Axial Nodes Research Articles

Application of new axial power distribution synthesis method using in-core detector signal in digital core protection system

ABSTRACT A new method for the generation of axial power distributions using artificial neural network (ANN) technique and real-time measured planar radial peaking factor, Fxy (hereinafter ‘Live Fxy’) method for digital core protection system of pressurized water reactors is presented. ANN with Simulated Annealing (SA) technique to find global optimum solution was used to calculate core average axial power distribution. In Live Fxy method, axial node-wise Fxys were calculated by multiplying pin/box factors to the measured assembly powers inferred from in-core detector signals without calculating detailed 3D power distributions. The hot pin power distribution for DNBR and LPD was then obtained by multiplying the core average axial power distribution and Fxys at axial nodes. The validation of the method was performed for various core conditions (e.g. core power levels, control rod positions, etc.) of Korean OPR1000 power plant. The result showed a decrease in RMS errors by 2.2% ~ 7.0% (3.6% on average), and the minimum thermal margins for DNBR and LPD were increased by 6.4% and 15.6%, respectively. The application of the method would improve the accuracy of axial power distribution and thermal margin, contributing to the operability and safety of digital core protection system.

Thermal-Hydraulic modelling and analysis of VVER-1200 reactor core

A mathematical model has been developed to simulate the thermal–hydraulic performance of the VVER-1200 pressurized water reactor under normal operation. The energy equation and the heat conduction equation are solved analytically in order to predict the coolant, clad and fuel temperature distributions. The core active length is divided into axial regions and the fuel rod is divided into radial zones, nodal calculation is performed for three types of cooling channels; the core mean channel with mean core power, and both the mean and hot channels of the most intensive energy fuel assembly. Through this model, the heat flux leading to the Departure from Nucleate Boiling (DNB) as well as the Departure from Nucleate Boiling Ratio (DNBR) predicted at each axial node for each channel using EPRI correlation. High accuracy correlations and/or models valid under the reactor operating conditions are selected to estimate the heat transfer coefficients under single-phase forced convection, subcooled boiling and bulk boiling regimes. The vapor quality and void fraction are estimated for boiling regimes as well. The model is then used to simulate the VVER-1200 reactor performance under both the rated and conservative operational parameters where boiling is predicted in the hot channel under both cases. The results are verified against the available calculations in the literature for coolant temperature, clad temperature and void fraction, where a very good agreement is achieved. The developed model is considered an appropriate tool for independent thermal–hydraulic safety assessment of VVER-1200 reactor core under steady-state operation.

Lamprothamnium sardoum sp. nov. (Characeae, Streptophyta): A new species of Lamprothamnium for Europe

Comprehensive charophyte surveys on the island of Sardinia, Italy revealed a novel species of Lamprothamnium occurring in a salt marsh in the vicinity of San Giovanni Sinis. Most of the discovery and description of charophyte species in Europe took place in the mid–late 1800s, so the discovery of a new species in the region is of note. The species is described and compared with the other species of Lamprothamnium known for the Mediterranean region of Europe and elsewhere. Lamprothamnium sardoum sp. nov. differs from all other species in having antheridia and oogonia clustered internal and external to the axial nodes and on the branchlets, and in the relative absence of sterile whorls, the length and width of its bract cells and decumbent stipulodes, and the persistence of the protonema on mature plants. In addition, data on hydrochemistry and accompanying flora of the Sardinian site of L. sardoum are presented together with proposals for management and conservation.

