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In oceanography, as in any scientific field, the goal is not to eliminate uncertainty in data, but instead to better quantify and clearly communicate its size and nature.

ObjectiveTo assess the cost effectiveness of once weekly rifapentine and isoniazid for 12 weeks (3HP) to the current standard care for latent tuberculosis (TB) infection (LTBI) in Iqaluit, Nunavut.DesignA cost-effectiveness analysis using a Markov model reflecting local practices for LTBI treatment.SettingA remote Canadian arctic community with a high incidence of TB.ParticipantsHypothetical patients with LTBI.InterventionsThe cost effectiveness of 3HP was compared with the existing standard of care in the study region which consists of 9 months of twice weekly isoniazid (9H) given by directly observed therapy.Outcome measuresEffectiveness was measured in quality-adjusted life years (QALYs) with model parameters were derived from historical programmatic data, a local implementation study of 3HP and published literature. Costs from the perspective of the Nunavut healthcare system were measured in 2019 US dollars and were obtained primarily from local, empirically collected data. Secondary health outcomes included estimated TB cases and TB deaths averted using 3HP versus 9H. One way and probabilistic sensitivity analyses were performed.ResultsThe 3HP regimen was dominant over 9H: costs were lower (US$628 vs US$924/person) and health outcomes slightly improved (20.14 vs 20.13 QALYs/person). In comparison to 9H, 3HP treatment resulted in fewer TB cases (27.89 vs 30.16/1000 persons) and TB deaths (2.29 vs 2.48/1000 persons). 3HP completion, initiation and risk of fatal adverse events were the primary drivers of cost effectiveness.ConclusionIn a remote Canadian arctic setting, using 3HP instead of 9H for LTBI treatment may result in cost savings and similar or improved health outcomes.

Pancreatic ductal adenocarcinoma (PDA) is a lethal malignancy that is currently the third leading cause of cancer related deaths. PDA creates a suppressive fibroinflammatory tumor microenvironment (TME) composed of stromal and immune cells that inhibit anti-tumor immune responses. Tumor associated macrophages (TAMs) account for a large percentage of the TME and have remarkably heterogeneous functions, with some subsets promoting anti-tumor responses while others suppress tumor specific T-cells. While many studies have highlighted macrophage heterogeneity in PDA, it remains unclear mechanisms regulating monocyte differentiation into pro vs anti-tumor populations. To understand monocyte differentiation in PDA, we performed trajectory analysis on scRNA-seq data from mouse and human tumors and identified predicted monocyte differentiation pathways toward either MHCII-hi anti-tumor TAMs or Trem2-hi pro-tumor TAMs. Using a newly designed monocyte tracking mouse (CCR2CreER x R26tdTomato) implanted with orthotopic tumors that express the click beetle luciferase (CB) neoantigen, we temporally tracked monocyte differentiation within tumors into TAM populations. Furthermore, using antibody depletion, we found that CD4 depletion led to increased monocyte differentiation into pro-tumor macrophages and a dramatic downregulation of PDL1 on monocyte derived TAMs. Finally, using Ifngr1−/− mice implanted with CB+ tumors, we identify that polarization toward anti-tumor macrophages was driven by IFNy, but TAM PDL1 expression was IFNy independent. Together these data are the first to address monocyte differentiation within PDA and identify previously unexpected role for CD4 T cells governing TAM differentiation program.

