was independent of the reactor biomass concentration. The maximum rate of substrate utilization and the half-velocity constants for ADF treatment were 28.4 g COD/L/d and 648 mg COD/L, respectively. For 1.2% ADF, the biomass yield and endogenous decay coefficients were 0.027 g VSS/g COD and 0.012 d-1 , respectively.

Pham, Thi Tham

63

Immobilized humic substances as redox mediator for the simultaneous removal of phenol and Reactive Red 2 in a UASB reactor.  

PubMed

The present study reports a novel treatment concept combining the redox-mediating capacity of immobilized humic substances with the biodegrading activity of anaerobic sludge for the simultaneous removal of two representative pollutants of textile wastewaters (e.g., phenol and Reactive Red 2 (RR2)) in a high-rate anaerobic reactor. The use of immobilized humic substances (1 g total organic carbon (TOC)?L(-1), supported on an anion exchange resin) in an upflow anaerobic sludge blanket (UASB) reactor increased the decolorization efficiency of RR2 (?90 %), extent of phenol oxidation (?75 %), and stability as compared to a control UASB reactor operated without immobilized humic substances, which collapsed after 120 days of dye introduction (50-100 mg L(-1)). Increase in the concentration of immobilized humic substances (2 g TOC L(-1)) further enhanced the stability and efficiency of the UASB reactor. Detection of aniline in the effluent as RR2 reduction product confirmed that reduction of RR2 was the major mechanism of dye removal. This is the first demonstration of immobilized humic substances serving as effective redox mediators for the removal of recalcitrant pollutants from wastewater in a high-rate anaerobic bioreactor. The novel treatment concept could also be applicable to remove a wide variety of contaminants susceptible to redox conversion, which are commonly found in different industrial sectors. PMID:24013221

Martínez, Claudia M; Celis, Lourdes B; Cervantes, Francisco J

2013-09-07

64

Biomethanation of poultry litter leachate in UASB reactor coupled with ammonia stripper for enhancement of overall performance.  

PubMed

In the present study possibility of coupling stripper to remove ammonia to the UASB reactor treating poultry litter leachate was studied to enhance the overall performance of the reactor. UASB reactor with stripper as ammonia inhibition control mechanism exhibited better performance in terms of COD reduction (96%), methane yield (0.26m(3)CH(4)/kg COD reduced), organic loading rate (OLR) (18.5kg COD m(-3)day(-1)) and Hydraulic residence time (HRT) (12h) compared to the UASB reactor without stripper (COD reduction: 92%; methane yield: 0.21m(3)CH(4)/kg COD reduced; OLR: 13.6kg CODm(-3)day(-1); HRT: 16h). The improved performance was due to the reduction of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) in the range of 75-95% and 80-95%, respectively by the use of stripper. G/L (air flow rate/poultry leachate flow rate) in the range of 60-70 and HRT in the range of 7-9min are found to be optimum parameters for the operation of the stripper. PMID:18524578

Gangagni Rao, A; Sasi Kanth Reddy, T; Surya Prakash, S; Vanajakshi, J; Joseph, Johny; Jetty, Annapurna; Rajashekhara Reddy, A; Sarma, P N

2008-06-03

65

Effects of bioaugmentation strategies in UASB reactors with a methanogenic consortium for removal of phenolic compounds  

SciTech Connect

The removal of phenol, ortho- (op) and para- (p-) cresol was studied with two series of UASB reactors using unacclimatized granular sludges bioaugmented with a consortium enriched against these substances. The parameters studied were the amount of inoculum added to the sludges and the method of immobilization of the inoculum. Two methods were used, adsorption to the biomass or encapsulation with calcium alginate beads. In the bioaugmentation by adsorption experiment, and with a 10% inoculum, complete phenol removal was obtained after 36 d, while 178 d were required in the control reactor. For p-cresol, 95% removal was obtained in the bioaugmented reactor on day 48 while 60 d were required to achieve 90% removal in the control reactor. For o-cresol, the removals were only marginally better with the bioaugmented reactors. Tests performed with the reactors biomass under non-limiting substrate concentrations showed that the specific activities of the bioaugmented biomasses were larger than the original biomass for phenol, and p-cresol even after 276 of operations, showing that the inoculum bacteria successfully colonized the sludge granules. Immobilization of the inoculum by encapsulation in calcium alginate beads, was performed with 10% of the inoculum. Results showed that the best activities were obtained when the consortium was encapsulated alone and the beads added to the sludges. This reactor presented excellent activity and the highest removal of the various phenolic compounds a few days after start-up. After 90 d, a high-phenolic compounds removal was still observed, demonstrating the effectiveness of the encapsulation technique for the start-up and maintenance of high-removal activities.

Hajji, K.T.; Lepine, F.; Bisaillon, J.G.; Beaudet, R.; Hawari, J.; Guiot, S.R.

2000-02-20

66

Heavy metal removal in an UASB-CW system treating municipal wastewater.  

PubMed

The objective of the present study was to investigate for the first time the long-term removal of heavy metals (HMs) in a combined UASB-CW system treating municipal wastewater. The research was carried out in a field pilot plant constituted for an up-flow anaerobic sludge bed (UASB) digester as a pretreatment, followed by a surface flow constructed wetland (CW) and finally by a subsurface flow CW. While the UASB showed (pseudo) steady state operational conditions and generated a periodical purge of sludge, CWs were characterised by the progressive accumulation and mineralisation of retained solids. This paper analyses the evolution of HM removal from the water stream over time (over a period of 4.7year of operation) and the accumulation of HMs in UASB sludge and CW sediments at two horizons of 2.7 and 4.0year of operation. High removal efficiencies were found for some metals in the following order: Sn>Cr>Cu>Pb>Zn>Fe (63-94%). Medium removal efficiencies were registered for Ni (49%), Hg (42%), and Ag (40%), and finally Mn and As showed negative percentage removals. Removal efficiencies of total HMs were higher in UASB and SF units and lower in the last SSF unit. PMID:23942017

de la Varga, D; Díaz, M A; Ruiz, I; Soto, M

2013-08-12

67

Biodegradation of 1,1,2,2-tetrachloroethane in Upflow anaerobic sludge blanket (UASB) reactor.  

PubMed

This study examines the performance of bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactor in treating simulated wastewaters containing 1,1,2,2-tetrachloroethane (TeCA). Reactors R1 (control) and R2 (containing TeCA) were operated at Hydraulic Retention Times (HRTs) of 36, 30, 24, 18 and 12 h. The removal of TeCA decreased from 99.85% to 98.40% as the HRT was lowered down from 36 to 12 h. The maximum TeCA dechlorination rate and the half velocity coefficient were 0.2 d(-1) and 18.58 mg TeCA/l, respectively. The Organic Loading Rate (OLR) was varied from 1.5 to 3.1 kg/m(3)/d to yield various substrate:co-substrate ratios and the overall removal of TeCA throughout this study was more than 99%. The average effluent TeCA concentration at optimum HRT (24 h) and substrate:co-substrate ratio (100:1) was less than 0.1 mg/l. The granules within the reactor were 0.1-3.2 mm in size with a heterogeneous bacterial population. PMID:19699084

Basu, Debolina; Gupta, S K

2009-08-20

68

Anaerobic treatment of fish meal process waste-water in a UASB reactor at high pH  

Microsoft Academic Search

The influence of high pH on anaerobic degradation of fish process waste-water with a high total ammonia concentration was investigated in an upflow anaerobic sludge blanket (UASB) reactor. More than 99% of volatile fatty acids and trimethylamine in the process waste-water were degraded up to pH 7.9. Above pH 7.9 only the conversion of acetate was slightly decreased. At pH

M. Sandberg; B. K. Ahring

1992-01-01

69

Performance of uasb reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste  

Microsoft Academic Search

This study was conducted to investigate the performance of the upflow anaerobic sludge blanket (UASB) reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste. The chemical oxygen demand (COD) removal efficiency was consistently over 96% up to the loading rates of 15.8gCOD\\/ld. The methane production rate increased to 5.5l\\/ld. Of all the COD removed, 92%

H. S Shin; S. K Han; Y. C Song; C. Y Lee

2001-01-01

70

Anaerobic biotransformation of four3-carbon compounds (acrolein, acrylic acid, allyl alcohol and n-propanol) in UASB reactors  

Microsoft Academic Search

Anaerobic biotransformation of the 3-carbon compounds, namely acrolein, acrylic acid, allyl alcohol, and n-propanol was investigated in upflow anaerobic sludge blanket (UASB) reactors containing granular cultures. The toxic effects of acrolein, acrylic acid, and allyl alcohol on an acetate-enriched Methanosarcina culture were determined. Furthermore, process staging, effect of operational parameters such as influent concentration, F\\/M ratio and loading rate were

G. N. Demirer; R. E. Speece

1998-01-01

71

Enhanced treatment of wastewater from the vitamin C biosynthesis industry using a UASB reactor supplemented with zero-valent iron  

Microsoft Academic Search

The effects of zero-valent iron (Fe) on the performance of a mesophilic upflow anaerobic sludge blanket (UASB) reactor treating high-strength wastewater from the vitamin C biosynthesis industry (VCW) was investigated during a 200-day period. The results showed that the chemical oxygen demand (COD) removal efficiency, CH4 content in biogas, specific methanogenic activity of sludge, and phosphate removal efficiency were significantly

Rongjiu Shi; Hui Xu; Ying Zhang

2011-01-01

72

Different types of sludge granules in UASB reactors treating acidified wastewaters.  

PubMed

The influence of a high energy substrate, i.e. sucrose, on the granular sludge yield and the development of different types of granular sludge was investigated by using Upflow Anaerobic Sludge Bed (UASB) reactors fed with synthetic wastewater. The feed COD was a mixture of volatile fatty acids (VFA) i.e., 20, 40, and 40% of the COD as C2-, C3-, and C4-VFA, respectively. Furthermore, experiments were carried out in which 10 and 30% of the VFA COD was substituted with sucrose. The following distinctly different types of granules were observed in each testrun: in the reactor fed with solely VFA, black (B) and white (W) granules developed; in the reactor fed with a mixture of 90% VFA and 10% sucrose, three types of granules i.e., B, W, and grey (G) granules could be seen; in the reactor fed with 70% VFA and 30% sucrose, only W and G granules were found. The granular sludge yield increased proportional to the amount of sucrose COD. At steady-state performance of the reactors, specific acidogenic (SAA) and methanogenic (SMA) activity tests on these granules revealed that B granules had the highest SMA with low SAA. The W granules had very high SMA with low SAA. G granules gave the highest SAA with a considerable SMA. Measurement of coenzyme F420 revealed that B granules consist mainly of acetoclastic methanogens. The fore-mentioned tests were supplemented with analyses of the wash-out cells present in the reactor effluent and the results suggested that acidogens, if present, prevail at the granule surface. The B granules were particularly rich in Ca, Mn, and Zn minerals. The size distribution analysis showed that the granule diameter increased in the following order: B < W < G granules. The biogas bubbles tended to adhere to the B and W granules but not so strongly to the G granules. PMID:8821788

Thaveesri, J; Daffonchio, D; Liessens, B; Verstraete, W

1995-11-01

73

Integration of kinetic modeling and desirability function approach for multi-objective optimization of UASB reactor treating poultry manure wastewater.  

PubMed

An integrated multi-objective optimization approach within the framework of nonlinear regression-based kinetic modeling and desirability function was proposed to optimize an up-flow anaerobic sludge blanket (UASB) reactor treating poultry manure wastewater (PMW). Chen-Hashimoto and modified Stover-Kincannon models were applied to the UASB reactor for determination of bio-kinetic coefficients. A new empirical formulation of volumetric organic loading rate was derived for the first time for PMW to estimate the dimensionless kinetic parameter (K) in the Chen-Hashimoto model. Maximum substrate utilization rate constant and saturation constant were predicted as 11.83 g COD/L/day and 13.02 g COD/L/day, respectively, for the modified Stover-Kincannon model. Based on four process-related variables, three objective functions including a detailed bio-economic model were derived and optimized by using a LOQO/AMPL algorithm, with a maximum overall desirability of 0.896. The proposed optimization scheme demonstrated a useful tool for the UASB reactor to optimize several responses simultaneously. PMID:22705511

Yetilmezsoy, Kaan

2012-05-26

74

Anaerobic treatment of methanol condensate from pulp mill compared with anaerobic treatment of methanol using mesophilic UASB reactors.  

PubMed

The feasibility of anaerobic treatment of methanol condensate from pulp and paper mill in UASB reactor was investigated and compared with the anaerobic treatment of methanol. The UASB reactor treating methanol condensate was operated for 480 days with minimum problems of overload. COD removal from methanol condensate and methanol under normal operating conditions ranged from 84-86% to 86-98%, respectively. Under optimal conditions (OLR=5.0 g COD L(-1)day(-1), COD(influent)=11.40 g L(-1)) a methane yield of 0.29 NL CH(4) per g COD(removed) (at standard temperature and pressure) was achieved during the treatment of methanol condensate. The recovery time of the microorganisms after several overloads was decreasing each time probably due to the adaptation to methanol condensate. These findings indicate that methanol condensate can be efficiently treated in a UASB reactor with the benefit of biogas production. As a bonus effect of the treatment, much of the smell of the feed was eliminated. PMID:23073058

Badshah, Malik; Parawira, Wilson; Mattiasson, Bo

2012-08-31

75

Enhancing the start-up of a UASB reactor treating domestic wastewater by adding a water extract of Moringa oleifera seeds  

Microsoft Academic Search

Water extract of Moringa oleifera seeds (WEMOS) was used to enhance the start-up of a self-inoculated upflow anaerobic sludge blanket (UASB) reactor treating raw domestic wastewater. Two reactors labelled control (RC) and WEMOS addition (RM) were started without special inoculum. Both reactors were fed continuously for 22 weeks with domestic wastewater containing an average total chemical oxygen demand (COD) of

Y. Kalogo; A. M'Bassiguié Séka; W. Verstraete

2001-01-01

76

A fuzzy-logic-based model to predict biogas and methane production rates in a pilot-scale mesophilic UASB reactor treating molasses wastewater.  

PubMed

A MIMO (multiple inputs and multiple outputs) fuzzy-logic-based model was developed to predict biogas and methane production rates in a pilot-scale 90-L mesophilic up-flow anaerobic sludge blanket (UASB) reactor treating molasses wastewater. Five input variables such as volumetric organic loading rate (OLR), volumetric total chemical oxygen demand (TCOD) removal rate (R(V)), influent alkalinity, influent pH and effluent pH were fuzzified by the use of an artificial intelligence-based approach. Trapezoidal membership functions with eight levels were conducted for the fuzzy subsets, and a Mamdani-type fuzzy inference system was used to implement a total of 134 rules in the IF-THEN format. The product (prod) and the centre of gravity (COG, centroid) methods were employed as the inference operator and defuzzification methods, respectively. Fuzzy-logic predicted results were compared with the outputs of two exponential non-linear regression models derived in this study. The UASB reactor showed a remarkable performance on the treatment of molasses wastewater, with an average TCOD removal efficiency of 93 (+/-3)% and an average volumetric TCOD removal rate of 6.87 (+/-3.93) kg TCOD(removed)/m(3)-day, respectively. Findings of this study clearly indicated that, compared to non-linear regression models, the proposed MIMO fuzzy-logic-based model produced smaller deviations and exhibited a superior predictive performance on forecasting of both biogas and methane production rates with satisfactory determination coefficients over 0.98. PMID:20609515

Turkdogan-Aydinol, F Ilter; Yetilmezsoy, Kaan

2010-06-18

77

PVA-gel beads enhance granule formation in a UASB reactor.  

PubMed

PVA-gel beads were used as a biocarrier in a lab-scale UASB reactor treating synthetic wastewater composed of corn steep liquor (CSL) with the aim of evaluating its use as a growth nucleus to enhance granule formation. Over 117 days of operation, the organic loading rate was increased to 22.5kgCOD/m3/day with an influent COD of about 10.8g/L at an HRT of 12h with COD removal efficiencies greater than 87%. By the end of the study period, the PVA-gel turned black and granule formation was achieved as compared with the formation of much fewer natural granules without the PVA-gel nucleus. No filamentous bacteria were found on the surface or interior of the PVA-gel beads. The PVA-gel granules had an average settling velocity 200m/h (5cm/s), and a biomass attachment of 0.93g VSS/g PVA-gel. The required time for formation of PVA-gel granules was thus demonstrated to be shorter than that of ordinary sludge granules under the experimental conditions used in this study. PMID:18400493

Wenjie, Zhang; Dunqiu, Wang; Yasunori, Koga; Taichi, Yamamoto; Li, Zhang; Kenji, Furukawa

2008-04-08

78

Quantification of organic and nitrogen removal in downflow hanging sponge (DHS) systems as a post-treatment of UASB effluent.  

PubMed

The aim of this research was to investigate the nature and composition of organic substrate in two down-flow hanging sponge (DHS) systems using mixed fungal (FDHS) and bacterial (BDHS) cultures treatment for UASB effluent of tapioca starch wastewater, evaluated by COD fractionations and two material balances. The random type DHS reactors were operated as modular columns consisting of four identical segments connected vertically. Results of the wastewater characterization showed that carbonaceous fractions were varied on a function of DHS height. Two balances applied to experimental data were for chemical oxygen demand (COD) and nitrogen (N). Results of mass balance calculations can also be used to examine the process behavior of two DHS systems to improve the organic and nitrogen removal mechanisms. PMID:21045340

Wichitsathian, B; Racho, P

2010-01-01

79

Biogas production from wheat straw in batch and UASB reactors: the roles of pretreatment and seaweed hydrolysate as a co-substrate.  

PubMed

This research evaluated biogas production in batch and UASB reactors from pilot-scale acid catalysed steam pretreated and enzymatic hydrolysed wheat straw. The results showed that the pretreatment was efficient and, a sugar yield of 95% was obtained. The pretreatment improved the methane yield (0.28 m(3)/kg VS(added)) by 57% compared to untreated straw. Treatment of the straw hydrolysate with nutrient supplementation in a UASB reactor resulted in a high methane production rate, 2.70 m(3)/m(3).d at a sustainable OLR of 10.4 kg COD/m(3).d and with a COD reduction of 94%. Alternatively, co-digestion of the straw and seaweed hydrolysates in a UASB reactor also maintained a stable anaerobic process and can thus reduce the cost of nutrients addition. We have shown that biogas production from wheat straw can be competitive by pretreatment, high methane production rate in UASB reactors and also by co-digestion with seaweed hydrolysate. PMID:23196235

Nkemka, Valentine Nkongndem; Murto, Marika

2012-11-02

80

Maximum removal rate of propionic acid as a sole carbon source in UASB reactors and the importance of the macro- and micro-nutrients stimulation  

Microsoft Academic Search

The maximum propionic acid (HPr) removal rate (RHPr) was investigated in two lab-scale Upflow Anaerobic Sludge Bed (UASB) reactors. Two feeding strategies were applied by modifying the hydraulic retention time (HRT) in the UASBHRT and the influent HPr concentration in the UASBHPr, respectively. The experiment was divided into three main phases: phase 1, influent with only HPr; phase 2, HPr

Jingxing Ma; Lucy Jubeki Mungoni; Willy Verstraete; Marta Carballa

2009-01-01

81

Biotic and abiotic processes contribute to successful anaerobic degradation of cyanide by UASB reactor biomass treating brewery waste water.  

PubMed

In contrast to the general aerobic detoxification of industrial effluents containing cyanide, anaerobic cyanide degradation is not well understood, including the microbial communities involved. To address this knowledge gap, this study measured anaerobic cyanide degradation and the rearrangements in bacterial and archaeal microbial communities in an upflow anaerobic sludge blanket (UASB) reactor biomass treating brewery waste water using bio-methane potential assays, molecular profiling, sequencing and microarray approaches. Successful biogas formation and cyanide removal without inhibition were observed at cyanide concentrations up to 5 mg l(-1). At 8.5 mg l(-1) cyanide, there was a 22 day lag phase in microbial activity, but subsequent methane production rates were equivalent to when 5 mg l(-1) was used. The higher cumulative methane production in cyanide-amended samples indicated that part of the biogas was derived from cyanide degradation. Anaerobic degradation of cyanide using autoclaved UASB biomass proceeded at a rate more than two times lower than when UASB biomass was not autoclaved, indicating that anaerobic cyanide degradation was in fact a combination of simultaneous abiotic and biotic processes. Phylogenetic analyses of bacterial and archaeal 16S rRNA genes for the first time identified and linked the bacterial phylum Firmicutes and the archaeal genus Methanosarcina sp. as important microbial groups involved in cyanide degradation. Methanogenic activity of unadapted granulated biomass was detected at higher cyanide concentrations than reported previously for the unadapted suspended biomass, making the aggregated structure and predominantly hydrogenotrophic nature of methanogenic community important features in cyanide degradation. The combination of brewery waste water and cyanide substrate was thus shown to be of high interest for industrial level anaerobic cyanide degradation. PMID:23726700

Novak, Domen; Franke-Whittle, Ingrid H; Pirc, Elizabeta Tratar; Jerman, Vesna; Insam, Heribert; Logar, Romana Marinšek; Stres, Blaž

2013-04-25

82

The techology of wastewater treatment and energy recovery based on UASB reactor  

Microsoft Academic Search

As a kind of high efficient equipment of waster treatment, Up-flow Anaerobic sludge Blanket(UASB)has many advantages, such as effluent quality, steady operation, broad application on treatment high concentration organic wasters. Due to the high COD consistency of the wastewater from starch production, the expense of the treatment are always very high. The paper started with the advantages of Up-flow Anaerobic

Yi Sun; Yu-wen Li

2010-01-01

83

Influence of hydraulic retention time on UASB post-treatment with UF membranes.  

PubMed

A pilot UASB reactor coupled with an external ultrafiltration (UF) membrane was operated under three different hydraulic retention times (HRT) for domestic wastewater treatment. The aim was to assess the HRT influence on system performance and fouling. The highest concentrations of COD, total solids, extracellular polymeric substances (EPS) and soluble microbial products (SMP) in UASB effluent and permeate were found when the UASB reactor was operated under the lowest HRT studied (4 hours); although the fulfillment of Mexican Standard for wastewater reclamation was not compromised. This fact could be attributed to the higher shear stress forces inside the UASB reactor when it was operated at low HRT, which promoted the release of biopolymeric substances in its effluent. Besides, the fouling propensity in the UASB effluent was worsened with HRT reduction, by increasing the fouling rate and the specific cake resistance. Based on these results, it is recommended to avoid operating the UASB reactor at low HRTs (less than 4 hours) in order to control SMP and EPS fouling potential. The results presented also suggest that HRT reduction has a detrimental effect on performance and fouling. PMID:22156136

Salazar-Peláez, M L; Morgan-Sagastume, J M; Noyola, A

2011-01-01

84

A further study of the anaerobic biotreatment of malt whisky distillery pot ale using an UASB system.  

PubMed

Pot ale from a pilot-scale malt whisky distillery was treated using a mesophilic upflow anaerobic sludge blanket (UASB) digester. Stable operation was observed at organic loading rates (OLRs) of 5.46 kg COD/m3 day or less when the pot ale was diluted with tap water. Digester failure occurred when undiluted pot ale was used, even though OLR was less than 5 kg COD/m3 day. Overall performance was worse than that observed previously when UASB digesters were used to treat pot ale from a different source supplemented with trace elements. A substantial proportion of effluent chemical oxygen demand (COD) was present as volatile fatty acids (VFA), particularly during periods of reactor stress, indicating that overall performance was limited by the rate of VFA conversion. Wastewater alkalinity rose during digestion. The sludge which developed in the reactor was flocculent but did not form compact granules. PMID:11333034

Goodwin, J A; Finlayson, J M; Low, E W

2001-06-01

85

Investigation and optimization of the novel UASB-MFC integrated system for sulfate removal and bioelectricity generation using the response surface methodology (RSM).  

PubMed

COD/sulfate ratio and hydraulic residence time (HRT), both of which influence sulfate loadings jointly, are recognized as the most two important affecting factors for sulfate removal and bioelectricity generation in the novel up-flow anaerobic sludge blanket reactor-microbial fuel cell (UASB-MFC) integrated system. The response surface methodology (RSM) was employed for the optimization of this system and the optimum condition with COD/sulfate ratio of 2.3 and HRT of 54.3h was obtained with the target of maximizing the power output. In terms of maximizing the total sulfate removal efficiency, the obtained optimum condition was COD/sulfate ratio of 3.7 and HRT of 55.6h. Experimental results indicated the undistorted simulation and reliable optimized results. These demonstrated that RSM was effective to evaluate and optimize the UASB-MFC system for sulfate removal and energy recovery, providing a promising guide to further improvement of the system for potential applications. PMID:22985846

Zhang, Baogang; Zhang, Jing; Yang, Qi; Feng, Chuanping; Zhu, Yuling; Ye, Zhengfang; Ni, Jinren

2012-08-19

86

Effect of loading rate variation on soybean protein wastewater treatment by UASB reactor  

NASA Astrophysics Data System (ADS)

In order to improve the efficiency and evaluate the feasibility of anaerobic digestion for treatment of soybean protein wastewater. The stability and performance of the Up-Flow Anaerobic Sludge Blanket (UASB) process was investigated at different organic loading rates (OLRS) and hydraulic retention times over 200 days. When chemical oxygen demand (COD) reached maximum, the loading rate was adjusted in a small way and indicators such as VFA, pH and COD in effluent as well as gas production are observed. These experimental results clearly showed that, the most proper corresponding organic loading rate (OLR) and hydraulic retention time were 6 kg/ (m3.d) (COD = 6000 mg/L) and 24 h respectively. Up to 85% of COD was removed and the CH4 production rate of 3.2 m3/(m3.d) was obtained. The produced biogas contained 72% of CH4. In the mean time, anaerobic sludge multiplies more faster and exiguous particles appeared. Granules with diameter 1-3 mm.

Sun, Yi; Li, Yongfeng; Guo, Zi-Rui; Jiao, An-Ying; Han, Wei; Yang, Chuan-Ping

2010-11-01

87

Optimization of linear alkylbenzene sulfonate (LAS) degradation in UASB reactors by varying bioavailability of LAS, hydraulic retention time and specific organic load rate.  

PubMed

Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the bioavailability of LAS based on the concentration of biomass in the system (1.3-16 g TS/L), the hydraulic retention time (HRT), which was operated at 6, 35 or 80 h, and the concentration of co-substrates as specific organic loading rates (SOLR) ranging from 0.03-0.18 g COD/g TVS.d. The highest degradation rate of LAS (76%) was related to the lowest SOLR (0.03 g COD/g TVS.d). Variation of the HRT between 6 and 80 h resulted in degradation rates of LAS ranging from 18% to 55%. Variation in the bioavailability of LAS resulted in discrete changes in the degradation rates (ranging from 37-53%). According to the DGGE profiles, the archaeal communities exhibited greater changes than the bacterial communities, especially in biomass samples that were obtained from the phase separator. The parameters that exhibited more influence on LAS degradation were the SOLR followed by the HRT. PMID:23196232

Okada, Dagoberto Y; Delforno, Tiago P; Esteves, Andressa S; Sakamoto, Isabel K; Duarte, Iolanda C S; Varesche, Maria B A

2012-10-26

88

Fluorescence-based monitoring of tracer and substrate distribution in an UASB reactor.  

PubMed

In this work, rhodamine-related fluorescence was measured on-line at four reactor heights in order to study hydrodynamics within an upflow anaerobic sludge bed reactor. A linear dependence of the dispersion coefficient (D) on the upflow velocity was observed, while the influence of the organic loading rate (OLR) was insignificant. Furthermore, the Bodenstein number of the reactor loaded with granulated sludge was found to be position-dependent with the largest values measured at the bottom of the sludge bed. This trend was not observed in the reactor without sludge. Chemical oxygen demand (COD) and volatile fatty acid (VFA) concentrations were measured at the same reactor heights as in rhodamine tests using conventional off-line analytical methods and on-line multiwavelength fluorometry. Significant spatial COD and VFA gradients were observed at organic loading rates above 6g COD l(R)(-1)d(-1) and linear upflow velocities below 0.8m h(-1). PMID:16674989

Lou, S J; Tartakovsky, B; Zeng, Y; Wu, P; Guiot, S R

2006-05-03

89

Degradation of 2, 4 DCP by sequential biological–advanced oxidation process using UASB and UV\\/TiO 2\\/H 2O 2  

Microsoft Academic Search

Sequential biological–advanced oxidation process (AOP) was taken up in the present work for the degradation of 2, 4 dichlorophenol (2, 4 DCP). Up-flow anaerobic sludge blanket (UASB) reactor and UV\\/H2O2\\/TiO2 system were used to carry out degradation of 2, 4 DCP. Anaerobic pretreatment dehalogenated the parent compound thereby producing lighter and less toxic compounds. UASB system was able to achieve

Abhilasha Dixit; Ashwin J. Tirpude; A. K. Mungray; M. Chakraborty

2011-01-01

90

Co-digestion to support low temperature anaerobic pretreatment of municipal sewage in a UASB-digester.  

PubMed

The aim of this work was to demonstrate that co-digestion improves soluble sewage COD removal efficiency in treatment of low temperature municipal sewage by a UASB-digester system. A pilot scale UASB-digester system was applied to treat real municipal sewage, and glucose was chosen as a model co-substrate. Co-substrate was added in the sludge digester to produce additional methanogenic biomass, which was continuously recycled to inoculate the UASB reactor. Soluble sewage COD removal efficiency increased from 6 to 23%, which was similar to its biological methane potential (BMP). Specific methanogenic activity of the UASB and of the digester sludge at 15°C tripled to a value respectively of 43 and 39mg CH4-COD/(gVSSd). Methane production in the UASB reactor increased by more than 90% due to its doubled methanogenic capacity. Therefore, co-digestion is a suitable approach to support a UASB-digester for pretreatment of low temperature municipal sewage. PMID:24080295

Zhang, Lei; Hendrickx, Tim L G; Kampman, Christel; Temmink, Hardy; Zeeman, Grietje

2013-09-12

91

Syntrophobacter sulfatireducens sp. nov., a novel syntrophic, propionate-oxidizing bacterium isolated from UASB reactors.  

PubMed

Two obligate anaerobes, TB8106(T) and WZH410, which degraded propionate in syntrophic association with methanogens, were isolated from two upflow anaerobic sludge blanket reactors, one treating brewery wastewater and the other bean curd wastewater. The strains were Gram-negative, non-spore-forming and non-motile. Cells were egg-shaped, with a size of 1.0-1.3 x 1.8-2.2 microm. Growth was observed at 20-48 degrees C and pH 6.2-8.8. Both strains converted propionate to acetate and methane in co-culture with methanogens, and grew on propionate plus sulfate in pure culture, with a doubling time of 52-55 h at 37 degrees C. Sulfate and thiosulfate both served as electron acceptors for propionate degradation. The DNA G + C contents of the two strains were 58.5 and 58.7 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strains were closely related to a propionate-oxidizing syntrophic bacterium, Syntrophobacter fumaroxidans DSM 10017(T) (94.7 % similarity). However, the novel strains could not ferment fumarate, and grew at a more alkaline pH range than Syntrophobacter fumaroxidans. Moreover, the novel isolates had obviously higher growth rates on propionate plus sulfate (0.12 day(-1)) than Syntrophobacter fumaroxidans DSM 10017(T) (0.024 day(-1)). Therefore, a novel species, Syntrophobacter sulfatireducens sp. nov., is proposed, with strain TB8106(T) (=AS 1.5016(T) = DSM 16706(T)) as the type strain. PMID:15879275

Chen, Shuangya; Liu, Xiaoli; Dong, Xiuzhu

2005-05-01

92

Proteiniphilum acetatigenes gen. nov., sp. nov., from a UASB reactor treating brewery wastewater.  

PubMed

Two proteolytic, strictly anaerobic bacterial strains (TB107(T) and TB6-6) were isolated from the granule sludge of an upflow anaerobic sludge blanket reactor treating brewery wastewater. The strains were Gram-negative, non-spore-forming and motile. Cells were rod-shaped (0.6-0.9x1.9-2.2 microm). Growth of the strains was observed at 20-45 degrees C and pH 6.0-9.7. The strains were proteolytic. Yeast extract, peptone, pyruvate, glycine and l-arginine could be used as carbon and energy sources. Weak growth was also observed with tryptone, l-serine, l-threonine and l-alanine as carbon and energy sources. Both strains did not use any of the tested carbohydrates, alcohols and fatty acids except pyruvate. Acetic acid and NH3 were produced from yeast extract, peptone and l-arginine, and propionic acid was also produced from yeast extract. Pyruvate was converted to acetic acid and CO2. Gelatin was not hydrolysed. Indole and H2S were not produced. The two strains did not grow in medium containing 20 % bile. Addition of strain TB107T to a syntrophic propionate-degrading co-culture accelerated the propionate-degradation rate. The predominant cellular fatty acid was the branched-chain fatty acid anteiso-C(15 : 0) (46.21 %). The genomic DNA G+C contents of strains TB107T and TB6-6 were 46.6 and 48.9 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the two strains represent a new phyletic sublineage within the Cytophaga-Flavobacterium-Bacteroides (CFB) group, with <91 % 16S rRNA gene sequence similarity to the closest species with validly published names. On the basis of polyphasic evidence from this study, a new genus and species, Proteiniphilum acetatigenes gen. nov., sp. nov., is proposed, with strain TB107T (=JCM 12891T=AS 1.5024T) as the type strain. PMID:16280479

Chen, Shuangya; Dong, Xiuzhu

2005-11-01

93

Nitrogen and sulfide removal from effluent of UASB reactor in a sequencing fed-batch biofilm reactor under intermittent aeration.  

PubMed

Simultaneous nitrification/denitrification (SND) coupled with sulfide oxidation may be suitable for the post treatment of effluents from anaerobic reactors. These effluents contain ammonium, which must be nitrified, and sulfide, which could be used as an endogenous electron donor for autotrophic denitrification. The SND process occurred in a sequencing fed-batch biofilm reactor of 8h cycles, operated under intermittent aeration. The effect of the start-up period and the feeding strategy were evaluated. The previous establishment of nitrification process with subsequent application of sulfide in low concentrations was the best start-up strategy to enable the occurrence of SDN. The fed-batch mode with sulfide application in excess only in the anoxic periods was the best feeding strategy, providing average efficiencies of 85.7% and 53.0% for nitrification and denitrification, respectively. However, the low overall nitrogen removal efficiency and some operational constraints indicated that autotrophic denitrification using sulfide in a single SBR was not suitable for SND under the assayed conditions. PMID:22789473

Moraes, B S; Orrú, J G T; Foresti, E

2012-07-10

94

Aromatic Amine Degradation in a UASB\\/CSTR Sequential System Treating Congo Red Dye  

Microsoft Academic Search

In this study an anaerobic (upflow anaerobic sludge blanket reactor)\\/aerobic (completely stirred tank reactor) sequential system was used to treat a synthetic wastewater with minerals and co-substrate together with 100–4000 mg L of Congo Red dye (Direct red 28) (CR), which is a banned azo dye in Turkey. The effect of hydraulic retention time (HRT) on the decolorization and the COD removal

Mustafa I?ik; Delia Teresa Sponza

2003-01-01

95

Hydrodynamic characteristics of UASB bioreactors.  

PubMed

The hydrodynamic characteristics of UASB bioreactors operated under different organic loading and hydraulic loading rates were studied, using three laboratory scale models treating concocted sucrose wastewater. Residence time distribution (RTD) analysis using dispersion model and tanks-in-series model was directed towards the characterization of the fluid flow pattern in the reactors and correlation of the hydraulic regime with the biomass content and biogas production. Empty bed reactors followed a plug flow pattern and the flow pattern changed to a large dispersion mixing with biomass and gas production. Effect of increase in gas production on the overall hydraulics was insignificant. PMID:23505813

John, Siby; Tare, Vinod

2011-10-01

96

Anaerobic treatment of pre-hydrolysate liquor (PHL) from a rayon grade pulp mill: pilot and full-scale experience with UASB reactors.  

PubMed

Pilot studies were carried out for the treatment of pre-hydrolysate liquor (PHL), a high strength effluent (COD: 70,000-80,000 mg/l) emanating from a rayon grade pulp mill using up-flow anaerobic sludge blanket reactor (UASB). Substrate inhibition was avoided with optimum COD feed of around 25,000 mg/l. This was achieved by diluting the PHL with a low strength effluent stream known as alkali back wash (ABW) available in the plant and also by partially recycling the reactor liquid outlet. An optimum organic loading rate (OLR) of 10 could be achieved with a COD reduction of 70-75%, a BOD reduction of 85-90% and a methane yield of 0.31-0.33 m3/kg of COD reduced. The pilot scale studies also revealed that addition of milk of lime (MOL) was essential for neutralization and buffering and DAP and urea to supplement the nutrients in the PHL. Based on the pilot studies, a full-scale high rate biomethanation plant was designed and erected for treating the PHL, which after some modification showed similar performance for COD, BOD reduction and methane yield. PMID:16330206

Rao, A Gangagni; Bapat, A N

2005-12-02

97

NUCLEAR REACTOR CONTROL SYSTEM  

DOEpatents

A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

Epler, E.P.; Hanauer, S.H.; Oakes, L.C.

1959-11-01

98

Improved vortex reactor system  

DOEpatents

An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.

Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

1995-01-01

99

Effect of effluent recycling and shock loading on the biodegradation of complex phenolic mixture in hybrid UASB reactors.  