하이브리드 유하액막 증발기 성능에 관한 수치적 연구

The purpose of this study was to develop steady-state model of hybrid falling film evaporator, and to analyze performance of the heat exchanger. R1233zd(E) which is one of the low GWP refrigerants was selected as a working fluid. The steady state model was developed, based on the heat transfer correlations from previous studies for falling film evaporation and pool boiling using R1233zd(E). Based on the analysis results according to the number of nodes, the number os axial nodes was selected as 24. Performance analysis was conducted with respect to evaporator pressure, axial direction liquid refrigerant supply ratio from tray, rows of pipe for pool boiling region, and maximum heat transfer coefficient of falling film region. For the same heat capacity of the evaporator, the length of the pipe should extend approximately 3.6 times, when evaporator operation pressure increases from 49.2 to 58.4 kPa. The length of the pipe can be reduced approximately 18% as the number of rows for pool boiling region increases from one to three. The axial direction liquid refrigerant supply ratio from the tray also affects the performance of the evaporator. Compared to the equal supply ratio case, the pipe length must increase approximately 9%, when the axial direction liquid refrigerant supply ratio is 9:1 for the same cooling capacity. As the maximum heat transfer coefficient at falling film region increases from 5000 to 11000 W/m2K,the length of the pipe can be reduced approximately 27%.

High temporal accuracy elastic wave simulation with new time–space domain implicit staggered‐grid finite‐difference schemes

Implicit staggered-grid finite-difference methods are attractive for elastic wave modelling due to significantly enhanced spatial accuracy compared to explicit ones. However, the central-grid finite-difference operators used to approximate the temporal derivatives result in a limited accuracy in time. Temporal high-order finite-difference methods have the ability to weaken the temporal dispersion and improve the modelling stability. It is noted that the previous temporal high-order and spatial implicit finite-difference methods are all designed in the space domain for performing acoustic wave propagation. To implement 2-D elastic wave simulation with high-order accuracy both in space and time, we propose two time–space domain implicit staggered-grid finite-difference schemes, in which the spatial derivatives are approximated by the weighted average of a few extra off-axial nodes and axial nodes of the conventional cross-stencil. We derive the P- and S-wave dispersion relations of the whole elastic wave equation and estimate the finite-difference coefficients via a variable substitution-based Taylor-series expansion. Our Taylor-series expansion-based new scheme yields high-order temporal and spatial accuracy. Besides, the spatial accuracy can be further enhanced by our newly proposed linear optimization strategy, which benefits from easy implementation since we only optimize the axial spatial coefficients via a least-squares strategy and set the off-axial temporal coefficients the same as the solution of the Taylor-series expansion method. Besides, the P- and S-wave separation approach is adopted to propagate the P- and S-wavefields with the P- and S-wave dispersion relation-based finite-difference operators, respectively. Our two new schemes are more capable of suppressing the numerical dispersion and exhibit better stability performance compared to conventional one, as we will illustrate via a detailed analysis of dispersion, stability and numerical experiments. In addition, a comparison of computation times demonstrates the efficiency advantage of two new schemes since small operator lengths and large time steps are allowed.

Augmentation of lymphoid tissues in the human immune system mouse to advance host directed therapies for HIV

Abstract The study of HIV infection and pathogenicity in physical reservoirs requires a biologically relevant model which resembles the human immune system and physiology. The human immune system (HIS) mouse is well established as a model of HIV, but defects in immune tissue reconstitution remain a challenge for examining pathology in tissues. Herein we show that exogenous injection of the human cytokine FLT-3L into the HSC cord blood HIS mouse model significantly expanded the total area of axial lymph nodes and the circulating percentage of human T cells, thus enabling us to visualize and quantify HIV infectivity in the secondary lymphoid tissues of the spleen and axial node. Further, we detected cell death and T cell depletion in tissues, consistent with HIV pathogenesis. Treatment with the caspase-1 inhibitor VX-765 significantly decreased viral load as measured by gag qPCR, and apoptosis as measured by TUNEL assay, in the spleen. A significant restoration of CD4+ T cells in the spleen due to VX-765 treatment was observed via flow cytometry. In situ hybridization further demonstrated a significant decrease in viral RNA in both the spleen and axial lymph nodes. Transcriptomic analysis further revealed an upregulation in host HIV restriction factors such as APOBR, SAMHD1 and APOBEC3A as a result of VX-765 administration. These findings demonstrate FLT-3L as a mechanism whereby the human immune environment in HIS mice can be enhanced to support investigations of HIV pathogenesis and immune outcomes in tissue compartments. Preliminary results indicate that targeting inflammasome pathways with VX-765 in HIS mice treated with FLT-3L, and infected with HIV, preserved T cell populations and decreased viral load. Supported by R01 A1HL129881, NIH/NHLBI

A Predictive Model for Nonsentinel Node Status after Sentinel Lymph Node Biopsy in Sentinel Lymph Node-Positive Chinese Women with Early Breast Cancer.