Background Structured self-management education (SSME) for people with type 2 diabetes mellitus (T2DM) improves biomedical and psychological outcomes, whilst being cost-effective. Yet uptake in the UK remains low. An ‘Embedding Package’ addressing barriers and enablers to uptake at patient, health care professional and organisational levels has been developed. The aim of this study was to test the feasibility of conducting a subsequent randomised controlled trial (RCT) to evaluate the Embedding Package in primary care, using a mixed methods approach. Methods A concurrent mixed methods approach was adopted. Six general practices in the UK were recruited and received the intervention (the Embedding Package). Pseudonymised demographic, biomedical and SSME data were extracted from primary care medical records for patients recorded as having a diagnosis of T2DM. Descriptive statistics assessed quantitative data completeness and accuracy. Quantitative data were supplemented and validated by a patient questionnaire, for which two recruitment methods were trialled. Where consent was given, the questionnaire and primary care data were linked and compared. The cost of the intervention was estimated. An integrated qualitative study comprising ethnography and stakeholder and patient interviews explored the process of implementation, sustainability of change and ‘fit’ of the intervention. Qualitative data were analysed using a thematic framework guided by the Normalisation Process Theory (NPT). Results Primary care data were extracted for 2877 patients. The primary outcome for the RCT, HbA1c, was over 90% complete. Questionnaires were received from 423 (14.7%) participants, with postal invitations yielding more participants than general practitioner (GP) prompts. Ninety-one percent of questionnaire participants consented to data linkage. The mean cost per patient for the Embedding Package was £8.94, over a median follow-up of 162.5 days. Removing the development cost, this reduces to £5.47 per patient. Adoption of ethnographic and interview methods in the collection of data was appropriate, and the use of NPT, whilst challenging, enhanced the understanding of the implementation process. The need to delay the collection of patient interview data to enable the intervention to inform patient care was highlighted. Conclusions It is feasible to collect data with reasonable completeness and accuracy for the subsequent RCT, although refinement to improve the quality of the data collected will be undertaken. Based on resource use data collected, it was feasible to produce cost estimates for each individual component of the Embedding Package. The methods chosen to generate, collect and analyse qualitative data were satisfactory, keeping participant burden low and providing insight into potential refinements of the Embedding Package and customisation of the methods for the RCT. Trial registration ISRCTN, ISRCTN21321635, Registered 07/07/2017—retrospectively registered.

Background: The incidence of TB among Inuit is the highest in Canada. A significantly shorter latent TB infection (LTBI) treatment with rifapentine and isoniazid once weekly for 12 weeks (3HP) is now available in limited settings in Canada. Methods: A prospective open -label 2-year observational postmarketing study was conducted introducing 3HP for the first time in Canada in Iqaluit followed by a program rollout in Qikiqtarjuaq, Nunavut. Results: A total of 247 people were offered 3HP, 102 in the Iqaluit postmarketing study and 145 in the Qikiqtarjuaq program roll out. Although statistical significance was not reached, more people who started treatment completed treatment in the 3HP group (Iqaluit, 60/73 (82.2%) and Qikiqtarjuaq, 89/115 (77.4%)) than in the historical control 9INHgroup (306/420 = 72.9%) (p = 0.2). Most of the adverse events in 3HP treated patients were associated with mild discomfort but no disruption of normal daily activity. Not drinking alcohol was associated with increased 3HP completion (OR 13.33, 95% CI, 2.27–78.20) as was not taking concomitant medications (OR 7.19, 95% CI, 1.47–35.30). Conclusions: The present study supports the feasibility and safety profile of 3HP for the treatment of LTBI in Nunavut.

Background Approximately 425 million people globally have diabetes, with ~ 90% of these having Type 2 Diabetes Mellitus (T2DM). This is a condition that leads to a poor quality of life and increased risk of serious health complications. Structured self-management education (SSME) has been shown to be effective in improving glycaemic control and patient related outcome measures and to be cost-effective. However, despite the demonstrated benefits, attendance at SSME remains low. An intervention has been developed to embed SSME called the ‘Embedding Package’. The intervention aims to address barriers and enhance enablers to uptake of SSME at patient, healthcare professional and organisational levels. It comprises a marketing strategy, user friendly and effective referral pathways, new roles to champion SSME and a toolkit of resources. Methods A mixed methods study incorporating a wait-list cluster randomised trial and ethnographic study, including 66 UK general practices, will be conducted with two intervention start times (at 0 and 9 months), each followed by an active delivery phase. At 18 months, the intervention will cease to be actively delivered and a 12 month observational follow-up phase will begin. The intervention, the Embedding Package, aims to increase SSME uptake and subsequent improvements in health outcomes, through a clear marketing strategy, user friendly and effective referral pathways, a local clinical champion and an ‘Embedder’ and a toolkit of resources for patients, healthcare professionals and other key stakeholders. The primary aim is, through increasing uptake to and attendance at SSME, to reduce HbA1c in people with T2DM compared with usual care. Secondary objectives include: assessing whether there is an increase in referral to and uptake of SSME and improvements in biomedical and psychosocial outcomes; an assessment of the sustainability of the Embedding Package; contextualising the process of implementation, sustainability of change and the ‘fit’ of the Embedding Package; and an assessment of the cost-effectiveness of the Embedding Package. Discussion This study will assess the effectiveness, cost-effectiveness and sustainability of the Embedding Package, an intervention which aims to improve biomedical and psychosocial outcomes of people with T2DM, through increased referral to and uptake of SSME. Trial registration International Standard Randomised Controlled Trials Number ISRCTN23474120. Assigned 05/04/2018. The study was prospectively registered. On submission of this manuscript practice recruitment is complete, participant recruitment is ongoing and expected to be completed by the end of 2019.