PubMed

This study describes the feasibility of anaerobic treatment of synthetic coal wastewater using four identical 13.5L (effective volume) bench scale hybrid up flow anaerobic sludge blanket (HUASB) reactors (R1, R2, R3 and R4) under mesophilic (27+/-5 degrees C) conditions. Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg/L and phenolics concentration of 752 mg/L was used as substrate. Effluent recirculation was employed at four different effluent to feed recirculation ratios (R/F) of 0.5, 1.0, 1.5 and 2.0 for 100 days to study the effect of recirculation on the performance of the reactors. Phenolics and COD removal was found to improve with increase in effluent recirculation. An effluent to feed recycle ratio of 1.0 resulted in maximum removal of phenolics and COD. Phenolics and COD removal improved from 88% and 92% to 95% each, respectively. The concentration of volatile fatty acids in the effluent was lower than the influent when effluent to feed recirculation was employed. Effect of shock loading on the reactors revealed that phenolics shock load up to 2.5 times increase in the normal input phenolics concentration in the form of continuous shock load for 4days did not affect the reactors performance irreversibly. PMID:17714941

Ramakrishnan, Anushuya; Gupta, Sudhir Kumar

2007-08-21

100

Quantitative comparison of stability of ANAMMOX process in different reactor configurations  

Microsoft Academic Search

A new stability evaluating system for ANAMMOX comprising three instability indices i.e. coefficient of variation ratio, coefficient of range ratio and coefficient of regression function derivative was established. Three lab-scale ANAMMOX reactors viz upflow anaerobic sludge blanket (UASB) reactor, upflow stationary fixed film (USFF) reactor and anaerobic sequencing batch reactor (ASBR) were compared for their stability based on the established

Ren-cun Jin; Bao-lan Hu; Ping Zheng; Mahmood Qaisar; An-hui Hu; Ejazul Islam

2008-01-01

101

Reactor vessel support system  

DOEpatents

A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

Golden, Martin P. (Trafford, PA); Holley, John C. (McKeesport, PA)

1982-01-01

102

Improved vortex reactor system  

DOEpatents

An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.

Diebold, J.P.; Scahill, J.W.

1995-05-09

103

NEUTRONIC REACTOR SYSTEM  

DOEpatents

A system is described which includes a neutronic reactor containing a dispersion of fissionable material in a liquid moderator as fuel and a conveyor to which a portion of the dispersion may be passed and wherein the self heat of the slurry evaporates the moderator. Means are provided for condensing the liquid moderator and returning it to the reactor and for conveying the dried fissionable material away from the reactor.

Goett, J.J.

1961-01-24

104

A further study of the anaerobic biotreatment of malt whisky distillery pot ale using an UASB system  

Microsoft Academic Search

Pot ale from a pilot-scale malt whisky distillery was treated using a mesophilic upflow anaerobic sludge blanket (UASB) digester. Stable operation was observed at organic loading rates (OLRs) of 5.46 kg COD\\/m3 day or less when the pot ale was diluted with tap water. Digester failure occurred when undiluted pot ale was used, even though OLR was less than 5

J. A. S. Goodwin; J. M. Finlayson; E. W. Low

2001-01-01

105

Biological hydrogen production in a UASB reactor with granules. I: Physicochemical characteristics of hydrogen-producing granules.  

PubMed

Hydrogen-producing granules with an excellent settling ability were cultivated in an upflow anaerobic sludge blanket reactor treating a sucrose-rich synthetic wastewater. The physicochemical characteristics of granules were evaluated in this study. The mature granules had a diameter ranging from 1.0 to 3.5 mm and an average density of 1.036 +/- 0.005 g/mL, whereas they had good settling ability and a high settling velocity of 32-75 m/h. The low ratio of proteins/carbohydrates for the extracellular polymeric substances (EPS) in the granules suggests that carbohydrates rather than proteins, might play a more important role in the formation of the H(2)-producing granules. The contact angle of the mature granules, 54 +/- 2 degrees , was larger than that of the seed sludge (38 +/- 2 degrees ), indicating that the microbial cells in the H(2)-producing granules had higher hydrophobicity. The granules had fractal nature with a fractal dimension of 1.78. Their porosities were in the range of 0-0.70, and increased with increasing granule size. The ratios between the observed and predicted settling velocities by Stokes' law were in a range of 1.00-1.50, and the fluid collection efficiency of the granules ranged from 0 to 0.19, indicating that their permeabilities were lower and that there was little advective flow through their interior. Experimental results also suggest that molecular diffusion appeared to play an important role in the mass transfer through the H(2)-producing granules. PMID:16615143

Mu, Yang; Yu, Han-Qing

2006-08-01

106

Microbial distribution in UASB granules and its resulting effects  

Microsoft Academic Search

Microscopic (SEM and TEM) examinations of biogranules sampled from various UASB (Upflow Anaerobic Sludge Blanket) reactors indicated that microbes are densely packed. The microbial distribution is strongly dependent upon the degradation thermodynamics and kinetics of individual substrates. Biogranules degrading carbohydrates exhibited typically a layered distribution with a surface layer populated with hydrolytic\\/fermentative acidogens, a mid-layer comprising syntrophic colonies and an

H. H. P. Fang

2000-01-01

107

NEUTRONIC REACTOR SYSTEM  

DOEpatents

A reactor system incorporating a reactor of the heterogeneous boiling water type is described. The reactor is comprised essentially of a core submerged adwater in the lower half of a pressure vessel and two distribution rings connected to a source of water are disposed within the pressure vessel above the reactor core, the lower distribution ring being submerged adjacent to the uppcr end of the reactor core and the other distribution ring being located adjacent to the top of the pressure vessel. A feed-water control valve, responsive to the steam demand of the load, is provided in the feedwater line to the distribution rings and regulates the amount of feed water flowing to each distribution ring, the proportion of water flowing to the submerged distribution ring being proportional to the steam demand of the load. This invention provides an automatic means exterior to the reactor to control the reactivity of the reactor over relatively long periods of time without relying upon movement of control rods or of other moving parts within the reactor structure.

Treshow, M.

1959-02-10

108

MUNICIPAL WASTEWATER TREATMENT IN AN ANAEROBIC DIGESTER?CONSTRUCTED WETLAND SYSTEM  

Microsoft Academic Search

An experimental plant was constituted for an upflow anaerobic sludge blanket (UASB) reactor with an active volume of 25.5 m and two horizontal constructed wetlands of 75 m each. The first wetland was a superficial flow (SF) system and the second a subsurface flow (SSF) system. The UASB reactor was fed with 60–73 m3 d of raw domestic wastewater from

I. Ruiz; J. A. Álvarez; M. A. Díaz; L. Serrano; M. Soto

2008-01-01

109

Strategies for augmenting the pentachlorophenol degradation potential of UASB anaerobic granules.  

PubMed

Anaerobic degradation of pentachlorophenol (PCP) is an example of a process that may benefit from enrichment or bioaugmentation. In one approach, enrichment acceleration was attempted by applying an on-line control-based selective stress strategy to a native anaerobic upflow sludge bed (UASB) system; this strategy linked PCP loading rate to methane production. As a result, the reactor biomass potential for PCP complete dechlorination reached a rate of 4 mg g(-1) volatile suspended solid (VSS) day(-1) within a period of 120 days. In another approach, a pure culture, Desulfitobacterium frappieri PCP-1, a strictly anaerobic Gram-positive bacterium, was used to augment the granular biomass of the UASB reactor. This also resulted in a specific degradation rate of 4 mg PCPg(-1) VSS day(-1); however, this potential was attained within 56 days. Fluorescent in situ hybridization (FISH) showed that the PCP-1 strain was able to rapidly attach to the granule and densely colonize the outer biofilm layer. PMID:12188570

Guiot, S R; Tartakovsky, B; Lanthier, M; Lévesque, M J; Manuel, M F; Beaudet, R; Greer, C W; Villemur, R

2002-01-01

110

UASB Treatment of Methanolic Pulp Wastewater with Addition of Waste Starch and Incinerated Ash  

NASA Astrophysics Data System (ADS)

The pulp wastewater consists mainly of methanol. It is expected to treat using upflow anaerobic sludge blanket (UASB) process. Paper manufactories also produce waste starch and incinerated ash. The integrated treating for these wastes is desirable. In this study, two UASB reactors were operated to treat pulp wastewater with addition of waste starch and with addition of incinerated ash, receptively. Continuous operations of a UASB reactor treating pulp wastewater with addition of waste starch (PS reactor) and a UASB reactor treating pulp wastewater with addition of incinerated ash (PA reactor) , were investigated at mesophilic conditions. The PS reactor performed well with an average 93.7% total CODCr and 97.3% soluble CODCr removal efficiency in average at a maximum volumetric loading rate (VLR) of 16.0 kgCOD/m3/d. The PA reactor was also successfully operated with an average 95.3% total CODCr and 97.5% soluble CODCr removal efficiency in average at a maximum VLR of 14.6 kgCOD/m3/d. Successfully developed granules were obtained after over 140 days of operation in both reactors, and the granules were 1 to 2 mm in mean diameter. Microbial analysis revealed the genus Methanomethylovorans was predominant in the granules of both reactors.

Takahashi, Shintaro; Kobaysashi, Takuro; Li, Yu-You; Harada, Hideki

111

Landfill leachate treatment with combined uasb and fenton coagulation  

Microsoft Academic Search

A two?stage process was developed for the treatment of landfill leachate in Hong Kong. The leachate contained 15700 mg\\/L of chemical oxygen demand (COD) and 2300 mg\\/L of ammonia?nitrogen (NH3?N). In the first stage, it was treated in a UASB (upflow anaerobic sludge blanket) reactor at 37° C. The process removed 89%?91% COD on average within a 6.6 days hydraulic

Peng Wang; Ivan W. C. Lau; Herbert H. P. Fang; Ding Zhou

2000-01-01

112

A built-in zero valent iron anaerobic reactor to enhance treatment of azo dye wastewater.  

PubMed

Waste scrap iron was packed into an upflow anaerobic sludge blanket (UASB) reactor to form a zero valent iron (ZVI) - UASB reactor system for treatment of azo dye wastewater. The ZVI acted as a reductant to decrease ORP in the reactor by more than 40 mv and functioned as an acid buffer to increase the pH in the reactor from 5.44 to 6.29, both of which improved the performance of the anaerobic reactor. As a result, the removal of color and COD in this reactor was 91.7% and 53%, respectively, which was significantly higher than that of a reference UASB reactor without ZVI. The UV-visible spectrum demonstrated that absorption bands of the azo dye from the ZVI-UASB reactor were substantially reduced. The ZVI promoted methanogenesis, which was confirmed by an increase in CH(4) content in the biogas from 47.9% to 64.8%. The ZVI bed was protected well from rusting, which allowed it to function stably. The effluent could be further purified only by pH adjustment because the Fe(2+) released from ZVI served as a flocculent. PMID:21330722

Zhang, Yaobin; Jing, Yanwen; Quan, Xie; Liu, Yiwen; Onu, Pascal

2011-01-01

113

Attrition reactor system  

DOEpatents

A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur. 2 figures.

Scott, C.D.; Davison, B.H.

1993-09-28

114

Community onsite treatment of cold strong sewage in a UASB-septic tank.  

PubMed

Two community onsite UASB-septic tanks namely R1 and R2 were operated under two different HRT (2 days for R1 and 4 days for R2) in parallel over a year and monitored over the cold half of the year. During the monitoring period, the sewage was characterised by a high COD(tot) of 905mg/l with a high fraction of COD(ss), viz. about 43.7%, and rather low temperature of 17.3 degrees C. The achieved removal efficiencies in R1 and R2 for COD(tot), COD(sus), COD(col), COD(dis), BOD(5) and TSS were "51%, 83%, 20%, 24%, 45% and 74%" and "54%, 87%, 10%, 28%, 49% and 78%", respectively. The difference in the removal efficiencies of those parameters in R1 and R2 is marginal and was only significant (p<0.05) for COD(sus). The sludge filling period of the reactors is expected to be 4-7 years. In view of that, the UASB-septic tank system is a robust and compact system as it can be adequately designed in Palestine at 2 days HRT. PMID:18778934

Al-Jamal, Wafa; Mahmoud, Nidal

2008-09-07

115

FLOW SYSTEM FOR REACTOR  

DOEpatents

A reactor is designed with means for terminating the reaction when returning coolant is below a predetermined temperature. Coolant flowing from the reactor passes through a heat exchanger to a lower reservoir, and then circulates between the lower reservoir and an upper reservoir before being returned to the reactor. Means responsive to the temperature of the coolant in the return conduit terminate the chain reaction when the temperature reaches a predetermined minimum value. (AEC)

Zinn, W.H.

1963-06-11

116

ATP content and biomass activity in sequential anaerobic/aerobic reactors.  

PubMed

Specific ATP content of volatile solids was measured to characterize the sludge activity in a sequential an-aerobic/aerobic wastewater treatment system, with an upflow anaerobic sludge blanket (UASB) reactor and a three-phase aerobic fluidized bed (AFB) reactor. The wastewater COD level was 2000-3000 mg/L in simulation of real textile waste-water. The ATP content and the specific ATP contents of volatile solids at different heights of the UASB reactor and those of the suspended and immobilized biomass in the AFB reactor were measured. In the UASB reactor, the maximum value of specific ATP (0.85 mg ATP/g VS) was obtained at a hydraulic retention time (HRT) 7.14 h in the blanket solution. In the AFB reactor, the specific ATP content of suspended biomass was higher than that of immobilized biomass and increased with hydraulic retention time reaching a maximum value of 1.6 mg ATP/g VS at hydraulic retention time 4.35 h. The ATP content of anaerobes in the UASB effluent declined rapidly under aerobic conditions following a 2nd-order kinetic model. PMID:15101110

Chen, Hong

2004-06-01

117

NEUTRONIC REACTOR SYSTEM  

DOEpatents

Gas-cooled solid-moderator type reactors wherein the fissionable fuel and moderator materials are each in the form of solid pebbles, or discrete particles, and are substantially homogeneously mixed in the proper proportion and placed within the core of the reactor are described. The shape of these discrete particles must be such that voids are present between them when mixed together. Helium enters the bottom of the core and passes through the voids between the fuel and moderator particles to absorb the heat generated by the chain reaction. The hot helium gas is drawn off the top of the core and may be passed through a heat exchanger to produce steam.

Daniels, F.

1957-10-15

118

Physicochemical factors affecting the E. coli removal in a rotating biological contactor (RBC) treating UASB effluent  

Microsoft Academic Search

The removal mechanism of E. coli from UASB effluent using a Rotating Biological Contractor (RBC) has been investigated. Preliminary batch experiments in a RBC indicate a first-order removal kinetics. Variation in the dissolved oxygen concentration and E. coli counts over the depth of the RBC has been recorded and indicates that the RBC is not a completely mixed reactor. Therefore

Ahmed Tawfik; Bram Klapwijk; Joost Van Buuren; Fatma El-Gohary; Gatze Lettinga

2004-01-01

119

Comparison of mesophilic and thermophilic upflow anaerobic sludge blanket reactors treating instant coffee production wastewater  

Microsoft Academic Search

Stable anaerobic digestion of settled instant coffee wastewater was achieved for over 100 days in mesophilic (35°C) and termophilic (55°C) UASB reactors. Thermophilic upflow anaerobic sludge blankets (UASBs) were seeded with mesophilic granules and converted to thermophilic operation by raising the temperature to 55°C in one step. Successful thermophilic operation was achieved within 28 days. Both mesophilic and thermophilic UASBs

Richard M. Dinsdale; Freda R. Hawkes; Dennis L. Hawkes

1997-01-01

120

Ultrasonic inspection of reactor systems  

SciTech Connect

The subject of this presentation is ultrasonic inspection of reactor systems. This paper describes two current programs underway at Savannah River Site which provide state-of-the-art ultrasonic inspections of weld heat-affected zones in the primary cooling loop of the Savannah River Site reactors. It also describes the automated remote inspection equipment being developed and employed; briefly describe the procedures being used; and give you a general idea of the future direction of two major programs: Moderator Piping Inspection Program and the Reactor Tank Wall Weld Inspection Program. The objective of these programs is to provide inspection techniques to more fully determine the condition of the reactor primary system and provide data for prediction of maintenance needs and remaining service life. Detection and sizing of intergranular stress corrosion cracking is the focus of these programs.

Majzlik, E.J. Jr.

1989-01-01

121

Automatic reactor protection system tester  

SciTech Connect

In a pressurized water reactor (PWR) plant, the role of protection systems is to continuously monitor reactor physical parameters. If abnormal operating conditions are detected, these systems trigger protective and safeguard actions. On typical 900-MW(electric) PWR units, the reactor protection system consists of more than 30 electrical cabinets per train, i.e., per subsystem part of the safety injection system, each cabinet containing several hundreds of relays. In normal operation, protection systems are on standby. Should one or more of their components fail, this failure could remain undetected. This is why safety authorities require periodic testing of these systems. To eliminate the risk of reactor trip during reactor protection system testing, Framatome has developed a completely automatic tester. Only one technician in the control room is necessary to use this tester, which automatically carries out all the operations previously done manually. For one train, the test lasts only 40 min instead of 10 h. Test sequences are programmed in solid-state memories. The existing relay circuitry of each unit is analyzed beforehand to make any adaptions required by the use of the automatic tester.

Jahnke, S.; Raimondo, E.

1988-01-01

122

Effect of temperature on continuous fermentative lactic acid (LA) production and bacterial community, and development of LA-producing UASB reactor.  

PubMed

A frequently used fermentation manner in lactic acid (LA) production, batch fermentation by pure cultures, has a limited practicability: low volumetric productivity and high energy consumption. In this study, continuous LA fermentation was performed in a completely stirred tank reactor at 12h HRT, inoculated with anaerobic digester sludge. Glucose (25 g COD/L) was used as a feedstock and temperature was increased from 35 to 60°C. LA production significantly increased from 50°C, which was negligible up to 45°C, with obvious bacterial community change. At 50 and 55°C, LA production was maximized, reaching 23 g COD/L, corresponding to 92% LA conversion efficiency. Pyrosequencing analysis showed that microbial diversity was simplified at 50-60°C, and the sequences closely related with Bacillus coagulans became predominant, followed by Lactobacillus fermentum. An LA-producing upflow ananerobic sludge blanket reactor was successfully developed, which enhanced the productivity up to 4.8 gLA/L/h by shortening HRT to 4h. PMID:22750503

Kim, Dong-Hoon; Lim, Wan-Taek; Lee, Mo-Kwon; Kim, Mi-Sun

2012-05-23

123

A new methodology combining PCR, cloning, and sequencing of clones discriminated by RFLP for the study of microbial populations: application to an UASB reactor sample.  

PubMed

This work describes a methodology combining DNA extraction, polymerase chain reaction amplification with primers targeting 16S ribosomal RNA genes, cloning, and sequencing of clones previously analyzed by restriction fragment length polymorphism (RFLP), which can be applied to study the microbial diversity in a given habitat. The methodology allows the minimization of the sequencing effort, which is particularly relevant when analyzing large numbers of clones. The methodology does not require particularly skilled personnel and can easily be adaptable to the molecular characterization of virtually any particular microbial population, provided that both adequate primers and suitable restriction enzymes for RFLP analysis of the clone library have been chosen. An example of application is presented, in which a sample taken from a continuously operating upflow anaerobic sludge blanket reactor was analyzed. RFLP analysis of the initial 162 clones with HaeIII allowed the identification of only 28 distinct profiles. As expected, identical RFLP profiles corresponded to identical nucleotide sequences. PMID:19844706

Ramos, Christian G; Grilo, André M; Sousa, Sílvia A; Barbosa, Marta L; Nadais, Helena; Leitão, Jorge H

2010-01-01

124

Reactor refueling containment system  

DOEpatents

This report describes a method of refueling a nuclear reactor whereby the drive mechanism is disengaged and removed by activating a jacking mechanism that raises the closure head. The area between the barrier plate and closure head is exhausted through the closure head penetrations. The closure head, upper drive mechanism, and bellows seal are lifted away and transported to a safe area. The barrier plate acts as the primary boundary and each drive and control rod penetration has an elastomer seal preventing excessive tritium gases from escaping. The individual instrumentation plugs are disengaged allowing the corresponding fuel assembly to be sealed and replaced.

Gillett, J.E.; Meuschke, R.E.

1992-12-31

125

Reactor core isolation cooling system  

DOEpatents

A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.

Cooke, Franklin E. (San Jose, CA)

1992-01-01

126

Decontaminating reactor coolant systems  

SciTech Connect

Chemical agents and processes that reduce radioactivity levels where people must work make repairs in the coolant circuits of nuclear power reactors faster and less costly. The low-oxidation-state metal ions (LOMI) chemical process quickly dissolves tough corrosion films that hold radioactive isotopes. Radiation fields on pipe surfaces can be cut by a factor of 20 before repair crews go to work. The two-step LOMI process reagents weaken bonds between oxygen and iron atoms by a spontaneous electron transfer from vanadium to iron. This interrupts the lattice, and iron oxide is easily dissolved by picolinic acid. While cost is the prime factor, since exposure limits must be complied with in any event, safety is the ultimate issue, not only in worker health, but in the reliability and quality of the work done under specific time pressures. 4 references, 5 figures.

Whitaker, R.; Wood, C.

1984-06-01

127

Effect of chitosan on UASB treating POME during a transition from mesophilic to thermophilic conditions  

Microsoft Academic Search

The effects of chitosan addition on treatment of palm oil mill effluent were investigated using two lab-scale upflow anaerobic sludge bed (UASB) reactors: (1) with chitosan addition at the dosage of 2mg chitosan per g volatile suspended solids on the first day of the operation (R1), (2) without chitosan addition (the control, R2). The reactors were inoculated with mesophilic anaerobic

Maneerat Khemkhao; Boonyarit Nuntakumjorn; Somkiet Techkarnjanaruk; Chantaraporn Phalakornkule

2011-01-01

128

UASB treatment of wastewater containing concentrated benzoate  

SciTech Connect

The upflow anaerobic sludge blanket (UASB) process removed 97--99% of soluble chemical oxygen demand (COD) from wastewater containing concentrated benzoate at 37 C, pH 7.5, a hydraulic retention time of 9.8 h, and loading rates up to 30.6 g-COD/(L {center_dot} day) based on the reactor volume. About 95.2% of the total COD removed was converted to methane; 0.034 g of volatile suspended solids (VSS) was yielded for each gram of COD removed. The highly settleable granules were 1--3 mm in size with a layered microstructure and were composed in abundance of bacteria resembling the benzoate-degrading Syntrophus buswellii. Two interesting observations have led to the postulation that the degradation of benzoate into acetate was probably conducted completely inside the cell of Syntrophus buswellii-like bacteria: (1) no fatty acids except acetate were found in the effluent; and (2) the granules showed very limited butyrate-degrading capability and could not degrade propionate. This study demonstrated the feasibility of removing aromatic pollutants in wastewater by anaerobic processes.

Li, Y.Y.; Fang, H.H.P.; Chen, T.; Chui, H.K. [Univ. of Hong Kong (Hong Kong). Civil and Structural Engineering Dept.

1995-10-01

129

Solvent refined coal reactor quench system  

DOEpatents

There is described an improved SRC reactor quench system using a condensed product which is recycled to the reactor and provides cooling by evaporation. In the process, the second and subsequent reactors of a series of reactors are cooled by the addition of a light oil fraction which provides cooling by evaporation in the reactor. The vaporized quench liquid is recondensed from the reactor outlet vapor stream.

Thorogood, Robert M. (Macungie, PA)

1983-01-01

130

Solvent refined coal reactor quench system  

DOEpatents

There is described an improved SRC reactor quench system using a condensed product which is recycled to the reactor and provides cooling by evaporation. In the process, the second and subsequent reactors of a series of reactors are cooled by the addition of a light oil fraction which provides cooling by evaporation in the reactor. The vaporized quench liquid is recondensed from the reactor outlet vapor stream. 1 fig.

Thorogood, R.M.

1983-11-08

131

Rapid starting methanol reactor system  

DOEpatents

The invention relates to a methanol-to-hydrogen cracking reactor for use with a fuel cell vehicular power plant. The system is particularly designed for rapid start-up of the catalytic methanol cracking reactor after an extended shut-down period, i.e., after the vehicular fuel cell power plant has been inoperative overnight. Rapid system start-up is accomplished by a combination of direct and indirect heating of the cracking catalyst. Initially, liquid methanol is burned with a stoichiometric or slightly lean air mixture in the combustion chamber of the reactor assembly. The hot combustion gas travels down a flue gas chamber in heat exchange relationship with the catalytic cracking chamber transferring heat across the catalyst chamber wall to heat the catalyst indirectly. The combustion gas is then diverted back through the catalyst bed to heat the catalyst pellets directly. When the cracking reactor temperature reaches operating temperature, methanol combustion is stopped and a hot gas valve is switched to route the flue gas overboard, with methanol being fed directly to the catalytic cracking reactor. Thereafter, the burner operates on excess hydrogen from the fuel cells.

Chludzinski, Paul J. (38 Berkshire St., Swampscott, MA 01907); Dantowitz, Philip (39 Nancy Ave., Peabody, MA 01960); McElroy, James F. (12 Old Cart Rd., Hamilton, MA 01936)

1984-01-01

132

Quality of brackish aquaculture sludge and its suitability for anaerobic digestion and methane production in an upflow anaerobic sludge blanket (UASB) reactor  

Microsoft Academic Search

Intensive recirculating aquaculture systems (RAS) produce high volumes of biosolid waste. The high salinity of brackish\\/marine sludge limits its use in landfill sites and waste outflows and it is a source of pollution. A reduction in sludge mass would therefore minimize the potential environmental hazard and economic burden stemming from its disposal. The aims of the current study were: 1)

Natella Mirzoyan; Shmuel Parnes; Alon Singer; Yossi Tal; Kevin Sowers; Amit Gross

2008-01-01

133

Sedimentological evolution in an UASB treating SYNTHES, a new representative synthetic sewage, at low loading rates.  

PubMed

The changes in the sedimentological attributes of the sludge bed in an upflow anaerobic sludge blanket (UASB) reactor fed with a low-strength wastewater mimicking raw domestic sewage were assessed in this study. The reactor was inoculated with 250 ml of granular sludge from a full-scale UASB reactor. The organic loading rate (OLR) varied from 1 to 2 g COD/ld. During the half-year long study, the reactor was operated at hydraulic retention times (HRTs) of 4.8 and 10 h, at 33 degrees C. Sludge sedimentology showed that the original granular sludge experienced serious instability and disintegration, leading to a much finer final grain assemblage, mainly due to substrate transfer limitation and cell starvation at the interior of larger granules. With time, the size uniformity tended to decrease, sphericity tended to increase, the skewness of the granule size distribution became negative, and the kurtosis became peaked and leptokurtic. In spite of the observed size reduction, reactor efficiency increased to a CODtotal removal of 96%. Biomass (sludge) yield was 0.012 g VS/g COD removed. The CH4 content of the biogas was high (up to 96%). This study thus highlights the treatment of a new type of wastewater with the deployment of the UASB reactor. It also reports the evolutionary trend of the biomass particle size distribution, making reference to a classic sedimentological appraisal. PMID:15062822

Aiyuk, Sunny; Verstraete, Willy

2004-07-01

134

UASB/flash aeration enable complete treatment of municipal wastewater for reuse.  

PubMed

A simple, efficient and cost-effective method for municipal wastewater treatment is examined in this paper. The municipal wastewater is treated using an upflow anaerobic sludge bed (UASB) reactor followed by flash aeration (FA) as the post-treatment, without implementing aerobic biological processes. The UASB reactor was operated without recycle, at hydraulic retention time (HRT) of 8 h and achieved consistent removal of BOD, COD and TSS of 60-70% for more than 12 months. The effect of FA on UASB effluent post-treatment was studied at different HRT (15, 30 and 60 min) and dissolved oxygen (DO) concentrations (low DO = 1-2 mg/L and high DO = 5-6 mg/L). The optimum conditions for BOD, COD and sulfide removal were 30-60 min HRT and high DO concentration inside the FA tank. The final effluent after clarification was characterized by BOD and COD values of 28-35 and 50-58 mg/L, respectively. Sulfides were removed by more than 80%, but the fecal coliform only by ~2 log. The UASB followed by FA is a simple and efficient process for municipal wastewater treatment, except for fecal coliform, enabling water and nutrients recycling to agriculture. PMID:22218993

Khan, Abid Ali; Gaur, Rubia Zahid; Lew, Beni; Diamantis, Vasileios; Mehrotra, Indu; Kazmi, A A

2012-01-05

135

Reactor control rod timing system  

DOEpatents

A fluid driven jet-edge whistle timing system for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.

Wu, Peter T. K. (Clifton Park, NY)

1982-01-01

136

Nuclear reactor degassing method and degassing system  

Microsoft Academic Search

Control rods are inserted into the core of a nuclear reactor in operation to shut down the reactor output. Before completion of entire control rod insertion, a high-temperature coolant flowing in piping for a reactor water clean-up system is sprayed into the space in the upper portion of the reactor vessel. As the space is under negative pressure, oxygen existing

M. Yamamoto; H. Igarashi; S. Mitani; K. Ohsumi; Y. Takashima

1985-01-01

137

ATP content and biomass activity in sequential anaerobic\\/aerobic reactors  

Microsoft Academic Search

Specific ATP content of volatile solids was measured to characterize the sludge activity in a sequential anaerobic\\/aerobic\\u000a wastewater treatment system, with an upflow anaerobic sludge blanket (UASB) reactor and a three-phase aerobic fluidized bed\\u000a (AFB) reactor. The wastewater COD level was 2000–3000 mg\\/L in simulation of real textile waste-water. The ATP content and\\u000a the specific ATP contents of volatile solids

Chen Hong

2004-01-01

138

ATP content and biomass activity in sequential anaerobic\\/aerobic reactors  

Microsoft Academic Search

Specific ATP content of volatile solids was measured to characterize the sludge activity in a sequential an- aerobic\\/aerobic wastewater treatment system, with an upflow anaerobic sludge blanket (UASB) reactor and a three-phase aerobic fluidized bed (AFB) reactor. The wastewater COD level was 2000?3000 mg\\/L in simulation of real textile waste- water. The ATP content and the specific ATP contents of

CHEN Hong

2004-01-01

139

Closed DHS system to prevent dissolved methane emissions as greenhouse gas in anaerobic wastewater treatment by its recovery and biological oxidation.  

PubMed

Anaerobic wastewater treatment has been focused on its eco-friendly nature in terms of the improved energy conservation and reduction in carbon dioxide emissions. However, the anaerobic process discharges unrecovered methane as dissolved methane. In this study, to prevent the emission of dissolved methane from up-flow anaerobic sludge blanket (UASB) reactors used to treat sewage and to recover it as useful gas, we employed a two-stage down-flow hanging sponge (DHS) reactor as a post-treatment of the UASB reactor. The closed DHS reactor in the first stage was intended for the recovery of dissolved methane from the UASB reactor effluent; the reactor could successfully recover an average of 76.8% of the influent dissolved methane as useful gas (containing methane over 30%) with hydraulic retention time of 2 h. During the experimental period, it was possible to maintain the recovered methane concentrations greater than 30% by adjusting the air supply rate. The remaining dissolved methane after the first stage was treated by the next step. The second closed DHS reactor was operated for oxidation of the residual methane and polishing of the remaining organic carbons. The reactor had a high performance and the influent dissolved methane was mostly eliminated to approximately 0.01 mgCOD L(-1). The dissolved methane from the UASB reactor was completely eliminated--by more than 99%--by the post-treatment after the two-stage closed DHS system. PMID:20418639

Matsuura, N; Hatamoto, M; Sumino, H; Syutsubo, K; Yamaguchi, T; Ohashi, A

2010-01-01

140

Evaluation of a Novel Integrated Bioreactor—AOS System for Treating Oil-Containing Restaurant Wastewater on Site in Hong Kong  

Microsoft Academic Search

AOS system is an anaerobic digestion reactor (A-section, UASB or UBF), oxidation degradation reactor (O-section, aerobic biofilm reactor), and physical sedimentation tank (S-section) 3-in-1 integrated reactor. The compact bioreactor was applied to treat oil-containing restaurant's wastewater on site in Hong Kong. The treatment efficiency was observed at different HRT. Experimental results indicated that the AOS system for treating oil-containing restaurant

L. Wang; Q. Zhou; H. Chua

2005-01-01

141

Improvement of COD and color removal from UASB treated poultry manure wastewater using Fenton's oxidation.  

PubMed

The applicability of Fenton's oxidation as an advanced treatment for chemical oxygen demand (COD) and color removal from anaerobically treated poultry manure wastewater was investigated. The raw poultry manure wastewater, having a pH of 7.30 (+/-0.2) and a total COD of 12,100 (+/-910) mg/L was first treated in a 15.7 L of pilot-scale up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated for 72 days at mesophilic conditions (32+/-2 degrees C) in a temperature-controlled environment with three different hydraulic retention times (HRT) of 15.7, 12 and 8.0 days, and with organic loading rates (OLR) between 0.650 and 1.783 kg COD/(m3day). Under 8.0 days of HRT, the UASB process showed a remarkable performance on total COD removal with a treatment efficiency of 90.7% at the day of 63. The anaerobically treated poultry manure wastewater was further treated by Fenton's oxidation process using Fe2+ and H2O2 solutions. Batch tests were conducted on the UASB effluent samples to determine the optimum operating conditions including initial pH, effects of H2O2 and Fe2+ dosages, and the ratio of H2O2/Fe2+. Preliminary tests conducted with the dosages of 100 mg Fe2+/L and 200 mg H2O2/L showed that optimal initial pH was 3.0 for both COD and color removal from the UASB effluent. On the basis of preliminary test results, effects of increasing dosages of Fe2+ and H2O2 were investigated. Under the condition of 400 mg Fe2+/L and 200 mg H2O2/L, removal efficiencies of residual COD and color were 88.7% and 80.9%, respectively. Under the subsequent condition of 100 mg Fe2+/L and 1200 mg H2O2/L, 95% of residual COD and 95.7% of residual color were removed from the UASB effluent. Results of this experimental study obviously indicated that nearly 99.3% of COD of raw poultry manure wastewater could be effectively removed by a UASB process followed by Fenton's oxidation technology used as a post-treatment unit. PMID:17643817

Yetilmezsoy, Kaan; Sakar, Suleyman

2007-06-12

142

Liquid metal cooled nuclear reactor plant system  

DOEpatents

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting for fuel decay during reactor shutdown, or heat produced during a mishap. The reactor system is enhanced with sealing means for excluding external air from contact with the liquid metal coolant leaking from the reactor vessel during an accident. The invention also includes a silo structure which resists attack by leaking liquid metal coolant, and an added unique cooling means.

Hunsbedt, Anstein (Los Gatos, CA); Boardman, Charles E. (Saratoga, CA)

1993-01-01

143

APPLICATION OF THE UASB INOCULATED WITH FLOCCULENT AND GRANULAR SLUDGE IN TREATING SEWAGE AT DIFFERENT HYDRAULIC SHOCK LOADS  

Microsoft Academic Search

In this study the sludge resistant to step and transient hydraulic shock loads have been investigated into two types of sludge, flocculent against granular, in the UASB reactors treating sewage with high solids contents. In this experiment, decreasing in the HRT (step shock loads) was used to examine how far the HRT can be further reduced without considerable change in

Tarek Sabry

2005-01-01

144

Physicochemical factors affecting the E.coli removal in a rotating biological contactor (RBC) treating UASB effluent  

Microsoft Academic Search

The removal mechanism of E. coli from UASB effluent using a Rotating Biological Contractor (RBC) has been investigated. Preliminary batch experiments in a RBC indicate a first-order removal kinetics. Variation in the dissolved oxygen concentration and E. coli counts over the depth of the RBC has been recorded and indicates that the RBC is not a completely mixed reactor. Therefore

A. Tafwik; A. Klapwijk; Buuren van J. C. L; F. El-Gohary; G. Lettinga

2004-01-01

145

UASB treatment of wastewater with VFA and alcohol generated during hydrogen fermentation of food waste  

Microsoft Academic Search

The performance of an upflow anaerobic sludge blanket (UASB) reactor treating wastewater with volatile fatty acids (VFA) and alcohol generated during hydrogen fermentation of food waste was investigated. The chemical oxygen demand (COD) removal efficiency exceeded 96% up to the loading rates of 12.9g COD\\/Ld, corresponding to a food\\/microorganism ratio of 0.61g COD\\/g VSSd. The methane production rate increased to

Sun-Kee Han; Sang-Hyoun Kim; Hang-Sik Shin

2005-01-01

146

Reactor noise in accelerator driven systems  

Microsoft Academic Search

Reactor noise methods have long been used for measuring reactor kinetics parameters in low power critical and sub critical reactors. The recent interest in accelerator driven sub critical systems (ADS) and the necessity of monitoring their degree of sub criticality has created a renewed interest in these methods. In this paper we derive formulae for interpreting some of the classical

S. B. Degweker

2003-01-01

147

A Fail-Safe Reactor Safety System  

Microsoft Academic Search

A highly reliable solid state reactor safety system operated in dynamic mode is described. Direct current signals from detectors for reactor control are converted to pulse signals, which are continuously generated by the circuit until some abnormal condition occurs.The design and construction of several kinds of logic circuits used for reactor control are explained in detail. The fail-safe property of

Tornio TSUNODA; Seiichiro GOTOH; Eiji SUZUKI

1967-01-01

148

Two-stage anaerobic digestion of tomato, cucumber, common reed and grass silage in leach-bed reactors and upflow anaerobic sludge blanket reactors.  

PubMed

Anaerobic digestion of tomato, cucumber, common reed and grass silage was studied in four separate two-stage reactor configuration consisting of leach bed reactor (LBR) and upflow anaerobic sludge blanket reactor (UASB). LBR studies showed that COD solubilization for cucumber and grass silage was higher (50%) than tomato (35%) and common reed (15%). Results also showed that 31-39% of initial TKN present in tomato and cucumber was solubilized in the leachates and 47-54% of the solubilized TKN was converted to NH(4)-N. The corresponding values for common reed and grass silage were 38-50% and 18-36%, respectively. Biomethanation of the leachates in UASB reactors resulted in methane yields of 0.03-0.14 m(3) CH(4) kg(-1)VS(fed) for the studied crop materials. Thus, high COD solubilization, high nitrogen mineralization and solubilization rates were feasible during anaerobic digestion of lignocellulosic materials in a two-stage LBR-UASB reactor system. PMID:21316953

Jagadabhi, Padma Shanthi; Kaparaju, Prasad; Rintala, Jukka

2011-01-22

149

SIMPLIFIED SODIUM GRAPHITE REACTOR SYSTEM  

Microsoft Academic Search

This patent relates to a nuclear power reactor comprising a reactor ; vessel, shielding means positioned at the top of said vessel, means sealing said ; reactor vessel to said shielding means, said vessel containing a quantity of ; sodium, a core tank, unclad graphite moderator disposed in said tank, means ; including a plurality of process tubes traversing said

1963-01-01

150

Two-step upflow anaerobic sludge bed system for sewage treatment under subtropical conditions with posttreatment in waste stabilization ponds.  