Background Axial lymph node dissection (ALND) is needed in patients with positive sentinel lymph node (SLN). ALND is easy to cause upper limb edema. Therefore, accurate prediction of nonsentinel lymph nodes (non-SLN) which may not need ALND can avoid excessive dissection and reduce complications. We constructed a new prognostic model to predict the non-SLN metastasis of Chinese breast cancer patients. Methods We enrolled 736 patients who underwent sentinel lymph node biopsy (SLNB); 228 (30.98%) were diagnosed with SLNB metastasis which was determined by intraoperative pathological detection and further accepted ALND. We constructed a prediction model by univariate analysis, multivariate analysis, “R” language, and binary logistic regression in the abovementioned 228 patients and verified this prediction model in 60 patients. Results Based on univariate analysis using α = 0.05 as the significance level for type I error, we found that age (P=0.045), tumor size (P=0.006), multifocality (P=0.011), lymphovascular invasion (P=0.003), positive SLN number (P=0.009), and negative SLN number (P=0.034) were statistically significant. Age was excluded in multivariate analysis, and we constructed a predictive equation to assess the risk of non-SLN metastasis: Logit(P)=Ln(P/1 − P)=0.267∗a+1.443∗b+1.078∗c+0.471∗d − 0.618∗e − 2.541 (where “a” represents tumor size, “b” represents multifocality, “c” represents lymphovascular invasion, “d” represents the number of metastasis of SLN, and “e” represents the number of SLNs without metastasis). AUCs for the training group and validation group were 0.715 and 0.744, respectively. When setting the risk value below 22.3%, as per the prediction equation's low-risk interval, our model predicted that about 4% of patients could avoid ALND. Conclusions This study established a model which demonstrated good prognostic performance in assessing the risk of non-SLN metastasis in Chinese patients with positive SLNs.

Planar Weak Form Quadrature Beam Elements Based on Absolute Nodal Coordinate Formulation: A Structural Mechanics Approach

A planar nonlinear weak form quadrature beam element of arbitrary number of axial nodes is proposed on the basis of the absolute nodal coordinate formulation (ANCF). Elastic forces of the element are established through geometrically exact beam theory, resulting in good consistency with classical beam theory. Two examples with strong geometrical nonlinearity are presented to verify the effec-tiveness of the formulation.

Eigenfrequencies and eigenmodes of anisotropic thick cylindrical shell

Thick cylindrical shells are used in various applications, and there are many studies on strength and vibration analysis. In vibration analysis of isotropic and orthotropic thick cylindrical shells, it is commonly assumed that displacements are affected by rotational inertia and shear deformation and the shell thickness does not change during deformation. On the other hand, vibration analysis of orthotropic cylinders has been studied based on three-dimensional analysis theory without these assumptions. However, vibration analysis of thick cylindrical shells based on three-dimensional analysis theory has not been conducted. Previously, we studied an orthotropic parallelepiped as a single continuum and reported the relationships between dimensions and natural angular frequencies and vibration modes. In this report, a thick cylindrical shell with deformation in thickness direction and orthotropy is investigated. The natural angular frequencies and modal functions of the axisymmetric vibration are derived using three-dimensional analytical theory. In the calculation example, the relationship between dimensionless axial wavenumber and natural angular frequencies and modal functions of the model with varying thickness ratios are illustrated. The frequency veering of natural angular frequencies occurs, and the wavenumber where the frequency veering occurs depends on the thickness ratio. The number of radial nodes varies independently of the frequency veering, and the sign of the slope of radial node vs. dimensionless wavenumber changes around the wavenumber where veering occurs. The number of axial nodes and their positions vary only around the value of the wavenumber where veering occurs.