Background A remote arctic region of Canada predominantly populated by Inuit with the country’s highest incidence of tuberculosis. Methods The study was undertaken to describe the latent tuberculosis infection (LTBI) cascade of care and identify factors associated with non-initiation and non-completion of LTBI treatment. Data were extracted retrospectively from medical records for all patients with a tuberculin skin test (TST) implanted in Iqaluit, Nunavut between January 2012 and March 2016. Associations between demographic and clinical factors and both treatment non-initiation among and treatment non-completion were identified using log binomial regression models where convergence could be obtained and Poisson models with robust error variance where convergence was not obtained. Results Of 2303 patients tested, 439 (19.1%) were diagnosed with LTBI. Treatment was offered to 328 patients, was initiated by 246 (75.0% of those offered) and was completed by 186 (75.6% of initiators). In multivariable analysis, older age (adjust risk ratio [aRR] 1.17 per 5-year increase, 95%CI:1.09–1.26) and undergoing TST due to employment screening (aRR 1.63, 95%CI:1.00–2.65, compared to following tuberculosis exposure) were associated with increased non-initiation of treatment. Older age (aRR 1.13, 95%CI: 1.03–1.17, per 5-year increase) was associated with increased non-completion of treatment. Conclusions A similar rate of treatment initiation and higher rate of treatment completion were found compared to previous North American studies. Interventions targeting older individuals and those identified via employment screening may be considered to help to address the largest losses in the cascade of care.

Prevention of excessive periphyton standing crop (quantified as chlorophyll a) is among primary objectives for river management. Defensible instream nutrient criteria to achieve periphyton chlorophyll a targets at the site scale require robust predictive models. Such models have proved elusive because peak chlorophyll a depends on multiple factors in addition to nutrients. A key predictor may be accrual period, which depends on river flow variability and the flow magnitudes (effective flows, EF) at which periphyton biomass removal is initiated. In this study we used a seven-year dataset from 44 gravel-bed river sites in the Manawatū-Whanganui region, New Zealand, to explore the relative importance of accrual period, nutrients, and other variables in explaining peak chlorophyll a, using a regression approach. We also assessed the effect of combining data from multiple years. Previous empirical studies have used a universal flow metric (3 × median flow) to define accrual period (Da3). We calculated site-specific EF, which varied from 2 × to 15 × median flow. Accrual period based on EF (DaEF) outperformed Da3 in models. However, in the study region, more variance in chlorophyll a was explained by conductivity (EC) and dissolved inorganic nitrogen (DIN) than by DaEF. The best models derived from multi-year datasets included EC, DIN and DaEF as predictors and accounted for up to 82% of the variance in peak chlorophyll a. Models from annual data were weaker and more variable in strength and predictors. The models indicated that EC and DaEF should be considered when setting DIN criteria for periphyton outcomes in the study region. The principles we used in developing the models may have broad relevance to the management of periphyton in other regions.