PubMed

A pilot-scale sewage treatment system consisting of two upflow anaerobic sludge bed (UASB) reactors followed by five waste stabilization ponds (WSPs) in series was studied under subtropical conditions. The first UASB reactor started up in only 1 mo (stable operation, high chemical oxygen demand [COD] removal efficiency, low volatile fatty acids concentration in the effluent, alkalinity ratio above 0.7, biogas production above 0.1 Nm3/kg of CODremoved). Removal efficiencies up to 90% were obtained in the anaerobic steps at a hydraulic retention time of 6 + 4 h (80% removal in the first step). Fecal coliform removal in the whole system was 99.9999% (99.94% in anaerobic steps and 99.98% in WSPs). COD balances over UASB reactors are provided. A minimum set of data necessary to build COD balances is proposed. Intermittent sludge washout was detected in the reactors with the COD balances. Sludge washout from single-step UASB reactors should be monitored and minimized in order to ensure constant compliance with discharge standards, especially when no posttreatment is provided. The system combined high COD and fecal coliform removal efficiency with an extremely low effluent concentration, complying with discharge standards, and making it an attractive option for sewage treatment in subtropical regions. PMID:12794292

Seghezzo, Lucas; Trupiano, Aníbal P; Liberal, Viviana; Todd, Patrick G; Figueroa, María E; Gutiérrez, Marcelo A; Da Silva Wilches, Ana C; Iribarnegaray, Martín; Guerra, Raquel G; Arena, Angélica; Cuevas, Carlos M; Zeeman, Grietje; Lettinga, Gatze

151

The role of sludge retention time in the hydrolysis and acidification of lipids, carbohydrates and proteins during digestion of primary sludge in CSTR systems  

Microsoft Academic Search

The effect of the sludge retention time (SRT) between 3 and 15days, on hydrolysis, acidification and methanogenesis of domestic sewage was researched by simulating a sludge bed segment of an upflow anaerobic sludge bed (UASB) system as a completely stirred tank reactor (CSTR). The CSTR systems were fed with primary sludge (settled solids of domestic sewage) as the influent at

Yehuda Miron; Grietje Zeeman; Jules B van Lier; Gatze Lettinga

2000-01-01

152

Reactor noise in accelerator driven systems – II  

Microsoft Academic Search

Reactor Noise in accelerator driven systems (ADS) is expected to show differences from critical or radioactive source driven sub-critical systems due to the periodically pulsed source and its non-Poisson character. A theory of ADS Reactor Noise, incorporating these features was worked out by us and has been published earlier. The present paper is a continuation of the earlier work and

S. B. Degweker; Y. S. Rana

2007-01-01

153

TREAT Reactor Control and Protection System  

SciTech Connect

The main control algorithm of the Transient Reactor Test Facility (TREAT) Automatic Reactor Control System (ARCS) resides in Read Only Memory (ROM) and only experiment specific parameters are input via keyboard entry. Prior to executing an experiment, the software and hardware of the control computer is tested by a closed loop real-time simulation. Two computers with parallel processing are used for the reactor simulation and another computer is used for simulation of the control rod system. A monitor computer, used as a redundant diverse reactor protection channel, uses more conservative setpoints and reduces challenges to the Reactor Trip System (RTS). The RTS consists of triplicated hardwired channels with one out of three logic. The RTS is automatically tested by a digital Dedicated Microprocessor Tester (DMT) prior to the execution of an experiment. 6 refs., 5 figs., 1 tab.

Lipinski, W.C.; Brookshier, W.K.; Burrows, D.R.; Lenkszus, F.R.; McDowell, W.P.

1985-01-01

154

Mathematical Modelling of Anaerobic Reactors Treating Domestic Wastewater: Rational Criteria for Model Use  

Microsoft Academic Search

Anaerobic digestion modelling is an established method for assessing anaerobic wastewater treatment for design, systems analysis,\\u000a operational analysis, and control. Anaerobic treatment of domestic wastewater is a relatively new, but rapidly maturing technology,\\u000a especially in developing countries, where the combination of low cost, and moderate-good performance are particularly attractive.\\u000a The key emerging technology is high-rate anaerobic treatment, particularly UASB reactors.

Damien J. Batstone

2006-01-01

155

Cooling system for a nuclear reactor  

DOEpatents

A cooling system for a gas-cooled nuclear reactor is disclosed which includes at least one primary cooling loop adapted to pass coolant gas from the reactor core and an associated steam generator through a duct system having a main circulator therein, and at least one auxiliary cooling loop having communication with the reactor core and adapted to selectively pass coolant gas through an auxiliary heat exchanger and circulator. The main and auxiliary circulators are installed in a common vertical cavity in the reactor vessel, and a common return duct communicates with the reactor core and intersects the common cavity at a junction at which is located a flow diverter valve operative to effect coolant flow through either the primary or auxiliary cooling loops.

Amtmann, Hans H. (Rancho Santa Fe, CA)

1982-01-01

156

SIMPLIFIED SODIUM GRAPHITE REACTOR SYSTEM  

DOEpatents

This patent relates to a nuclear power reactor comprising a reactor vessel, shielding means positioned at the top of said vessel, means sealing said reactor vessel to said shielding means, said vessel containing a quantity of sodium, a core tank, unclad graphite moderator disposed in said tank, means including a plurality of process tubes traversing said tank for isolating said graphite from said sodium, fuel elements positioned in said process tubes, said core tank being supported in spaced relation to the walls and bottom of said reactor vessel and below the level of said sodium, neutron shielding means positioned adjacent said core tank between said core tank and the walls of said vessel, said neutron shielding means defining an annuiar volume adjacent the inside wall of said reactor vessel, inlet plenum means below said core tank for providing a passage between said annular volume and said process tubes, heat exchanger means removably supported from the first-named shielding means and positioned in said annular volume, and means for circulating said sodium over said neutron shielding means down through said heat exchanger, across said inlet plenum and upward through said process tubes, said last-named means including electromagnetic pumps located outside said vessel and supported on said vessel wall between said heat exchanger means and said inlet plenum means. (AEC)

Dickinson, R.W.

1963-03-01

157

Treatment of domestic wastewater in an up-flow anaerobic sludge blanket reactor followed by moving bed biofilm reactor.  

PubMed

The performance of a laboratory-scale sewage treatment system composed of an up-flow anaerobic sludge blanket (UASB) reactor and a moving bed biofilm reactor (MBBR) at a temperature of (22-35 degrees C) was evaluated. The entire treatment system was operated at different hydraulic retention times (HRT's) of 13.3, 10 and 5.0 h. An overall reduction of 80-86% for COD(total); 51-73% for COD(colloidal) and 20-55% for COD(soluble) was found at a total HRT of 5-10 h, respectively. By prolonging the HRT to 13.3 h, the removal efficiencies of COD(total), COD(colloidal) and COD(soluble) increased up to 92, 89 and 80%, respectively. However, the removal efficiency of COD(suspended) in the combined system remained unaffected when increasing the total HRT from 5 to 10 h and from 10 to 13.3 h. This indicates that, the removal of COD(suspended) was independent on the imposed HRT. Ammonia-nitrogen removal in MBBR treating UASB reactor effluent was significantly influenced by organic loading rate (OLR). 62% of ammonia was eliminated at OLR of 4.6 g COD m(-2) day(-1). The removal efficiency was decreased by a value of 34 and 43% at a higher OLR's of 7.4 and 17.8 g COD m(-2) day(-1), respectively. The mean overall residual counts of faecal coliform in the final effluent were 8.9 x 10(4) MPN per 100 ml at a HRT of 13.3 h, 4.9 x 10(5) MPN per 100 ml at a HRT of 10 h and 9.4 x 10(5) MPN per 100 ml at a HRT of 5.0 h, corresponding to overall log(10) reduction of 2.3, 1.4 and 0.7, respectively. The discharged sludge from UASB-MBBR exerts an excellent settling property. Moreover, the mean value of the net sludge yield was only 6% in UASB reactor and 7% in the MBBR of the total influent COD at a total HRT of 13.3 h. Accordingly, the use of the combined UASB-MBBR system for sewage treatment is recommended at a total HRT of 13.3 h. PMID:19404682

Tawfik, A; El-Gohary, F; Temmink, H

2009-04-30

158

REACTOR: An Expert System for Diagnosis and Treatment of Nuclear Reactor Accidents  

Microsoft Academic Search

REACTOR is an expert system under development at EG&G Idaho, Inc., that will assist operators in the diagnosis and treatment of nuclear reactor accidents. This paper covers the background of the nuclear industry and why expert system tech- nology may prove valuable in the reactor control room. Some of the basic features of the REACTOR system are discussed, and future

William R. Nelson

1982-01-01

159

Performance of the PRISM (power reactor - innovative, small module) reactor's passive decay heat removal system  

Microsoft Academic Search

The PRISM (power reactor - innovative, small module) modular reactor concept has a totally passive decay heat removal system referred to as the reactor vessel auxiliary cooling system (RVACS) that rejects heat from the reactor by radiation and natural convection of air. The system is inherently reliable and is not subject to the failure modes commonly associated with active cooling

P. M. Magee; A. Hunsbedt

1989-01-01

160

Flexible Conversion Ratio Fast Reactor Systems Evaluation  

SciTech Connect

Conceptual designs of lead-cooled and liquid salt-cooled fast flexible conversion ratio reactors were developed. Both concepts have cores reated at 2400 MWt placed in a large-pool-type vessel with dual-free level, which also contains four intermediate heat exchanges coupling a primary coolant to a compact and efficient supercritical CO2 Brayton cycle power conversion system. Decay heat is removed passively using an enhanced Reactor Vessel Auxiliary Cooling System and a Passive Secondary Auxiliary Cooling System. The most important findings were that (1) it is feasible to design the lead-cooled and salt-cooled reactor with the flexible conversion ratio (CR) in the range of CR=0 and CR=1 n a manner that achieves inherent reactor shutdown in unprotected accidents, (2) the salt-cooled reactor requires Lithium thermal Expansion Modules to overcme the inherent salt coolant's large positive coolant temperature reactivity coefficient, (3) the preferable salt for fast spectrum high power density cores is NaCl-Kcl-MgCl2 as opposed to fluoride salts due to its better themal-hydraulic and neutronic characteristics, and (4) both reactor, but attain power density 3 times smaller than that of the sodium-cooled reactor.

Neil Todreas; Pavel Hejzlar

2008-06-30

161

Removal of 3-chlorobenzoate using an upflow anaerobic sludge blanket reactor under light conditions.  

PubMed

The possibility of 3-chlorobenzoate removal from water using an upflow anaerobic sludge blanket (UASB) reactor without the addition of any extra dechlorinating culture under light conditions has been studied on a laboratory scale. Benzoate removal was observed in the first three months of operation under light conditions, but the 3-chlorobenzoate removal was not observed. After three months of operation under light conditions, the 3-chlorobenzoate concentration in the UASB reactor effluent gradually decreased to less than 1 mg x h(-1). The 3-chlorobenzoate concentration in the effluent did not increase under dark conditions. The DOC concentration in the effluent decreased according to the removal of the 3-chlorobenzoate by the UASB granules. These results indicated that granules in the UASB reactor provided the 3-chlorobenzoate removability after 80-100 d of adaptation to the 3-chlorobenzoate, and that the UASB reactor is useful for 3-chlorobenzoate removal. PMID:12188536

Sawayama, S; Tsukahara, K; Yagishita, T

2002-01-01

162

Liquid metal fusion reactor systems  

Microsoft Academic Search

The main conceptual designs of liquid metal blanket, methods of pressure drop decrease in the strong magnetic field of the fusion reactor are being discussed. Special features of the flows of electrically conductive fluids in the strong magnetic fields (N? M? 1) are examined. The approximate limits of the transition to the linear (Stokes) flow in the characteristic elements of

B. G. Karasev; A. V. Tananaev

1990-01-01

163

Commercialized fast reactor cycle systems and reactor core performance of the promising fast reactors  

Microsoft Academic Search

The Feasibility Study on Commercialized Fast Reactor (FR) Cycle Systems is under progress in order to propose prominent FR cycle systems that will respond to the diverse needs of society in the future. The design studies on various FR system concepts have been achieved and then the evaluations of potential to achieve the development targets have been also carried out.

Shoji Kotake; Yoshihiko Sakamoto; Yutaka Sagayama

2005-01-01

164

Decolorization and COD reduction of UASB pretreated poultry manure wastewater by electrocoagulation process: A post-treatment study  

Microsoft Academic Search

The performance of electrocoagulation (EC) technique for decolorization and chemical oxygen demand (COD) reduction of anaerobically pretreated poultry manure wastewater was investigated in a laboratory batch study. Two identical 15.7-L up-flow anaerobic sludge blanket (UASB) reactors were first run under various organic and hydraulic loading conditions for 216 days. Effects of operating parameters such as type of sacrificial electrode material,

Kaan Yetilmezsoy; Fatih Ilhan; Zehra Sapci-Zengin; Suleyman Sakar; M. Talha Gonullu

2009-01-01

165

Microchannel Reactor System for Catalytic Hydrogenation  

Microsoft Academic Search

We successfully demonstrated a novel process intensification concept enabled by the;\\u000adevelopment of microchannel reactors, for energy efficient catalytic hydrogenation reactions at;\\u000amoderate temperature, and pressure, and low solvent levels. We designed, fabricated, evaluated,;\\u000aand optimized a laboratory-scale microchannel reactor system for hydrogenation of onitroanisole;\\u000aand a proprietary BMS molecule. In the second phase of the program, as a prelude

Adeniyi Lawal; Woo Lee; Ron Besser; Donald Kientzler; Luke Achenie

2010-01-01

166

Integrated Systems Analysis of the PIUS Reactor.  

National Technical Information Service (NTIS)

Results are presented of a systems failure analysis of the PIUS plant systems that are used during normal reactor operation and postulated accidents. The study was performed to provide the NRC with an understanding of the behavior of the plant. The study ...

R. Fullwood P. Kroeger J. Higgins R. Youngblood H. Cheng

1993-01-01

167

Microrecirculation reactor system for characterization of immobilized enzymes  

Microsoft Academic Search

A differential microrecirculation reactor was developed for kinetic analysis of both soluble and immobilized enzymes. The reactor system was easily fabricated within the laboratory from readily available materials. The disposable, small reactors allowed for in situ weight determination of the enzyme beads. Routinely, only a 1 ml liquid volume of substrate was used for each kinetic assay. The reactor system

James B. Taylor; Harold E. Swaisgood

1980-01-01

168

Reliability Assessment of SMART Reactor Protection System  

SciTech Connect

Component failure rates and integrated system reliability of the SMART reactor protection system were analyzed. The analysis tool of the study was the RELEX 7 computer program developed by Relex Software Corporation. The RELEX software is a PC based computer program which includes the part stress analysis models and the RBD analysis model to calculate component and system reliability. The component failure rate data for the study was selected from the MIL-HDBK-217F. (authors)

Won Young, Yun; Choong Heui, Jeong [Korea Institute of Nuclear Safety, P. O. Box 114, Yusong Post Office, Daejeon (Korea, Republic of); Seong Hun, Kim; Sang Yong, Lee [Sam Chang Enterprise Co. LTD, 974-1, Goyen-ri, Woongchon-myon, Ulju-gun, Ulsan (Korea, Republic of)

2006-07-01

169

Sampling System for a Boiling Reactor NPP.  

National Technical Information Service (NTIS)

Investigations and pilot running of the nuclear power plant with a VK-50 boiling reactor reveal the necessity of normalizing the design system of water sampling and of mandatory replacement of the needle-type throttle device by a helical one. A method for...

A. I. Zabelin E. D. Yakovleva Y. A. Solov'ev

1976-01-01

170

NON-CORROSIVE REACTOR FUEL SYSTEM  

Microsoft Academic Search

A non-corrosive nuclear reactor fuel system was developed utilizing a ; molten plutonium-- iron alloy fuel having about 2 at.% carbon and contained in a ; tantalum vessel. This carbon reacts with the interior surface of the tantalum ; vessel to form a plutonium resistant self-healing tantalum carbide film. (AEC)

Herrick

1962-01-01

171

Reactor control rod timing system. [LMFBR  

DOEpatents

A fluid driven jet-edge whistle timing system is described for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.

Wu, P.T.K.

1980-03-18

172

Control Systems for the KIWI-A Nuclear Reactors  

Microsoft Academic Search

This paper presents an overall picture of the Kiwi-A reactor control systems. The techniques of analysis and design of the control systems, the reactor power and propellant flow rate control hardware, the control system performance during tests, and special measurements made on the control systems to check analytical predictions are discussed. Problems presented by future reactors and some new control

G. K. Hess; H. B. Demuth; E. A. Brown; R. R. Mohler

1962-01-01

173

Reactor based Voltage Regulators for Single Wire Earth Return Systems  

Microsoft Academic Search

Single wire earth return systems, (SWER), are the lowest cost technology for rural power distribution and have global application. Voltage regulation is the determining factor for system capacity for long SWER systems. In long systems, directly connected shunt reactors are often used to compensate the effects of line to ground capacitance. The replacement of fixed shunt reactors with controllable reactors

Peter Wolfs; Steven Senini; Anthony Loveday; Jon Turner; Rockhampton Australia

174

Trip setpoint analysis for the reactor protection system of an advanced integral reactor  

Microsoft Academic Search

The trip setpoints for the reactor protection system of a 65-MWt advanced integral reactor have been analyzed through sensitivity evaluations by using the Transients and Setpoint Simulation\\/System-integrated Modular Reactor code. In the analysis, an inadvertent control rod withdrawal event has been considered as an initiating event because this event results in the worst consequences from the viewpoint of the minimum

Soo Hyung Yang; Soo Hyung Kim; Young Jong Chung; Sung Quun Zee

2007-01-01

175

Fluidized bed reactor system and method having a heat exchanger  

Microsoft Academic Search

A fluidized bed reactor system is described comprising a reactor, means for supporting a fluidized bed of combustible particulate material in said reactor, heat exchange means disposed adjacent said reactor, separating means for receiving a mixture of flue gases and entrained particulate material from said fluidized bed and separating said particulate material from said flue gases, means for passing said

Garcia-Mallol

1993-01-01

176

10 CFR 50.46a - Acceptance criteria for reactor coolant system venting systems.  

Code of Federal Regulations, 2013 CFR

...Acceptance criteria for reactor coolant system venting...Section 50.46a Energy NUCLEAR REGULATORY COMMISSION...Acceptance criteria for reactor coolant system venting systems. Each nuclear power reactor must be provided...

2013-01-01

177

Containment system for supercritical water oxidation reactor  

DOEpatents

A system is described for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary. 2 figures.

Chastagner, P.

1994-07-05

178

Radiolytic production of chemical fuels in fusion reactor systems  

Microsoft Academic Search

Miley's energy flow diagram for fusion reactor systems is extended to include radiolytic production of chemical fuel. Systematic study of the economics and the overall efficiencies of fusion reactor systems leads to a criterion for evaluating the potential of radiolytic production of chemical fuel as a means of enhancing the performance of a fusion reactor system. The ecumenicity of the

Fish

1977-01-01

179

Combination of upflow anaerobic sludge blanket (UASB) and membrane bioreactor (MBR) for berberine reduction from wastewater and the effects of berberine on bacterial community dynamics.  

PubMed

Berberine is a broad-spectrum antibiotic extensively used in personal medication. The production of berberine results in the generation of wastewater containing concentrated residual berberine. However, few related studies up to date focus on berberine removal from wastewaters. In this study, a lab-scale upflow anaerobic sludge blanket (UASB)-membrane bioreactor (MBR) process was developed for berberine removal from synthetic wastewater. The performance of the UASB-MBR system on berberine, COD and NH(4)(+)--N removal was investigated at different berberine loadings. And the effects of berberine on bacterial communities were evaluated using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Results showed that, as the increase of berberine loadings, UASB performance was affected remarkably, whereas, efficient and stable performance of MBR ensured the overall removal rates of berberine, COD and NH(4)(+)--N consistently reached up to 99%, 98% and 98%, respectively. Significant shifts of bacterial community structures were detected in both UASB and MBR, especially in the initial operations. Along with the increase of berberine loadings, high antibiotic resisting species and some functional species, i.e. Acinetobacter sp., Clostridium sp., Propionibacterium sp., and Sphingomonas sp. in UASB, as well as Sphingomonas sp., Methylocystis sp., Hydrogenophaga sp. and Flavobacterium sp. in MBR were enriched in succession. PMID:23280052

Qiu, Guanglei; Song, Yonghui; Zeng, Ping; Duan, Liang; Xiao, Shuhu

2012-12-12

180

Microchannel Reactor System for Catalytic Hydrogenation  

SciTech Connect

We successfully demonstrated a novel process intensification concept enabled by the development of microchannel reactors, for energy efficient catalytic hydrogenation reactions at moderate temperature, and pressure, and low solvent levels. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for hydrogenation of onitroanisole and a proprietary BMS molecule. In the second phase of the program, as a prelude to full-scale commercialization, we designed and developed a fully-automated skid-mounted multichannel microreactor pilot plant system for multiphase reactions. The system is capable of processing 1 – 10 kg/h of liquid substrate, and an industrially relevant immiscible liquid-liquid was successfully demonstrated on the system. Our microreactor-based pilot plant is one-of-akind. We anticipate that this process intensification concept, if successfully demonstrated, will provide a paradigm-changing basis for replacing existing energy inefficient, cost ineffective, environmentally detrimental slurry semi-batch reactor-based manufacturing practiced in the pharmaceutical and fine chemicals industries.

Adeniyi Lawal; Woo Lee; Ron Besser; Donald Kientzler; Luke Achenie

2010-12-22

181

Optimized Battery-Type Reactor Primary System Design Utilizing Lead  

Microsoft Academic Search

A number of small and medium size reactors are being developed worldwide as well as large electricity generation reactors for co-generation, district heating or desalination. The Seoul National University has started to develop 23 MWth BORIS (Battery Optimized Reactor Integral System) as a multi-purpose reactor. BORIS is an integral-type optimized fast reactor with an ultra long life core. BORIS is

Yong H. Yu; Hyoung M. Son; Il S. Lee; Kune Y. Suh

2006-01-01

182

Reactor component inventory system at FFTF  

SciTech Connect

A reliable inventory control system was developed at the Fast Flux Test Facility (FFTF) to keep track of the occupancy of 900 refueling facility locations, to compile historical data on the movement of each reactor assembly, and to simulate assembly moves. The simulate capability is valuable because it allows verification of documents before they are issued for use in the plant, and eliminates the possibility of planning illegal or impossible moves. The system is installed on a UNIVAC 1100 computer and is maintained using a data base management system by Sperry Univac called MAPPER.

Ordonez, C.R.; Redekopp, R.D.; Reed, E.A.

1985-02-01

183

Improving hydrolysis of food waste in a leach bed reactor.  

PubMed

This paper examines the rate of degradation of food waste in a leach bed reactor (LBR) under four different operating conditions. The effects of leachate recirculation at a low and high flow rate are examined with and without connection to an upflow anaerobic sludge blanket (UASB). Two dilution rates of the effective volume of the leach bed reactors were investigated: 1 and 6 dilutions per LBR per day. The increase in dilution rate from 1 to 6 improved the destruction of volatile solids without connection to the UASB. However connection to the UASB greatly improved the destruction of volatile solids (by almost 60%) at the low recirculation rate of 1 dilution per day. The increase in volatile solids destruction with connection to the UASB was attributed to an increase in leachate pH and buffering capacity provided by recirculated effluent from the UASB to the leach beds. The destruction of volatile solids for both the low and high dilution rates was similar with connection to the UASB, giving 82% and 88% volatile solids destruction respectively. This suggests that the most efficient leaching condition is 1 dilution per day with connection to the UASB. PMID:23886490

Browne, James D; Allen, Eoin; Murphy, Jerry D

2013-07-22

184

Reductive decolourisation of sulphonated mono and diazo dyes in one- and two-stage anaerobic systems.  

PubMed

This work assessed the application of one- and two-stage mesophilic anaerobic systems to colour removal of sulphonated mono and diazo dyes with ethanol as electron donor. The dyes Congo Red (CR), Reactive Black 5 (RB5) and Reactive Red 2 (RR2) were selected as model compounds and tested separately in seven different periods. The one-stage system (R(1)) consisted of a single up-flow anaerobic sludge blanket (UASB) reactor, whereas the two-stage system (R(2)) consisted of an acidogenic UASB reactor (R(A)), a settler and a methanogenic UASB reactor (R(M)). For CR and RB5, no remarkable difference was observed between the colour removal performance of both anaerobic systems R(1) and R(2). The experiments with RR2 revealed that R(2) was more efficient on colour removal than R(1), showing efficiencies almost 2-fold (period VI) and 2.5-fold (period VII) higher than those found by R(1). Additionally, R(2) showed a higher stability, giving a good prospect for application to textile wastewaters. Finally, the acidogenic reactor (R(A)) had an important role in the overall decolourisation achieved by R(2) during the experiments with CR and RB5 (>78 %), whereas for RR2, a more recalcitrant dye, R(A) was responsible for up to 38 % of the total colour removal. PMID:23456307

da Silva, Marcos Erick Rodrigues; Firmino, Paulo Igor Milen; dos Santos, André Bezerra

2013-03-03

185

Nuclear reactor pressure vessel support system  

DOEpatents

A support system for nuclear reactor pressure vessels which can withstand all possible combinations of stresses caused by a postulated core disrupting accident during reactor operation. The nuclear reactor pressure vessel is provided with a flange around the upper periphery thereof, and the flange includes an annular vertical extension formed integral therewith. A support ring is positioned atop of the support ledge and the flange vertical extension, and is bolted to both members. The plug riser is secured to the flange vertical extension and to the top of a radially outwardly extension of the rotatable plug. This system eliminates one joint through which fluids contained in the vessel could escape by making the fluid flow path through the joint between the flange and the support ring follow the same path through which fluid could escape through the plug risers. In this manner, the sealing means to prohibit the escape of contained fluids through the plug risers can also prohibit the escape of contained fluid through the securing joint.

Sepelak, George R. (McMurray, PA)

1978-01-01

186

Performance evaluation and operating strategies of dissolved-air flotation system treating poultry slaughterhouse wastewater  

Microsoft Academic Search

The wastewater treatment plant at a poultry slaughterhouse (Céu Azul Alimentos Ltda) comprises a dissolved-air flotation (DAF) system and two upflow anaerobic sludge blanket (UASB) reactors. Diagnosis of the primary treatment unit pointed out the saturation pressure maintained below the recommended values and the non-recycling DAF-effluent as critical points. The DAF system operation, using 24mg Al3+\\/l, polyaluminum chloride (PAC) associated

I. R. de Nardi; T. P. Fuzi; V. Del Nery

2008-01-01

187

Applications of Modern Control Theory to Nuclear Reactor Systems.  

National Technical Information Service (NTIS)

The paper presents a survey of the application of analytical and computational techniques of modern control theory for the estimation, identification and control of nuclear reactor systems. Included are discussions of models for nuclear reactors, optimum ...

A. P. Sage J. L. Melsa

1969-01-01

188

Natural circulating passive cooling system for nuclear reactor containment structure  

Microsoft Academic Search

This paper discusses a passive cooling, natural circulation system. It is for the containment structure of a nuclear reactor plant which is isolated from containment material within the reactor containment and provides overpressure protection within the containment housing.

P. F. Gou; G. E. Wade

1990-01-01

189

The Liquid Annular Reactor System (LARS) propulsion  

NASA Astrophysics Data System (ADS)

A new concept for very high specific impulse (greater than 2,000 seconds) direct nuclear propulsion is described. The concept, termed LARS (Liquid Annular Reactor System) uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (approximately 6,000 K). Operating pressure is moderate (approximately 10 atm), with the result that the outlet hydrogen is virtually 100 percent dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use 7 rotating fuel elements, are beryllium moderated and have critical radii of approximately 100 cm (core L/D is approximately 1.5).

Powell, J.; Ludewig, H.; Horn, F.; Lenard, R.

190

The liquid annular reactor system (LARS) propulsion  

NASA Astrophysics Data System (ADS)

A new concept for very high specific impulse (>~2000 seconds) direct nuclear propulsion is described. The concept, termed LARS (Liquid Annular Reactor System) uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (~6000 K). Operating pressure is moderate (~10 atm), with the result that the outlet hydrogen is virtually 100% dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use 7 rotating fuel elements, are beryllium moderated and have critical radii of ~100 cm (core L/D~=1.5).

Maise, George; Lazareth, Otto W.; Horn, Frederic; Powell, James R.; Ludewig, Hans; Lenard, Roger X.

1991-01-01

191

The Liquid Annular Reactor System (LARS) propulsion  

NASA Astrophysics Data System (ADS)

A new concept for very high specific impulse (greater than 2000 seconds) direct nuclear propulsion is described. The concept, termed LARS (Liquid Annular Reactor System) uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (about 6000 K). Operating pressure is moderate (about 10 atm), with the result that the outlet hydrogen is virtually 100 percent dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use 7 rotating fuel elements, are beryllium moderated and have critical radii of about 100 cm.

Maise, George; Lazareth, Otto W.; Horn, Frederick; Powell, James R.; Ludewig, Hans; Lenard, Roger X.

192

Systems analysis of the CANDU 3 Reactor  

SciTech Connect

This report presents the results of a systems failure analysis study of the CANDU 3 reactor design; the study was performed for the US Nuclear Regulatory Commission. As part of the study a review of the CANDU 3 design documentation was performed, a plant assessment methodology was developed, representative plant initiating events were identified for detailed analysis, and a plant assessment was performed. The results of the plant assessment included classification of the CANDU 3 event sequences that were analyzed, determination of CANDU 3 systems that are ``significant to safety,`` and identification of key operator actions for the analyzed events.

Wolfgong, J.R.; Linn, M.A.; Wright, A.L.; Olszewski, M.; Fontana, M.H. [Oak Ridge National Lab., TN (United States)

1993-07-01

193

Pilot-scale anaerobic treatment of domestic wastewater in upflow anaerobic sludge bed and anaerobic baffled reactors at ambient temperatures  

Microsoft Academic Search

The efficiencies of an upflow anaerobic sludge bed (UASB) reactor and an anaerobic baffled reactor (ABR) were compared for the treatment of domestic wastewater at ambient temperatures. Two pilot-scale anaerobic biological reactors were operated for about two years at ambient conditions at psychrophilic and\\/or sub-mesophilic temperatures. The average total chemical oxygen demand removal was 56 and 58% in the UASB

Selma Ç. Ayaz; Lütfi Akça; Özgür Akta?; Nur F?nd?k; ?zzet Öztürk

2012-01-01

194

Anaerobic treatment of a chemical synthesis-based pharmaceutical wastewater in a hybrid upflow anaerobic sludge blanket reactor  

Microsoft Academic Search

In this study, performance of a lab-scale hybrid up-flow anaerobic sludge blanket (UASB) reactor, treating a chemical synthesis-based pharmaceutical wastewater, was evaluated under different operating conditions. This study consisted of two experimental stages: first, acclimation to the pharmaceutical wastewater and second, determination of maximum loading capacity of the hybrid UASB reactor. Initially, the carbon source in the reactor feed came

Yalcin Askin Oktem; Orhan Ince; Paul Sallis; Tom Donnelly; Bahar Kasapgil Ince

2008-01-01

195

Passive compact molten salt reactor (PCMSR), modular thermal breeder reactor with totally passive safety system  

NASA Astrophysics Data System (ADS)

Design Study Passive Compact Molten Salt Reactor (PCMSR) with totally passive safety system has been performed. The term of Compact in the PCMSR name means that the reactor system is designed to have relatively small volume per unit power output by using modular and integral concept. In term of modular, the reactor system consists of three modules, i.e. reactor module, turbine module and fuel management module. The reactor module is an integral design that consists of reactor, primary and intermediate heat exchangers and passive post shutdown cooling system. The turbine module is an integral design of a multi heating, multi cooling, regenerative gas turbine. The fuel management module consists of all equipments related to fuel preparation, fuel reprocessing and radioactive handling. The preliminary calculations show that the PCMSR has negative temperature and void reactivity coefficient, passive shutdown characteristic related to fuel pump failure and possibility of using natural circulation for post shutdown cooling system.

Harto, Andang Widi

2012-06-01

196

Passive compact molten salt reactor (PCMSR), modular thermal breeder reactor with totally passive safety system  

SciTech Connect

Design Study Passive Compact Molten Salt Reactor (PCMSR) with totally passive safety system has been performed. The term of Compact in the PCMSR name means that the reactor system is designed to have relatively small volume per unit power output by using modular and integral concept. In term of modular, the reactor system consists of three modules, i.e. reactor module, turbine module and fuel management module. The reactor module is an integral design that consists of reactor, primary and intermediate heat exchangers and passive post shutdown cooling system. The turbine module is an integral design of a multi heating, multi cooling, regenerative gas turbine. The fuel management module consists of all equipments related to fuel preparation, fuel reprocessing and radioactive handling. The preliminary calculations show that the PCMSR has negative temperature and void reactivity coefficient, passive shutdown characteristic related to fuel pump failure and possibility of using natural circulation for post shutdown cooling system.

Harto, Andang Widi [Engineering Physics Department, Faculty of Engineering, Gadjah Mada University (Indonesia)

2012-06-06

197

Passive cooling safety system for liquid metal cooled nuclear reactors  

DOEpatents

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of partitions surrounding the reactor vessel in spaced apart relation forming intermediate areas for circulating heat transferring fluid which remove and carry away heat from the reactor vessel. The passive cooling system includes a closed primary fluid circuit through the partitions surrounding the reactor vessel and a partially adjoining secondary open fluid circuit for carrying transferred heat out into the atmosphere.

Hunsbedt, Anstein (Los Gatos, CA); Boardman, Charles E. (Saratoga, CA); Hui, Marvin M. (Sunnyvale, CA); Berglund, Robert C. (Saratoga, CA)

1991-01-01

198

Indirect passive cooling system for liquid metal cooled nuclear reactors  

DOEpatents

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of partitions surrounding the reactor vessel in spaced apart relation forming intermediate areas for circulating heat transferring fluid which remove and carry away heat from the reactor vessel. The passive cooling system includes a closed primary fluid circuit through the partitions surrounding the reactor vessel and a partially adjoining secondary open fluid circuit for carrying transferred heat out into the atmosphere.

Hunsbedt, Anstein (Los Gatos, CA); Boardman, Charles E. (Saratoga, CA)

1990-01-01

199

EFFECT OF STARCH ADDITION ON THE PERFORMANCE AND SLUDGE CHARACTERIZATION OF UASB PROCESS TREATING METHANOLIC WASTEWATER  

NASA Astrophysics Data System (ADS)

A mesophilic(35℃) UASB reactor treating synthetic wastewater containing methanol with addition of starch was continuously operated for over 430 days by changing the organic loading rate from 2.5 to 120kg-COD/m3.d. The microbial community structure of the granules was analyzed with the molecular tools and its metabolic characteristics were evaluated using specific methanogenic activity tests. The process was successfully operated with over 98% soluble COD removal efficiency at VLR 30kg-COD/m3.d for approximately 300 days, and granulation satisfactory proceeded. The results of cloning and fluorescence in situ hybridization analysis suggest that groups related the genus Methanomethylovorans and the genus Methanosaeta were predominant in the reactor although only the genus Methanomethylovorans was predominant in the reactor treating methanolic wastewater in the previous study. Abundance of the granules over 0.5 mm in diameter in the reactor treating methanolic wastewater with addition of starch was 3 times larger than that in the reactor treating methanolic wastewater. Specific methanogenic activity tests in this study indicate that the methanol-methane pathway and the methanol-H2/CO2-methane pathway were predominant, and however, there was a certain level of activity for acetate-methane pathway unlike the reactor treating methanolic wastewater. These results suggest addition of starch might be responsible for diversifying the microbial community and encouraging the granulation.

Yan, Feng; Kobayashi, Takuro; Takahashi, Shintaro; Li, Yu-You; Omura, Tatsuo

200

Nuclear reactor cooling system decontamination reagent regeneration  

DOEpatents

An improved method for decontaminating the coolant system of water-cooled nuclear power reactors and for regenerating the decontamination solution. A small amount of one or more weak-acid organic complexing agents is added to the reactor coolant, and the pH is adjusted to form a decontamination solution which is circulated throughout the coolant system to dissolve metal oxides from the interior surfaces and complex the resulting metal ions and radionuclide ions. The coolant containing the complexed metal ions and radionuclide ions is passed through a strong-base anion exchange resin bed which has been presaturated with a solution containing the complexing agents in the same ratio and having the same pH as the decontamination solution. As the decontamination solution passes through the resin bed, metal-complexed anions are exchanged for the metal-ion-free anions on the bed, while metal-ion-free anions in the solution pass through the bed, thus removing the metal ions and regenerating the decontamination solution.