Calculation and Analysis of Critical Heat Flux at LWR Passive Safety Design

Critical heat flux (MDNBR) is one parameter for safe nuclear reactor operation. The magnitude of MDNBR is determined by local heat flux. When it is sufficiently high, it will cause a change in heat equilibrium and deteriorate nuclear fuel structure. To obtain assurance for nuclear reactor safety in safe criteria, Calculation and analysis of Critical heat flux of 630 MWe passive LWR was carried out at steady state and transient condition. The study used COBRA IV-I sub channel program coupled with critical heat flux correlation of EPRI-Columbia and W-3. The program models the core into 1/8 sections, each of which is divided into 83 sub-channels in radial direction and 40 nodes in axial direction, including 8 sub-channels of the hottest assembly. Normalized coast down flow and reactor power decay at initial phase is 10 second after loss of flow accident (LOFA) caused by anticipated primary pump failure. The effects of all input parameters, such as radial nodes, axial nodes, mix coefficient, velocity of coolant mass entering the core and power variation, have been identified. Evaluation of the results of safety calculation indicates that MDNBR, cladding temperature, and hot channel temperature are 1.83, 349°C and 2033°C, respectively. As the licensing limits for those parameters are 1.3, 1850°C, and 2840°C, it is concluded that the design of 630 MWe passive LWR has met the licensing criteria of safety. Modelling for safety analysis of passive LWR employs COBRA IV-I program. The results show that this program can be used to calculate hydraulic safety parameters with sub-channel model.

Multiphysics Modeling and Validation of Spent Fuel Isotopics Using Coupled Neutronics/Thermal-Hydraulics Simulations

Multiphysics coupling of neutronics/thermal-hydraulics models is essential for accurate modeling of nuclear reactor systems with physics feedback. In this work, SCALE/TRACE coupling is used for neutronic analysis and spent fuel validation of BWR assemblies, which have strong coolant feedback. 3D axial power profiles with coolant feedback are captured in these advanced simulations. The methodology is applied to two BWR assemblies (2F2DN23/SF98 and 2F2D1/F6), discharged from the Fukushima Daini-2 unit. Coupling is performed externally, where the SCALE/T5-DEPL module transfers axial power data in all axial nodes to TRACE, which in turn calculates the coolant density and temperature for each of these nodes. Within a burnup step, the data exchange process is repeated until convergence of all coupling parameters (axial power, coolant density, and coolant temperature) is observed. Analysis of axial power, criticality, and coolant properties at the assembly level is used to verify the coupling process. The 2F2D1/F6 benchmark seems to have insignificant void feedback compared to 2F2DN23/SF98 case, which experiences large power changes during operation. Spent fuel isotopic data are used to validate the coupling methodology, which demonstrated good results for uranium isotopes and satisfactory results for other actinides. This work has a major challenge of lack of documented data to build the coupled models (boundary conditions, control rod history, spatial location in the core, etc.), which encourages more advanced methods to approximate such missing data to achieve better modeling and simulation results.

Investigations on a typical small modular PWR using coupled neutronic-thermal-mechanical evaluations to achieve long-life cycle-length

The main purpose of this study was to design small modular PWR with power of 150 MWth for long life operation, based on the coupled neutronic and thermal-mechanical evaluations. In this regard, pitch and fuel rod diameter were changed from 0.9 cm to 2.5 cm and 0.6 cm–0.96 cm, respectively; and desirable pairs (pitch - fuel rod diameter) were obtained. Neutronic parameters such as excess reactivity, maximum to average ratio of the radial neutron flux and fuel burnup were calculated using MCNP code. Also, thermal-mechanical parameters of the fuel rod including fuel centerline temperature, cladding hoop stress and fuel rod internal gas pressure were computed using FRAPCON code. Independency of results from number of axial nodes in FRAPCON code was analyzed. The number of axial nodes was considered 40 to ensure the accuracy of the FRAPCON results. Neutronic and thermal-mechanical cost values for each pair were calculated and Pareto front of the desirable pairs were obtained. Based on the results, eight desirable pairs were selected. By assuming equal importance for neutronic and thermal-mechanical parameters, total cost value was defined and pair of (1.1, 0.64) was selected as the most desirable one. Finally, fuel cycle lifetime was assessed for desirable pair considering neutronic (criticality and burnup) and thermal-mechanical (cladding strain, oxidation and hydriding as well as fuel rod internal gas pressure) limits. It was observed that fuel cycle lifetime was enhanced to 1750 days (40 GWD/ton).