The Very High Temperature Reactor (VHTR) using gas-cooled reactor technology is anticipated to be the reactor type for the Next Generation Nuclear Plant (NGNP). In this reactor concept with an indirect power cycle system, a high-temperature and high integrity Intermediate Heat Exchanger (IHX) with high effectiveness is required to efficiently transfer the core thermal output to a secondary fluid for electricity generation, hydrogen production, and/or industrial process heat applications. At present, there is no proven IHX concept for VHTRs. The current Technology Readiness Level (TRL) status issued by NGNP to all components associated with the IHX for reduced nominal reactor outlet temperatures of 750–800 °C is 3 on a 1–10 scale, with 10 indicating complete technological maturity. Among the various potential IHX concepts available, diffusion bonded heat exchangers (henceforth called printed circuit heat exchangers, or PCHEs) appear promising for NGNP applications. The design and fabrication of this key component of NGNP with Alloy 617, a candidate high-temperature structural material for NGNP applications, are the primary focus of this paper. In the current study, diffusion bonding of Alloy 617 has been demonstrated, although the optimum diffusion bonding process parameters to engineer a quasi interface-free joint are yet to be determined. The PCHE fabrication related processes, i.e., photochemical etching and diffusion bonding are discussed for Alloy 617 plates. In addition, the authors’ experiences with these non-conventional machining and joining techniques are discussed. Two PCHEs are fabricated using Alloy 617 plates and are being experimentally investigated for their thermal-hydraulic performance in a High-Temperature Helium Facility (HTHF). The HTHF is primarily of Alloy 800H construction and is designed to facilitate experiments at temperatures and pressures up to 800 °C and 3 MPa, respectively. Furthermore, some preliminary microstructural and mechanical property characterization studies of representative diffusion bonded Alloy 617 specimens are presented. The characterization studies are restricted and less severe from an NGNP perspective but provide sufficient confidence to ensure safe operation of the heat exchangers in the HTHF. The test results are used to determine the design operating conditions for the PCHEs fabricated.

When looking at the challenge of detecting threats, such as viruses, on our networks, we can make a useful analogy with something in the real world with which we are all familiar. What are the chances that one of the employees at your company is carrying a biological virus? It can be difficult to decide what constitutes malicious behaviour on a network. And if we respond too quickly to alerts from security systems, time, money and resources are wasted in chasing false positives. Threat indexes provide a more measured and reliable indication of problems. And they can be implemented very easily using flow technologies already built into all recently networking equipment, explains Mike Patterson of Plixer International.

The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is conducting research on the Very High Temperature Reactor (VHTR) design concept for the Next Generation Nuclear Plant (NGNP) Project. The reactor design will be a graphite moderated, thermal neutron spectrum reactor that will produce electricity and hydrogen in a highly efficient manner. The NGNP reactor core will be either a prismatic graphite block type core or a pebble bed core. The NGNP will use very high-burnup, low-enriched uranium, TRISO-coated fuel, and have a projected plant design service life of 60 years. The VHTR concept is considered to be the nearest-term reactor design that has the capability to efficiently produce hydrogen. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during reactor core-accidents. The objectives of the NGNP Project are to: Demonstrate a full-scale prototype VHTR that is commercially licensed by the U.S. Nuclear Regulatory Commission, and Demonstrate safe and economical nuclear-assisted production of hydrogen and electricity. The DOE laboratories, led by the INL, perform research and development (R&D) that will be critical to the success of the NGNP, primarily in the areas of: high temperature gas reactor fuels behaviour, high temperature materials qualification, design methods development and validation, hydrogen production technologies energy conversion. This paper presents current R&D work that addresses fundamental thermal hydraulics issues that are relevant to a variety of possible NGNP designs.

The next generation nuclear plant (NGNP) will most likely produce electricity and process heat, with both being considered for hydrogen production. To capture nuclear process heat, and transport it to a distant industrial facility requires a high temperature system of heat exchangers, pumps and/or compressors. The heat transfer system is particularly challenging not only due to the elevated temperatures (up to ∼1300 K) and industrial scale power transport (≥50 MW), but also due to a potentially large separation distance between the nuclear and industrial plants (100+ m) dictated by safety and licensing mandates. The work reported here is the preliminary analysis of two-phase thermosyphon heat transfer performance with alkali metals. A thermosyphon is a thermal device for transporting heat from one point to another with quite extraordinary properties. In contrast to single-phased forced convective heat transfer via ‘pumping a fluid’, a thermosyphon (also called a wickless heat pipe) transfers heat through the vaporization/condensing process. The condensate is further returned to the hot source by gravity, i.e., without any requirement of pumps or compressors. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. Two-phase heat transfer by a thermosyphon has the advantage of high enthalpy transport that includes the sensible heat of the liquid, the latent heat of vaporization, and vapor superheat. In contrast, single-phase forced convection transports only the sensible heat of the fluid. Additionally, vapor-phase velocities within a thermosyphon are much greater than single-phase liquid velocities within a forced convective loop. Thermosyphon performance can be limited by the sonic limit (choking) of vapor flow and/or by condensate entrainment. Proper thermosyphon requires analysis of both.