Anstine, Larry D. (San Jose, CA); James, Dean B. (Saratoga, CA); Melaika, Edward A. (Berkeley, CA); Peterson, Jr., John P. (Livermore, CA)

1985-01-01

201

Sliding mode control of the space nuclear reactor system  

Microsoft Academic Search

The automatic control system (ACS) of the space nuclear reactor power system TOPAZ II that generates electricity from nuclear heat using in-core thermionic converters is considered. Sliding mode control technique is applied to the reactor system controller design in order to improve robustness and accuracy of tracking of a thermal power reference profile in a start-up regime and a payload

Y. B. Shtessel

1998-01-01

202

Space reactor power systems with no single point failures  

Microsoft Academic Search

Nuclear reactor power systems could revolutionize space exploration and support human outpost on the moon and Mars. This paper reviews various energy conversion technologies for use in space reactor power systems and provides estimates of the system's net efficiency and specific power, and the specific area of the radiator. The suitable combinations of the energy conversion technologies and the nuclear

Mohamed S. El-Genk

2008-01-01

203

Neutron Sensors in the SP100 Reactor Control System  

Microsoft Academic Search

The reference reactor control approach for the mature Generic Flight System (GFS) utilizes highly reliable and diversc reactor outlet temperature measurements for control and protection. Although system dynamic analyses demonstrated that this approach is satisfactory for various modes of operation (including transients involving failure or de radation of equipment), the use of a Neutron Monitoring System (NbS) for initial startup

Frank J. Halfen; Sang K. Rhow; John E. Savanyo; Jennifer E. Shelamer

1990-01-01

204

NEUTRONIC REACTOR OPERATIONAL METHOD AND CORE SYSTEM  

DOEpatents

Homogeneous neutronic reactor systems are described wherein an aqueous fuel solution is continuously circulated through a spherical core tank. The pumped fuel solution-is injected tangentially into the hollow spherical interior, thereby maintaining vigorous rotation of the solution within the tank in the form of a vortex; gaseous radiolytic decomposition products concentrate within the axial vortex cavity. The evolved gas is continuously discharged through a gas- outlet port registering with an extremity of the vortex cavity. and the solution stream is discharged through an annular liquid outlet port concentrically encircling the gas outlet by virtue of which the vortex and its cavity are maintained precisely axially aligned with the gas outlet. A primary heat exchanger extracts useful heat from the hot effluent fuel solution before its recirculation into the core tank. Hollow cylinders and other alternative core- tank configurations defining geometric volumes of revolution about a principal axis are also covered. AEC's Homogeneous Reactor Experiment No. 1 is a preferred embodiment.

Winters, C.E.; Graham, C.B.; Culver, J.S.; Wilson, R.H.

1960-07-19

205

Nuclear reactor fuel rod attachment system  

DOEpatents

A reusable system is described for removably attaching a nuclear reactor fuel rod to a support member. A locking cap is secured to the fuel rod and a locking strip is fastened to the support member. The locking cap has two opposing fingers shaped to form a socket having a body portion. The locking strip has an extension shaped to rigidly attach to the socket's body portion. The locking cap's fingers are resiliently deflectable. For attachment, the locking cap is longitudinally pushed onto the locking strip causing the extension to temporarily deflect open the fingers to engage the socket's body portion. For removal, the process is reversed.

Not Available

1980-09-17

206

Nuclear reactor fuel rod attachment system  

DOEpatents

A reusable system for removably attaching a nuclear reactor fuel rod (12) to a support member (14). A locking cap (22) is secured to the fuel rod (12) and a locking strip (24) is fastened to the support member (14). The locking cap (22) has two opposing fingers (24a and 24b) shaped to form a socket having a body portion (26). The locking strip has an extension (36) shaped to rigidly attach to the socket's body portion (26). The locking cap's fingers are resiliently deflectable. For attachment, the locking cap (22) is longitudinally pushed onto the locking strip (24) causing the extension (36) to temporarily deflect open the fingers (24a and 24b) to engage the socket's body portion (26). For removal, the process is reversed.

Christiansen, David W. (Kennewick, WA)

1982-01-01

207

Biological tannery wastewater treatment using two stage UASB reactors  

Microsoft Academic Search

Wastewater discharged from tannery industries is highly complex, concentrated, and toxic. In view of the varying nature of discharged wastewater and the numerous small industries in Egypt, there is a need for highly efficient treatment processes that are simple to operate and have low\\/reasonable construction and operation costs. This study investigated the possibility of applying innovative low cost biological treatment

Mahmoud A. El-Sheikh; Hazem I. Saleh; Joeseph R. Flora; Mahmoud R. AbdEl-Ghany

2011-01-01

208

Long-term adaptation of methanol-fed thermophilic (55 °C) sulfate-reducing reactors to NaCl  

Microsoft Academic Search

A laboratory-scale upflow anaerobic sludge bed (UASB) reactor was operated during 273 days at increasing NaCl concentrations (0.5–12.5 g NaCl l -1) to assess whether the stepwise addition of the salt NaCl results in the acclimation of that sludge. The 6.5-l thermophilic (55 °C), sulfidogenic [a chemical oxygen demand (COD) to SO 4 2- ratio of 0.5] UASB reactor operated at an organic loading

M. V. G. Vallero; G. Lettinga; P. N. L. Lens

2003-01-01

209

Parametric systems analysis of the modular stellarator reactor  

Microsoft Academic Search

The close coupling in the stellarator\\/torsatron\\/heliotron between coil design (winding law, peak field, current density, forces), magnetics topology (transform, shear, well depth) and plasma performance (equilibrium, stability, transport, beta) complicates reactor assessment more than for most magnetic confinement systems. In order to provide an additional degree of resolution of this problem for the Modular Stellarator Reactor (MSR), a parametric systems

R. L. Miller; R. A. Krakowski; C. G. Bathke

1983-01-01

210

High-Temperature Engineering Test Reactor door valve monitor system  

Microsoft Academic Search

This manual describes the detector design features, performance, and operating characteristics of the High-Temperature Engineering Test Reactor (HTTR) Door Valve Monitor System spent-fuel monitor. The HTTR Door Valve Monitor System (HDVM) is installed in the HTTR door valve to provide unattended monitoring data for the transfer of spent fuel through the door valve on the top of the reactor. The

H. O. Menlove; M. E. Abhold; D. H. Beddingfield; K. E. Kroncke; J. Baca; S. Nakagawa

1998-01-01

211

Liquid metal cooled nuclear reactors with passive cooling system  

DOEpatents

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of cooling medium flow circuits which cooperate to remove and carry heat away from the fuel core upon loss of the normal cooling flow circuit to areas external thereto.

Hunsbedt, Anstein (Los Gatos, CA); Fanning, Alan W. (San Jose, CA)

1991-01-01

212

Development of MultiFunctional Telerobotic Systems for Reactor Dismantlement  

Microsoft Academic Search

This report summarizes technological features of advanced telerobotic systems for reactor dismantling application developed at the Japan Atomic Energy Research Institute. Taking into consideration the special environmental conditions in reactor dismantling, major effort was made to develop multifunctional telerobotic system of high reliability which can be used to perform various complex tasks in an unstructured environment and operated in an

Yoshio FUJII; Hozumi USUI; Yoshikuni SHINOHARA

1992-01-01

213

PRISM reactor system design and analysis of postulated unscrammed events  

SciTech Connect

Key safety characteristics of the PRISM reactor system include the passive reactor shutdown characteristics and the passive shutdown heat removal system, RVACS. While these characteristics are simple in principle, the physical processes are fairly complex, particularly for the passive reactor shutdown. It has been possible to adapt independent safety analysis codes originally developed for the Clinch River Breeder Reactor review, although some limitations remain. In this paper, the analyses of postulated unscrammed events are discussed, along with limitations in the predictive capabilities and plans to correct the limitations in the near future. 6 refs., 4 figs.

Van Tuyle, G.J.; Slovik, G.C. (Brookhaven National Lab., Upton, NY (United States)); Rosztoczy, Z.; Lane, J. (Nuclear Regulatory Commission, Washington, DC (United States))

1991-01-01

214

Exhaust system with emissions storage device and plasma reactor  

DOEpatents

An exhaust system for a combustion system, comprising a storage device for collecting NO.sub.x, hydrocarbon, or particulate emissions, or mixture of these emissions, and a plasma reactor for destroying the collected emissions is described. After the emission is collected in by the storage device for a period of time, the emission is then destroyed in a non-thermal plasma generated by the plasma reactor. With respect to the direction of flow of the exhaust stream, the storage device must be located before the terminus of the plasma reactor, and it may be located wholly before, overlap with, or be contained within the plasma reactor.

Hoard, John W. (Livonia, MI)

1998-01-01

215

Design of a 25-kWe Surface Reactor System Based on SNAP Reactor Technologies  

SciTech Connect

A Hastelloy-X clad, sodium-potassium (NaK-78) cooled, moderated spectrum reactor using uranium zirconium hydride (UZrH) fuel based on the SNAP program reactors is a promising design for use in surface power systems. This paper presents a 98 kWth reactor for a power system the uses multiple Stirling engines to produce 25 kWe-net for 5 years. The design utilizes a pin type geometry containing UZrHx fuel clad with Hastelloy-X and NaK-78 flowing around the pins as coolant. A compelling feature of this design is its use of 49.9% enriched U, allowing it to be classified as a category III-D attractiveness and reducing facility costs relative to highly-enriched space reactor concepts. Presented below are both the design and an analysis of this reactor's criticality under various safety and operations scenarios.

Dixon, David D. [Nuclear Systems Design Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Hiatt, Matthew T. [Nuclear Systems Design Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843 (United States); Poston, David I.; Kapernick, Richard J. [Nuclear Systems Design Group, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2006-01-20

216

Design of a 25-kWe Surface Reactor System Based on SNAP Reactor Technologies  

NASA Astrophysics Data System (ADS)

A Hastelloy-X clad, sodium-potassium (NaK-78) cooled, moderated spectrum reactor using uranium zirconium hydride (UZrH) fuel based on the SNAP program reactors is a promising design for use in surface power systems. This paper presents a 98 kWth reactor for a power system the uses multiple Stirling engines to produce 25 kWe-net for 5 years. The design utilizes a pin type geometry containing UZrHx fuel clad with Hastelloy-X and NaK-78 flowing around the pins as coolant. A compelling feature of this design is its use of 49.9% enriched U, allowing it to be classified as a category III-D attractiveness and reducing facility costs relative to highly-enriched space reactor concepts. Presented below are both the design and an analysis of this reactor's criticality under various safety and operations scenarios.

Dixon, David D.; Hiatt, Matthew T.; Poston, David I.; Kapernick, Richard J.

2006-01-01

217

77 FR 36014 - Initial Test Program of Emergency Core Cooling Systems for Boiling-Water Reactors  

Federal Register 2010, 2011, 2012, 2013

...Cooling Systems for Boiling-Water Reactors AGENCY: Nuclear Regulatory Commission...Cooling Systems for Boiling- Water Reactors.'' This guide describes methods...systems (ECCSs) for boiling-water reactors (BWRs). DATES: Submit...

2012-06-15

218

77 FR 15812 - Initial Test Program of Condensate and Feedwater Systems for Light-Water Reactors  

Federal Register 2010, 2011, 2012, 2013

...Feedwater Systems for Light-Water Reactors'' is temporarily identified...systems, including condensate storage and supply, for light-water reactors (LWRs) and for startup...EFW) systems for pressurized- water reactors (PWRs). This...

2012-03-16

219

77 FR 55877 - Initial Test Program of Condensate and Feedwater Systems for Light-Water Reactors  

Federal Register 2010, 2011, 2012, 2013

...Condensate Systems for Boiling Water Reactor Power Plants.'' This...systems in all types of light water reactor facilities; and (2...systems, including condensate storage and supply, for light-water reactors (LWRs) and for...

2012-09-11

220

Autotrophic ammonium removal from reject water: partial nitrification and anammox in one?reactor versus two?reactor systems  

Microsoft Academic Search

Removal of total nitrogen from anaerobically digested sludge reject water by a fully autotrophic process in either one? or two?reactor systems was compared. Autotrophic nitrogen removal is currently most often applied in the one?reactor system primarily in the DEMON configuration. The two?reactor systems had a similar nitrogen removal rate to the one?reactor systems. It was evident that the limiting step

L. W. Jaroszynski; J. A. Oleszkiewicz

2011-01-01

221

Safety and control systems of the Purnima reactor  

Microsoft Academic Search

''PURNIMA'', a zero energy fast reactor, is ine latest addition to the ; family of reactors at Trombay. The extremely small mean prompt neutron life-time ; (1) and a low delayed neutron fraction ( BETA \\/sub eff\\/) of this concentrated Pu\\/; sup 239\\/ fuelled fast critical assembly d emand quick-acting and highly efficient ; control and safety systems. The salient

M. Srinivasan; M. Dharmadhikari; B. N. Karkera; P. N. Mahindroo; A. K. Ray; S. N. Seshadri

1973-01-01

222

Pressurized reactor system and a method of operating the same  

Microsoft Academic Search

A method and apparatus are provided for operating a pressurized reactor system in order to precisely control the temperature within a pressure vessel in order to minimize condensation of corrosive materials from gases on the surfaces of the pressure vessel or contained circulating fluidized bed reactor, and to prevent the temperature of the components from reaching a detrimentally high level,

Isaksson

1996-01-01

223

Fission product scrubbing system for a nuclear reactor  

Microsoft Academic Search

A fission product scrubbing system is described for a nuclear reactor including a containment building defining a containment space for accommodating reactor components, comprising (a) means defining a water tank in the containment building; (b) a dividing wall extending into the water tank for separating the water tank into a first and a second compartment; (c) means defining a collection

1986-01-01

224

Nuclear design analysis of a multicavity gas core reactor system  

Microsoft Academic Search

The Innovative Nuclear Space Power Institute (INSPI) at the University of Florida has undertaken extensive research to establish the scientific feasibility and engineering validation of gaseous core reactor and energy conversion systems that have core power densities of a kilowatt per cubic centimeter and reactor masses of a kilogram per thermal megawatt for burstpower space applications. Gaseous core fission concepts

M. M. Panicker; E. T. Dugan; S. Anghaie

1987-01-01

225

Recent Work on Sodium-Cooled Reactor Purification Systems.  

National Technical Information Service (NTIS)

Fast Flux Test Facility (FFTF) cold traps, including the Reactor Primary Cold Trap, the Reactor Secondary Cold Trap and the Closed Loop Cold Trap were fabricated and their thermal performances measured on sodium test systems. The cold traps all met reacto...

C. C. McPheeters G. R. Bloom

1978-01-01

226

Monitoring circuit for reactor safety systems  

DOEpatents

The ratio between the output signals of a pair of reactor safety channels is monitored. When ratio falls outside of a predetermined range, it indicates that one or more of the safety channels has malfunctioned.

Keefe, Donald J. (Lemont, IL)

1976-01-01

227

Gaseous Fuel Reactors for Power Systems.  

National Technical Information Service (NTIS)

The Los Alamos Scientific Laboratory is participating in a NASA-sponsored program to demonstrate the feasibility of a gaseous uranium fueled reactor. The work is aimed at acquiring experimental and theoretical information for the design of a prototype pla...

H. H. Helmick F. C. Schwenk

1978-01-01

228

A fast shutdown system for SRS (Savannah River Site) reactors  

SciTech Connect

Power has been sharply reduced at Savannah River Site (SRS) reactors in large part to ensure that no bulk boiling occurs during hypothesized loss of coolant accidents. A fast shutdown system is essential to regain much of this lost power. Computations and experiments indicate that a He-3 injection system will serve this function. Instrumented tests of a full system are planned for early 1991 for one of the SRS reactors. 4 refs., 7 figs., 1 tab.

Baumann, N.P.

1990-01-01

229

Applying an electric field in a built-in zero valent iron--anaerobic reactor for enhancement of sludge granulation.  

PubMed

A zero valent iron (ZVI) bed with a pair of electrodes was installed in an upflow anaerobic sludge blanket (UASB) reactor to create an enhanced condition to increase the rate of anaerobic granulation. The effects of an electric field and ZVI on granulation were investigated in three UASB reactors operated in parallel: an electric field enhanced ZVI-UASB reactor (reactor R1), a ZVI-UASB reactor (reactor R2) and a common UASB reactor (reactor R3). When a voltage of 1.4 V was supplied to reactor R1, COD removal dramatically increased from 60.3% to 90.7% over the following four days, while the mean granule size rapidly grew from 151.4 ?m to 695.1 ?m over the following 38 days. Comparatively, COD removal was lower and the increase in granule size was slower in the other two reactors (in the order: R1 > R2 > R3). The electric field caused the ZVI to more effectively buffer acidity and maintain a relatively low oxidation-reduction potential in the reactor. In addition, the electric field resulted in a significant increase in ferrous ion leaching and extracellular polymeric substances (EPS) production. These changes benefited methanogenesis and granulation. Scanning electron microscopy (SEM) images showed that different microorganisms were dominant in the external and internal layers of the reactor R1 granules. Additionally, fluorescence in situ hybridization (FISH) analysis indicated that the relative abundance of methanogens in reactor R1 was significantly greater than in the other two reactors. Taken together, these results suggested that the use of ZVI combined with an electric field in an UASB reactor could effectively enhance the sludge granulation. PMID:20965541

Liu, Yiwen; Zhang, Yaobin; Quan, Xie; Chen, Shuo; Zhao, Huimin

2010-10-19

230

Gas-cooled reactor for space power systems  

NASA Astrophysics Data System (ADS)

Reactor characteristics based on extensive development work on the 500 MWt reactor for the Pluto nuclear ramjet are described for space power systems useful in the range of 2 to 20 MWe for operating time of 1 yr. The modest pressure drop through the prismatic ceramic core is supported at the outlet end by a ceramic dome which also serves as a neutron reflector. Three core materials are considered which are useful at temperatures up to about 2000 K. Most of the calculations are based on a beryllium oxide with uranium dioxide core. Reactor control is accomplished by use of a burnable poison, a variable leakage reflector, and internal control rods. Reactivity swings of 20 percent are obtained with 12 internal boron-10 rods for the size cores studied. Criticality calculations were performed using the ALICE Monte Carlo code. The inherent high temperature capability of the reactor design removes the reactor as a limiting condition on system performance. The low fuel inventories required, particularly for beryllium oxide reactors, make space power systems based on gas cooled near thermal reactors a lesser safeguard risk than those based on fast reactors.

Walter, C. E.; Pearson, J. S.

1987-05-01

231

REACTOR  

DOEpatents

The system conteraplates ohmically heating a gas to high temperatures such as are useful in thermonuclear reactors of the stellarator class. To this end the gas is ionized and an electric current is applied to the ionized gas ohmically to heat the gas while the ionized gas is confined to a central portion of a reaction chamber. Additionally, means are provided for pumping impurities from the gas and for further heating the gas. (AEC)

Spitzer, L. Jr.

1962-01-01

232

Gas-cooled reactor power systems for space  

NASA Astrophysics Data System (ADS)

Large amounts of electric power are required for some of the systems envisioned in support of SDI. Since various applications are being considered, and an overall power architecture study has not been completed, the required power levels and corresponding operating times for specific systems are not known. The characteristics of six designs for power levels of 2, 10 and 20 MWe for operating time of 1 and 7 yrs are described. The operating conditions for these arbitrary designs were chosen to minimize system specific mass. Both gas and liquid cooled reactors are considered. The designs discussed draw heavily on the Pluto project experience. Gas cooled thermal reactors coupled with Brayton cycle power conversion appear to provide reasonable multimegawatt space power systems. An advanced radiation design must be developed which can meet the mass limit assumed. The inherent high temperature capability of the reactors considered removes the reactor as a limiting condition on system performance.

Walter, Carl E.

233

A study of two-stage anaerobic digestion of solid potato waste using reactors under mesophilic and thermophilic conditions.  

PubMed

A two-stage anaerobic digestion process operated under mesophilic and thermophilic conditions was investigated for the treatment of solid potato waste to determine optimal methane yield, efficiency of operation and process stability. A solid-bed reactor was used for hydrolysis/acidification stage while an upflow anaerobic sludge blanket (UASB) reactor was used in the second stage, for methanogenesis. Three sets of conditions were investigated: (1) mesophilic + mesophilic, (II) mesophilic + thermophilic and (III) thermophilic + thermophilic in the hydrolysis/acidification and methanogenesis reactors, respectively. The methane yield was higher under mesophilic conditions (0.49 l CH4 g COD(-1)degraded) than thermophilic conditions (0.41 l CH4 g COD(-1)degraded) with reference to the methanogenic reactors. (COD)--chemical oxygen demand. However, the digestion period was shorter in systems II and III than in system I. Also, in system III the UASB reactor (thermophilic conditions) could handle a higher organic loading rate (OLR) (36 g COD 1(-1)d(-1)) than in system I (11 g COD 1(-1)d(-1)) (mesophilic conditions) with stable operation. Higher OLRs in the methanogenic reactors resulted in reactor failure due to increasing total volatile fatty acid levels. In all systems, the concentration of propionate was one of the highest, higher than acetic acid, among the volatile fatty acids in the effluent. The results show the feasibility of using a two-stage system to treat solid potato waste under both mesophilic and thermophilic conditions. If the aim is to treat solid potato waste completely within a short period of time thermophilic conditions are to be preferred, but to obtain higher methane yield mesophilic conditions are preferable and therefore there is a need to balance methane yield and complete digestion period when dealing with large quantities of solid potato waste. PMID:18290530

Parawira, W; Murto, M; Read, J S; Mattiasson, B

2007-11-01

234

Metrology/viewing system for next generation fusion reactors  

SciTech Connect

Next generation fusion reactors require accurate measuring systems to verify sub-millimeter alignment of plasma-facing components in the reactor vessel. A metrology system capable of achieving such accuracy must be compatible with the vessel environment of high gamma radiation, high vacuum, elevated temperature, and magnetic field. This environment requires that the system must be remotely deployed. A coherent, frequency modulated laser radar system is being integrated with a remotely operated deployment system to meet these requirements. The metrology/viewing system consists of a compact laser transceiver optics module which is linked through fiber optics to the laser source and imaging units that are located outside of the harsh environment. The deployment mechanism is a telescopic-mast positioning system. This paper identifies the requirements for the International Thermonuclear Experimental Reactor metrology and viewing system, and describes a remotely operated precision ranging and surface mapping system.

Spampinato, P.T.; Barry, R.E.; Chesser, J.B.; Menon, M.M. [Oak Ridge National Lab., TN (United States); Dagher, M.A. [Boeing Rocketdyne Div., Canoga Park, CA (United States)

1997-02-01

235

Post Impact Behavior of Mobile Reactor Core Containment Systems.  

National Technical Information Service (NTIS)

The reactor core containment vessel temperatures after impact, and the design variables that affect the post impact survival of the system are analyzed. The heat transfer analysis includes conduction, radiation, and convection in addition to the core mate...

R. L. Puthoff W. G. Parker L. E. Vanbibber

1972-01-01

236

Emergency heat removal system for a nuclear reactor  

DOEpatents

A heat removal system for nuclear reactors serving as a supplement to an Emergency Core Cooling System (ECCS) during a Loss of Coolant Accident (LOCA) comprises a plurality of heat pipes having one end in heat transfer relationship with either the reactor pressure vessel, the core support grid structure or other in-core components and the opposite end located in heat transfer relationship with a heat exchanger having heat transfer fluid therein. The heat exchanger is located external to the pressure vessel whereby excessive core heat is transferred from the above reactor components and dissipated within the heat exchanger fluid.

Dunckel, Thomas L. (Potomac, MD)

1976-01-01

237

Digital, remote control system for a 2-MW research reactor  

SciTech Connect

A fault-tolerant programmable logic controller (PLC) and operator workstations have been programmed to replace the hard-wired relay control system in the 2-MW Bulk Shielding Reactor (BSR) at Oak Ridge National Laboratory. In addition to the PLC and remote and local operator workstations, auxiliary systems for remote operation include a video system, an intercom system, and a fiber optic communication system. The remote control station, located at the High Flux Isotope Reactor 2.5 km from the BSR, has the capability of rector startup and power control. The system was designed with reliability and fail-safe features as important considerations. 4 refs., 3 figs.

Battle, R.E.; Corbett, G.K.

1988-01-01

238

Parametric systems analysis of the Modular Stellarator Reactor (MSR)  

Microsoft Academic Search

The close coupling in the stellarator\\/torsatron\\/heliotron (S\\/T\\/H) between coil design, magnetics topology, and plasma performance complicates the reactor assessment more so than for most magnetic confinement systems. To provide an additional degree of resolution of this problem for the Modular Stellarator Reactor (MSR), a parametric systems model was applied. This model reduces key issues associated with plasma performance, first wall\\/blanket\\/shield

R. L. Miller; R. A. Krakowski; C. G. Bathke

1982-01-01

239

Natural circulating passive cooling system for nuclear reactor containment structure  

DOEpatents

A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

Gou, Perng-Fei (Saratoga, CA); Wade, Gentry E. (Saratoga, CA)

1990-01-01

240

Passive cooling system for nuclear reactor containment structure  

DOEpatents

A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

Gou, Perng-Fei (Saratoga, CA); Wade, Gentry E. (Saratoga, CA)

1989-01-01

241

Reactor systems modeling for ICF hybrids  

SciTech Connect

The computational models of ICF reactor subsystems developed by LLNL and TRW are described and a computer program was incorporated for use in the EPRI-sponsored Feasibility Assessment of Fusion-Fission Hybrids. Representative parametric variations have been examined. Many of the ICF subsystem models are very preliminary and more quantitative models need to be developed and included in the code.

Berwald, D.H.; Meier, W.R.

1980-10-01

242

Autonomous Control of Space Reactor Systems  

SciTech Connect

Autonomous and semi-autonomous control is a key element of space reactor design in order to meet the mission requirements of safety, reliability, survivability, and life expectancy. Interrestrial nuclear power plants, human operators are avilable to perform intelligent control functions that are necessary for both normal and abnormal operational conditions.

Belle R. Upadhyaya; K. Zhao; S.R.P. Perillo; Xiaojia Xu; M.G. Na

2007-11-30

243

Reference Reactor Module for the Affordable Fission Surface Power System  

NASA Astrophysics Data System (ADS)

Surface fission power systems on the Moon and Mars may provide the first US application of fission reactor technology in space since 1965. The requirements of many surface power applications allow the consideration of systems with much less development risk than most other space reactor applications, because of modest power (10s of kWe) and no driving need for minimal mass (allowing temperatures <1000 K). The Affordable Fission Surface Power System (AFSPS) study was completed by NASA/DOE to determine the cost of a modest performance, low-technical risk surface power system. This paper describes the reference AFSPS reactor module concept, which is designed to provide a net power of 40 kWe for 8 years on the lunar surface; note, the system has been designed with technologies that are fully compatible with a Martian surface application. The reactor concept uses stainless-steel based, UO2-fueled, liquid metal-cooled fission reactor coupled to free-piston Stirling converters. The reactor shielding approach utilizes both in-situ and launched shielding to keep the dose to astronauts much lower than the natural background radiation on the lunar surface. One of the important ``affordability'' attributes is that the concept has been designed to minimize both the technical and programmatic safety risk.

Poston, David I.; Kapernick, Richard J.; Dixon, David D.; Amiri, Benjamin W.; Marcille, Thomas F.

2008-01-01

244

Reference Reactor Module for the Affordable Fission Surface Power System  

SciTech Connect

Surface fission power systems on the Moon and Mars may provide the first US application of fission reactor technology in space since 1965. The requirements of many surface power applications allow the consideration of systems with much less development risk than most other space reactor applications, because of modest power (10s of kWe) and no driving need for minimal mass (allowing temperatures <1000 K). The Affordable Fission Surface Power System (AFSPS) study was completed by NASA/DOE to determine the cost of a modest performance, low-technical risk surface power system. This paper describes the reference AFSPS reactor module concept, which is designed to provide a net power of 40 kWe for 8 years on the lunar surface; note, the system has been designed with technologies that are fully compatible with a Martian surface application. The reactor concept uses stainless-steel based, UO{sub 2}-fueled, liquid metal-cooled fission reactor coupled to free-piston Stirling converters. The reactor shielding approach utilizes both in-situ and launched shielding to keep the dose to astronauts much lower than the natural background radiation on the lunar surface. One of the important 'affordability' attributes is that the concept has been designed to minimize both the technical and programmatic safety risk.

Poston, David I.; Kapernick, Richard J.; Dixon, David D.; Amiri, Benjamin W.; Marcille, Thomas F. [Nuclear Systems Design Group, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545 (United States)

2008-01-21

245

Gas-cooled reactor power systems for space  

SciTech Connect

In this paper the characteristics of six designs for power levels of 2, 10, and 20 MWe for operating times of 1 and 7 y are described. The operating conditions for these arbitrary designs were chosen to minimize system specific mass. The designs are based on recent work which benefits from earlier analyses of nuclear space power systems conducted at our Laboratory. Both gas- and liquid-cooled reactors had been considered. Pitts and Walter (1970) reported on the results of a detailed study of a 10-MWe lithium-cooled reactor in a potassium Rankine system. Unpublished results (1966) of a computer analysis provide details of an argon-cooled reactor in an argon Brayton system. The gas-cooled reactor design was based on extensive development work on the 500-MWth reactor for the nuclear ramjet (Pluto) as described by Walter (1964). The designs discussed here draw heavily on the Pluto project experience, which culminated in a successful full-power ground test as reported by Reynolds (1964). At higher power levels gas-cooled reactors coupled with Brayton systems with advanced radiator designs become attractive.

Walter, C.E.

1987-01-01

246

Granulation of Anammox microorganisms in up-flow reactors  

Microsoft Academic Search

Experimental studies were performed to evaluate the feasibility of granulation of Anammox microorganisms for biomass retention in up-flow reactors. Two experimental studies, one using a 6.4-L lab-scale reactor with synthetic medium and the other using a 200-L pilot-scale reactor with half-nitrified reject water from a sludge digester were conducted. To enhance the granulation process, seed granules from a UASB reactor

U. Imajo; T. Tokutomi; K. Furukawa

2004-01-01

247

New reactor technology: safety improvements in nuclear power systems.  

PubMed

Almost 450 nuclear power plants are currently operating throughout the world and supplying about 17% of the world's electricity. These plants perform safely, reliably, and have no free-release of byproducts to the environment. Given the current rate of growth in electricity demand and the ever growing concerns for the environment, nuclear power can only satisfy the need for electricity and other energy-intensive products if it can demonstrate (1) enhanced safety and system reliability, (2) minimal environmental impact via sustainable system designs, and (3) competitive economics. The U.S. Department of Energy with the international community has begun research on the next generation of nuclear energy systems that can be made available to the market by 2030 or earlier, and that can offer significant advances toward these challenging goals; in particular, six candidate reactor system designs have been identified. These future nuclear power systems will require advances in materials, reactor physics, as well as thermal-hydraulics to realize their full potential. However, all of these designs must demonstrate enhanced safety above and beyond current light water reactor systems if the next generation of nuclear power plants is to grow in number far beyond the current population. This paper reviews the advanced Generation-IV reactor systems and the key safety phenomena that must be considered to guarantee that enhanced safety can be assured in future nuclear reactor systems. PMID:18049233

Corradini, M L

2007-11-01

248

[Effect of pilot UASB-SFSBR-MAP process for the large scale swine wastewater treatment].  

PubMed

In this paper, a treatment process consisted of UASB, step-fed sequencing batch reactor (SFSBR) and magnesium ammonium phosphate precipitation reactor (MAP) was built to treat the large scale swine wastewater, which aimed at overcoming drawbacks of conventional anaerobic-aerobic treatment process and SBR treatment process, such as the low denitrification efficiency, high operating costs and high nutrient losses and so on. Based on the treatment process, a pilot engineering was constructed. It was concluded from the experiment results that the removal efficiency of COD, NH4(+) -N and TP reached 95.1%, 92.7% and 88.8%, the recovery rate of NH4(+) -N and TP by MAP process reached 23.9% and 83.8%, the effluent quality was superior to the discharge standard of pollutants for livestock and poultry breeding (GB 18596-2001), mass concentration of COD, TN, NH4(+) -N, TP and SS were not higher than 135, 116, 43, 7.3 and 50 mg x L(-1) respectively. The process developed was reliable, kept self-balance of carbon source and alkalinity, reached high nutrient recovery efficiency. And the operating cost was equal to that of the traditional anaerobic-aerobic treatment process. So the treatment process could provide a high value of application and dissemination and be fit for the treatment pf the large scale swine wastewater in China. PMID:23745404

Wang, Liang; Chen, Chong-Jun; Chen, Ying-Xu; Wu, Wei-Xiang

2013-03-01

249

Architecture of the ETR (experimental test reactor) systems code  

SciTech Connect

TETRA, a tokamak systems code capable of modeling experimental test reactors (ETRs), was developed in a joint effort by participants of the fusion community. The first version of this code was constructed to model devices similar to the Tokamak Ignition/Burn Engineering Reactor (TIBER) in configuration and design. A major feature of this code is its ability to perform optimization studies. Future work will include broadening the scope of the code, particularly in the area of materials selection, to more accurately simulate tokamak configurations such as the Next European Torus (NET) and the Fusion Engineering Reactor (FER). 18 refs., 2 figs., 4 tabs.

Reid, R.L.; Galambos, J.D.

1987-01-01

250

Air systems problems at US light water reactors  

Microsoft Academic Search

This paper provides a review and evaluation of the potential safety implications associated with air system problems at US light water reactors. It provides an analysis of operating data, focusing on degraded air systems and the vulnerability of safety-related equipment to common-mode failures associated with air systems. The data are analyzed from the perspectives of trends and patterns, risk assessments,

Ornstein

1987-01-01

251

Prospective Nuclear Reactor Power Systems for Space Based Radar Missions.  

National Technical Information Service (NTIS)

This document summarizes the characteristics of 10 kW(e) and 50 kW(e) space reactor power systems utilizing four types of power conversion systems. The Brayton, organic Rankine and thermoelectric systems represent near-to-intermediate term technologies. O...

1975-01-01

252

A Theory of Reactor Diagnosis in Feedback Systems  

Microsoft Academic Search

A unified theory is presented for diagnosis of power reactors with feedback mechanism. In terms of correlation functions calculated from stationary time series data, a feedback system can be expressed by an equivalent innovation model. From the formalism the identifiability of open loop transfer functions in the feedback system is discussed under conditions; (1) the minimum phase system, (2) the

Kuniharu KISHIDA; Nobuhide SUDA

1994-01-01

253

The feasibility study on perfect burning reactor system  

Microsoft Academic Search

The system of 100% natural uranium burning with once-through fuel cycle is defined as the Perfect Burning Reactor System (PBRS). This kind of nuclear system can be expected to have some good characteristic such as resource efficiency, radiotoxicity reduction, proliferation and nuclear safety. Therefore, the feasibility of the concept is studied in this paper. The preliminary results show that the

Nobuo Nakae

2005-01-01

254

Thermal Stress Calculations for Heatpipe-Cooled Reactor Power Systems  

NASA Astrophysics Data System (ADS)

A heatpipe-cooled fast reactor concept has been under development at Los Alamos National Laboratory for the past several years, to be used as a power source for nuclear electric propulsion (NEP) or as a planetary surface power system. The reactor core consists of an array of modules that are held together by a core lateral restraint system. Each module includes a single heatpipe surrounded by 3-6 clad fuel pins. As part of this development effort, a partial array of a candidate heatpipe-cooled reactor is to be tested in the SAFE-100 experimental program at the Marshall Space Flight Center. The partial array comprises 19 3-pin modules, which are powered by resistance heaters. This paper describes the analyses that were performed in support of this test program, to assess thermal and structural performance and to specify the test conditions needed to simulate reactor operating conditions.

Kapernick, Richard J.; Guffee, Ray M.

2003-01-01

255

Simulation of the modified K reactor supplementary safety system  

SciTech Connect

The supplementary safety system (SSS) of the K reactor provides a second line of defense to shut down the reactor if the safety and control rods fail to scram. The SSS was originally designed to inject a neutron poison solution (ink) into the reactor tank via spargers. Recently, concerns arose that the ink inventory might run out before the ink front returned to the moderator during a loss-of-ac-power transient in which the coolant pumps coast down. Thus, a new system has been added to inject additional ink through the pump suctions so that ink will arrive in the core before depletion of the sparger ink. The MODFLOW code was developed to calculate the moderator flow distribution in Savannah River site (SRS) reactors, including the effects of inertia and stratification from buoyancy forces.

Paik, I.K.; Canas, L.R. (Westinghouse Savannah River Co., Aiken, SC (United States)); Peterson, P.F. (Univ. of California, Berkeley (United States))

1991-01-01

256

Light Water Reactor-Pressure Vessel Surveillance project computer system  

SciTech Connect

A dedicated process control computer has been implemented for regulating the metallurgical Pressure Vessel Wall Benchmark Facility (PSF) at the Oak Ridge Research Reactor. The purpose of the PSF is to provide reliable standards and methods by which to judge the radiation damage to reactor pressure vessel specimens. Benchmark data gathered from the PSF will be used to improve and standardize procedures for assessing the remaining safe operating lifetime of aging reactors. The computer system controls the pressure vessel specimen environment in the presence of gamma heating so that in-vessel conditions are simulated. Instrumented irradiation capsules, in which the specimens are housed, contain temperature sensors and electrical heaters. The computer system regulates the amount of power delivered to the electrical heaters based on the temperature distribution within the capsules. Time-temperature profiles are recorded along with reactor conditions for later correlation with specimen metallurgical changes.

Merriman, S.H.

1980-10-01

257

Fluid flow distribution system for fluidized bed reactor  

SciTech Connect

This patent describes an improved flow distribution system for a catalytic reactor plenum chamber for a gas-liquid-solids ebulated bed reactor. It includes a baffled nozzle device containing at least two baffle plates usually oriented substantially normal to the nozzle inlet flow direction for providing good mixing and uniform flow distribution of gas-liquid materials in the lower portion of the plenum. It is used in a combination with distribution grid to effect a substantially uniform flow distribution of the gas/liquid mixture upwardly into the ebullated catalyst bed. A sparger can be provided in the plenum above the baffled flow distributor device for feeding additional gas-liquid mixture into the reactor. The flow distribution system provides a substantially uniform flow distribution of the gas-liquid mixture into the ebullated bed and thereby provides fouling-free operation of the reactor.

Li, A.S.; Eccles, R.M.