Coupled Neutron and Gamma Heating Calculation Based on VARIANT Transport Solutions

For accurate assessment of nuclear heating in fast reactors, a new coupled neutron and gamma heating calculation scheme has been developed based on VARIANT nodal transport solutions of neutron and gamma flux distributions. The MC2-3 code was extended to generate multigroup neutron and gamma cross sections and kinetic energy release in materials (KERMA) factors, and a utility program CURVE was developed to reconstruct detailed pin and duct wall powers from VARIANT output files. The improved heating calculation scheme has been verified against MCNP6 Monte Carlo reference solutions for the Advanced Burner Test Reactor (ABTR) and Experimental Breeder Reactor II (EBR-II) benchmark problems. Compared to the existing coupled heating calculation method based on DIF3D diffusion theory solutions, the new heating calculation scheme utilizes more accurate gamma cross sections and KERMA factors, accounts for the transport effects, and eliminates the approximations in the existing pin power reconstruction scheme. As a result, it produces more accurate assembly and pin power distributions. For both the ABTR and EBR-II problems, the maximum assembly power error was ~1% in fuel assemblies and ~2% in instrumented structure assemblies, and the maximum error in pin segment powers in an axial node of fuel assembly was ~4%. In the blankets of the EBR-II problem, the maximum error in pin segment powers was increased to ~8%, mainly due to the lower power level and the relatively large error in the nodal power of the VARIANT solution.

Model updates and performance evaluations on fuel performance code FEMAXI-8 for light water reactor fuel analysis

ABSTRACT FEMAXI-8 is the latest version of the fuel performance code FEMAXI, which has been developed by the Japan Atomic Energy Agency (JAEA) to analyze the thermal and mechanical behavior of a single fuel rod under primarily normal operation conditions and anticipated transient conditions. The development after the release of the previous version FEMAXI-7 addressed modeling on thermal and mechanical effects of fuel pellet relocation, fission gas release, fission-gas-induced swelling, etc., to provide a better description of fuel behavior observed in irradiation tests and underlying phenomena. Another key advance is the introduction of new mechanical calculation options with the intension of producing an improved treatment of various factors that affects stability of calculation, namely, time step control and nonlinear factors such as pellet cracking, contact between axial nodes, and axial friction between fuel pellets and cladding tube. Such factors were a primary source of numerical problems encountered by former versions of FEMAXI and have hindered thorough assessment of their predictive performance. A validation analysis performed against 168 irradiation test cases using a set of consistent calculation models implemented in FEMAXI-8 revealed that the new version makes reasonable predictions in terms of fuel center temperature, fission gas release, rod free volume, and cladding deformation, under steady-state and power ramp conditions.

Metastatic Cervical and Supraclavicular Lymphadenopathy from Prostate Mimicking Lymphoma: A Case Series

Prostate cancer is the second most common cancer in men worldwide and the commonest cause of mortality in men. It is the commonest diagnosed cancer in African men. The earliest and common sites of metastasis are the axial skeleton and regional lymph nodes. Initial presentation of the metastatic disease with cervical or supraclavicular lymphadenopathy is rarely reported. We report 3 cases of metastatic cancer of the prostate presenting initially to physicians with huge cervical and supraclavicular lymph nodes enlargement which on biopsy revealed metastatic adenocarcinoma. On further evaluation, there were non-bothersome storage symptoms, elevated prostate specific antigen and abnormal digital rectal examination. Transrectal ultrasound (TRUS)-guided biopsy of hypoechoic nodules revealed high-grade adenocarcinoma of the prostate on histopathological examination. The cervical and supraclavicular lymphadenopathy resolved after commencement of androgen deprivation therapy. We advocate for prostate cancer screening in African men above 50 years of age presenting with cervical or supraclavicular lymphadenopthy to primary care physicians even in the absence of lower urinary tract symptoms.