Tritium behaviors in the very high temperature gas reactor (VHTR)/high temperature steam electrolysis (HTSE) system have been analyzed by the TPAC developed by Idaho National Laboratory (INL). The reference system design and conditions were based on the indirect parallel configuration between a VHTR and a HTSE. The analyses were based on the SOBOL method, a modern uncertainty and sensitivity analyses method using variance decomposition and Monte Carlo method. A total of 14 parameters have been taken into account associated with tritium sources, heat exchangers, purification systems, and temperatures. Two sensitivity indices (first order index and total index) were considered, and 15,360 samples were totally used for solution convergence. As a result, important parameters that affect tritium concentration in the hydrogen product have been identified and quantified with the rankings. Several guidelines and recommendations for reducing modeling uncertainties have been also provided throughout the discussions along with some useful ideas for mitigating tritium contaminations in the hydrogen product.

A tritium permeation analyses code (TPAC) has been developed at Idaho National Laboratory (INL) by using MATLAB SIMULINK package for analysis of tritium behaviors in the VHTR integrated with hydrogen production and process heat application systems. The modeling is based on the mass balance of tritium-containing species and hydrogen (i.e., HT, H 2 , HTO, HTSO 4 , and TI) coupled with a variety of tritium source, sink, and permeation models. The code includes: (1) tritium sources from ternary fission and neutron reactions with 6 Li, 7 Li 10 B, and 3 He; (2) tritium purification system; (3) leakage of tritium with coolant; (4) permeation through pipes, vessels, and heat exchangers; (5) electrolyzer for high temperature steam electrolysis (HTSE); and (6) isotope exchange for SI process. Verification of the code has been performed by comparisons with the analytical solutions, the experimental data, and the benchmark code results based on the Peach Bottom reactor design. The results showed that all the governing equations are well implemented into the code and correctly solved. This paper summarizes all the background, the theory, the code structures, and some verification results related to the TPAC code development at INL.

Prader-Willi syndrome (PWS) is characterized by life-threatening childhood-onset hyperphagia, obesity and, uniquely, high plasma levels of ghrelin, the orexigenic gastric hormone. Somatostatin suppresses ghrelin secretion in normal subjects. We therefore examined the effect of somatostatin on plasma ghrelin and appetite in four male PWS adults fasted overnight in a double-blind, placebo-controlled, randomized cross-over study. Subjects received an intravenous infusion of somatostatin (250 microg/hr) or saline for 300 min, and had blood samples taken every 30 min for measurement of plasma ghrelin and PYY3-36 (anorexigenic intestinal hormone) by radio-immunoassay, and glucose. Appetite was measured by counting sandwiches eaten over a 60 min free food access period from +120 min. Despite somatostatin lowering fasting plasma ghrelin by 60 +/- 2% (P = 0.04) to levels seen in non-PWS men, there was no associated reduction in food intake (105 +/- 9% of food intake during saline infusion, P = 0.6). Somatostatin also lowered plasma PYY levels by 45 +/- 16% (P = 0.04), and produced post-prandial hyperglycemia (P = 0.04). We conclude that either hyperghrelinemia may not contribute to hyperphagia in PWS adults, or perhaps concomitant reductions in anorexigenic gastrointestinal hormones by somatostatin counteracted any anorexigenic effect of lowering orexigenic ghrelin. Somatostatin analogues may therefore not be an effective therapy for obesity in PWS. Larger chronic studies with long-acting somatostatin analogues will be needed to determine their benefits and risks in treating PWS obesity.