1987-10-27

258

Fuel systems for compact fast space reactors  

SciTech Connect

About 200 refractory metal clad ceramic fuel pins have been irradiated in thermal reactors under the 1200 K to 1550 K cladding temperature conditions of primary relevance to space reactors. This paper reviews performance with respect to fissile atom density, operating temperatures, fuel swelling, fission gas release, fuel-cladding compatibility, and consequences of failure. It was concluded that UO/sub 2/ and UN fuels show approximately equal performance potential and that UC fuel has lesser potential. W/Re alloys have performed quite well as cladding materials, and Ta, Nb, and Mo/Re alloys, in conjunction with W diffusion barriers, show good promise. Significant issues to be addressed in the future include high burnup swelling of UN, effects of UO/sub 2/-Li coolant reaction in the event of fuel pin failure, and development of an irradiation performance data base with prototypically configured fuel pins irradiated in a fast neutron flux.

Cox, C.M.; Dutt, D.S.; Karnesky, R.A.

1983-12-01

259

Development of a microchannel catalytic reactor system  

Microsoft Academic Search

The purpose of this article is to demonstrate the applicability of microreactors for use in catalytic reactions at elevated\\u000a temperatures. Microchannels were fabricated on both sides of a silicon wafer by wet chemical etching after pattern transfer\\u000a using a negative photoresist. The walls of the reactor channel were coated with a platinum layer, for use as a sample catalyst,\\u000a by

Katsuki Kusakabe; Shigeharu Morooka; Hideaki Maeda

2001-01-01

260

Nuclear reactor heat transport system component low friction support system  

DOEpatents

A support column for a heavy component of a liquid metal fast breeder reactor heat transport system which will deflect when the pipes leading coolant to and from the heavy component expand or contract due to temperature changes includes a vertically disposed pipe, the pipe being connected to the heavy component by two longitudinally spaced cycloidal dovetail joints wherein the distal end of each of the dovetails constitutes a part of the surface of a large diameter cylinder and the centerlines of these large diameter cylinders intersect at right angles and the pipe being supported through two longitudinally spaced cycloidal dovetail joints wherein the distal end of each of the dovetails constitutes a part of the surface of a large diameter cylinder and the centerlines of these large diameter cylinders intersect at right angles, each of the cylindrical surfaces bearing on a flat and horizontal surface.

Wade, Elman E. (Ruffs Dale, PA)

1980-01-01

261

Fluid flow distribution system for fluidized bed reactor  

Microsoft Academic Search

This patent describes an improved flow distribution system for a catalytic reactor plenum chamber for a gas-liquid-solids ebulated bed reactor. It includes a baffled nozzle device containing at least two baffle plates usually oriented substantially normal to the nozzle inlet flow direction for providing good mixing and uniform flow distribution of gas-liquid materials in the lower portion of the plenum.

A. S. Li; R. M. Eccles

1987-01-01

262

Conceptual Design of a Lunar Regolith Clustered-Reactor System  

Microsoft Academic Search

It is proposed that a fast-fission, heatpipe-cooled, lunar-surface power reactor system be divided into subcritical units that could be launched safely without the incorporation of additional spectral shift absorbers or other complex means of control. The reactor subunits are to be emplaced directly into the lunar regolith utilizing the regolith not just for shielding but as the reflector material to

John Darrell Bess

2009-01-01

263

The combined hybrid system: A symbiotic thermal reactor/fast reactor system for power generation and radioactive waste toxicity reduction  

SciTech Connect

If there is to be a next generation of nuclear power in the United States, then the four fundamental obstacles confronting nuclear power technology must be overcome: safety, cost, waste management, and proliferation resistance. The Combined Hybrid System (CHS) is proposed as a possible solution to the problems preventing a vigorous resurgence of nuclear power. The CHS combines Thermal Reactors (for operability, safety, and cost) and Integral Fast Reactors (for waste treatment and actinide burning) in a symbiotic large scale system. The CHS addresses the safety and cost issues through the use of advanced reactor designs, the waste management issue through the use of actinide burning, and the proliferation resistance issue through the use of an integral fuel cycle with co-located components. There are nine major components in the Combined Hybrid System linked by nineteen nuclear material mass flow streams. A computer code, CHASM, is used to analyze the mass flow rates CHS, and the reactor support ratio (the ratio of thermal/fast reactors), IFR of the system. The primary advantages of the CHS are its essentially actinide-free high-level radioactive waste, plus improved reactor safety, uranium utilization, and widening of the option base. The primary disadvantages of the CHS are the large capacity of IFRs required (approximately one MW{sub e} IFR capacity for every three MW{sub e} Thermal Reactor) and the novel radioactive waste streams produced by the CHS. The capability of the IFR to burn pure transuranic fuel, a primary assumption of this study, has yet to be proven. The Combined Hybrid System represents an attractive option for future nuclear power development; that disposal of the essentially actinide-free radioactive waste produced by the CHS provides an excellent alternative to the disposal of intact actinide-bearing Light Water Reactor spent fuel (reducing the toxicity based lifetime of the waste from roughly 360,000 years to about 510 years).

Hollaway, W.R.

1991-08-01

264

Advanced Fuel Cycle Economic Analysis of Symbiotic Light-Water Reactor and Fast Burner Reactor Systems  

SciTech Connect

The Advanced Fuel Cycle Economic Analysis of Symbiotic Light-Water Reactor and Fast Burner Reactor Systems, prepared to support the U.S. Advanced Fuel Cycle Initiative (AFCI) systems analysis, provides a technology-oriented baseline system cost comparison between the open fuel cycle and closed fuel cycle systems. The intent is to understand their overall cost trends, cost sensitivities, and trade-offs. This analysis also improves the AFCI Program’s understanding of the cost drivers that will determine nuclear power’s cost competitiveness vis-a-vis other baseload generation systems. The common reactor-related costs consist of capital, operating, and decontamination and decommissioning costs. Fuel cycle costs include front-end (pre-irradiation) and back-end (post-iradiation) costs, as well as costs specifically associated with fuel recycling. This analysis reveals that there are large cost uncertainties associated with all the fuel cycle strategies, and that overall systems (reactor plus fuel cycle) using a closed fuel cycle are about 10% more expensive in terms of electricity generation cost than open cycle systems. The study concludes that further U.S. and joint international-based design studies are needed to reduce the cost uncertainties with respect to fast reactor, fuel separation and fabrication, and waste disposition. The results of this work can help provide insight to the cost-related factors and conditions needed to keep nuclear energy (including closed fuel cycles) economically competitive in the U.S. and worldwide. These results may be updated over time based on new cost information, revised assumptions, and feedback received from additional reviews.

D. E. Shropshire

2009-01-01

265

Pressurized reactor system and a method of operating the same  

DOEpatents

A method and apparatus are provided for operating a pressurized reactor system in order to precisely control the temperature within a pressure vessel in order to minimize condensation of corrosive materials from gases on the surfaces of the pressure vessel or contained circulating fluidized bed reactor, and to prevent the temperature of the components from reaching a detrimentally high level, while at the same time allowing quick heating of the pressure vessel interior volume during start-up. Super-atmospheric pressure gas is introduced from the first conduit into the fluidized bed reactor and heat derived reactions such as combustion and gasification are maintained in the reactor. Gas is exhausted from the reactor and pressure vessel through a second conduit. Gas is circulated from one part of the inside volume to another to control the temperature of the inside volume, such as by passing the gas through an exterior conduit which has a heat exchanger, control valve, blower and compressor associated therewith, or by causing natural convection flow of circulating gas within one or more generally vertically extending gas passages entirely within the pressure vessel (and containing heat exchangers, flow rate control valves, or the like therein). Preferably, inert gas is provided as a circulating gas, and the inert gas may also be used in emergency shut-down situations. In emergency shut-down reaction gas being supplied to the reactor is cut off, while inert gas from the interior gas volume of the pressure vessel is introduced into the reactor. 2 figs.

Isaksson, J.M.

1996-06-18

266

Pressurized reactor system and a method of operating the same  

DOEpatents

A method and apparatus are provided for operating a pressurized reactor system in order to precisely control the temperature within a pressure vessel in order to minimize condensation of corrosive materials from gases on the surfaces of the pressure vessel or contained circulating fluidized bed reactor, and to prevent the temperature of the components from reaching a detrimentally high level, while at the same time allowing quick heating of the pressure vessel interior volume during start-up. Superatmospheric pressure gas is introduced from the first conduit into the fluidized bed reactor and heat derived reactions such as combustion and gassification are maintained in the reactor. Gas is exhausted from the reactor and pressure vessel through a second conduit. Gas is circulated from one part of the inside volume to another to control the temperature of the inside volume, such as by passing the gas through an exterior conduit which has a heat exchanger, control valve, blower and compressor associated therewith, or by causing natural convection flow of circulating gas within one or more generally vertically extending gas passages entirely within the pressure vessel (and containing heat exchangers, flow rate control valves, or the like therein). Preferably, inert gas is provided as a circulating gas, and the inert gas may also be used in emergency shut-down situations. In emergency shut-down reaction gas being supplied to the reactor is cut off, while inert gas from the interior gas volume of the pressure vessel is introduced into the reactor.

Isaksson, Juhani M. (Karhula, FI)

1996-01-01

267

Theoretical study of a two-stage methanogenic reactor system  

SciTech Connect

A two-stage methanogenic reactor system consists of two biological reactors (acidogenic and methanogenic) connected in series. In order to derive a qualitative model of the acidogenic reactor it is important to understand the phenomena necessary for the degradation of the cellulosic material to take place. The sequence of events can be generally described as: (1) diffusion of the bacteria to the pores of the biomass, (2) diffusion of the bacteria into the pores, (3) adsorption of the cellulase enzymes onto the surface of the substrate, (4) degradation of the cellulose via cellulase enzymes, and (5) the conversion of the cellulose degradation products into organic volatile acids by a mixed consortia of anaerobic bacteria. The resulting set of simultaneous nonlinear equations for the above phenomena were solved numerically using a double collocation procedure. Comparisons of several modes of reactor operation (batch, semi-continuous, and continuous) and different modes of bacterial diffusion (Brownian, motility, and chemotaxis) were then made. The methanogenic reactor was assumed to be a packed bed biofilm reactor for which two reactor models are derived. One model, for low influent concentrations, utilizes a limiting substrate concentration to determine the thickness of the biofilm. The other model, derived for high influent concentrations, neglects internal diffusion in the biofilm. Both models agree very well with the exact numerical solutions.

Skowlund, C.T.

1987-01-01

268

Software reliability and safety in nuclear reactor protection systems  

SciTech Connect

Planning the development, use and regulation of computer systems in nuclear reactor protection systems in such a way as to enhance reliability and safety is a complex issue. This report is one of a series of reports from the Computer Safety and Reliability Group, Lawrence Livermore that investigates different aspects of computer software in reactor National Laboratory, that investigates different aspects of computer software in reactor protection systems. There are two central themes in the report, First, software considerations cannot be fully understood in isolation from computer hardware and application considerations. Second, the process of engineering reliability and safety into a computer system requires activities to be carried out throughout the software life cycle. The report discusses the many activities that can be carried out during the software life cycle to improve the safety and reliability of the resulting product. The viewpoint is primarily that of the assessor, or auditor.

Lawrence, J.D. [Lawrence Livermore National Lab., CA (United States)

1993-11-01

269

Microalgal reactors: a review of enclosed system designs and performances.  

PubMed

One major challenge to industrial microalgal culturing is to devise and develop technical apparata, cultivation procedures and algal strains susceptible of undergoing substantial increases in efficiency of use of solar energy and carbon dioxide. Despite several research efforts developed to date, there is no such thing as "the best reactor system"- defined, in an absolute fashion, as the one able to achieve maximum productivity with minimum operation costs, irrespective of the biological and chemical system at stake. In fact, choice of the most suitable system is situation-dependent, as both the species of alga available and the final purpose intended will play a role. The need of accurate control impairs use of open-system configurations, so current investigation has focused mostly on closed systems. In this review, several types of closed bioreactors described in the technical literature as able to support production of microalgae are comprehensively presented and duly discussed, using transport phenomenon and process engineering methodological approaches. The text is subdivided into subsections on: reactor design, which includes tubular reactors, flat plate reactors and fermenter-type reactors; and processing parameters, which include gaseous transfer, medium mixing and light requirements. PMID:17137294

Carvalho, Ana P; Meireles, Luís A; Malcata, F Xavier

270

General Electric Reactor Protection System Unavailability, 1984-1995  

SciTech Connect

An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U.S. General Electric commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.

C. D. Gentillon; D. Rasmuson (USNRC); H. Hamzehee; M. B. Calley; S. A. Eide; T. Wierman (INEEL)

1999-08-01

271

General Electric Reactor Protection System Unavailability, 1984--1995  

SciTech Connect

An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U. S. General Electric commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.

Eide, Steven Arvid; Calley, Michael Brennan; Gentillon, Cynthia Ann; Wierman, Thomas Edward; Hamzehee, H.; Rasmuson, D.

1999-08-01

272

Westinghouse Reactor Protection System Unavailability, 1984--1995  

SciTech Connect

An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U. S. Westinghouse commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.

Eide, Steven Arvid; Calley, Michael Brennan; Gentillon, Cynthia Ann; Wierman, Thomas Edward; Rasmuson, D.; Marksberry, D.

1999-08-01

273

Westinghouse Reactor Protection System Unavailability, 1984-1995  

SciTech Connect

An analysis was performed of the safety-related performance of the reactor protection system (RPS) at U.S. Westinghouse commercial reactors during the period 1984 through 1995. RPS operational data were collected from the Nuclear Plant Reliability Data System and Licensee Event Reports. A risk-based analysis was performed on the data to estimate the observed unavailability of the RPS, based on a fault tree model of the system. Results were compared with existing unavailability estimates from Individual Plant Examinations and other reports.

C. D. Gentillon; D. Marksberry (USNRC); D. Rasmuson; M. B. Calley; S. A. Eide; T. Wierman (INEEL)

1999-08-01

274

Fluidized bed reactor system and method having a heat exchanger  

SciTech Connect

A fluidized bed reactor system is described comprising a reactor, means for supporting a fluidized bed of combustible particulate material in said reactor, heat exchange means disposed adjacent said reactor, separating means for receiving a mixture of flue gases and entrained particulate material from said fluidized bed and separating said particulate material from said flue gases, means for passing said separated particulate material to said heat exchange means, means for passing air through said separated particulate material in said heat exchange means to fluidize said separated material, means disposed in said heat exchange means for passing a coolant in a heat exchange relation to said separated material to transfer heat from said separated material to said coolant, and means for supplying additional heat to said separated material in said heat exchange means to control the temperature of said coolant.

Garcia-Mallol, J.A.

1993-08-31

275

Different Mechanisms for Establishing Liquid Walls in Advanced Reactor Systems  

NASA Astrophysics Data System (ADS)

The APEX study is investigating the use of free flowing liquid surfaces to form the inner surface of the chamber around a fusion plasma. In this study the modeling of APEX hybrid reactor produced by using ARIES-RS hybrid reactor technology, was performed by using the Monte Carlo code and ENF/B-V-VI nuclear data. The most important feature of APEX hybrid reactor is that the first wall surrounding the plasma is liquid. The advantages of utilizing a liquid wall are high power density capacity, good power transformation productivity the magnitude of the reactor's operational duration, low failure percentage, short maintenance time and the inclusion of the system's simple technology and material. Around the fusion chamber, molten salt Li2BeF4 and natural lithium were used as cooling materials. The result of the study indicated that fissile material production UF4 and ThF4 heavy metal salt increased nearly at the same percentage.

Hançerlio?ullari, Aybaba; Cini, Mesut

2013-04-01

276

Hybrid Plasma Reactor/Filter for Transportable Collective Protection Systems  

SciTech Connect

Pacific Northwest National Laboratory (PNNL) has performed an assessment of a Hybrid Plasma/Filter system as an alternative to conventional methods for collective protection. The key premise of the hybrid system is to couple a nonthermal plasma (NTP) reactor with reactive adsorption to provide a broader envelope of protection than can be provided through a single-solution approach. The first step uses highly reactive species (e.g. oxygen radicals, hydroxyl radicals, etc.) created in a nonthermal plasma (NTP) reactor to destroy the majority (~75% - 90%) of an incoming threat. Following the NTP reactor an O3 reactor/filter uses the O3 created in the NTP reactor to further destroy the remaining organic materials. This report summarizes the laboratory development of the Hybrid Plasma Reactor/Filter to protect against a ‘worst-case’ simulant, methyl bromide (CH3Br), and presents a preliminary engineering assessment of the technology to Joint Expeditionary Collective Protection performance specifications for chemical vapor air purification technologies.

Josephson, Gary B.; Tonkyn, Russell G.; Frye, J. G.; Riley, Brian J.; Rappe, Kenneth G.

2011-04-06

277

STORS: BATTELLE-NORTHWEST'S SLUDGE TO OIL REACTOR SYSTEM  

EPA Science Inventory

A continuous primary sewage sludge thermochemical conversion system was designed, built, and operated for over 100 hr during 1984 at Battelle-Northwest. This was designated as the STORS (Sludge-to-Oil-Reactor System), because the major product was a burnable oil. Starting with 20...

278

Screening reactor steam\\/water piping systems for water hammer  

Microsoft Academic Search

A steam\\/water system possessing a certain combination of thermal, hydraulic and operational states, can, in certain geometries, lead to a steam bubble collapse induced water hammer. These states, operations, and geometries are identified. A procedure that can be used for identifying whether an unbuilt reactor system is prone to water hammer is proposed. For the most common water hammer, steam

1997-01-01

279

Diagnostics of vibrations in induction motor-pump system used for reactor core cooling system  

Microsoft Academic Search

Analysis and diagnostics of vibration in industrial systems play a significant rule to prevent severe damages. This paper proposes a non-linear model to simulate the torsional vibration in the reactor core cooling system. Simulation results of an operating reactor core cooling system set with the actual parameters are presented to validate the accuracy and reliability of the proposed analytical method.

S. A. Qutb; A. M. Abdel-Hamid; A. Mansour; S. E. Soliman

2006-01-01

280

Reactor Controllability of 3-Region-Core Molten Salt Reactor System - A Study on Load Following Capability  

SciTech Connect

The Molten Salt Reactor (MSR) systems are liquid-fueled reactors that can be used for actinide burning, production of electricity, production of hydrogen, and production of fissile fuels (breeding). Thorium (Th) and uranium-233 ({sup 233}U) are fertile and fissile of the MSR systems, and dissolved in a high-temperature molten fluoride salt (fuel salt) with a very high boiling temperature (up to 1650 K), that is both the reactor nuclear fuel and the coolant. The MSR system is one of the six advanced reactor concepts identified by the Generation IV International Forum (GIF) as a candidate for cooperative development. In the MSR system, fuel salt flows through a fuel duct constructed around a reactor core and fuel channel of a graphite moderator accompanied by fission reaction and heat generation, and flows out to an external-loop system consisted of a heat exchanger and a circulation pump. Due to the motion of fuel salt, delayed neutron precursors that are one of the source of neutron production make to change their position between the fission reaction and neutron emission events and decay even occur in the external loop system. Hence the reactivity and effective delayed neutron precursor fraction of the MSR system are lower than those of solid fuel reactor systems such as Boiling Water Reactors (BWRs) and Pressurised Water Reactor (PWRs). Since all of the presently operating nuclear power reactors utilize solid fuel, little attention had been paid to the MSR analysis of the reactivity loss and reactor characteristics change caused by the fuel salt circulation. Sides et al. and Shimazu et al. developed MSR analytical models based on the point reactor kinetics model to consider the effect of fuel salt flow. Their models represented a reactor as having six zones for fuel salt and three zones for the graphite moderator. Since their models employed the point reactor kinetics model and the rough temperature approximation, their results were not sufficiently accurate to consider the effect of fuel salt flow. (authors)

Takahisa Yamamoto; Koshi Mitachi; Masatoshi Nishio [Toyohashi University of Technology, 1-1, Hibarigaoka, Tempaku-cho, Toyohashi-shi Aichi, 4418580 (Japan)

2006-07-01

281

Optimized Battery-Type Reactor Primary System Design Utilizing Lead  

SciTech Connect

A number of small and medium size reactors are being developed worldwide as well as large electricity generation reactors for co-generation, district heating or desalination. The Seoul National University has started to develop 23 MWth BORIS (Battery Optimized Reactor Integral System) as a multi-purpose reactor. BORIS is an integral-type optimized fast reactor with an ultra long life core. BORIS is being designed to meet the Generation IV nuclear energy system goals of sustainability, safety, reliability and economics. Major features of BORIS include 20 consecutive years of operation without refueling; elimination of an intermediate heat transport loop and main coolant pump; open core without individual subassemblies; inherent negative reactivity feedback; and inherent load following capability. Its one mission is to provide incremental electricity generation to match the needs of developing nations and especially remote communities without major electrical grid connections. BORIS consists of a reactor module, heat exchanger, coolant module, guard vessel, reactor vessel auxiliary cooling system (RVACS), secondary system, containment and the seismic isolation. BORIS is designed to generate 10 MWe with the resulting thermal efficiency of 45 %. BORIS uses lead as the primary system coolant because of the inherent safety of the material. BORIS is coupled with a supercritical carbon dioxide Brayton cycle as the secondary system to gain a high cycle efficiency in the range of 45 %. The reference core consists of 757 fuel rods without assembly with an active core height of 0.8 m. The BORIS core consists of single enrichment zone composed of a Pu-MA (minor actinides)-U-N fuel and a ferritic-martensitic stainless steel clad. This study is intended to set up appropriate reactor vessel geometry by performing thermal hydraulic analysis on RVACS using computational fluid dynamics codes; to examine the liquid metal coolant behavior along the subchannels; to find out whether the given flux profiles and geometrical arrangement of fuel rods yield reasonable flow distribution during nominal operation using a subchannel analysis code; and to determine the natural circulation capability of the BORIS primary coolant system by calculating the total pressure drop in the system. (authors)

Yu, Yong H.; Son, Hyoung M.; Lee, Il S.; Suh, Kune Y. [Seoul National University, San 56-1 Sillim-dong, Gwanak-gu, Seoul, 151-742 (Korea, Republic of)

2006-07-01

282

Incipient Transient Detection in Reactor Systems: Experimental and Theoretical Investigation  

SciTech Connect

The main goal of this research was to develop a method for detecting reactor system transients at the earliest possible time through a comprehensive experimental, testing and benchmarking program. This approach holds strong promise for developing new diagnostic technologies that are non-intrusive, generic and highly portable across different systems. It will help in the design of new generation nuclear power reactors, which utilize passive safety systems with a reliable and non-intrusive multiphase flow diagnostic system to monitor the function of the passive safety systems. The main objective of this research was to develop an improved fuzzy logic based detection method based on a comprehensive experimental testing program to detect reactor transients at the earliest possible time, practically at their birth moment. A fuzzy logic and neural network based transient identification methodology and implemented in a computer code called PROTREN was considered in this research and was compared with SPRT (Sequentially Probability Ratio Testing) decision and Bayesian inference. The project involved experiment, theoretical modeling and a thermal-hydraulic code assessment. It involved graduate and undergraduate students participation providing them with exposure and training in advanced reactor concepts and safety systems. In this final report, main tasks performed during the project period are summarized and the selected results are presented. Detailed descriptions for the tasks and the results are presented in previous yearly reports (Revankar et al 2003 and Revankar et al 2004).

Lefteri H. Tsoukalas; S.T. Revankar; X Wang; R. Sattuluri

2005-09-27

283

Method for passive cooling liquid metal cooled nuclear reactors, and system thereof  

DOEpatents

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of partitions surrounding the reactor vessel in spaced apart relation forming intermediate areas for circulating heat transferring fluid which remove and carry away heat from the reactor vessel.

Hunsbedt, Anstein (Los Gatos, CA); Busboom, Herbert J. (San Jose, CA)

1991-01-01

284

Modifications Done in the IPR-R1 Reactor and Their Auxiliary Systems.  

National Technical Information Service (NTIS)

The improvements done in the IPR-R1 reactor for adequateness of operation conditions and increase of irradiation sample capability. The cooling systems, reactor pool, system of control rods were substituted. The optimization of transfer pneumatic system w...

F. Maretti V. A. Amorim J. G. Coura

1986-01-01

285

Inertial fusion energy power reactor fuel recovery system  

SciTech Connect

A conceptual design is proposed to support the recovery of un-expended fuel, ash, and associated post-detonation products resident in plasma exhaust from a {approx}2 GWIFE direct drive power reactor. The design includes systems for the safe and efficient collection, processing, and purification of plasma exhaust fuel components. The system has been conceptually designed and sized such that tritium bred within blankets, lining the reactor target chamber, can also be collected, processed, and introduced into the fuel cycle. The system will nominally be sized to process {approx}2 kg of tritium per day and is designed to link directly to the target chamber vacuum pumping system. An effort to model the fuel recovery system (FRS) using the Aspen Plus engineering code has commenced. The system design supports processing effluent gases from the reactor directly from the exhaust of the vacuum pumping system or in batch mode, via a buffer vessel in the Receiving and Analysis System. Emphasis is on nuclear safety, reliability, and redundancy as to maximize availability. The primary goal of the fuel recovery system design is to economically recycle components of direct drive IFE fuel. The FRS design is presented as a facility sub-system in the context of supporting the larger goal of producing safe and economical IFE power. (authors)

Gentile, C. A.; Kozub, T.; Langish, S. W.; Ciebiera, L. P. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Nobile, A.; Wermer, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Sessions, K. [Savannah River National Laboratory, Aiken, SC 29808 (United States)

2008-07-15

286

Rotating solid radiative coolant system for space nuclear reactors  

NASA Astrophysics Data System (ADS)

The RING power system described in this paper is proposed as a primary or emergency heat rejection system for advanced space reactor power applications. The system employs a set of four (4) counter-rotating, 90 degree offset, coolant-carrying rings. The rings (segmented, corrugated, finned, thin-walled pipes, filled with liquid lithium) pass through a cavity heat exchanger and reradiate the absorbed heat to the space environment.

Apley, W. J.; Babb, A. L.

1988-05-01

287

Modeling and performance of the MHTGR (Modular High-Temperature Gas-Cooled Reactor) reactor cavity cooling system  

Microsoft Academic Search

The Reactor Cavity Cooling System (RCCS) of the Modular High- Temperature Gas-Cooled Reactor (MHTGR) proposed by the U.S. Department of Energy is designed to remove the nuclear afterheat passively in the event that neither the heat transport system nor the shutdown cooling circulator subsystem is available. A computer dynamic simulation for the physical and mathematical modeling of and RCCS is

Conklin

1990-01-01

288

Neutral-beam systems for magnetic fusion reactors  

Microsoft Academic Search

Neutral beams for magnetic fusion reactors are at an early stage of development, and require considerable effort to make them into the large, reliable, and efficient systems needed for future power plants. To optimize their performance and establish specific goals for component development, systematic analysis of the beamlines is essential. Three ion source characteristics are discussed: arc-cathode life, gas efficiency,

Joel H. Fink

1982-01-01

289

Remotely operable fuel transfer system for nuclear reactor  

Microsoft Academic Search

A fuel transfer system is described for transferring fuel assemblies through a transfer tube extending between, and having respective ends thereof disposed in, corresponding fuel assembly exchange locations of a fuel storage and handling building and a containment structure for a nuclear reactor. Corresponding valves disposed at the ends of the transfer tube are remotely, selectively operable to a closed

R. T. Jr

1987-01-01

290

Modification of the Core Cooling System of TRIGA 2000 Reactor  

SciTech Connect

To accomplish safety requirements, a set of actions has to be performed following the recommendations of the IAEA safety series 35 applied to research reactor. Such actions are considered in modernization of the old system, improving the core cooling system and safety evaluations. Due to the complexity of the process and the difficulty in putting the apparatus in the reactor core, analytical and experimental study on the determination of flow and temperature distribution in the whole coolant channel are difficult to be done. In the present work, a numerical study of flow and temperature distribution in the coolant channel of TRIGA 2000 has been carried out using CFD package. For this study, simulations were carried out on 3-D tested model. The model consists of the reactor tank, thermal and thermalizing column, reflector, rotary specimen rack, chimney, fuel element, primary pipe, diffuser, beam tube and a part of the core are constructed by 1.50 million unstructured tetrahedral cell elements. The results show that for the initial condition (116 fuel elements in the core) and for the inlet temperature of 24 deg. C and the primary velocity of 5.6 m/s, there no boiling phenomena occur in the coolant channel. Due to this result, it is now possible to improve the core cooling system of TRIGA 2000 reactor. Meanwhile, forced flow from the diffuser system only affected the flow pattern in the outside of chimney and put on a small effect to the fluid flow's velocity in the inside of chimney.

Umar, Efrizon; Fiantini, Rosalina [National Nuclear Energy Agency of Indonesia, Jalan Tamansari 71, Bandung, 40132 (Indonesia)

2010-06-22

291

Neutron Cross Section Covariances: Recent Workshop and Advanced Reactor Systems  

NASA Astrophysics Data System (ADS)

The recent Workshop on Neutron Cross Section Covariances, organized by BNL and attended by more than 50 scientists, responded to demands of many user groups, including advanced reactor systems, for uncertainty and correlation information. These demands can be explained by considerable progress in advanced neutronics simulation that probe covariances and their impact on design and operational margins of nuclear systems. The Workshop addressed evaluation methodology, recent evaluations as well as user's perspective, marking era of revival of covariance development that started some two years ago. We illustrate urgent demand for covariances in the case of advanced reactor systems, including fast actinide burner under GNEP, new generation of power reactors, Gen-IV, and reactors under AFCI. A common feature of many of these systems is presence of large amount of minor actinides and fission products that require improved nuclear data. Advanced simulation codes rely on quality input, to be obtained by adjusting the data library, such as the new ENDF/B-VII.0, by considering integral experiments as currently pursued by GNEP. To this end the nuclear data community is developing covariances for formidable amount of 112 materials (isotopes).

Oblozinsky, Pavel

2008-10-01

292

Winding insulation in electromagnetic systems for Tokamak reactor plants  

Microsoft Academic Search

Magnetic containment of the plasma in nuclear fusion reactors of the Tokamak type requires electromagnets with insulation which must withstand high temperatures and thermal shocks as well as ionizing radiation in various forms and electric fields, and mechanical loads. Insulation materials to ensure adequate thermophysical and mechanical properties are evaluated, followed by design of insulation systems with satisfactory performance characteristics.

V. V. Maslov; S. G. Trubachev

1985-01-01

293

The liquid annular reactor system (LARS) for deep space exploration  

Microsoft Academic Search

A new propulsion concept for high ? V space missions, termed LARS (Liquid Annular Reactor System), uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (-6000 K). The molten fuel is contained in a lower-temperature solid container which rotates to stabilize and hold in the liquid layer by centripetal force. Containment of ultra high temperature molten

H. Ludewig; M. Todosow; J. R. Powell

1999-01-01

294

A novel extruder-feeder reactor system for biomass liquefaction  

Microsoft Academic Search

A need existed in the 1970's to pump high concentrations of biomass solids into reactors under high pressure on a continuous basis. A modified plasticating single screw extruder was developed, capable of pumping slurries as high as 60 wt % wood as compared to only 10-20 wt % in conventional piston pump systems. The ability to handle such concentrated slurries

D. H. White; D. Wolf; B. Reyes; Y. Zhao

1987-01-01

295

Modification of the Core Cooling System of TRIGA 2000 Reactor  

NASA Astrophysics Data System (ADS)

To accomplish safety requirements, a set of actions has to be performed following the recommendations of the IAEA safety series 35 applied to research reactor. Such actions are considered in modernization of the old system, improving the core cooling system and safety evaluations. Due to the complexity of the process and the difficulty in putting the apparatus in the reactor core, analytical and experimental study on the determination of flow and temperature distribution in the whole coolant channel are difficult to be done. In the present work, a numerical study of flow and temperature distribution in the coolant channel of TRIGA 2000 has been carried out using CFD package. For this study, simulations were carried out on 3-D tested model. The model consists of the reactor tank, thermal and thermalizing column, reflector, rotary specimen rack, chimney, fuel element, primary pipe, diffuser, beam tube and a part of the core are constructed by 1.50 million unstructured tetrahedral cell elements. The results show that for the initial condition (116 fuel elements in the core) and for the inlet temperature of 24°C and the primary velocity of 5.6 m/s, there no boiling phenomena occur in the coolant channel. Due to this result, it is now possible to improve the core cooling system of TRIGA 2000 reactor. Meanwhile, forced flow from the diffuser system only affected the flow pattern in the outside of chimney and put on a small effect to the fluid flow's velocity in the inside of chimney.

Umar, Efrizon; Fiantini, Rosalina

2010-06-01

296

Ensuring required reliability for nuclear reactor protection systems  

Microsoft Academic Search

One of the fundamental questions arising in nuclear plant design is ensuring safe operation in various operating regimes. Safe reactor operation is achieved not only by ensuring high values for the equipment reliability indicators during normal operation, but also by the correct actions of plant staff and of the safety systems. Since the failure of various types of equipment can

A. I. Pereguda; A. A. Petrenko

1989-01-01

297

Cooling System Design Options for a Fusion Reactor  

Microsoft Academic Search

The objective of a fusion power reactor is to produce electricity safely and reliably. Accordingly, the design, objective of the heat transport system is to optimize power production, safety, and reliability. Such an optimization process, however, is constrained by many factors, including, among others: public safety, worker safety, steam cycle efficiency, reliability, and cost. As these factors impose conflicting requirements,

Antonio Natalizio; Jan Collén; Gottfried Vieider

1997-01-01

298

Remote control system for a 2-MW research reactor  

SciTech Connect

A fault-tolerant programmable logic controller (PLC) and operator workstations have been programmed to replace the hard-wired relay control system in the 2-MW Bulk Shielding Reactor at Oak Ridge National Laboratory. In addition to the PLC and remote and local operator workstations, auxiliary systems include a video system, an intercom system, and a fiber optic communication system. The equipment has been designed with reliability and fail-safe features as important considerations. Significant features of the system are described. 2 refs., 4 figs., 1 tab.

Battle, R.E.; Corbett, G.K.

1988-01-01

299

Anaerobic treatment of a chemical synthesis-based pharmaceutical wastewater in a hybrid upflow anaerobic sludge blanket reactor.  

PubMed

In this study, performance of a lab-scale hybrid up-flow anaerobic sludge blanket (UASB) reactor, treating a chemical synthesis-based pharmaceutical wastewater, was evaluated under different operating conditions. This study consisted of two experimental stages: first, acclimation to the pharmaceutical wastewater and second, determination of maximum loading capacity of the hybrid UASB reactor. Initially, the carbon source in the reactor feed came entirely from glucose, applied at an organic loading rate (OLR) 1 kg COD/m(3) d. The OLR was gradually step increased to 3 kg COD/m(3) d at which point the feed to the hybrid UASB reactor was progressively modified by introducing the pharmaceutical wastewater in blends with glucose, so that the wastewater contributed approximately 10%, 30%, 70%, and ultimately, 100% of the carbon (COD) to be treated. At the acclimation OLR of 3 kg COD/m(3) d the hydraulic retention time (HRT) was 2 days. During this period of feed modification, the COD removal efficiencies of the anaerobic reactor were 99%, 96%, 91% and 85%, and specific methanogenic activities (SMA) were measured as 240, 230, 205 and 231 ml CH(4)/g TVS d, respectively. Following the acclimation period, the hybrid UASB reactor was fed with 100% (w/v) pharmaceutical wastewater up to an OLR of 9 kg COD/m(3) d in order to determine the maximum loading capacity achievable before reactor failure. At this OLR, the COD removal efficiency was 28%, and the SMA was measured as 170 ml CH(4)/g TVS d. The hybrid UASB reactor was found to be far more effective at an OLR of 8 kg COD/m(3) d with a COD removal efficiency of 72%. At this point, SMA value was 200 ml CH(4)/g TVS d. It was concluded that the hybrid UASB reactor could be a suitable alternative for the treatment of chemical synthesis-based pharmaceutical wastewater. PMID:17449241

Oktem, Yalcin Askin; Ince, Orhan; Sallis, Paul; Donnelly, Tom; Ince, Bahar Kasapgil

2007-04-20

300

Expert systems for fault diagnosis in nuclear reactor control  

NASA Astrophysics Data System (ADS)

An expert system for accident analysis and fault diagnosis for the Loss Of Fluid Test (LOFT) reactor, a small scale pressurized water reactor, was developed for a personal computer. The knowledge of the system is presented using a production rule approach with a backward chaining inference engine. The data base of the system includes simulated dependent state variables of the LOFT reactor model. Another system is designed to assist the operator in choosing the appropriate cooling mode and to diagnose the fault in the selected cooling system. The response tree, which is used to provide the link between a list of very specific accident sequences and a set of generic emergency procedures which help the operator in monitoring system status, and to differentiate between different accident sequences and select the correct procedures, is used to build the system knowledge base. Both systems are written in TURBO PROLOG language and can be run on an IBM PC compatible with 640k RAM, 40 Mbyte hard disk and color graphics.

Jalel, N. A.; Nicholson, H.

1990-11-01

301

A gas-cooled reactor surface power system  

SciTech Connect

A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life-cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors found on numerous university campuses. The fuel is uranium nitride clad in Nb1{percent}Zr, which has been extensively tested under the SP-100 program. The fuel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fuel and stabilizing the geometry against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality can not occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars. {copyright} {ital 1999 American Institute of Physics.}

Lipinski, R.J.; Wright, S.A.; Lenard, R.X.; Harms, G.A. [Sandia National Laboratories, MS-1146, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States)

1999-01-01

302

A gas-cooled reactor surface power system  

NASA Astrophysics Data System (ADS)

A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life-cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors found on numerous university campuses. The fuel is uranium nitride clad in Nb1%Zr, which has been extensively tested under the SP-100 program. The fuel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fuel and stabilizing the geometry against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality can not occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars.