Gear and Runge–Kutta Numerical Discretization Methods in Differential Equations of Adsorption in Adsorption Heat Pump

The main aim of this paper was to find the correct method of calculating equations of heat and mass transfer for the adsorption process and to calculate it numerically in reasonable time and with proper accuracy. An adsorption heat pump with a silica gel adsorbent and water adsorbate is discussed. We developed a mathematical model of temperature and uptake changes in the adsorber/desorber comprising the set of heat and mass balance partial differential equations (PDEs), together with the initial and boundary conditions and solved it by the numerical method of lines (NMOL). Spatial discretization was performed with equally spaced axial nodes and the PDEs were reduced to a set of ordinary differential equations (ODEs). We focused on the comparison of results obtained when the set of heat and mass balance ODEs for an adsorber was solved using: (1) the Runge–Kutta fixed step size fourth-order method (RKfixed), (2) the Runge–Kutta–Fehlberg 4.5th-order method with a variable step size (RK45), and (3) the Gear Backward Differentiation Formulae numerical (Gear BDF) methods. In our experience, all three types of ODE numerical methods (RKfixed, RK45, and Gear BDF) can be applied in simple models to model an adsorber with attention on their limitations. The Gear BDF method usually requires much fewer steps than the RK45 method for almost the same calculating time. RK methods require many more steps to obtain results, and the calculating time depends on accuracy or defined time step. Moreover, one should pay attention to the number of nodes or possible oscillations.

Nuclide inventory calculation based on modeled fuel assembly specifications and burnup histories for Fukushima Dai-ichi NPP Units 1–3

ABSTRACT In order to evaluate heterogeneity in nuclear inventories in the fuel debris of Units 1–3 of the Fukushima Dai-ichi Nuclear Power Plant (NPP), detailed burnup calculations of fuel assemblies were performed. Applying publicly available information, specifications were modeled for the five different types of fuel assemblies loaded in the cores before the shutdown for the accident. The assembly burnup histories reported by Nishihara et al. were used to develop power histories at 24 axial nodes of the fuel assemblies adopting the measured data on the axial burnup profiles of similar fuel assemblies. A correlation between axial node power and an in-channel void fraction was derived from the typical BWR core simulation analysis results and applied to the above-mentioned axial node power histories to obtain the in-channel void fraction histories. Then the burnup and cooling calculations were performed with CASMO5 and ORIGEN2.2 for each batch of fuel assemblies with the same irradiation periods. The calculated results were used to estimate the locally maximum contents of the nuclides such as 235U, 238Pu, 239Pu, 240Pu, 241Pu, 241Am, 242Cm, 243Cm, 244Cm, 90Sr, 134Cs, 137Cs, and 154Eu, which are important in the safety evaluation of the process of the disposal of the fuel debris.

Smart sensing of the axial power and offset in NPPs using GMDH method

The status of nuclear power plants’ conditions must be checked to avoid initial events which may eventually lead to accidents. Axial power and axial offset (AO) are key parameters which are usually used to state 3-dimensional core power peaking, in the form of a practical parameter. Group method of data handling (GMDH) has a wide range of applications. Here, a GMDH is used and modified as an efficient method to predict the axial power and AO of the reactor core as well as fuel assemblies. In this paper, axial power offset of the whole reactor core is reconstructed by using in-core detectors. By using the developed GMDH algorithm, the optimum relationship between the independent in-core detector signals and the dependent variables, the core axial power and AO, is determined. Two separate sets of big data are prepared and analyzed. The first set includes power at each of 24 axial nodes at different core states. The second set is similar to the first set except as it also contains fuel assembly data.