OBJECTIVESThe effects of direct intramyocardial injection of the plasmid encoding vascular endothelial growth factor (phVEGF165) in the border zone of myocardial infarct tissue in rat hearts were investigated.BACKGROUNDControversy exists concerning the ability of VEGF to induce angiogenesis and enhance coronary flow in the myocardium.METHODSSprague-Dawley rats received a ligation of the left coronary artery to induce myocardial infarction (MI). At 33.1 ± 6.5 days, the rats were injected with phVEGF165 at one location and control plasmid at a second location (500 μg DNA, n = 24) or saline (n = 16). After 33.1 ± 5.7 days, the hearts were excised for macroscopic and histologic analysis. Regional blood flow ratios were measured in 18 rats by radioactive microspheres.RESULTSphVEGF165-treated sites showed macroscopic angioma-like structures at the injection site while control DNA and saline injection sites did not. By histology, 21/24 phVEGF165-treated hearts showed increased focal epicardial blood vessel density and angioma-like formation. Quantitative morphometric evaluation in 20 phVEGF165-treated hearts revealed 44.4 ± 10.5 vascular structures per field in phVEGF165-treated hearts versus 21.4 ± 4.7 in control DNA injection sites (p < 0.05). Regional myocardial blood flow ratios between the injection site and noninfarcted area did not demonstrate any difference between phVEGF165-treated hearts (0.9 ± 0.2) and saline-treated hearts (0.7 ± 0.1).CONCLUSIONSInjection of DNA for VEGF in the border zone of MI in rat hearts induced angiogenesis. Angioma formation at the injection sites did not appear to contribute to regional myocardial blood flow, which may be a limitation of gene therapy for this application.

Background: Costs for large animal studies have escalated. Therefore there is a need to develop small animal models of non-ischemic cardiac failure and accurate non-invasive techniques that will allow serial quantitation of left ventricular function. Objectives: The purpose of our study was to determine the efficacy and reliability of adriamycin for inducing cardiomyopathy in rats. We hypothesized that high frequency transthoracic 2-dimensional and M-mode echocardiography would allow for serial testing of cardiac function in this small animal model. Methods: Adriamycin was administered at a dose of 2.5 mg/kg intravenously once a week for 10 weeks in 54 rats. Transthoracic echocardiography by use of a 7.5 MHz transducer was performed in 19 rats at baseline and additionally at 12 weeks after beginning of adriamycin therapy to measure left ventricular dimensions and calculate fractional shortening. Results: The mortality rate during the treatment period was 11%, but increased to 52% at 13 weeks. Transthoracic echocardiography provided adequate visualization of left ventricular dimensions and cardiac function in a parasternal short axis view. In follow-up echocardiography, pericardial effusion was detected in 8/19 rats (42%). Compared to baseline, end-diastolic diameters increased from 0.56±0.06 to 0.64±0.08 mm ( p

In this study, 149 WAIS-R protocols were analyzed that were completed by 22 graduate students enrolled in an individual intelligence testing course to ascertain the effectiveness of practice administrations in developing examiner competency. Students made numerous errors, such as assigning too few or too many points to responses and obtaining incorrect basals or ceilings. No improvement was noted over five practice administrations. Errors were reduced over 10 administrations, but students were still making 10.2 errors per protocol. Findings indicate that the standard practice of having students complete only four practice administrations of the WAIS-R does not reduce the number of examiner errors students make. Even completing as many as 10 practice administrations does not develop adequate examiner proficiency. Therefore, current methods for teaching assessment courses need to be modified in order to minimize examiner errors. Until such modifications are made, in-service training and careful interpretation of Full Scale WAIS-R scores are needed.