Lipinski, Ronald J.; Wright, Steven A.; Lenard, Roger X.; Harms, Gary A.

1999-01-01

303

A Gas-Cooled Reactor Surface Power System  

SciTech Connect

A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life- cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors found on numerous university campuses. The fuel is uranium nitide clad in Nb 1 %Zr, which has been extensively tested under the SP-I 00 program The fiel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fbel and stabilizing the geometty against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality cannot occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars.

Harms, G.A.; Lenard, R.X.; Lipinski, R.J.; Wright, S.A.

1998-11-09

304

A gas-cooled reactor surface power system  

SciTech Connect

A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life-cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors found on numerous university campuses. The fuel is uranium nitride clad in Nb1%Zr, which has been extensively tested under the SP-100 program. The fuel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fuel and stabilizing the geometry against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality can not occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars.

Lipinski, Ronald J.; Wright, Steven A.; Lenard, Roger X.; Harms, Gary A. [Sandia National Laboratories, MS-1146, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States)

1999-01-22

305

Gap and impact of LMR (Liquid Metal Reactor) piping systems and reactor components  

SciTech Connect

Because of high operation temperature, the LMR (Liquid Metal Reactor) plant is characterized by the thin-walled piping and components. Gaps are often present to allow free thermal expansion during normal plant operation. Under dynamic loadings, such as seismic excitation, if the relative displacement between the components exceeds the gap distance, impacts will occur. Since the components and piping become brittle over their design lifetime, impact is of important concern for it may lead to fractures of components and other serious effects. This paper deals with gap and impact problems in the LMR reactor components and piping systems. Emphasis is on the impacts due to seismic motion. Eight sections are contained in this paper. The gap and impact problems in LMR piping systems are described and a parametric study is performed on the effects of gap-induced support nonlinearity on the dynamics characteristics of the LMR piping systems. Gap and impact problems in the LMR reactor components are identified and their mathematical models are illustrated, and the gap and impact problems in the seismic reactor scram are discussed. The mathematical treatments of various impact models are also described. The uncertainties in the current seismic impact analyses of LMR components and structures are presented. An impact test on a 1/10-scale LMR thermal liner is described. The test results indicated that several clusters of natural modes can be excited by the impact force. The frequency content of the excited modes depends on the duration of the impact force; the shorter the duration, the higher the frequency content.

Ma, D.C.; Gvildys, J.; Chang, Y.W.

1987-01-01

306

The combined hybrid system: A symbiotic thermal reactor\\/fast reactor system for power generation and radioactive waste toxicity reduction  

Microsoft Academic Search

If there is to be a next generation of nuclear power in the United States, then the four fundamental obstacles confronting nuclear power technology must be overcome: safety, cost, waste management, and proliferation resistance. The Combined Hybrid System (CHS) is proposed as a possible solution to the problems preventing a vigorous resurgence of nuclear power. The CHS combines Thermal Reactors

Hollaway

1991-01-01

307

Expert system for online surveillance of nuclear reactor coolant pumps  

DOEpatents

This report describes an expert system for online surveillance of nuclear reactor coolant pumps. This system provides a means for early detection of pump or sensor degradation. Degradation is determined through the use of a statistical analysis technique, sequential probability ratio test, applied to information from several sensors which are responsive to differing physical parameters. The results of sequential testing of the data provide the operator with an early warning of possible sensor or pump failure.

Gross, K.C.; Singer, R.M.; Humenik, K.E.

1992-12-31

308

Aging study of boiling water reactor high pressure injection systems  

Microsoft Academic Search

The purpose of high pressure injection systems is to maintain an adequate coolant level in reactor pressure vessels, so that the fuel cladding temperature does not exceed 1,200°C (2,200°F), and to permit plant shutdown during a variety of design basis loss-of-coolant accidents. This report presents the results of a study on aging performed for high pressure injection systems of boiling

D. A. Conley; J. L. Edson; C. F. Fineman

1995-01-01

309

Neutral-beam systems for magnetic-fusion reactors  

SciTech Connect

Neutral beams for magnetic fusion reactors are at an early stage of development, and require considerable effort to make them into the large, reliable, and efficient systems needed for future power plants. To optimize their performance to establish specific goals for component development, systematic analysis of the beamlines is essential. Three ion source characteristics are discussed: arc-cathode life, gas efficiency, and beam divergence, and their significance in a high-energy neutral-beam system is evaluated.

Fink, J. H.

1981-08-10

310

pNitrophenol removal in a sequential anaerobic migrating blanket reactor (AMBR)\\/aerobic completely stirred tank reactor (CSTR) system  

Microsoft Academic Search

In this study, the anaerobic treatability of p-nitrophenol (p-NP) was investigated in an anaerobic\\/aerobic sequential reactor system. During the anaerobic stage the target compound is modified via degradation and then the intermediate product is more readily biodegradable by the aerobic phase. Lab-scale anaerobic migrating blanket reactor (AMBR) and a completely stirred tank reactor (CSTR) were used sequentially to investigate the

Delia Teresa Sponza; Özlem Selçuk Ku?çu

2005-01-01

311

Transient flow analysis in reactor coolant pump systems during flow coastdown period  

Microsoft Academic Search

The rapid flow transient calculation in reactor coolant pump system is important in the safety analysis of a nuclear reactor. An accurate transient analysis of flow coastdown is also important and necessary for the design and manufacture of a reactor coolant pump. Only under the reliable work of a reactor coolant pump the safety of a nuclear power plant can

Hong Gao; Feng Gao; Xianchao Zhao; Jie Chen; Xuewu Cao

2011-01-01

312

Heat removal performance of auxiliary cooling system for the high temperature engineering test reactor during scrams  

Microsoft Academic Search

The auxiliary cooling system of the high temperature engineering test reactor (HTTR) is employed for heat removal as an engineered safety feature when the reactor scrams in an accident when forced circulation can cool the core. The HTTR is the first high temperature gas-cooled reactor in Japan with reactor outlet gas temperature of 950 °C and thermal power of 30 MW.

Takeshi Takeda; Yukio Tachibana; Tatsuo Iyoku; Satsuki Takenaka

2003-01-01

313

A passive automated personnel accountability system for reactor emergency preparedness  

SciTech Connect

In 1985 a project was undertaken at the N Reactor on the Hanford Site to develop an automated personnel accountability system to ensure accountability of all personnel within 30 minutes of a site evacuation. The decision to develop such a system was made after a full-scale evacuation drill showed that the manual accountability system in use at the time was inadequate to meet the 30-minute requirement. Accountability systems at commercial nuclear power plants were evaluated, but found to be unsuitable because they were not passive, that is, they required action on part of the user for the system to work. Approximately 2500 people could be required to evacuate the 100-N Area. Therefore, a card key system or badge exchange system was judged not to be feasible. A passive accountability system was desired for N Reactor to allow personnel to enter and leave the site in a more timely manner. To meet the need for an automated accountability system at N Reactor, a special Evacuation Accountability System (EVACS) was designed and developed. The EVACS system has three basic components: the transponder, a credit card-sized device worn with the security badge; portal monitors, which are electronically activated by the transponder; and a computer information system that contains the personnel data base. Each person wearing a transponder is accounted for automatically by walking through a portal. In this paper, a description of the hardware and software will be presented, together with problems encountered and lessons learned while adapting an existing technology to this particular use. The system is currently installed and requires acceptance testing before becoming operational.

Zimmerman, R.O.; DeLisle, G.V.; Hickey, E.E.

1988-04-01

314

Extreme thermophilic biohydrogen production from wheat straw hydrolysate using mixed culture fermentation: effect of reactor configuration.  

PubMed

Hydrogen production from hemicellulose-rich wheat straw hydrolysate was investigated in continuously-stirred tank reactor (CSTR), up-flow anaerobic sludge bed (UASB) reactor, and anaerobic filter (AF) reactor. The CSTR was operated at an hydraulic retention time (HRT) of 3 days, and the UASB and AF reactors were operated at 1 day HRT, using mixed extreme thermophiles at 70 °C. The highest hydrogen production yield of 212.0±6.6 mL-H?/g-sugars, corresponding to a hydrogen production rate of 821.4±25.5 mL-H?/dL was achieved with the UASB reactor. Lowering the HRT to 2.5 days caused cell mass washout in the CSTR, while the UASB and AF reactors gave fluctuating and reducing hydrogen production at a 0.5-day HRT. The original rate and yield were recovered when the HRT was increased back to 1 day. These results demonstrate that reactor configuration is an important factor for enhancing and stabilizing H? production. PMID:20554199

Kongjan, Prawit; Angelidaki, Irini

2010-10-01

315

D-He-3 spherical torus fusion reactor system study  

NASA Astrophysics Data System (ADS)

This system study extrapolates present physics knowledge and technology to predict the anticipated characteristics of D-He3 spherical torus fusion reactors and their sensitivity to uncertainties in important parameters. Reference cases for steady-state 1000 MWe reactors operating in H-mode in both the 1st stability regime and the 2nd stability regime were developed and assessed quantitatively. These devices would a very small aspect ratio (A=1,2), a major radius of about 2.0 m, an on-axis magnetic field less than 2 T, a large plasma current (80-120 MA) dominated by the bootstrap effect, and high plasma beta (greater than O.6). The estimated cost of electricity is in the range of 60-90 mills/kW-hr, assuming the use of a direct energy conversion system. The inherent safety and environmental advantages of D-He3 fusion indicate that this reactor concept could be competitive with advanced fission breeder reactors and large-scale solar electric plants by the end of the 21st century if research and development can produce the anticipated physics and technology advances.

Macon, William A., Jr.

1992-04-01

316

Small space reactor power systems for unmanned solar system exploration missions  

Microsoft Academic Search

A preliminary feasibility study of the application of small nuclear reactor space power systems to the Mariner Mark II Cassini spacecraft\\/mission was conducted. The purpose of the study was to identify and assess the technology and performance issues associated with the reactor power system\\/spacecraft\\/mission integration. The Cassini mission was selected because study of the Saturn system was identified as a

Harvey S. Bloomfield

1987-01-01

317

Clean-up sub-system for chemical decontamination of nuclear reactor primary systems  

SciTech Connect

This patent describes a chemical decontamination clean-up system for use on-line in a nuclear reactor primary system. It comprises: a back-flushable filter; means within the nuclear reactor primary system for pumping primary system fluids from the nuclear reactor primary system downstream to the back-flushable filter and thereafter through the decontamination system; a plurality of demineralizer banks arranged in parallel, each demineralizer bank comprising one or more demineralizers arranged in parallel wherein primary system fluids are demineralized; means for selectively directing the pumped primary system fluids from the back-flushable filter to a particular demineralizer bank; and means for returning primary system fluids from the demineralizer banks to the primary system.

Corpora, G.J.; Schlonski, J.S.; Bauer, F.I.; Miller, P.E.

1992-02-18

318

REACTOR  

DOEpatents

A breeder reactor is described, including a mass of fissionable material that is less than critical with respect to unmoderated neutrons and greater than critical with respect to neutrons of average energies substantially greater than thermal, a coolant selected from sodium or sodium--potassium alloys, a control liquid selected from lead or lead--bismuth alloys, and means for varying the quantity of control liquid in the reactor. (AEC)

Szilard, L.

1963-09-10

319

Reactor Subsystem Simulation for Nuclear Hybrid Energy Systems  

SciTech Connect

Preliminary system models have been developed by Idaho National Laboratory researchers and are currently being enhanced to assess integrated system performance given multiple sources (e.g., nuclear + wind) and multiple applications (i.e., electricity + process heat). Initial efforts to integrate a Fortran-based simulation of a small modular reactor (SMR) with the balance of plant model have been completed in FY12. This initial effort takes advantage of an existing SMR model developed at North Carolina State University to provide initial integrated system simulation for a relatively low cost. The SMR subsystem simulation details are discussed in this report.

Shannon Bragg-Sitton; J. Michael Doster; Alan Rominger

2012-09-01

320

Real-time, multitasking control system for reactor inspection robots  

SciTech Connect

The Equipment Engineering Division of the Department of Energy's Savannah River Laboratory in Aiken, South Carolina has developed a remote system to perform ultrasonic (UT) and eddy current (ET) wall weld inspections inside the nuclear reactors at the site. The basic components of the inspection system include an inspection robot and control hardware, a supervisory computer, and ultrasonic and eddy current data collection and analysis computers. The ultrasonic and eddy current systems are responsible for driving the transducers, and digitizing, displaying, and storing the information. 7 figs.

Byrne, T.J.; Jenkins, J.B.; Lewis, W.I.; Park, L.R.; Reeves, G.E.

1988-01-01

321

Advanced Test Reactor risk-based management system instruction manual  

SciTech Connect

This report documents the use of the risk-based management system (RBMS) developed for the Advanced Test Reactor. This RBMS has been implemented to apply the probabilistic risk assessment (PRA) models and results to day-to-day management, operations, maintenance, and engineering decisions. Descriptions of ongoing improvements to the PRA and to the RBMS tools and methodologies will be added to the manual as they are completed. 10 refs., 7 tabs.

Thatcher, T.A.

1991-01-01

322

The research reactor radiation emergency countermeasure system in Korea  

Microsoft Academic Search

A disaster prevention system was established for a radiation emergency from an operation of a research reactor with a thermal power of 30MWth in Korea. A national radiation disaster countermeasure organization was set up to cope with the radiation emergency classified into three cases whose effective doses were more than 1mSv\\/h inside the nuclear facility, inside the site boundary and

Hee Reyoung Kim; Geun-Sik Choi; Wanno Lee; Kun Ho Chung; Mun Ja Kang; Chang-Woo Lee

2010-01-01

323

Advanced Test Reactor risk-based management system instruction manual  

Microsoft Academic Search

This report documents the use of the risk-based management system (RBMS) developed for the Advanced Test Reactor. This RBMS has been implemented to apply the probabilistic risk assessment (PRA) models and results to day-to-day management, operations, maintenance, and engineering decisions. Descriptions of ongoing improvements to the PRA and to the RBMS tools and methodologies will be added to the manual

Thatcher

1991-01-01

324

Designing visual displays and system models for safe reactor operations  

SciTech Connect

The material presented in this paper is based on two studies involving the design of visual displays and the user`s prospective model of a system. The studies involve a methodology known as Neuro-Linguistic Programming and its use in expanding design choices from the operator`s perspective image. The contents of this paper focuses on the studies and how they are applicable to the safety of operating reactors.

Brown-VanHoozer, S.A.

1995-12-31

325

PWR full-reactor coolant system decontamination  

SciTech Connect

The overall objective of the current program is to identify and address all aspects of full system decontamination with the purpose of qualifying at least one process for PWR use. The objective of the current study is to provide baseline data on the performance of materials on the primary side after exposure to one cycle of the LOMI fault testing. This data supplements prior information obtained after exposure to three cycles of LOMI testing. The technical significance of this excursion will be determined in a subsequent task. The general corrosion characteristics of over 39 materials were evaluated for some combinations of material, type of specimen (coupon and creviced coupons), and loop velocity (0, 5, 20 and 150 ft/sec). At velocities of less than or equal to 20 ft/sec, sixteen types of specimens were employed to evaluate localized corrosion and stress corrosion cracking. Specimens were examined after one cycle. Also included in this exposure were specimens added to provide more information on the effect of LOMI fault exposure one: (1) surface roughening of Stellite 156; (2) crevice corrosion of chromium plated 304 stainless steel with the open end gap increased from 3 to {approximately} 9 mils; (3) susceptibility of Inconel X-750 (HTH) to subsequent stress corrosion cracking, (4) loss of chromium plate from threads of 304 stainless steel bolts torqued into stainless steel collars; (5) crack initiation in an Alloy 600 tube known to be susceptible to primary water stress corrosion cracking; and (6) surface alternation of stressed Inconel X-750 springs with the spring temper.

Aspden, R.G.; Pessall, N.; Grand, T.F. (Westinghouse Electric Corp., Pittsburgh, PA (United States))

1992-01-01

326

Substrate removal evaluation of granular anammox process in a pilot-scale upflow anaerobic sludge blanket reactor  

Microsoft Academic Search

Process kinetics can present necessary information for granular anammox process but little study focused on the nitrogen removal kinetics of pilot-scale anammox granular process is available. In this study, the substrate removal kinetics in a pilot-scale anammox granular reactor were investigated by inoculating anammox granules in to an UASB reactor, which was then operated at different hydraulic retention times and

Shou-Qing Ni; Shihwu Sung; Qin-Yan Yue; Bao-Yu Gao

327

Thermal stress calculations for heatpipe-cooled reactor power systems  

NASA Astrophysics Data System (ADS)

A heatpipe-cooled fast reactor concept has been under development at Los Alamos National Laboratory for the past several years, to be used as a power source for nuclear electric propulsion (NEP) or as a planetary surface power system. The reactor core consists of an array of modules that are held together by a core lateral restraint system. Each module comprises a single heatpipe surrounded by 3-6 clad fuel pins. As part of the design development and performance assessment activities for these reactors, specialized methods and models have been developed to perform thermal and stress analyses of the core modules. The methods have been automated so that trade studies can be readily performed, looking at design options such as module size, heatpipe and clad thickness, use of sleeves to contain the fuel, material type, etc. This paper describes the methods and models that have been developed, and presents thermal and stress analysis results for a Mars surface power system and a NEP power source. .

Kapernick, Richard J.; Guffee, Ray M.

2002-01-01

328

Advanced liquid-metal reactor IHTS (intermediate heat transport system) and SGS (steam generator system) design  

Microsoft Academic Search

The US Department of Energy (DOE) advanced liquid-metal reactor (ALMR) 1395-MW(electric) power plant design consists of three power blocks. A power block is composed of three identical 471-MW(thermal) reactor modules, each with its own steam generator system (SGS). The three saturated cycle SGSs are headered to provide steam to a common turbine generator system for the power block. The purpose

R. R. Lowrie; A. K. Dhalla; A. Potocnik; M. Hui

1990-01-01

329

10 CFR 50.46 - Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors.  

Code of Federal Regulations, 2010 CFR

...cooling systems for light-water nuclear power reactors. 50.46 Section 50...cooling systems for light-water nuclear power reactors. (a)(1)(i...or pressurized light-water nuclear power reactor fueled with...

2010-01-01

330

10 CFR 50.46 - Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors.  

Code of Federal Regulations, 2010 CFR

...cooling systems for light-water nuclear power reactors. 50.46 Section 50...cooling systems for light-water nuclear power reactors. (a)(1)(i...or pressurized light-water nuclear power reactor fueled with...

2009-01-01

331

Reactor coolant high-temperature filtration. Volume 3. Conceptual system designs and licensing concerns. Final report  

Microsoft Academic Search

Conceptual fluid system designs are presented for high temperature reactor coolant magnetic filtration systems. One of these is intended for application to any pressurized water reactor plant and is designated the generic design. The other is intended specifically for pressurized water reactors of the Byron design having RCS loops equipped with loop stop valves. A licensing issues evaluation for the

G. J. Corpora; J. L. Grover; M. L. Masch; T. L. Schulz; S. Shields; S. G. Sterrett; M. Troy

1984-01-01

332

Space-reactor system and subsystem investigations: Cost and schedule estimates for reactor and shield subsystems technology development. SP100 program  

Microsoft Academic Search

Cost and schedule estimates of the technology development for reactor and shielding subsystems of a 100-kWe class space reactor electric system are presented. The subsystems technology development (which includes reactor and shield subsystems ground testing) is supported by materials and processes development and component development. For the purpose of the cost estimate, seven generic types of reactor subsystems were used:

W. R. Determan; R. B. Harty; C. Hylin

1983-01-01

333

REACTOR  

DOEpatents

A pressurized water reactor in which automatic control is achieved by varying the average density of the liquid moderator-cooiant is patented. Density is controlled by the temperature and power level of the reactor ftself. This control can be effected by the use of either plate, pellet, or tubular fuel elements. The fuel elements are disposed between upper and lower coolant plenum chambers and are designed to permit unrestricted coolant flow. The control chamber has an inlet opening communicating with the lower coolant plenum chamber and a restricted vapor vent communicating with the upper coolant plenum chamber. Thus, a variation in temperature of the fuel elements will cause a variation in the average moderator density in the chamber which directly affects the power level of the reactor.

Roman, W.G.

1961-06-27

334

DABIE: A Data Banking System of Integral Experiments for Reactor Core Characteristics Computer Codes. User's Manual.  

National Technical Information Service (NTIS)

A data banking system of integral experiments for reactor core characteristics computer codes, DABIE, has been developed to lighten the burden on searching so many documents to obtain experiment data required for verification of reactor core characteristi...

K. Matsumoto Y. Naito S. Ohkubo H. Aoyanagi

1987-01-01

335

Fast Shutdown System tests in the Georgia Tech Research Reactor  

SciTech Connect

The Fast Shutdown System (FSS) is a new safety system design concept being considered for in installation in the Savannah River (SRS) production reactors. This system is expected to mitigate the consequences of a Design Basis Loss of Coolant Accident, and therefore allow higher operational power levels. A test of this system in the Georgia Tech Research Reactor is proposed to demonstrate the efficacy of this concept. Three tests will be conducted at full power (5MW) and one at low power (100kw). Two full power tests will be conducted with the FSS rod backfilled with one (1) atmosphere of He-4, and one with the rod evacuated. The low power conducted with the FSS rod evacuated. Neutron flux and pressure data will be collected with an independent data acquisition system (DAS). Safety issues associated with the performance of the Fast Shutdown System experiments are addressed in this report. The credible accident scenarios were analyzed using worst case scenarios to demonstrate that no significant nuclear or personnel safety hazards would result from the performance of the proposed experiments.

Wallace, J.M.

1990-03-16

336

A Novel Approach to Material Development for Advanced Reactor Systems  

SciTech Connect

OAK B188 A Novel Approach to Material Development for Advanced Reactor Systems. Year one of this project had three major goals. First, to specify, order and install a new high current ion source for more rapid and stable proton irradiation. Second, to assess the use low temperature irradiation and chromium pre-enrichment in an effort to isolate a radiation damage microstructure in stainless steels without the effects of RIS. Third, to prepare for the irradiation of reactor pressure vessel steel and Zircaloy. In year 1 quarter 1, the project goal was to order the high current ion source and to procure and prepare samples of stainless steel for low temperature proton irradiation.

Was, G.S.; Atzmon, M.; Wang, L.

1999-12-22

337

A Novel Approach to Material Development for Advanced Reactor Systems  

SciTech Connect

OAK B188 A Novel Approach to Material Development for Advanced Reactor Systems. Year one of this project had three major goals. First, to specify, order and install a new high current ion source for more rapid and stable proton irradiation. Second, to assess the use of low temperature irradiation and chromium pre-enrichment in an effort to isolate a radiation damage microstructure in stainless steel without the effects of RIS. Third, to initiate irradiation of reactor pressure vessel steel and Zircaloy. In year 1 quarter 3, the project goal was to complete irradiation of model alloys of RPV steels for a range of doses and begin sample characterization. We also planned to prepare samples for microstructure isolation in stainless steels, and to identify sources of Zircaloy for irradiation and characterization.

Was, G.S.; Atzmon, M.; Wang, L.

2000-06-27

338

Advanced High Temperature Reactor Systems and Economic Analysis  

SciTech Connect

The Advanced High Temperature Reactor (AHTR) is a design concept for a large-output [3400 MW(t)] fluoride-salt-cooled high-temperature reactor (FHR). FHRs, by definition, feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The AHTR's large thermal output enables direct comparison of its performance and requirements with other high output reactor concepts. As high-temperature plants, FHRs can support either high-efficiency electricity generation or industrial process heat production. The AHTR analysis presented in this report is limited to the electricity generation mission. FHRs, in principle, have the potential to be low-cost electricity producers while maintaining full passive safety. However, no FHR has been built, and no FHR design has reached the stage of maturity where realistic economic analysis can be performed. The system design effort described in this report represents early steps along the design path toward being able to predict the cost and performance characteristics of the AHTR as well as toward being able to identify the technology developments necessary to build an FHR power plant. While FHRs represent a distinct reactor class, they inherit desirable attributes from other thermal power plants whose characteristics can be studied to provide general guidance on plant configuration, anticipated performance, and costs. Molten salt reactors provide experience on the materials, procedures, and components necessary to use liquid fluoride salts. Liquid metal reactors provide design experience on using low-pressure liquid coolants, passive decay heat removal, and hot refueling. High temperature gas-cooled reactors provide experience with coated particle fuel and graphite components. Light water reactors (LWRs) show the potentials of transparent, high-heat capacity coolants with low chemical reactivity. Modern coal-fired power plants provide design experience with advanced supercritical-water power cycles. The current design activities build upon a series of small-scale efforts over the past decade to evaluate and describe the features and technology variants of FHRs. Key prior concept evaluation reports include the SmAHTR preconceptual design report,1 the PB-AHTR preconceptual design, and the series of early phase AHTR evaluations performed from 2004 to 2006. This report provides a power plant-focused description of the current state of the AHTR. The report includes descriptions and sizes of the major heat transport and power generation components. Component configuration and sizing are based upon early phase AHTR plant thermal hydraulic models. The report also provides a top-down AHTR comparative economic analysis. A commercially available advanced supercritical water-based power cycle was selected as the baseline AHTR power generation cycle both due to its superior performance and to enable more realistic economic analysis. The AHTR system design, however, has several remaining gaps, and the plant cost estimates consequently have substantial remaining uncertainty. For example, the enriched lithium required for the primary coolant cannot currently be produced on the required scale at reasonable cost, and the necessary core structural ceramics do not currently exist in a nuclear power qualified form. The report begins with an overview of the current, early phase, design of the AHTR plant. Only a limited amount of information is included about the core and vessel as the core design and refueling options are the subject of a companion report. The general layout of an AHTR system and site showing the relationship of the major facilities is then provided. Next is a comparative evaluation of the AHTR anticipated performance and costs. Finally, the major system design efforts necessary to bring the AHTR design to a pre-conceptual level are then presented.

Holcomb, David Eugene [ORNL; Peretz, Fred J [ORNL; Qualls, A L [ORNL

2011-09-01

339

Pressurized water nuclear reactor system with hot leg vortex mitigator  

DOEpatents

A pressurized water nuclear reactor system includes a vortex mitigator in the form of a cylindrical conduit between the hot leg conduit and a first section of residual heat removal conduit, which conduit leads to a pump and a second section of residual heat removal conduit leading back to the reactor pressure vessel. The cylindrical conduit is of such a size that where the hot leg has an inner diameter D.sub.1, the first section has an inner diameter D.sub.2, and the cylindrical conduit or step nozzle has a length L and an inner diameter of D.sub.3 ; D.sub.3 /D.sub.1 is at least 0.55, D.sub.2 is at least 1.9, and L/D.sub.3 is at least 1.44, whereby cavitation of the pump by a vortex formed in the hot leg is prevented.

Lau, Louis K. S. (Monroeville, PA)

1990-01-01

340

Reactor Controllability of 3-Region-Core Molten Salt Reactor System - A Study on Load Following Capability  

Microsoft Academic Search

The Molten Salt Reactor (MSR) systems are liquid-fueled reactors that can be used for actinide burning, production of electricity, production of hydrogen, and production of fissile fuels (breeding). Thorium (Th) and uranium-233 (²³³U) are fertile and fissile of the MSR systems, and dissolved in a high-temperature molten fluoride salt (fuel salt) with a very high boiling temperature (up to 1650

Takahisa Yamamoto; Koshi Mitachi; Masatoshi Nishio

2006-01-01

341

System for fuel rod removal from a reactor module  

DOEpatents

A robotic system for remote underwater withdrawal of the fuel rods from fuel modules of a light water breeder reactor includes a collet/grapple assembly for gripping and removing fuel rods in each module, which is positioned by use of a winch and a radial support means attached to a vertical support tube which is mounted over the fuel module. A programmable logic controller in conjunction with a microcomputer, provides control for the accurate positioning and pulling force of the rod grapple assembly. Closed circuit television cameras are provided which aid in operator interface with the robotic system.

Matchett, Richard L. (Bethel Park, PA); Roof, David R. (North Huntingdon, PA); Kikta, Thomas J. (Pittsburgh, PA); Wilczynski, Rosemarie (McKees Rocks, PA); Nilsen, Roy J. (Pittsburgh, PA); Bacvinskas, William S. (Bethel Park, PA); Fodor, George (Pittsburgh, PA)

1990-01-01

342

System for fuel rod removal from a reactor module  

DOEpatents

A robotic system for remote underwater withdrawal of the fuel rods from fuel modules of a light water breeder reactor includes a collet/grapple assembly for gripping and removing fuel rods in each module, which is positioned by use of a winch and a radial support means attached to a vertical support tube which is mounted over the fuel module. A programmable logic controller in conjunction with a microcomputer, provides control for the accurate positioning and pulling force of the rod grapple assembly. Closed circuit television cameras are provided which aid in operator interface with the robotic system. 7 figs.

Matchett, R.L.; Fodor, G.; Kikta, T.J.; Bacvinsicas, W.S.; Roof, D.R.; Nilsen, R.J.; Wilczynski, R.

1988-07-28

343

Water gas shift membrane reactor for CO 2 control in IGCC systems: techno-economic feasibility study  

Microsoft Academic Search

A novel reactor concept, the water gas shift membrane reactor (WGS-MR) for CO2 removal in IGCC systems has been investigated. In order to establish full insight in the possibilities of the application of such a reactor, a multidisciplinary feasibility study has been carried out comprising system integration studies, catalyst research, membrane research, membrane reactor modelling and bench scale membrane reactor

M Bracht; P. T Alderliesten; R Kloster; R Pruschek; G Haupt; E Xue; J. R. H Ross; M. K Koukou; N Papayannakos

1997-01-01

344

An automated fast transfer system at the research reactor Munich  

NASA Astrophysics Data System (ADS)

An automated fast sample transfer system for the determination of measurements of short-lived isotopes has been constructed at the Research Reactor Munich FRM. Instrumental neutron activation analysis and analysis of fissile materials by delayed neutron counting are performed on this transfer device. A LabVIEWTM program on a PC with WindowsNT operating system controls the whole pneumatic system via a PCI-1200 interface and four signal conditioning SCXI-modules of National Instruments. Infrared sensors are used to monitor key points in the transfer system. The sample capsule can be automatically removed from the ``rabbit'' in a special switch prior to spectrum collection. ?-Spectra are acquired by a HPGe detector with the Loss-Free-Counting method of Westphal. The delayed neutrons are measured by five 3He-detectors and a multichannel scaler. The transfer time is about 200ms. The system and its mode of operation for routine work will be described.

Li, X.; Henkelmann, R.; Baumgärtner, F.

2004-04-01

345

Nuclear plant-aging research on reactor protection systems  

SciTech Connect

This report presents the rsults of a review of the Reactor Trip System (RTS) and the Engineered Safety Feature Actuating System (ESFAS) operating experiences reported in Licensee Event Reports (LER)s, the Nuclear Power Experience data base, Nuclear Plant Reliability Data System, and plant maintenance records. Our purpose is to evaluate the potential significance of aging, including cycling, trips, and testing as contributors to degradation of the RTS and ESFAS. Tables are presented that show the percentage of events for RTS and ESFAS classified by cause, components, and subcomponents for each of the Nuclear Steam Supply System vendors. A representative Babcock and Wilcox plant was selected for detailed study. The US Nuclear Regulatory Commission's Nuclear Plant Aging Research guidelines were followed in performing the detailed study that identified materials susceptible to aging, stressors, environmental factors, and failure modes for the RTS and ESFAS as generic instrumentation and control systems. Functional indicators of degradation are listed, testing requirements evaluated, and regulatory issues discussed.

Meyer, L.C.

1988-01-01

346

Sewage treatment in an up-flow anaerobic sponge reactor followed by moving bed biofilm reactor based on polyurethane carrier material  

Microsoft Academic Search

Comparison of the performance of an up-flow anaerobic sponge reactor (UASR) versus a classical up-flow anaerobic sludge blanket (UASB) reactor for sewage treatment was investigated. Both reactors were operated at a hydraulic retention time (HRT) of 6.0 h and organic loading rate (OLR) of 2.3 kg COD m\\/d. The results obtained revealed that the UASR produced better effluent quality as

Ahmed Tawfik; Nagwa Badr; EnasAbu Taleb; Waleed El-Senousy

2012-01-01

347

Development of alternate extractant systems for fast reactor fuel cycle  

SciTech Connect

Due to the limitations of TBP in processing of high burn-up, Pu-rich fast reactor fuels, there is a need to develop alternate extractants for fast reactor fuel processing. In this context, our Centre has been examining the suitability of alternate tri-alkyl phosphates. Third phase formation in the extraction of Th(IV) by TBP, tri-n-amyl phosphate (TAP) and tri-2-methyl-butyl phosphate (T2MBP) from nitric acid media has been investigated under various conditions to derive conclusions on their application for extraction of Pu at macro levels. The chemical and radiolytic degradation of tri-n-amyl-phosphate (TAP) diluted in normal paraffin hydrocarbon (NPH) in the presence of nitric acid has been investigated by the measurement of plutonium retention in organic phase. The potential application of room temperature ionic liquids (RTILs) for reprocessing of spent nuclear fuel has been explored. Extraction of uranium (VI) and palladium (II) from nitric acid medium by commercially available RTIL and tri-n-butyl phosphate solution in RTIL have been studied and the feasibility of electrodeposition of uranium as uranium oxide (UO{sub 2}) and palladium (II) as metallic palladium from the loaded organic phase have been demonstrated. This paper describes results of the above studies and discusses the suitability of the systems for fast reactor fuel reprocessing. (authors)

Vasudeva Rao, P.R.; Suresh, A.; Venkatesan, K.A.; Srinivasan, T.G.; Raj, Baldev [Indira Gandhi Centre for Atomic Research, Kalpakkam - 603 102 (India)

2007-07-01

348

Instrument accuracy in reactor vessel inventory tracking systems  

SciTech Connect

Instrumentation needs for detection of inadequate core cooling. Studies of the Three Mile Island accident identified the need for additional instrumentation to detect inadequate core cooling (ICC) in nuclear power plants. Industry studies by plant owners and reactor vendors supported the conclusion that improvements were needed to help operators diagnose the approach to or existence of ICC as well as to provide more complete information for operator control of safety injection flow to minimize the consequences of such an accident. In 1980, the US Nuclear Regulatory Commission (NRC) required further studies by the industry and described ICC instrumentation design requirements that included human factors and environmental considerations. On December 10, 1982, NRC issued to Babcock and Wilcox (B and W) licensees orders for Modification of License and transmitted to pressurized water reactor licensees Generic Letter 82-28 to inform them of the revised NRC requirements. The instrumentation requirements include upgraded subcooling margin monitors (SMM), upgraded core exit thermocouples (CET), and installation of a reactor coolant inventory tracking system. NRC Regulatory Guide 1.97, which covers accident monitoring instrumentation, was revised (Rev. 3) to be consistent with the requirements of item II.F.2 of NUREG-0737.

Anderson, J.L.; Anderson, R.L.; Morelock, T.C.; Hauang, T.L.; Phillips, L.E.

1986-01-01

349

Behaviour of pharmaceuticals and endocrine disrupting chemicals in simplified sewage treatment systems.  

PubMed

This work assessed the behaviour of nine pharmaceuticals and/or endocrine disrupting chemicals (EDCs) in demo-scale upflow anaerobic sludge blanket reactors (UASB reactors) coupled to distinct simplified post-treatment units (submerged bed, polishing ponds, and trickling filters) fed on raw sewage taken from a municipality in Brazil. The dissolved concentration of the studied micropollutants in the raw and treated sewage was obtained using solid phase extraction (SPE) followed by analysis in a liquid chromatography system coupled to a hybrid high resolution mass spectrometer consisting of an ion-trap and time of flight (LC-MS-IT-TOF). The UASB reactors demonstrated that they were not appropriate for efficiently removing the assessed compounds from the sewage. Furthermore, this study demonstrated that the hydraulic retention time (HRT) was an important parameter for the removal of the hydrophilic and less biodegradable compounds, such as trimethoprim and sulfamethoxazole. The post-treatment units substantially increased the removal of most target micropollutants present in the anaerobic effluents, with a greater removal of micropollutants in simplified systems that require a large construction area, such as the submerged bed and polishing ponds, probably because of the higher HRT employed. Alternatively, compact post-treatment systems, such as trickling filters, tended to be less effective at removing most of the micropollutants studied, and the type of packing proved to be crucial for determining the fate of such compounds using trickling filters. PMID:23850766

Brandt, Emanuel M F; de Queiroz, Fernanda B; Afonso, Robson J C F; Aquino, Sérgio F; Chernicharo, Carlos A L

2013-07-11

350

Aging study of boiling water reactor high pressure injection systems  

SciTech Connect

The purpose of high pressure injection systems is to maintain an adequate coolant level in reactor pressure vessels, so that the fuel cladding temperature does not exceed 1,200{degrees}C (2,200{degrees}F), and to permit plant shutdown during a variety of design basis loss-of-coolant accidents. This report presents the results of a study on aging performed for high pressure injection systems of boiling water reactor plants in the United States. The purpose of the study was to identify and evaluate the effects of aging and the effectiveness of testing and maintenance in detecting and mitigating aging degradation. Guidelines from the United States Nuclear Regulatory Commission`s Nuclear Plant Aging Research Program were used in performing the aging study. Review and analysis of the failures reported in databases such as Nuclear Power Experience, Licensee Event Reports, and the Nuclear Plant Reliability Data System, along with plant-specific maintenance records databases, are included in this report to provide the information required to identify aging stressors, failure modes, and failure causes. Several probabilistic risk assessments were reviewed to identify risk-significant components in high pressure injection systems. Testing, maintenance, specific safety issues, and codes and standards are also discussed.