Abstract 3845: 24R,25-Dihydroxyvitamin D3 reduces tumor burden and metastasis in ER+ breast cancer in vivo

Abstract The purpose of this study was to investigate the effects of 24R,25-dihydroxyvitamin D3 (24,25), on tumor growth and metastasis in an in vivo estrogen receptor positive (ER+) orthotopic breast cancer model. 1α,25(OH)2D3 has been shown to have pro-apoptotic effects on breast cancer both in vitro and in vivo. 24,25, a naturally occurring metabolite, is present in human serum at concentrations up to 10 times higher than 1,25. Moreover, 1,25 regulates production of 24,25 by stimulating expression of the 24-hydroxylase. 6-8 week old female nod scid gamma IL2R mice were kept on an ad libitum vitamin D deficient diet. 15 days before surgery, mice were implanted with 1.7mg 0-order release estrogen (E2) pellets. In the first experiment, mice were given a fast-release pellet (45 days). In the second experiment, mice were given a slow-release (90 day) pellet. After 15 days of acclimation (day 0), mice were injected in the T4 mammary fat pad with 1M fluorescently labeled MCF7 cells (an ER+ breast cancer cell line) and cells in 50:50 PBS:Matrigel solution. Tumors were measured once a week starting at day 14 and tracked throughout the course of the study. On day 30, 24,25 treatment was initiated. Each experiment was divided into three groups: 0 ng 24,25, 25 ng 24,25, or 100 ng 24,25 per injection, with n=6-8 mice per group. Treatments were administered three times a week in a 50µL intraperitoneal injection. On day 70, mice were harvested and assessed for tumor burden and metastasis by fluorescence detection microscopy. Fluorescent tissues were marked ‘metastasis positive' and harvested for future immunohistochemical analysis. Mice that were given 24,25 three times weekly showed decreased tumor burden and metastasis as compared to controls. In the first experiment (45 day E2), 25ng and 100ng 24,25 treated mice had significantly lower relative tumor volumes than controls beginning on day 70. These 24,25 treated mice also showed significantly lower rates of left axial lymph node metastasis, and had statistically longer survival rates. The second experiment (90 day E2) had similar results. Mice treated with 25ng and 100ng 24,25 had decreased tumor burden as compared to 0ng controls on day 70. Mice given 24,25 had decreased lung metastasis; however, mice treated with 100ng 24,25 had increased rates of right axial lymph node metastasis. Altogether, mice in both groups that were treated with 100ng of 24,25 had decreased rates of left axial lymph node metastasis and lung metastasis as compared to controls, and statistically longer survival rates. Thus 24,25 could play a role in 1,25's anti-apoptotic effect on breast cancer, potentially via upregulation of 24,25. Citation Format: Anjali Verma, David Joshua Cohen, Chandana Muktipaty, Barbara D. Boyan, Zvi Schwartz. 24R,25-Dihydroxyvitamin D3 reduces tumor burden and metastasis in ER+ breast cancer in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3845.

ANALISIS PERBANDINGAN KINERJA PERANGKAT BAHAN BAKAR PLTN TIPE PWR AP 1000 DAN PWR 1000 MWe TIPIKAL DENGAN MENGGUNAKAN PROGRAM KOMPUTER

Abstract: Investigation of fuel element thermal-hydraulic characteristic is important step related to aspect of fuel bundle reactor design. This paper analyzes of the PWR AP1000 and PWR 1000 MWe Typical of fuel bundle thermal-hydraulic using RELAP5 code. Choosing PWR AP 1000 and PWR 1000 MWe Typical because the both of them have almost same power that is 3400 MWth and 3410 MWth but have differences on fuel bundle sum, the high of active core, and rod diameter. On the fuel bundle, there are 17x17 fuel rods that have a radial factor the power varies. Modelling of fuel bundle are divided into 4 channel groups, ie. power factor of 1.396, range power factor of 1.203 to 1.394, power factor of le then 1.198 down and bypass channel. Axially, the channels are divided into 3 zones there are stand-off assembly at the bottom, an active length of the channel and the zone of upper plenum. The active length divided into 10 axial nodes. The goal of this analysis is fuel bundle design validation of PWR AP 1000 and PWR 1000 MWe Typical and get thermal-hydraulic comparison for steady-state condition. The analysis result including cooling floe rate, axial temperature distribution of cladding and cooling temperature, heat flux and pressure drop. In steady condition, the model was verified with the parameter of AP-1000 and PWR 1000 thermal-hydraulic design in which shows a good agreement. Verification results show that the model is made still need refinement, however qualitatively within realistic limits. Further updating of the model will be done to get a better verification results.