The strategic goal of the Advance Reactors such as AHTR is to broaden the environmental and economic benefits of nuclear energy in the United States by producing power to meet growing energy demands and demonstrating its applicability to market sectors not being served by light water reactors

The strategic goal of the Small Modular Molten Salt Reactor (SM-MSR) is to broaden the environmental and economic benefits of nuclear energy in the United States by producing power to meet growing energy demands and demonstrating its applicability to market sectors not being served by light water reactors. Of primary importance is demonstrating that the SM-MSR can be operated safely and compete economically with larger reactors. Reactor outlet temperatures (ROTs) of SM-MSRs will likely be much higher (around 700°C) than light water reactors, thereby increasing the efficiency of electricity production and potentially providing process heat for industrial applications, which will help offset the higher per kilowatt costs generally associated with smaller reactors, making the SM-MSR more economically competitive. This paper compares thermal power cycles for given ROT, compares thermal performance using figure of merits and sensitivity study and discusses the comparative advantages of SM-MSRs.Copyright © 2011 by ASME

The DOE Nuclear Hydrogen Initiative (NHI) is investigating candidate technologies for large scale hydrogen production using high temperature gas-cooled reactors (HTGR) in concert with the Next Generation Nuclear Plant (NGNP) programme. The candidate processes include high temperature thermochemical and high temperature electrolytic processes which are being investigated in a sequence of experimental and analytic studies to establish the most promising and cost effective means of hydrogen production with nuclear energy. Although these advanced processes are in an early development stage, it is important that the projected economic potential of these processes be evaluated to assist in the prioritisation of research activities, and ultimately in the selection of the most promising processes for demonstration and deployment.

Dendrochronological studies have begun on two conifer species in the Stanley River area of western Tasmania. The chronology extends to 273 BC for Huon pine (Lagarostrobos franklinii) and to AD 1450 for celery-top pine (Phyllocladus aspleniifolius). Apart from living or recently felled trees, sections have been taken from 58 logs preserved in floodplain sediments. Two of these logs have late Pleistocene ages, centered around 13.0 and 12.7 k 14C yr bp. Four logs are between 8 and 9 ka BP, and one is centered at 7.3 ka bp. The remaining logs have various ages between 6.2 ka BP and the present. 14C measurements have been performed on decadal samples from the two late Pleistocene logs, providing short (260-yr) records of atmospheric 14C variations when plotted against individual ring numbers. Decadal measurements on the 7300-yr-old log have been wiggle-matched with 14C calibration curves from German oak and bristlecone pine. Measurements for the period, AD 1600–1800, show good agreement with northern hemisphere results, and a nearly zero offset between the hemispheres.

The next generation nuclear plant (NGNP), a very high temperature gas-cooled reactor (VHTR) concept, will provide the first demonstration of a closed-loop Brayton cycle at a commercial scale, producing a few hundred megawatts of power in the form of electricity and hydrogen. The power conversion unit for the NGNP will take advantage of the significantly higher reactor outlet temperatures of the VHTRs to provide higher efficiencies than can be achieved with the current generation of light water reactors. Besides demonstrating a system design that can be used directly for subsequent commercial deployment, the NGNP will demonstrate key technology elements that can be used in subsequent advanced power conversion systems for other Generation IV reactors. In anticipation of the design, development, and procurement of an advanced power conversion system for the NGNP, the system integration of the NGNP and hydrogen plant was initiated to identify the important design and technology options that must be considered in evaluating the performance of the proposed NGNP. As part of the system integration of the VHTRs and the hydrogen production plant, the intermediate heat exchanger is used to transfer the process heat from VHTRs to the hydrogen plant. Therefore, the design and configuration of the intermediate heat exchanger are very important. This paper describes analyses of one stage versus two-stage heat exchanger design configurations and simple stress analyses of a printed circuit heat exchanger (PCHE), helical-coil heat exchanger, and shell-and-tube heat exchanger.

This report describes the current capabilities of the INL to manage the NHI, the planned increases in capability to support NHI, and the cost and schedule and strategy for developing a commercially viable hydrogen production technology for deployment with NGNP.