Conley, D.A.; Edson, J.L.; Fineman, C.F. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

1995-03-01

351

One and two-stage upflow anaerobic sludge-bed reactor pretreatment of winery wastewater at 4–10°C  

Microsoft Academic Search

The operating performance of a single and two (in series) laboratory upflow anaerobic sludge-bed (UASB) reactors (2.7-L working\\u000a volume, recycle ratio varied from 1:1 to 1:18) treating diluted wine vinasse was investigated under psychrophilic conditions\\u000a (4–10°C). For a single UASB reactor seeded with granular sludge, the average organic loading rates (OLRs) applied were 4.7,\\u000a 3.7, and 1.7 g of chemical

Sergey V. Kalyuzhnyi; Marina A. Gladchenko; Vladimir I. Sklyar; Yekaterina S. Kizimenko; Sergey S. Shcherbakov

2001-01-01

352

Aging assessment of PWR (Pressurized Water Reactor) Auxiliary Feedwater Systems  

SciTech Connect

In support of the Nuclear Regulatory Commission's Nuclear Plant Aging Research (NPAR) Program, Oak Ridge National Laboratory is conducting a review of Pressurized Water Reactor Auxiliary Feedwater Systems. Two of the objectives of the NPAR Program are to identify failure modes and causes and identify methods to detect and track degradation. In Phase I of the Auxiliary Feedwater System study, a detailed review of system design and operating and surveillance practices at a reference plant is being conducted to determine failure modes and to provide an indication of the ability of current monitoring methods to detect system degradation. The extent to which current practices are contributing to aging and service wear related degradation is also being assessed. This paper provides a description of the study approach, examples of results, and some interim observations and conclusions. 1 fig., 1 tab.

Casada, D.A.

1988-01-01

353

Pressurized water reactor inherent core protection by primary system thermohydraulics  

SciTech Connect

Current light water reactors (LWRs) depend for the protection of core integrity on a multitude of active systems and components, such as instrumentation, cables, electronic logics, relays, actuators, etc., and on human judgment. This approach to safety has led to a complex and expensive plant design in which all parts of the plant where these systems are present must be protecte against damage due to, e.g., earthquake. It has also failed to persuade the public about the safety of the reactors because of the existing (but very small) probability of multiple failures leading to core meltdown. With the process inherent ultimate safety (PIUS) approach, this dependence on active systems is eliminated. The safety is now no longer a result of their intervention but is built into the thermohydraulics of the primary system itself. The PIUS primary system response to a number of severe anticipated transients without scram (ATWS) is described, as studied by means of a specially devel oped computer simulation program. The method is shown by which the thermohydraulic self-protection properties of the primary system terminates these ATWS transients, which could have severe consequences in a conventional LWR, with neither the core nor the rest of the plant suffering any damage (beyond the initial failure assumed). This has important economic consequences. The surveillance and control systems used to run the plant and the buildings in which they are housed can be designed as for a fossil plant, since they no longer have the ultimate responsibility for nuclear safety. The ensuing design simplification pays for the more expensive pressure vessel and primary system. Inherent safety is obtained as a bonus.

Babala, D.; Hannerz, K.

1985-08-01

354

Technological implications of SNAP reactor power system development on future space nuclear power systems  

SciTech Connect

Nuclear reactor systems are one method of satisfying space mission power needs. The development of such systems must proceed on a path consistent with mission needs and schedules. This path, or technology roadmap, starts from the power system technology data base available today. Much of this data base was established during the 1960s and early 1970s, when government and industry developed space nuclear reactor systems for steady-state power and propulsion. One of the largest development programs was the Systems for Nuclear Auxiliary Power (SNAP) Program. By the early 1970s, a technology base had evolved from this program at the system, subsystem, and component levels. There are many implications of this technology base on future reactor power systems. A review of this base highlights the need for performing a power system technology and mission overview study. Such a study is currently being performed by Rockwell's Energy Systems Group for the Department of Energy and will assess power system capabilities versus mission needs, considering development, schedule, and cost implications. The end product of the study will be a technology roadmap to guide reactor power system development.

Anderson, R.V.

1982-11-16

355

Passive cooling system for liquid metal cooled nuclear reactors with backup coolant flow path  

DOEpatents

A liquid metal cooled nuclear fission reactor plant having a passive auxiliary safety cooling system for removing residual heat resulting from fuel decay during reactor shutdown, or heat produced during a mishap. This reactor plant is enhanced by a backup or secondary passive safety cooling system which augments the primary passive auxiliary cooling system when in operation, and replaces the primary system when rendered inoperable.

Hunsbedt, Anstein (Los Gatos, CA); Boardman, Charles E. (Saratoga, CA)

1993-01-01

356

Screening reactor steam/water piping systems for water hammer  

SciTech Connect

A steam/water system possessing a certain combination of thermal, hydraulic and operational states, can, in certain geometries, lead to a steam bubble collapse induced water hammer. These states, operations, and geometries are identified. A procedure that can be used for identifying whether an unbuilt reactor system is prone to water hammer is proposed. For the most common water hammer, steam bubble collapse induced water hammer, six conditions must be met in order for one to occur. These are: (1) the pipe must be almost horizontal; (2) the subcooling must be greater than 20 C; (3) the L/D must be greater than 24; (4) the velocity must be low enough so that the pipe does not run full, i.e., the Froude number must be less than one; (5) there should be void nearby; (6) the pressure must be high enough so that significant damage occurs, that is the pressure should be above 10 atmospheres. Recommendations on how to avoid this kind of water hammer in both the design and the operation of the reactor system are made.

Griffith, P. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1997-09-01

357

Use of lead-bismuth coolant in nuclear reactors and accelerator-driven systems  

Microsoft Academic Search

Experience of using lead-bismuth coolant in reactors of Russian nuclear submarines is briefly presented. The salient points of the concept providing the safety of reactor facilities cooled by a lead-bismuth eutectic are covered. The key results of developments for use of a lead-bismuth coolant in nuclear reactors and accelerator-driven system, are presented.

B. F. Gromov; Yu. S. Belomitcev; E. I. Yefimov; M. P. Leonchuk; P. N. Martinov; Yu. I. Orlov; D. V. Pankratov; Yu. G. Pashkin; G. I. Toshinsky; V. V. Chekunov; B. A. Shmatko; V. S. Stepanov

1997-01-01

358

Feasibility Studies on Commercialized Fast Breeder Reactor System (2) Gas Cooled High Temperature FBR  

Microsoft Academic Search

Japan Nuclear Cycle Development Institute (JNC) and Electric Utilities have been conducting Feasibility Studies on Commercialized FBR Systems since July 1999 under the cooperation Agreement. In that studies the preliminary concepts of various types of fast breeder reactors such as sodium cooled, heavy metal cooled and gas cooled reactors etc. have been designed and evaluated. For the gas cooled reactors,

Yoshihiro Kiso; Jun Kobayashi; Masanori Kid; Masashi Nomura; Masakazu Ichimiya

359

Sandia Pulsed Reactor Facility (SPRF) Calculator-Assisted Pulse Analysis and Display System.  

National Technical Information Service (NTIS)

Two solid-metal fast burst type reactors (SPR II and SPR III) are operated at the Sandia Pulsed Reactor Facility. Since startup of the reactors, oscilloscope traces have been used to record (by camera) the pulse (power) shape while log N systems have meas...

B. F. Estes D. T. Berry

1980-01-01

360

Development of separable micro reactor system with integrated fluid control devices for personalized medicine  

Microsoft Academic Search

This paper introduces our project of the micro reactor system with fluid control devices; a micro pump, a micro mixer and a micro valve. A micro reactor creates a high speed and high efficiency chemical process and is expected to develop chemical products and medical devices for personalized medicine. The purpose of my work is to develop a micro reactor

Hironari Taniguchi; Koichi Suzumori; Takumi Nakahira; Chinami Ito; Takefumi Kanda

2007-01-01

361

Alternative Passive Decay-Heat Systems for the Advanced High-Temperature Reactor  

SciTech Connect

The Advanced High-Temperature Reactor (AHTR) is a low-pressure, liquid-salt-cooled high-temperature reactor for the production of electricity and hydrogen. The high-temperature (950 deg C) variant is defined as the liquid-salt-cooled very high-temperature reactor (LS-VHTR). The AHTR has the same safety goals and uses the same graphite-matrix coated particle fuel as do modular high-temperature gas-cooled reactors. However, the large AHTR power output [2400 to 4000 MW(t)] implies the need for a different type of passive decay-heat removal system. Because the AHTR is a low-pressure, liquid-cooled reactor like sodium-cooled reactors, similar types of decay-heat-removal systems can be used. Three classes of passive decay heat removal systems have been identified: the reactor vessel auxiliary cooling system which is similar to that proposed for the General Electric S-PRISM sodium-cooled fast reactor; the direct reactor auxiliary cooling system, which is similar to that used in the Experimental Breeder Reactor-II; and a new pool reactor auxiliary cooling system. These options are described and compared. (author)

Forsberg, Charles W. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6165 (United States)

2006-07-01

362

Coil system for a mirror-based hybrid reactor  

SciTech Connect

Two different superconducting coil systems for the SFLM Hybrid study - a quadrupolar mirror based fusion-fission reactor study - are presented. One coil system is for a magnetic field with 2 T at the midplane and a mirror ratio of four. This coil set consists of semiplanar coils in two layers. The alternative coil system is for a downscaled magnetic field of 1.25 T at the midplane and a mirror ratio of four, where a higher {beta} is required to achieve sufficient the neutron production. This coil set has one layer of twisted 3D coils. The 3D coils are expected to be considerably cheaper than the semiplanar, since NbTi superconductors can be used for most coils instead of Nb3Sn due to the lower magnetic field.

Hagnestal, A.; Agren, O.; Moiseenko, V. E. [Uppsala University, Angstroem laboratory, Division of Electricity, Box 534, SE-751 21 Uppsala (Sweden); Institute of Plasma Physics, National Science Center 'Kharkov Institute of Physics and Technology', Akademichna st. 1, 61108 Kharkiv (Ukraine)

2012-06-19

363

SP100 space reactor power system for lunar, Mars, and robotic exploration  

Microsoft Academic Search

The SP-100 power system is described which was developed for three missions, namely, Pluto Orbiter with nuclear electric propulsion; human-rated surface reactor power system for lunar and Mars exploration; and earth surveillance with an integrated nuclear electric propulsion system. The reactor power systems technology is being developed to meet these requirements so that the technical database, design tools, and specifications

Jack F. Mondt

1992-01-01

364

Treatment of dilute phenol\\/PCP wastewaters using the upflow anaerobic sludge blanket (USAB) reactor  

Microsoft Academic Search

UASB reactors started up well using phenol as the sole carbon source, and by day 46, COD removal efficiency was 100%. Pentachlorophenol (PCP) was then introduced at a concentration of 1 mg\\/l. Sequential appearance of tri-, di- and ultimately mono-chlorophenols was observed in the reactor effluent. After 70 days of operation, only 3-chlorophenol was detected in the reactor effluent. Increasing

Sheldon J. B. Duff; Kevin J. Kennedy; Amanda J. Brady

1995-01-01

365

Anaerobic Treatment of Yeast Effluent in an Expanded Granular Sludge Bed Reactor  

Microsoft Academic Search

The purpose of this study was to investigate the use of an anaerobic expanded granular sludge bed (EGSB) reactor, to treat high strength yeast wastewater. The EGSB reactor was seeded with granular sludge from the UASB reactor of a full-scale brewery factory. Experiment was done under operational condition of a total superficial up flow velocity(Vup) of 6m·h-1, Temperature of 30?,

Yan Zhi-yong; Wang Jing-song; Xie Lei

2010-01-01

366

The MAUS nuclear space reactor with ion propulsion system  

NASA Astrophysics Data System (ADS)

MAUS (Moltiplicatore Avanzato Ultracompatto Spaziale) is a nuclear reactor concept design capable to ensure a reliable, long-lasting, low-mass, compact energy supply needed for advanced, future space missions. The exploration of the solar system and the space beyond requires the development of nuclear energy generators for supplying electricity to space-bases, spacecrafts, probes or satellites, as well as for propelling ships in long space missions. For propulsion, the MAUS nuclear reactor could be used to power electric ion drive engines. An ion engine is able to build up to very high velocities, far greater than chemical propulsion systems, but has high power and long service requirements. The MAUS concept is described, together with the ion propulsion engine and together with the reference thermoionic process used to convert the thermal power into electricity. The design work has been performed at the Nuclear Engineering and Energy Conversion Department of the University of Rome “La Sapienza” starting from 1992 on an issue submitted by the Italian Space Agency (ASI), in cooperation with the research laboratories of ENEA.

Mainardi, Enrico

2006-06-01

367

High Flux Isotope Reactor system RELAP5 input model  

SciTech Connect

A thermal-hydraulic computational model of the High Flux Isotope Reactor (HFIR) has been developed using the RELAP5 program. The purpose of the model is to provide a state-of-the art thermal-hydraulic simulation tool for analyzing selected hypothetical accident scenarios for a revised HFIR Safety Analysis Report (SAR). The model includes (1) a detailed representation of the reactor core and other vessel components, (2) three heat exchanger/pump cells, (3) pressurizing pumps and letdown valves, and (4) secondary coolant system (with less detail than the primary system). Data from HFIR operation, component tests, tests in facility mockups and the HFIR, HFIR specific experiments, and other pertinent experiments performed independent of HFIR were used to construct the model and validate it to the extent permitted by the data. The detailed version of the model has been used to simulate loss-of-coolant accidents (LOCAs), while the abbreviated version has been developed for the operational transients that allow use of a less detailed nodalization. Analysis of station blackout with core long-term decay heat removal via natural convection has been performed using the core and vessel portions of the detailed model.

Morris, D.G.; Wendel, M.W.

1993-01-01

368

Chemical Looping Combustion System-Fuel Reactor Modeling  

SciTech Connect

Chemical looping combustion (CLC) is a process in which an oxygen carrier is used for fuel combustion instead of air or pure oxygen as shown in the figure below. The combustion is split into air and fuel reactors where the oxidation of the oxygen carrier and the reduction of the oxidized metal occur respectively. The CLC system provides a sequestration-ready CO2 stream with no additional energy required for separation. This major advantage places combustion looping at the leading edge of a possible shift in strict control of CO2 emissions from power plants. Research in this novel technology has been focused in three distinct areas: techno-economic evaluations, integration of the system into power plant concepts, and experimental development of oxygen carrier metals such as Fe, Ni, Mn, Cu, and Ca. Our recent thorough literature review shows that multiphase fluid dynamics modeling for CLC is not available in the open literature. Here, we have modified the MFIX code to model fluid dynamic in the fuel reactor. A computer generated movie of our simulation shows bubble behavior consistent with experimental observations.

Gamwo, I.K.; Jung, J. (ANL); Anderson, R.R.; Soong, Y.

2007-04-01

369

Fossil-fuel processing technical\\/professional services: comparison of Fischer-Tropsch reactor systems. Phase I, final report  

Microsoft Academic Search

The Fischer-Tropsch reaction was commercialized in Germany and used to produce military fuels in fixed bed reactors. It was recognized from the start that this reactor system had severe operating and yield limitations and alternative reactor systems were sought. In 1955 the Sasol I complex, using an entrained bed (Synthol) reactor system, was started up in South Africa. Although this

G. J. Thompson; M. L. Riekena; A. G. Vickers

1981-01-01

370

FAFTRCS: an experiment in computerized reactor safety systems  

SciTech Connect

Nuclear Power Plant availability and reliability could be improved by the integration of computers into the control environment. However, computer-based systems are historically viewed as being unreliable. This places a burden upon the designer to demonstrate adequate reliability and availability for the computer. The complexity associated with computers coupled with the manual nature of these demonstrations results in a high cost which typically has been justified for critical applications only. This paper investigates a methodology for automating this process and discusses a project which intends to apply this methodology to design verification and validation for a control system which will be installed and tested in an actual reactor control environment. 7 refs., 4 figs., 1 tab.

Chisholm, G.H.

1985-01-01

371

CADET: A decision support system for light water reactor safety  

SciTech Connect

CADET (Computer Aided DEcision Tool) is a decision support system for light water reactor safety which is designed for use on personal computers. As a decision support system, it provides a user-friendly data base program complemented with several computational capabilities. The data base component of the program provides users with pertinent data from a variety of sources. The computational portion of the program provides measures of consequence and risk, and a means for performing ''what if'' analyses with selected elements of the data base. Predictive capabilities incorporated into the present version of CADET include effects of time of containment failure, effects of containment leak rate, and influences of filtered venting on the outcome of accident sequences.

Nicolosi, S.L.; Hesse, D.J.

1988-09-01

372

Deployment of remote dismantlement systems at the CP5 reactor  

Microsoft Academic Search

The Chicago Pile 5 (CP-5) Reactor Facility is currently undergoing decontamination and decommissioning (D&D) at the Argonne National Laboratory (ANL) Illinois site. CP-5 was the principal nuclear reactor used to produce neutrons for scientific research at Argonne from 1954 to 1979. The CP-5 reactor was a heavy-water moderated, enriched uranium-fueled reactor with a graphite reflector. The CP-5 D&D project includes

D. B. Black; R. W. Ditch; D. R. Henley; L. S. Seifert

1997-01-01

373

A methodology for the risk analysis of fission-reactor space nuclear systems  

Microsoft Academic Search

Fission-reactor space nuclear power systems have been used on past space missions and their use is planned on future missions where power and mission profile requirements cannot not be satisfied by other system types. Fission-reactor space nuclear power systems pose a degree of risk due to the potential for radiation exposure under certain normal operating and postulated accident conditions. The

Bart W. Bartram; Seshagiri R. Tammara; Abraham Weitzberg

1992-01-01

374

Reactor control system upgrade for the McClellan Nuclear Radiation Center Sacramento, CA  

Microsoft Academic Search

Argonne National Laboratory is currently developing a new reactor control system for the McClellan Nuclear Radiation Facility. This new control system not only provides the same functionality as the existing control system in terms of graphic displays of reactor process variables, data archival capability, and manual, automatic, pulse and square-wave modes of operation, but adds to the functionality of the

1999-01-01

375

Anaerobic digestion model No. 1-based distributed parameter model of an anaerobic reactor: II. Model validation.  

PubMed

In this study, an ADM1-based distributed parameter model was validated using experimental results obtained in a laboratory-scale 10 L UASB reactor. Sensitivity analysis of the model parameters was used to select four parameters for estimation by a numerical procedure while other parameters were accepted from ADM1 benchmark simulations. The parameter estimation procedure used measurements of liquid phase components obtained at different sampling points in the reactor and under different operating conditions. Model verification used real time fluorescence-based measurements of chemical oxygen demand and volatile fatty acids at four sampling locations in the reactor. Overall, the distributed parameter model was able to describe the distribution of liquid phase components in the reactor and adequately simulated the effect of external recirculation on degradation efficiency. The model can be used in the design, analysis and optimization of UASB reactors. PMID:17889525

Tartakovsky, B; Mu, S J; Zeng, Y; Lou, S J; Guiot, S R; Wu, P

2007-09-21

376

N-reactor charge-discharge system analysis  

SciTech Connect

This report documents an analysis of the existing systems in the N-Reactor fuel flow path. It recommends equipment improvements and changes in that path to allow the charge-discharge rates to be increased to 500 tubes per outage without increasing reactor outage time. The estimated program cost of $14 million is projected over an estimated 3-year period. It does not include costs detailed as part of the existing restoration program or any costs that are considered as normal maintenance. The recommendations contained in this report provide a direction and goal for every critical aspect of the fuel flow path. The way in which these recommendations are implemented may greatly affect the schedule and costs. Previous studies by UNC have shown that enhanced fuel element handling has the potential of increasing productivity by 33 days at a cost benefit estimated at $18 million per year. Enhanced fuel handling provides the greatest potential for productivity improvement of any of the areas considered in these studies.

Tokarz, R.D.; Marr, G.D.; Nesbitt, J.F.

1982-09-01

377

Treatment of winery effluent with upflow anaerobic sludge blanket (UASB) – granular sludges enriched with Enterobacter sakazakii  

Microsoft Academic Search

Three upflow anaerobic sludge blankets (UASBs) were evaluated for the treatment of winery wastewater: the first was seeded with granular sludge enriched with Enterobacter sakazakii and reached a 90% COD removal within 17 d at hydraulic retention time of 24 h; the second was seeded with brewery granules and achieved 85% COD removal within 50 d, the third was seeded with just sludge

M. Keyser; R. C. Witthuhn; L.-C. Ronquest; T. J. Britz

2003-01-01

378

Acoustical gas core reactor with MHD power generation for burst power in a bimodal system  

Microsoft Academic Search

Research is being conducted on gas core reactors for space nuclear power to establish the scientific feasibility and engineering validation of a reactor and energy conversion system that can significantly improve specific power, dynamic performance and system efficiency. Rapid achievement of burst mode (GWe) operation at core power densities of 1 kW\\/mL and reactor masses of a kg\\/MWt are research

E. T. Dugan; A. M. Jacobs; C. C. Oliver; W. E. Lear Jr.

1987-01-01

379

Winding insulation in electromagnetic systems for Tokamak reactor plants  

NASA Astrophysics Data System (ADS)

Magnetic containment of the plasma in nuclear fusion reactors of the Tokamak type requires electromagnets with insulation which must withstand high temperatures and thermal shocks as well as ionizing radiation in various forms and electric fields, and mechanical loads. Insulation materials to ensure adequate thermophysical and mechanical properties are evaluated, followed by design of insulation systems with satisfactory performance characteristics. Data on neutron fluence energy characteristics and radiation absorption doses during neutron interactions are essential for such an evaluation. Materials considered for insulation in electromagnets with superconductor and cryoresistance windings are glass mica tape with epoxy compound impregnation, glass cloth with epoxy compound impregnation (STE), polyimide glass cloth with adhesive coating (LSNL), glass Textolite with epoxy phenolic binder (STEN), epoxy resin paste with mineral fillers (PE), and polyurethane compound modified by epoxy resin with mineral filler (KPU).

Maslov, V. V.; Trubachev, S. G.

1985-01-01

380

Manual calibration system for Daya Bay Reactor Neutrino Experiment  

NASA Astrophysics Data System (ADS)

The Daya Bay Reactor Neutrino Experiment has measured the last unknown neutrino mixing angle, ?13, to be non-zero at the 7.7? level. This is the most precise measurement to ?13 to date [1,2]. To further enhance the understanding of the response of the antineutrino detectors (ADs), a detailed calibration of an AD with the Manual Calibration System (MCS) was undertaken during the summer 2012 shutdown. The MCS is capable of placing a radioactive source with a positional accuracy of 25 mm in R direction, 12 mm in Z axis and 0.5° in ? direction. A detailed description of the MCS is presented followed by a summary of its performance in the AD calibration run.

Huang, H. X.; Ruan, X. C.; Ren, J.; Fan, C. J.; Chen, Y. N.; Lv, Y. L.; Wang, Z. H.; Zhou, Z. Y.; Hou, L.; Xin, B.; Yu, C. J.; Zhang, J. W.; Zhang, Y. H.; Bai, J. Z.; Zhuang, H. L.; He, W.; Liu, J. L.; Worcester, E.; Themann, H.; Ling, J. J.; Cherwinka, J.; Webber, D. M.

2013-09-01

381

Reactor protection system design using application specific integrated circuits  

SciTech Connect

Implementing reactor protection systems (RPS) or other engineering safeguard systems with application specific integrated circuits (ASICs) offers significant advantages over conventional analog or software based RPSs. Conventional analog RPSs suffer from setpoints drifts and large numbers of discrete analog electronics, hardware logic, and relays which reduce reliability because of the large number of potential failures of components or interconnections. To resolve problems associated with conventional discrete RPSs and proposed software based RPS systems, a hybrid analog and digital RPS system implemented with custom ASICs is proposed. The actual design of the ASIC RPS resembles a software based RPS but the programmable software portion of each channel is implemented in a fixed digital logic design including any input variable computations. Set point drifts are zero as in proposed software systems, but the verification and validation of the computations is made easier since the computational logic an be exhaustively tested. The functionality is assured fixed because there can be no future changes to the ASIC without redesign and fabrication. Subtle error conditions caused by out of order evaluation or time dependent evaluation of system variables against protection criteria are eliminated by implementing all evaluation computations in parallel for simultaneous results. On- chip redundancy within each RPS channel and continuous self-testing of all channels provided enhanced assurance that a particular channel is available and faults are identified as soon as possible for corrective actions. The use of highly integrated ASICs to implement channel electronics rather than the use of discrete electronics greatly reduces the total number of components and interconnections in the RPS to further increase system reliability. A prototype ASIC RPS channel design and the design environment used for ASIC RPS systems design is discussed.

Battle, R.E.; Bryan, W.L.; Kisner, R.A.; Wilson, T.L. Jr.

1992-01-01

382

Reactor protection system design using application specific integrated circuits  

SciTech Connect

Implementing reactor protection systems (RPS) or other engineering safeguard systems with application specific integrated circuits (ASICs) offers significant advantages over conventional analog or software based RPSs. Conventional analog RPSs suffer from setpoints drifts and large numbers of discrete analog electronics, hardware logic, and relays which reduce reliability because of the large number of potential failures of components or interconnections. To resolve problems associated with conventional discrete RPSs and proposed software based RPS systems, a hybrid analog and digital RPS system implemented with custom ASICs is proposed. The actual design of the ASIC RPS resembles a software based RPS but the programmable software portion of each channel is implemented in a fixed digital logic design including any input variable computations. Set point drifts are zero as in proposed software systems, but the verification and validation of the computations is made easier since the computational logic an be exhaustively tested. The functionality is assured fixed because there can be no future changes to the ASIC without redesign and fabrication. Subtle error conditions caused by out of order evaluation or time dependent evaluation of system variables against protection criteria are eliminated by implementing all evaluation computations in parallel for simultaneous results. On- chip redundancy within each RPS channel and continuous self-testing of all channels provided enhanced assurance that a particular channel is available and faults are identified as soon as possible for corrective actions. The use of highly integrated ASICs to implement channel electronics rather than the use of discrete electronics greatly reduces the total number of components and interconnections in the RPS to further increase system reliability. A prototype ASIC RPS channel design and the design environment used for ASIC RPS systems design is discussed.

Battle, R.E.; Bryan, W.L.; Kisner, R.A.; Wilson, T.L. Jr.

1992-08-01

383

IAEA coordinated research activities on materials for advanced reactor systems  

NASA Astrophysics Data System (ADS)

After the recent accident at the Fukushima Daiichi Nuclear Power Plant, public resentment towards nuclear energy is very high; however it is also important to emphasise that for other facilities the safety record has been remarkably good when compared to those of other new or conventional energy technologies. In addition to clear safety improvements new systems will have increased thermal efficiency, maximised fuel use, and reduced nuclear waste production. In order to initiate commercial deployment of power reactors, small scale demonstrations of such new systems are urgently needed. This will help to develop, test and qualify new structural materials with improved properties with respect to radiation, corrosion, thermal and other degradation processes. To solve all challenges related to the performance parameters of such materials, internationally driven efforts must focus on research, targeted testing, and final selection of appropriate materials. This is recognised as a key milestone in successful demonstration and future deployment of newly designed nuclear reactors. Because of clear synergies between fusion and fission research and development communities have been identified, closer cooperation of research groups has been stimulated. Although some operational conditions are expected to change, many basic features will remain similar. In addition to the material science effort, new experimental facilities are being developed for the study of high-radiation damage effects on the microstructure of candidate materials prior to their qualification.During last 5 years, the International Atomic Energy Agency (IAEA) launched several coordinated research activities in this specific, but very important field. This paper gives a summary of on-going IAEA activities related to the development and characterisation of structural and plasma facing materials for nuclear energy.

Zeman, A.; Inozemtsev, V.; Kamendje, R.; Beatty, R. L.

2013-11-01

384

Reliability evaluation of the Savannah River reactor leak detection system  

SciTech Connect

The Savannah River Reactors have been in operation since the mid-1950's. The primary degradation mode for the primary coolant loop piping is intergranular stress corrosion cracking. The leak-before-break (LBB) capability of the primary system piping has been demonstrated as part of an overall structural integrity evaluation. One element of the LBB analyses is a reliability evaluation of the leak detection system. The most sensitive element of the leak detection system is the airborne tritium monitors. The presence of small amounts of tritium in the heavy water coolant provide the basis for a very sensitive system of leak detection. The reliability of the tritium monitors to properly identify a crack leaking at a rate of either 50 or 300 lb/day (0.004 or 0.023 gpm, respectively) has been characterized. These leak rates correspond to action points for which specific operator actions are required. High reliability has been demonstrated using standard fault tree techniques. The probability of not detecting a leak within an assumed mission time of 24 hours is estimated to be approximately 5 {times} 10{sup {minus}5} per demand. This result is obtained for both leak rates considered. The methodology and assumptions used to obtain this result are described in this paper. 3 refs., 1 fig., 1 tab.

Daugherty, W.L.; Sindelar, R.L. (Westinghouse Savannah River Co., Aiken, SC (USA)); Wallace, I.T. (Westinghouse Electric Corp., Pittsburgh, PA (USA))

1991-01-01

385

Identification of seismic structures, systems and components of PHEC system of Fast Breeder Test Reactor  

Microsoft Academic Search

The reactor shutdown is followed by power decay and the decay heat removal is carried out by different decay heat removal (DHR) systems based on the plant configuration. In FBTR, normal mode of DHR is by the primary and secondary sodium loops and through steam generators (SG) with trap doors of the SG casing open. For DHR by normal mode,

S. Usha; C. Senthil Kumar; G. Srinivasan; P. C. Basu

2010-01-01

386

Anaerobic digestion Of a Petrochemical Wastewater using the UASB process  

Microsoft Academic Search

Anaerobic digestion of effluent from a petrochemical plant producing terephthalic acid has been tested using two Upflow Anaerobic\\u000a Sludge Blanket (USAB) reactors. The reactors were seeded with two different inocula: one from an anaerobic stabilization pond\\u000a receiving wasted sludge from the aerobic treatment plant of the petrochemical industry (reactor A); the other was an anaerobically\\u000a adapted activated sludge from a

J. P. Guyot; H. Macarie; A. Noyola

1990-01-01

387

A neutral beam injection system for the Tokamak Fusion Test Reactor  

Microsoft Academic Search

The Tokamak Fusion Test Reactor will be installed at the Princeton Plasma Physics Laboratory facility. This is a major step to reach the goal of fusion power using toroidal magnetic fields for plasma confinement. A major part of this test reactor will be four neutral beam injection systems. These systems will inject 20 MW of 120 kV neutral deuterium atoms

L. C. Pittenger; R. R. Stone; L. E. Valby; L. R. Pedrotti

1977-01-01

388

Self-locking drive system for rotating plug of a nuclear reactor  

Microsoft Academic Search

This disclosure describes a self locking drive system for rotating the plugs on the head of a nuclear reactor which is able to restrain plug motion if a seismic event should occur during reactor refueling. A servomotor is engaged via a gear train and a bull gear to the plug. Connected to the gear train is a feedback control system

1979-01-01

389

Self locking drive system for rotating plug of a nuclear reactor  

Microsoft Academic Search

A self locking drive system for rotating the plugs on the head of a nuclear reactor which is able to restrain plug motion if a seismic event whould occur during reactor refueling is described. A servomotor is engaged via a gear train and a bull gear to the plug. Connected to the gear train is a feedback control system which

1979-01-01

390

Self locking drive system for rotating plug of a nuclear reactor  

Microsoft Academic Search

This disclosure describes a self locking drive system for rotating the plugs on the head of a nuclear reactor which is able to restrain plug motion if a seismic event should occur during reactor refueling. A servomotor is engaged via a gear train and a bull gear to the plug. Connected to the gear train is a feedback control system

James E

1979-01-01

391

Conceptual design of laser fusion reactor KOYO-fast Concepts of reactor system and laser driver  

Microsoft Academic Search

We have carried out the design studies of KOYO-Fast laser fusion power plant, using fast ignition cone targets, DPSSL lasers, and LiPb liquid wall chambers. Using fast ignition targets, we could design a middle sized 300 MWe reactor module, with 200 MJ fusion pulse energy and 4 Hz rep-rates, and 1200MWe modular power plants with 4 reactor modules and a

Y. Kozaki; N. Miyanaga; T. Norimatsu; Y. Soman; T. Hayashi; H. Furukawa; M. Nakatsuka; K. Yoshida; H. Nakano; H. Kubomura; T. Kawashima; J. Nishimae; Y. Suzuki; N. Tsuchiya; T. Kanabe; T. Jitsuno; H. Fujita; J. Kawanaka; K. Tsubakimoto; Y. Fujimoto; J. Lu; S. Matsuoka; T. Ikegawa; Y. Owadano; K. Ueda; K. Tomabechi

2006-01-01

392

Secondary Startup Neutron Sources as a Source of Tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS)  

SciTech Connect

The hypothesis of this paper is that the Zircaloy clad fuel source is minimal and that secondary startup neutron sources are the significant contributors of the tritium in the RCS that was previously assigned to release from fuel. Currently there are large uncertainties in the attribution of tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS). The measured amount of tritium in the coolant cannot be separated out empirically into its individual sources. Therefore, to quantify individual contributors, all sources of tritium in the RCS of a PWR must be understood theoretically and verified by the sum of the individual components equaling the measured values.

Shaver, Mark W.; Lanning, Donald D.

2010-02-01

393

Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates  

PubMed Central

This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.

Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

2005-01-01

394

Determination of the Optimal and Economical Biofilter Depth in an Anaerobic Hybrid Reactor for Treating Livestock Industrial Wastewater  

Microsoft Academic Search

A laboratory scale anaerobic hybrid reactor (AHR) being comprised of UASB and anaerobic biofilter was used to study the different biofilter depth with corresponding different critical HRT (1) and HRT (2) in treating livestock industrial wastewater, where the critical HRT (1) was defined as the HRT which resulted in the total COD in the effluent of the AHR exceeding in

L. Wang; Q. Zhou; H. Chua

2005-01-01

395

Multi-Reactor Power System Configurations for Multimegawatt Nuclear Electric Propulsion.  

National Technical Information Service (NTIS)

A modular, multi-reactor power system and vehicle configuration for piloted nuclear electric propulsion (NEP) missions to Mars is presented. Such a design could provide enhanced system and mission reliability, allowing a comfortable safety margin for earl...

J. A. George

1991-01-01

396

Assessment of the advantages of a residual heat removal system inside the reactor pressure vessel.  

National Technical Information Service (NTIS)

In the framework of research on diversified means for removing the residual heat from pressurized water reactors, the CEA is studying a passive system called RRP (Refroidissement du Reacteur au Primaire, or primary circuit cooling system), which includes ...

G. M. Gautier

1995-01-01

397

Issues of verification and validation of application-specific integrated circuits in reactor trip systems.  

National Technical Information Service (NTIS)

Concepts of using application-specific integrated circuits (ASICs) in nuclear reactor safety systems are evaluated. The motivation for this evaluation stems from the difficulty of proving that software-based protection systems are adequately reliable. Imp...

R. E. Battle G. T. Alley

1993-01-01

398

Advanced Membrane Reactors in Energy Systems A Carbon-Free Conversion of Fossil Fuels  

Microsoft Academic Search

The purpose of this project is to develop hydrogen and CO2 selective membranes to allow combination of natural gas reforming with H2 or CO2 separation in separation enhanced reactors, i.e. membrane reactors, for carbon-free hydrogen production or electricity generation. To achieve this, the project comprises three distinct tasks: system and reactor analysis, membrane materials research and catalysis. Already in an

Paul van Beurden; Rick T. J. Reijers; Daniel Jansen; Jan Wilco Dijkstra; Steven C. A. Kluiters; Michiel C. Carbo; Virginie Feuillade; Wim G. Haije

399

Electromagnetic Pumps for Main Cooling Systems of Commercialized Sodium-Cooled Fast Reactor  

Microsoft Academic Search

An electromagnetic pump (EMP) has superior potential to improve the economic performance and ease of maintenance of sodium-cooled fast reactors. This study investigates the adequateness of a modular-type EMP system for large-sized (1,500MWe class) sodium-cooled fast reactors. A flow rate of over 500 m\\/min is required for the main circulating pump of such reactors. There is concern that such a

Kosuke AIZAWA; Yoshitaka CHIKAZAWA; Shoji KOTAKE; Kuniaki ARA; Rie AIZAWA; Hiroyuki OTA

2011-01-01

400

A long term radiological risk model for plutonium-fueled and fission reactor space nuclear system  

SciTech Connect

This report describes the optimization of the RISK III mathematical model, which provides risk assessment for the use of a plutonium-fueled, fission reactor in space systems. The report discusses possible scenarios leading to radiation releases on the ground; distinctions are made for an intact reactor and a dispersed reactor. Also included are projected dose equivalents for various accident situations. 54 refs., 31 figs., 11 tabs. (TEM)

Bartram, B.W.; Dougherty, D.K.