Field experiments were conducted in 1982 and 1983 on a Dothan sandy loam (Plinthic Paleudult) at Headland, AL, to investigate minimum-tillage production of peanuts (Arachis hypogaeaL.). The experiments included two peanut varieties: a) ‘Pronto’ (an earlier maturing Spanish type), and b) ‘Florunner’ (a later maturing runner type). Two row-spacing patterns were used: a) conventional 91-cm rows, and b) a modified twin 18-cm row pattern. A constant seeding rate (140 kg/ha) was used regardless of row spacing. Six herbicide systems were evaluated within each combination of variety and row spacing. The Florunner variety outyielded the Pronto variety across both years and weed management systems. Modified twin 18-cm rows outyielded conventional 91-cm rows across years and peanut varieties. Two of the six weed management systems were successful: 1) paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) + oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) (preemergence), paraquat (ground cracking), naptalam (N-1-naphthylphthalamic acid) + dinoseb (2-sec-butyl-4,6-dinitrophenol) (postemergence); and 2) paraquat + pendimethalin [N-(1-ethylpropyl-3,4-dimethyl-2,6-dinitrobenzenamine] (preemergence), acetochlor [2-chloro-N(ethoxymethyl)-6’-ethyl-o-acetotoluidide] + dinoseb (ground cracking), and cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazine-2-yl]amino]-2-methylpropionitrile} (early postdirected spray). Both systems provided the best overall control of Texas panicum (Panicum texanumBuckl. ♯ PANTE), Florida beggarweed [Desmodium tortuosum(Sw.) DC. ♯ DEDTO], and sicklepod (Cassia obtusifoliaL. ♯ CASOB) and were acceptable for use in minimum-tillage peanut production.

The Next Generation Nuclear Plant (NGNP) will most likely produce electricity and process heat, with both being considered for hydrogen production. To capture nuclear process heat, and transport it to a distant industrial facility requires a high temperature system of heat exchangers, pumps and/or compressors. The heat transfer system is particularly challenging not only due to the elevated temperatures (up to ∼ 1300K) and industrial scale power transport (≥50 MW), but also due to a potentially large separation distance between the nuclear and industrial plants (100+m) dictated by safety and licensing mandates. The work reported here is the preliminary analysis of two-phase thermosyphon heat transfer performance with alkali metals. A thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. In contrast to single-phased forced convective heat transfer via ‘pumping a fluid’, a thermosyphon (also called a wickless heat pipe) transfers heat through the vaporization / condensing process. The condensate is further returned to the hot source by gravity, i.e. without any requirement of pumps or compressors. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. Two-phase heat transfer by a thermosyphon has the advantage of high enthalpy transport that includes the sensible heat of the liquid, the latent heat of vaporization, and vapor superheat. In contrast, single-phase forced convection transports only the sensible heat of the fluid. Additionally, vapor-phase velocities within a thermosyphon are much greater than single-phase liquid velocities within a forced convective loop. Thermosyphon performance can be limited by the sonic limit (choking) of vapor flow and/or by condensate entrainment. Proper thermosyphon requires analysis of both.Copyright © 2008 by ASME

One key long-standing issue that must be overcome to fully realize the successful growth of nuclear power is to determine other benefits of nuclear energy apart from meeting the electricity demands. The Next Generation Nuclear Plant (NGNP) will most likely be producing electricity and heat for the production of hydrogen and/or oil retrieval from oil sands and oil shale to help in our national pursuit of energy independence. For nuclear process heat to be utilized, intermediate heat exchange is required to transfer heat from the NGNP to the hydrogen plant or oil recovery field in the most efficient way possible. Development of nuclear reactor-process heat technology has intensified the interest in liquid metals as heat transfer media because of their ideal transport properties. Liquid metal heat exchangers are not new in practical applications. An important rationale for considering liquid metals as the working fluid is because of the higher convective heat transfer coefficient. This explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. The production of electric power at higher efficiency via the Brayton Cycle, and hydrogen production, requires both heat at higher temperatures and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. Compact heat exchangers maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. High temperature IHX design requirements are governed in part by the allowable temperature drop between the outlet of NGNP and inlet of the process heat facility. In order to improve the characteristics of heat transfer, liquid metal phase change heat exchangers may be more effective and efficient. This paper explores the overall heat transfer characteristics and pressure drop of the phase change heat exchanger with Na as the heat exchanger coolant. In order to design a very efficient and effective heat exchanger one must optimize the design such that we have a high heat transfer and a lower pressure drop, but there is always a tradeoff between them. Based on NGNP operational parameters, a heat exchanger analysis with the sodium phase change is presented to show that the heat exchanger has the potential for highly effective heat transfer, within a small volume at reasonable cost.Copyright © 2008 by ASME