1987-01-01

401

Design of biochemical reactors mass transfer criteria for simple and complex systems  

Microsoft Academic Search

Biochemical reactors are treated as heterogeneous catalytic reactors in which physical mass transfer completely or significantly\\u000a controls the overall rate of the process being promoted in the reactor. The treatment used to develop basic design strategies\\u000a takes into account the special constraints imposed by biological and biochemical phenomena on the systems.\\u000a \\u000a By identifying the fundamental principles involved, generalized mass transfer

M. Moo-Young; H. Blanch

402

Reactor coolant system blowdown at Wolf Creek on September 17, 1994  

Microsoft Academic Search

335-343 September 17, 1994, an inadvertent blowdown occurred at Wolf Creek reactor; about 34 822 L (9 200 gal) of reactor coolant passed through the residual heat removal (RHR) system to the refueling water storage tank (RWST) while the Wolf Creek reactor was shut down in Mode 4 on RHR cooling [2.5 MPa and 149°C (350 psig and 300°F)]. This

J. V. Kauffman; S. L. Israel

1995-01-01

403

System Analysis for Decay Heat Removal in Lead-Bismuth Cooled Natural Circulated Reactors  

Microsoft Academic Search

Decay heat removal analyses for lead-bismuth cooled natural circulation reactors are described in this paper. A combined multi-dimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural circulation reactors. For the preliminary study, transient analysis has been performed for a 100 MWe lead-bismuth-cooled reactor designed by Argonne National Laboratory (ANL). In addition, decay heat

Takaaki Sakai; Yasuhiro Enuma; Takashi Iwasaki; Kazuhiro Ohyama

2002-01-01

404

System Analysis for Decay Heat Removal in Lead-Bismuth-Cooled Natural-Circulation Reactors  

Microsoft Academic Search

Decay heat removal analyses for lead-bismuth-cooled natural-circulation reactors are described in this paper. A combined multidimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural-circulation reactors. For the preliminary study, transient analysis has been performed for a 300-MW(thermal) lead-bismuth-cooled reactor designed by Argonne National Laboratory. In addition, decay heat removal characteristics of a 400-MW(electric)

Takaaki Sakai; Yasuhiro Enuma; Takashi Iwasaki

2004-01-01

405

Risk-informed design guidance for future reactor systems  

Microsoft Academic Search

Future reactor designs face an uncertain regulatory environment. It is anticipated that there will be some level of probabilistic insights in the regulations and supporting regulatory documents for Generation-IV nuclear reactors. Central to current regulations are design basis accidents (DBAs) and the general design criteria (GDC), which were established before probabilistic risk assessments (PRAs) were developed. These regulations implement a

Michael J. Delaney; George E. Apostolakis; Michael J. Driscoll

2005-01-01

406

OTUS - Reactor inventory management system based on ORIGEN2.  

National Technical Information Service (NTIS)

ORIGEN2 is a computer code that calculates nuclide composition and other characteristics of nuclear fuel. The use of ORIGEN2 requires good knowledge in reactor physics. However, once the input has been defined for a particular reactor type, the calculatio...

R. Poellaenen H. Toivonen J. Lahtinen T. Ilander

1995-01-01

407

Modeling and optimization of a conceptual thermonuclear fusion reactor system  

Microsoft Academic Search

From international meeting on the technology of controlled thermonuclear ; fusion experiments and the engineering aspects of fusion reactors; Austin, Texas, ; USA (20 Nov 1972). In technology of controlled thermonuclear fusion experiments ; and the engineering aspects of fusion reactors. This paper demonstrates how ; computer modeling and optimization techniques can be used to examine the complex ; interrelations

R. B. McCann; E. J. Jr. Powers

1974-01-01

408

Membrane integrated system in the fusion reactor fuel cycle  

Microsoft Academic Search

The future fusion reactor fuel will be a mixture of deuterium and tritium. Deuterium is produced using traditional separation technology. Tritium must be produced by means of a nuclear reaction between neutrons and lithium atoms within the reactor breeder which, in this study, is supposed to be a ceramic lithiated material. The tritium produced in the breeder needs a proper

A. Basile; V. Violante; F. Santella; E. Drioli

1995-01-01

409

Design and shakedown of an inclined liquid fluid-bed reactor system  

SciTech Connect

This report describes the design and shakedown testing of an inclined liquid fluid-bed reactor system. The system is being developed for processing tar sand with a recycle oil pyrolysis and extraction process to produce a high yield of specialty products. Also reported are the results of cold-flow model tests, which were used to assist in the design of the reactor system. Shakedown tests showed the potential of the process to recover the majority of the bitumen from Asphalt Ridge tar sand and also provided data for the future modifications to improve the reactor performance. Recommendations based on shakedown test results are made for improvements in the tar sand feed, product collection, and disparger components of the reactor system to permit better reactor control and operation. 2 refs., 4 figs.

Johnson, L.A. Jr.; Cha, Chang Yul

1987-09-01

410

Shielding considerations for advanced space nuclear reactor systems  

SciTech Connect

To meet the anticipated future space power needs, the Los Alamos National Laboratory is developing components for a compact, 100 kW/sub e/-class heat pipe nuclear reactor. The reactor uses uranium dioxide (UO/sub 2/) as its fuel, and is designed to operate around 1500 k. Heat pipes are used to remove thermal energy from the core without the use of pumps or compressors. The reactor heat pipes transfer mal energy to thermoelectric conversion elements that are advanced versions of the converters used on the enormously successful Voyager missions to the outer planets. Advanced versions of this heat pipe reactor could also be used to provide megawatt-level power plants. The paper reviews the status of this advanced heat pipe reactor and explores the radiation environments and shielding requirements for representative manned and unmanned applications.

Angelo, J.P. Jr.; Buden, D.

1982-01-01

411

10 CFR 50.46 - Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors.  

Code of Federal Regulations, 2013 CFR

...core cooling systems for light-water nuclear power reactors. 50.46 Section 50.46 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING...core cooling systems for light-water nuclear power reactors....

2013-01-01

412

78 FR 64029 - Cost-Benefit Analysis for Radwaste Systems for Light-Water-Cooled Nuclear Power Reactors  

Federal Register 2010, 2011, 2012, 2013

...Radwaste Systems for Light-Water-Cooled Nuclear Power Reactors AGENCY: Nuclear Regulatory Commission. ACTION: Regulatory...Radwaste Systems for Light-Water-Cooled Nuclear Power Reactors,'' in which the NRC made editorial...

2013-10-25

413

Passive cooling system for top entry liquid metal cooled nuclear reactors  

DOEpatents

A liquid metal cooled nuclear fission reactor plant having a top entry loop joined satellite assembly with a passive auxiliary safety cooling system for removing residual heat resulting from fuel decay during shutdown, or heat produced during a mishap. This satellite type reactor plant is enhanced by a backup or secondary passive safety cooling system which augments the primary passive auxiliary cooling system when in operation, and replaces the primary cooling system when rendered inoperative.

Boardman, Charles E. (Saratoga, CA); Hunsbedt, Anstein (Los Gatos, CA); Hui, Marvin M. (Cupertino, CA)

1992-01-01

414

Effect of reactor configuration on biogas production from wheat straw hydrolysate  

Microsoft Academic Search

The potential of wheat straw hydrolysate for biogas production was investigated in continuous stirred tank reactor (CSTR) and up-flow anaerobic sludge bed (UASB) reactors. The hydrolysate originated as a side stream from a pilot plant pretreating wheat straw hydrothermally (195°C for 10–12min) for producing 2nd generation bioethanol [Kaparaju, P., Serrano, M., Thomsen, A.B., Kongjan, P., Angelidaki, I., 2009. Bioethanol, biohydrogen

Prasad Kaparaju; María Serrano; Irini Angelidaki

2009-01-01

415

Space-reactor system and subsystem investigations: Cost and schedule estimates for reactor and shield subsystems technology development. SP-100 program  

NASA Astrophysics Data System (ADS)

Cost and schedule estimates of the technology development for reactor and shielding subsystems of a 100-kWe class space reactor electric system are presented. The subsystems technology development (which includes reactor and shield subsystems ground testing) is supported by materials and processes development and component development. For the purpose of the cost estimate, seven generic types of reactor subsystems were used: uranium-zirconium hydride, NaK-cooled thermal reactor; lithium-cooled, refractory-clad fast reactors; Na- or K-cooled fast reactor; in-core thermionic reactor; inert gas-cooled particle fuel reactor; inert gas-cooled metal-clad fast reactor; and heat pipe-cooled fast reactor. Also three levels of technology were included for each of the generic types of reactor subsystem: current, improved, and advanced. The data in this report encompass all these technology levels. The shielding subsystem uses both gamma (heavy-metal) and neutron (hydrogenous material) shields. The shields considered would be used in conjunction with unmanned payloads.

Determan, W. R.; Harty, R. B.; Hylin, C.

1983-06-01

416

Space-reactor system and subsystem investigations: cost and schedule estimates for reactor and shield subsystems technology development. SP-100 Program  

SciTech Connect

This report presents cost and schedule estimates of the technology development for reactor and shielding subsystems of a 100-kWe class space reactor electric system. The subsystems technology development (which includes reactor and shield subsystems ground testing) is supported by materials and processes development and component development. For the purpose of the cost estimate, seven generic types of reactor subsystems were used: uranium-zirconium hydride, NaK-cooled thermal reactor; lithium-cooled, refractory-clad fast reactor; Na- or K-cooled fast reactor; in-core thermionic reactor; inert gas-cooled particle fuel reactor; inert gas-cooled metal-clad fast reactor; and heat pipe-cooled fast reactor. Also three levels of technology were included for each of the generic types of reactor subsystem: current, improved, and advanced. The data in this report encompass all these technology levels. The shielding subsystem uses both gamma (heavy-metal) and neutron (hydrogenous material) shields. The shields considered in this report would be used in conjunction with unmanned payloads.

Determan, W.R.; Harty, R.B.; Hylin, C.

1983-06-30

417

SYSTEM EVALUATION OF THE FLOWABLE SOLIDS REACTOR. PHASE I SUMMARY REPORT FUEL STUDY  

Microsoft Academic Search

The proposed Flowable Solids Reactor (FSR) is a high temperature, ; circulating fuel, heterogeneous power reactor; the fuel material is a dry, ; granular solid which flows by gravity through vertical channels in a graphite ; moderator. Calculations indicate such a system, if practical, could produce ; power which would be competitive now with conventional steam plants in many areas

R. C. Oliver; H. K. Orbach; M. R. Dusbabek; J. A. Porter; A. Goldstein; R. H. Bishop

1958-01-01

418

High Temperature Water Heat Pipes Radiator for a Brayton Space Reactor Power System  

Microsoft Academic Search

A high temperature water heat pipes radiator design is developed for a space power system with a sectored gas-cooled reactor and three Closed Brayton Cycle (CBC) engines, for avoidance of single point failures in reactor cooling and energy conversion and rejection. The CBC engines operate at turbine inlet and exit temperatures of 1144 K and 952 K. They have a

Mohamed S. El-Genk; Jean-Michel Tournier

2006-01-01

419

Determination of the safety importance of systems of the Tehran research reactor using a PSA method  

Microsoft Academic Search

This paper presents the results of a research project performed to study the ranking of systems and components of the Tehran research reactor, important to safety, using a level 1 probabilistic safety assessment (PSA). The occurrence of an imbalance condition, i.e. a lack of equilibrium between heat generation and heat removal without reactor scram, was defined as the “Top Event”.

M. B Ghofrani; S. A Damghani

2002-01-01

420

Endothermic reactors for an ammonia based thermochemical solar energy storage and transport system  

Microsoft Academic Search

The ammonia dissociation reaction is one of a number of reactions which has been investigated for use in closed loop solar thermochemical energy storage systems, over a period of nearly two decades. A recent series of experiments with an electrically heated high pressure ammonia dissociation reactor has validated a two dimensional pseudo-homogenous theoretical reactor model, established rate parameters for the

K. Lovegrove; A. Luzzi

1996-01-01

421

Demountable low stress high field toroidal field magnet system for tokamak fusion reactors  

Microsoft Academic Search

A new type of superconducting magnet system for large fusion reactors is described in this report. Instead of winding large planar or multi-axis coils, as has been proposed in previous fusion reactor designs, the superconducting coils are made by joining together several prefabricated conductor sections. The joints can be unmade and sections removed if they fail. Conductor sections can be

J. Powell; D. Hsieh; J. Lehner; M. Suenaga

1977-01-01

422

Design of GA thermochemical water-splitting process for the Mirror Advanced Reactor System  

SciTech Connect

GA interfaced the sulfur-iodine thermochemical water-splitting cycle to the Mirror Advanced Reactor System (MARS). The results of this effort follow as one section and part of a second section to be included in the MARS final report. This section describes the process and its interface to the reactor. The capital and operating costs for the hydrogen plant are described.

Brown, L.C.

1983-04-01

423

Application of the membrane biological reactor system for combined sanitary and industrial wastewater treatment  

Microsoft Academic Search

In the early 1990s, the General Motors Corporation (GM) adopted the use of the membrane biological reactor (MBR) system for treatment of automotive manufacturing plant wastewaters both in the US and internationally. The MBR process consists of a suspended growth biological reactor combined with a membrane unit either located external to the bioreactor or mounted directly within the bioreactor. Recently,

Jeff A. Roberts; Paul M. Sutton; Prakash N. Mishra

2000-01-01

424

Modular Coils: A Promising Toroidal-Reactor-Coil System.  

National Technical Information Service (NTIS)

The concept of modular coils originated from a need to find reactor-relevant stellarator windings, but its usefulness can be extended to provide an externally applied, additional rotational transform in tokamaks. Considerations of (1) basic principles of ...

T. K. Chu H. P. Furth J. L. Johnson C. Ludescher K. E. Weimer

1981-01-01

425

Some Problems in Measuring the Reactivity of Large Reactor System.  

National Technical Information Service (NTIS)

The analysis of factors determining main characteristics of neutron flux spatial and temperature distribution in nuclear reactors is given. The criteria of applicability of point kinetics methods for measuring reactivity are formulated. The behaviour of s...

A. S. Kaminskij I. D. Krytov

1981-01-01

426

Physics Characterization of a Heterogeneous Sodium Fast Reactor Transmutation System  

SciTech Connect

The threshold-fission (fertile) nature of Am-241 is used to destroy this minor actinide by capitalizing upon neutron capture instead of fission within a sodium fast reactor. This neutron-capture and its subsequent decay chain leads to the breeding of even mass number plutonium isotopes. A slightly moderated target design is proposed for breeding plutonium in an axial blanket located above the active “fast reactor” driver fuel region. A parametric study on the core height and fuel pin diameter-to-pitch ratio is used to explore the reactor and fuel cycle aspects of this design. This study resulted in both a non-flattened and a pancake core geometry. Both of these designs demonstrated a high capacity for removing americium from the fuel cycle. A reactivity coefficient analysis revealed that this heterogeneous design will have comparable safety aspects to a homogeneous reactor of the same size.

Samuel E. Bays

2007-09-01

427

System Requirements Document for the Molten Salt Reactor Experiment  

SciTech Connect

The purpose of the conversion process is to convert the {sup 233}U fluoride compounds that are being extracted from the Molten Salt Reactor Experiment (MSRE) equipment to a stable oxide for long-term storage at Bldg. 3019.

Aigner, R.D.

2000-04-01

428

Effects of Dust Characteristics on Hot-Gas Filter Performance in a Transport Reactor System  

Microsoft Academic Search

This paper discusses the use of in-situ particulate sampling and ash characterization in analyzing the performance of a hot-gas filter installed on a transport reactor system at the Power Systems Development Facility (PSDF). In- situ measurements of the particulate loadings entering and leaving the hot-gas filter have been made during combustion-mode operation of the transport reactor system with four different

R. S. Dahlin; E. C. Landham

429

Analytical prediction and experimental verification of reactor safety system injection transient  

SciTech Connect

This paper describes the computer code that was developed for thermal hydraulic transient analysis of mixed phase fluid system and the flow tests that were carried out to validate the Code. A full scale test facility was designed to duplicate the Supplementary Shutdown System (SSS) of Savannah River Production Reactors. Several steady state and dynamic flow tests were conducted simulating the actual reactor injection transients. A dynamic multiphase fluid flow code was developed and validated with experimental results and utilized for system performance predictions and development of technical specifications for reactors. 3 refs.

Roy, B.N.; Nomm, E.

1991-01-01

430

Analytical prediction and experimental verification of reactor safety system injection transient  

SciTech Connect

This paper describes the computer code that was developed for thermal hydraulic transient analysis of mixed phase fluid system and the flow tests that were carried out to validate the Code. A full scale test facility was designed to duplicate the Supplementary Shutdown System (SSS) of Savannah River Production Reactors. Several steady state and dynamic flow tests were conducted simulating the actual reactor injection transients. A dynamic multiphase fluid flow code was developed and validated with experimental results and utilized for system performance predictions and development of technical specifications for reactors. 3 refs.

Roy, B.N.; Nomm, E.

1991-12-31

431

Advanced High-Temperature Reactor Dynamic System Model Development: April 2012 Status  

SciTech Connect

The Advanced High-Temperature Reactor (AHTR) is a large-output fluoride-salt-cooled high-temperature reactor (FHR). An early-phase preconceptual design of a 1500 MW(e) power plant was developed in 2011 [Refs. 1 and 2]. An updated version of this plant is shown as Fig. 1. FHRs feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The AHTR is designed to be a “walk away” reactor that requires no action to prevent large off-site releases following even severe reactor accidents. This report describes the development of dynamic system models used to further the AHTR design toward that goal. These models predict system response during warmup, startup, normal operation, and limited off-normal operating conditions. Severe accidents that include a loss-of-fluid inventory are not currently modeled. The scope of the models is limited to the plant power system, including the reactor, the primary and intermediate heat transport systems, the power conversion system, and safety-related or auxiliary heat removal systems. The primary coolant system, the intermediate heat transport system and the reactor building structure surrounding them are shown in Fig. 2. These systems are modeled in the most detail because the passive interaction of the primary system with the surrounding structure and heat removal systems, and ultimately the environment, protects the reactor fuel and the vessel from damage during severe reactor transients. The reactor silo also plays an important role during system warmup. The dynamic system modeling tools predict system performance and response. The goal is to accurately predict temperatures and pressures within the primary, intermediate, and power conversion systems and to study the impacts of design changes on those responses. The models are design tools and are not intended to be used in reactor qualification. The important details to capture in the primary system relate to flows within the reactor vessel during severe events and the resulting temperature profiles (temperature and duration) for major components. Critical components include the fuel, reactor vessel, primary piping, and the primary-to-intermediate heat exchangers (P-IHXs). The major AHTR power system loops are shown in Fig. 3. The intermediate heat transfer system is a group of three pumped salt loops that transports the energy produced in the primary system to the power conversion system. Two dynamic system models are used to analyze the AHTR. A Matlab/Simulink?-based model initiated in 2011 has been updated to reflect the evolving design parameters related to the heat flows associated with the reactor vessel. The Matlab model utilizes simplified flow assumptions within the vessel and incorporates an empirical representation of the Direct Reactor Auxiliary Cooling System (DRACS). A Dymola/Modelica? model incorporates a more sophisticated representation of primary coolant flow and a physics-based representation of the three-loop DRACS thermal hydraulics. This model is not currently operating in a fully integrated mode. The Matlab model serves as a prototype and provides verification for the Dymola model, and its use will be phased out as the Dymola model nears completion. The heat exchangers in the system are sized using spreadsheet-based, steady-state calculations. The detail features of the heat exchangers are programmed into the dynamic models, and the overall dimensions are used to generate realistic plant designs. For the modeling cases where the emphasis is on understanding responses within the intermediate and primary systems, the power conversion system may be modeled as a simple boundary condition at the intermediate-to-power conversion system heat exchangers.

Qualls, A.L.; Cetiner, M.S.; Wilson, T.L., Jr.

2012-04-30

432

Long-term performance of high-rate anaerobic reactors for the treatment of oily wastewater.  

PubMed

Complex oily wastewater from a food industry was treated in three different UASB reactors at different operating conditions. Although all three systems achieved fat, oil, and grease (FOG) and COD removal efficiencies above 80% at an organic loading of 3 kg COD/m3 x d, system performance deteriorated sharply at higher loading rates, and the presence of high FOG caused a severe sludge flotation resulting in failure. Initially, FOG accumulated onto the biomass which led to sludge flotation and washout of biomass. The loss of sludge in the bed increased the FOG loading to the biomass and failure ensued. Contrary to previous findings, accumulation of FOG rather than influent FOG concentrations or volumetric FOG loading rate was the most importantfactor governing the high-rate anaerobic reactor performance. The critical accumulated FOG loading was identified as 1.04 +/- 0.13 g FOG/g VSS for all three reactors. Furthermore, FOG accumulation onto the biomass was identified mainly as palmitic acid (>60%) whereas the feed LCFA contained only 30% of palmitic acid and 50% of oleic acid. PMID:17120582

Jeganathan, Jeganaesan; Nakhla, George; Bassi, Amarjeet

2006-10-15

433

Nuclear Electric-Capacity Expansion in Mexico: System Effects of Reactor Size and Cost.  

National Technical Information Service (NTIS)

This report evaluates the cost of different size nuclear reactors installed into Mexico's interconnected electric grid. Although larger units tend to increase reserve requirements, this system effect is relatively unimportant. Given projections of rapid c...

D. Abbey E. G. Uria G. Thayer R. P. Enriquez

1983-01-01

434

Mitigation of steam generator tube rupture in a pressurized water reactor with passive safety systems  

DOEpatents

The effects of steam generator tube ruptures in a pressurized water reactor are mitigated by reducing the pressure in the primary loop by diverting reactor coolant through the heat exchanger of a passive heat removal system immersed in the in containment refueling water storage tank in response to a high feed water level in the steam generator. Reactor coolant inventory is maintained by also in response to high steam generator level introducing coolant into the primary loop from core make-up tanks at the pressure in the reactor coolant system pressurizer. The high steam generator level is also used to isolate the start-up feed water system and the chemical and volume control system to prevent flooding into the steam header. 2 figures.

McDermott, D.J.; Schrader, K.J.; Schulz, T.L.

1994-05-03

435

3-D Monte Carlo analyses of shielding system in tokamak fusion reactor.  

National Technical Information Service (NTIS)

Within the framework of the ITER (International Tokamak Experimental Reactor) design program, 3D neutronics calculations were carried out to assess system shielding performances in the basic machine configuration by means of the Monte Carlo Neutron Photon...

M. Gallina L. Petrizzi V. Rado

1990-01-01

436

Development of long-lived radionuclide transmutation technology - Development of a code system for core analysis of the transmutation reactors.  

National Technical Information Service (NTIS)

The objective of this study is to develop a code system for core analysis= of the critical transmutation reactors utilizing fast neutrons. Core characteristics of the transmutation reactors were identified and four codes, HANCELL for pincell calculation, ...

N. Z. Cho Y. H. Kim T. H. Kim C. K. Jo C. J. Park

1996-01-01

437

Modeling the performance of “up-flow anaerobic sludge blanket” reactor based wastewater treatment plant using linear and nonlinear approaches—A case study  

Microsoft Academic Search

The paper describes linear and nonlinear modeling of the wastewater data for the performance evaluation of an up-flow anaerobic sludge blanket (UASB) reactor based wastewater treatment plant (WWTP). Partial least squares regression (PLSR), multivariate polynomial regression (MPR) and artificial neural networks (ANNs) modeling methods were applied to predict the levels of biochemical oxygen demand (BOD) and chemical oxygen demand (COD)

Kunwar P. Singh; Nikita Basant; Amrita Malik; Gunja Jain

2010-01-01

438

A station blackout simulation for the Advanced Neutron Source Reactor using the integrated primary and secondary system model  

Microsoft Academic Search

The Advanced Neutron Source Reactor (ANSR) is a research reactor to be built at Oak Ridge National Laboratory. This paper deals with thermal-hydraulic analysis of ANSR`s cooling systems during nominal and transient conditions, with the major effort focusing upon the construction and testing of computer models of the reactor`s primary, secondary and reflector vessel cooling systems. The code RELAP5 was

1994-01-01

439

Heat insulating system for a fast reactor shield slab  

DOEpatents

Improved thermal insulation for a nuclear reactor deck comprises many helical coil springs disposed in generally parallel, side-by-side laterally overlapping or interfitted relationship to one another so as to define a three-dimensional composite having both metal and voids between the metal, and enclosure means for holding the composite to the underside of the deck.

Kotora, J. Jr.; Groh, E.F.; Kann, W.J.; Burelbach, J.P.

1984-04-10

440

Mist reactors: principles, comparison of various systems, and case studies  

Microsoft Academic Search

Growing hairy roots in bioreactors has proven challenging. Here we summarize the recent work using a novel bioreactor, the mist reactor, for the culture of hairy roots from many plant species. Compared to most liquid-phase bioreactors, this gas- phase bioreactor offers a completely different environment for growing roots. Design, modeling, and some of the unique engineering aspects inherent to mist

Pamela Weathers; Chunzhao Liu; Melissa Towler; Barbara Wyslouzil

2008-01-01

441

MICROFABRICATION METHODS FOR MICROCHANNEL REACTORS AND SEPARATIONS SYSTEMS  

Microsoft Academic Search

The fabrication of a microchannel chemical solvent separation unit and a microchannel chemical reactor is described. The performance of the solvent separation unit was enhanced by improved kinetic effects resulting from short liquid\\/liquid contact times in the device. These effects were exploited to allow preferential extraction of solute species from a fluid waste stream. The completed unit consisted of a

P. M. MARTIN; D. W. MATSON; W. D. BENNETT

1999-01-01

442

Four hour purge. [Four Hour Purge of Reactor Cooling System  

Microsoft Academic Search

Much vagueness and lack of sound technical information surrounded the use of diatomaceous earth as an abrasive cleaner even though it had been used for this purpose almost from original plant start-up. In order to explore the application of purging under current conditions, this test was conceived by B Processing Operation to improve the flow of reactor cooling water and

R. B. Hall; J. H. Soehnlein

1961-01-01

443

THE INSTRUMENTATION SYSTEM OF THE KEMA SUSPENSION TEST REACTOR (KSTR)  

Microsoft Academic Search

The extensive instrumentation necessary for the KEMA Suspension Test ; Reactor was described. In addition to the apparatus for normal operating ; conditions, provisions must be made for very accurate measurements under certain ; conditions. The instrumentation necessary for incidental measurements were also ; described. (tr-auth);

van Zolingen

1963-01-01

444

Compact intermediate heat transport system for sodium cooled reactor  

Microsoft Academic Search

This patent describes a combination with a sodium cooled reactor having an intermediate heat exchanger for extracting heat in a nonradioactive secondary sodium loop from the sodium rector. It comprises: first and second upstanding closed cylindrical vessels, one of the cylindrical vessels being exterior of the other of the cylindrical vessels; the other of the cylindrical vessels being interior, smaller,

C. E. Boardman; J. P. Maurer

1990-01-01

445

Lunar electric power systems utilizing the SP-100 reactor coupled to dynamic conversion systems. Final report  

SciTech Connect

An integration study was performed by Rocketdyne under contract to NASA-LeRC. The study was concerned with coupling an SP-0100 reactor to either a Brayton or Stirling power conversion system. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the NASA Space Exploration Initiative 90-day study. Reliability studies were initially performed to determine optimum power conversion redundancy. This study resulted in selecting three operating engines and one stand-by unit. Integration design studies indicated that either the Brayton or Stirling power conversion systems could be integrated with the PS-100 reactor. The Stirling system had an integration advantage because of smaller piping size and fewer components. The Stirling engine, however, is more complex and heavier than the Brayton rotating unit, which tends to off-set the Stirling integration advantage. From a performance consideration, the Brayton had a 9 percent mass advantage, and the Stirling had a 50 percent radiator advantage.

Harty, R.B.; Durand, R.E.

1993-03-01

446

Lunar electric power systems utilizing the SP-100 reactor coupled to dynamic conversion systems  

NASA Astrophysics Data System (ADS)

An integration study was performed by Rocketdyne under contract to NASA-LeRC. The study was concerned with coupling an SP-0100 reactor to either a Brayton or Stirling power conversion system. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the NASA Space Exploration Initiative 90-day study. Reliability studies were initially performed to determine optimum power conversion redundancy. This study resulted in selecting three operating engines and one stand-by unit. Integration design studies indicated that either the Brayton or Stirling power conversion systems could be integrated with the PS-100 reactor. The Stirling system had an integration advantage because of smaller piping size and fewer components. The Stirling engine, however, is more complex and heavier than the Brayton rotating unit, which tends to off-set the Stirling integration advantage. From a performance consideration, the Brayton had a 9 percent mass advantage, and the Stirling had a 50 percent radiator advantage.

Harty, Richard B.; Durand, Richard E.

1993-03-01

447

Effect of influent pH and alkalinity on the removal of chlorophenols in sequential anaerobic–aerobic reactors  

Microsoft Academic Search

This study was carried out to determine the effect of influent pH and alkalinity on the performance of sequential UASB and RBC reactors for the removal of 2-CP and 2,4-DCP from two different simulated wastewaters. The performance of methanogens at low (8.0) pH values and at sufficiently high alkalinity (1500–3500mg\\/l as CaCO3) is described in this paper. Sequential reactors were

Partha Sarathi Majumder; S. K. Gupta

2009-01-01

448

Graphic-object information system {open_quotes}research base for reactor materials science{close_quotes}  

SciTech Connect

An information system developed for reactor materials research is described. The information system incorporates an expert system, MATREKS, and a heirarchial data base. The data base contains information from 20 Russian research reactors. The information system structure, data base structure, search methods, system output modes, and technical facilities and software required are briefly discussed. 6 refs., 2 figs.

Markina, N.V.; Lebedeva, E.E.; Arkhangel`skii, N.V.; Semenov, S.B.; Moiseev, A.L.

1994-11-01

449

Feasibility study for a passive trip system to prevent a runaway reaction in a batch reactor.  

PubMed

Reactors for carrying out exothermic reactions are amongst others equipped with trip systems. Normally these are active systems requiring a number of components such as sensors, pumps or valves to function for a successful trip. They may, for example, use the injection of a reaction inhibitor or the dumping of the reactor contents into a knock-out tank. The availability of such systems, i.e. their probability of functioning on demand, largely depends on their degree of redundancy. However, the possibility of common cause failures places a limit on increasing their availability by raising their degree of redundancy. Nevertheless, a trip system may reach a high availability if instead of stepping up its redundancy a passive system is used. The design of such a passive trip system for batch reactors is described and its feasibility is demonstrated by experimental investigations of three different types of reactions. PMID:19268455

Jablonski, D; Hauptmanns, U

2009-02-07

450

Initial results of systems analysis of the ETR/ITER (Engineering Test Reactor/International Thermonuclear Experimental Reactor) design space  

SciTech Connect

Preliminary versions of the Engineering Test Reactor (ETR) systems code TETRA (Tokamak Engineering Test Reactor Analysis), which determines design solutions by the method of constrained optimization, are used to characterize the International Thermonuclear Experimental Reactor (ITER) and its design parameter space. We find that the physics objectives of high ignition margin and high plasma current lead to minimum size at relatively low aspect ratios (A = 2.5-3.0), while the engineering objective of high neutron wall load (W/sub L/ /approx gt/ 1.0 MW/m/sup 2/) leads to minimum size at higher A (/approximately/3.5). For minimum-size ITERs, the optimal toroidal field coil (TFC) designs fall within a narrow range of maximum fields (10-11 T) with R varying over only a few percent despite a factor of two change in the winding pack current density J/sub wp/. The major radius of the design is found to be sensitive to changes in elongation, inboard distances (such as plasma scrape-off), inductive flux capability, plasma temperature, beta limit, and ignition margin. A preliminary characterization of the US ITER designs with plasma current I/sub p/ > 15 MA and R < 4.5 m has been obtained by combining the engineering assumptions for devices such as the Tokamak Ignition/Burn Engineering Reactor (TIBER) with the physics assumptions for devices such as the Compact Ignition Tokamak (CIT) and the Next European Torus (NET). These devices can accommodate a range of full- to reduced-bore, driven (Q < 10), steady-state plasmas for the engineering phase that produces high neutron wall load and fluence. 12 refs., 4 figs., 3 tabs.

Peng, Y.K.M.; Galambos, J.D.; Reid, R.L.; Strickler, D.J.; Kalsi, S.; Deleanu, L.

1987-01-01

451

Material Issues of Blanket Systems for Fusion Reactors - Compatibility with Cooling Water -  

NASA Astrophysics Data System (ADS)

Environmental assisted cracking (EAC) is one of the material issues for the reactor core components of light water power reactors(LWRs). Much experience and knowledge have been obtained about the EAC in the LWR field. They will be useful to prevent the EAC of water-cooled blanket systems of fusion reactors. For the austenitic stainless steels and the reduced-activation ferritic/martensitic steels, they clarifies that the EAC in a water-cooled blanket does not seem to be acritical issue. However, some uncertainties about influences on water temperatures, water chemistries and stress conditions may affect on the EAC. Considerations and further investigations elucidating the uncertainties are discussed.

Miwa, Yukio; Tsukada, Takashi; Jitsukawa, Shiro

452

LWR (Light Water Reactor) power plant simulations using the AD10 and AD100 systems  

Microsoft Academic Search

Boiling (BWR) and Pressurized (PWR) Water Reactor Power Plants are being simulated at BNL with the AD10 and AD100 Peripheral Processor Systems. The AD10 system has been used for BWR simulations since 1984 for safety analyses, emergency training and optimization studies. BWR simulation capabilities have been implemented recently on the AD100 system and PWR simulation capabilities are currently being developed

W. Wulff; H. S. Cheng; C. J. Chien; J. Y. Jang; H. C. Lin; A. N. Mallen; S. J. Wang

1989-01-01

453

On a simplified system for steam production in nuclear power plants with pressurized water reactors  

Microsoft Academic Search

The paper develops the idea of a new system of steam production (Simplified System for Steam Production, SSSP) in nuclear power plants (NPPs) with PWR reactors, which is simplified as compared to the system used in the classical NPP of this type where steam is produced by steam generators (SGs). With the SSSP, expanders are used instead of SGs. The

Mircea Cârdu; Marian Dumitru

1999-01-01

454

Optimal reliable control system design for steam generators in pressurized water reactors  

Microsoft Academic Search

An optimal reliable control system has been designed to control the steam generator's water level in a pressurized water reactor. The control system uses a multiple-controller configuration so that even if part of the controller fails, the control system still functions well. The value of the controller parameters is obtained by means of an optimization algorithm, thus guaranteeing the performance

W. Wu; C. Lin

1994-01-01

455

Thyristor Controlled Reactor Methods to Increase the Capacity of Single Wire Earth Return Systems  

Microsoft Academic Search

Single wire earth return systems are a widely applied low cost power distribution method used in many rural areas. In Central Queensland a single SWER system supplying approximately 100kW may extend more than 300km. These systems often use shunt reactors to compensate the effects of line to ground capacitance. Recent patterns of load growth are forcing the upgrading of these

Peter Wolfs; Steven Senini; Anthony Loveday; Jon Turner; Rockhampton Australia

456

Risk assessment of a fusion-reactor fuel-processing system  

Microsoft Academic Search

The probabilistic risk assessment (PRA) methodology provides a means to systematically examine the potential for accidents that may result in a release of hazardous materials. This report presents the PRA for a typical fusion reactor fuel processing system. The system used in the analysis is based on the Tritium Systems Test Assembly, which is being operated at the Los Alamos

S. Z. Bruske; D. F. Holland

1983-01-01

457

Risk-based management system development for the Advanced Test Reactor  

Microsoft Academic Search

A Risk-Based Management System (RBMS) is being developed to facilitate the use of the Advanced Test Reactor (ATR) probabilistic risk assessment to support ATR operation. Most ATR RBMS questions can best be answered using the System Analysis and Risk Assessment System (SARA) developed at the Idaho National Engineering Laboratory. However, some applications may require employment of the other four codes

M. L. Davis; S. A. Eide

1990-01-01

458

Fossil-fuel processing technical/professional services: comparison of Fischer-Tropsch reactor systems. Phase I, final report  

SciTech Connect

The Fischer-Tropsch reaction was commercialized in Germany and used to produce military fuels in fixed bed reactors. It was recognized from the start that this reactor system had severe operating and yield limitations and alternative reactor systems were sought. In 1955 the Sasol I complex, using an entrained bed (Synthol) reactor system, was started up in South Africa. Although this reactor was a definite improvement and is still operating, the literature is filled with proponents of other reactor systems, each claiming its own advantages. This report provides a summary of the results of a study to compare the development potential of three of these reactor systems with the commercially operating Synthol-entrained bed reactor system. The commercial Synthol reactor is used as a benchmark against which the development potential of the other three reactors can be compared. Most of the information on which this study is based was supplied by the M.W. Kellogg Co. No information beyond that in the literature on the operation of the Synthol reactor system was available for consideration in preparing this study, nor were any details of the changes made to the original Synthol system to overcome the operating problems reported in the literature. Because of conflicting claims and results found in the literature, it was decided to concentrate a large part of this study on a kinetic analysis of the reactor systems, in order to provide a theoretical analysis of intrinsic strengths and weaknesses of the reactors unclouded by different catalysts, operating conditions and feed compositions. The remainder of the study considers the physical attributes of the four reactor systems and compares their respective investment costs, yields, catalyst requirements and thermal efficiencies from simplified conceptual designs.

Thompson, G.J.; Riekena, M.L.; Vickers, A.G.

1981-09-01

459

Sodium coolant purification systems for a nuclear power station equipped with a BN-1200 reactor  

NASA Astrophysics Data System (ADS)

Both traditional coolant purification methods (by means of traps and sorbents for removing cesium), the use of which supported successful operation of nuclear power installations equipped with fast-neutron reactors with a sodium coolant, and the possibility of removing oxygen from sodium through the use of hot traps are analyzed in substantiating the purification system for a nuclear power station equipped with a BN-1200 reactor. It is shown that a cold trap built into the reactor vessel must be a mandatory component of the reactor plant primary coolant circuit's purification system. The use of hot traps allows oxygen to be removed from the sodium coolant down to permissible concentrations when the nuclear power station operates in its rated mode. The main lines of works aimed at improving the performance characteristics of cold traps are suggested based on the results of performed investigations.

Alekseev, V. V.; Kovalev, Yu. P.; Kalyakin, S. G.; Kozlov, F. A.; Kumaev, V. Ya.; Kondrat'ev, A. S.; Matyukhin, V. V.; Pirogov, E. P.; Sergeev, G. P.; Sorokin, A. P.; Torbenkova, I. Yu.

2013-05-01

460

Destruction of chlorobenzene and carbon tetrachloride in a two-stage molten salt oxidation reactor system  

Microsoft Academic Search

Molten salt oxidation (MSO) is one of the promising alternative destruction technologies for chlorinated organics, because it is capable of trapping chlorine during organic destruction. This study investigated the characteristics of a two-stage MSO reactor system for the destruction of CCl4 and C6H5Cl. Investigated parameters were the MSO reactor temperature (from 1023K to 1223K) and the excess oxidizing air feed

Hee-Chul Yang; Yong-Jun Cho; Hee-Chul Eun; Eung-Ho Kim

2008-01-01