ANALYSIS OF CS-137 TO CS-134 ACTIVITY RATIO FOR FAILED FUEL EXPOSURE ESTIMATION

The Cs-134 to Cs-137 activity ratio of the Cs-134 and Cs-137 fission products released from failed fuel rods into primary coolant is very useful to identify the exposure along with the fuel batch of the failed fuel. The calculated and measured Cs-137 to Cs-134 radioactivity ratios of failed BWR and PWR fuels are compared and analyzed for better understanding of their relationship.  Moreover, the impacts of power uprate and fuel reload outage on calculated Cs-137 to Cs-134 activity ratios are studied and the physics behind the impacts are provided

Safety Features of Advanced and Economic Simplified Boiling Water Reactors

The Advanced Boiling Water Reactor (ABWR) and the Economic Simplified Boiling Water Reactor (ESBWR) are two kinds of contemporary, advanced, commercially available nuclear power reactors. Reactor internal pumps in an ABWR improve performance while eliminating the large recirculation pumps in earlier BWRs. The utilization of natural circulation and passive safety systems in the ESBWR design simplifies nuclear reactor system designs, reduces cost, and provides a reliable stability solution for inherently safe operation. The conceptually reliable stability solution for inherently safe ESBWR operation is developed by establishing a sufficiently high natural circulation flow line, which has a core flow margin at least 5% higher than the stability boundary flow at 100% rated power of a conventional BWR, and then by designing a high flow natural circulation system to achieve this high natural circulation flow line. The performance analyses for the ESBWR Emergency Core Cooling System (ECCS) show that: (1) the core remains covered with a large margin and there is no core heat up in the ESBWR for any break size, (2) the long-term containment pressure increases gradually with time, in the order of hours, and the peak pressure is below the design value with a large margin, and (3) the margins depend on the containment volumes and water inventories. These safety design features ensure inherently safe ESBWR operation. Enhanced safety features based on lessons learned from the Fukushima nuclear accident are added in ABWR’s and ESBWR’s safety designs. The major enhancements are the further prevention of station blackout and loss of ultimate heat sink

Study of ratio of tritium concentration in plants water to tritium concentration in air moisture for chronic atmospheric release of tritium

AbstractSpecific activity models (SA) are often used to estimate tritium concentration in the plants for chronic-release of atmospheric HTO in some regulatory models by some countries and commissions. In such models, a major assumption is that the value of specific activity of tritium of tritium oxide in vegetation to the specific activity of tritium of tritium oxide in air moisture is maintained at a constant ratio (R). The value of R is an important factor in determining tritium concentration and dose from chronic atmospheric release. But the value of R recommended is different from different models. Concentrations of tritium in plants will be have huge difference in plants because of the difference of the value of R, and this in turn would result in difference of ingestion dose via food chain. Some studies suggested that a site-specific distribution of R should be developed in suing a specific activity model. In this study, distribution of R is established for the Qinshan NPP Base. The environmental monitoring data of tritium concentration in five type plants (rapeseed, tea, cabbage, radish and rice) and air at three sampling points (Xiajiawan, Qinlian and Ganpu) around Qinshan NPP Base(QNNP) over a 4 years period as the basis for analysis, and the tritium ratio(R) between plant water and air moisture were determined. The results showed the average value of R of five plants were 0.103, 0.687, 1.055, 0.695 and 0.183 respectively. These values of R are mostly consistent with the law presented by foreign literature, only the value of R for cabbage is greater than the value of R for foliage vegetation presented by foreign reports. This is partly attributable to the difference of experimental conditions. The concentration of HTO of vegetations around QNNP could be assessed using the values of R recommended by this report for chronic release of atmospheric HTO

Look, Listen and Learn - A Multimodal LSTM for Speaker Identification

Speaker identification refers to the task of localizing the face of a person who has the same identity as the ongoing voice in a video. This task not only requires collective perception over both visual and auditory signals, the robustness to handle severe quality degradations and unconstrained content variations are also indispensable. In this paper, we describe a novel multimodal Long Short-Term Memory (LSTM) architecture which seamlessly unifies both visual and auditory modalities from the beginning of each sequence input. The key idea is to extend the conventional LSTM by not only sharing weights across time steps, but also sharing weights across modalities. We show that modeling the temporal dependency across face and voice can significantly improve the robustness to content quality degradations and variations. We also found that our multimodal LSTM is robustness to distractors, namely the non-speaking identities. We applied our multimodal LSTM to The Big Bang Theory dataset and showed that our system outperforms the state-of-the-art systems in speaker identification with lower false alarm rate and higher recognition accuracy.Comment: The 30th AAAI Conference on Artificial Intelligence (AAAI-16

Development of a trench cutting re-mixing deep wall method model test device

The trench cutting re-mixing deep wall (TRD) is a new type of underground waterproof curtain. Mixing uniformity is the key index affecting the efficiency and quality of this method. However, because of many influencing factors, existing theories cannot be used to express the relationship between various factors and mixing uniformity. By analyzing the cutting and mixing process of the TRD method, the main factors affecting the uniformity of the mixing were obtained. A model test device was designed and manufactured, based on Buckingham's pi theorem. The validity of the model test device was verified through a comparative analysis of model and field test results. The model test device was demonstrated to be able to simulate the mixing process of the TRD method. The results provide guidance for promotion and better application of the TRD method

Accurate Single Stage Detector Using Recurrent Rolling Convolution

Most of the recent successful methods in accurate object detection and localization used some variants of R-CNN style two stage Convolutional Neural Networks (CNN) where plausible regions were proposed in the first stage then followed by a second stage for decision refinement. Despite the simplicity of training and the efficiency in deployment, the single stage detection methods have not been as competitive when evaluated in benchmarks consider mAP for high IoU thresholds. In this paper, we proposed a novel single stage end-to-end trainable object detection network to overcome this limitation. We achieved this by introducing Recurrent Rolling Convolution (RRC) architecture over multi-scale feature maps to construct object classifiers and bounding box regressors which are "deep in context". We evaluated our method in the challenging KITTI dataset which measures methods under IoU threshold of 0.7. We showed that with RRC, a single reduced VGG-16 based model already significantly outperformed all the previously published results. At the time this paper was written our models ranked the first in KITTI car detection (the hard level), the first in cyclist detection and the second in pedestrian detection. These results were not reached by the previous single stage methods. The code is publicly available.Comment: CVPR 201

Overview on Steady-state Nuclear Methods for BWR Nuclear Core Design and Analysis

An overview on nuclear methods for boiling water reactors (BWR) core design and analysis is provided based on the ANS Standard 19.3. The steady-state BWR nuclear methods, composed of neutron cross section library generation method, lattice physics method and core physics method, are systematically reviewed and associated computer codes in common use for BWR core design and analysis are listed. Verification and validation, the two complementary aspects in determining the range of applicability of the calculation system, are discussed extensively. The biases and uncertainties for the predictions from the calculation system over its demonstrated range of applicability are also discussed

Preoperative Diagnosis of Fallopian Tube Carcinoma by Transvaginal Sonography, MRI and CA125

AbstractPrimary fallopian tube carcinoma is the least common of the gynecological malignancies and rarely diagnosed preoperatively. We report the case of a 70-year-old woman with primary tubal carcinoma, which was diagnosed preoperatively on the basis of elevated CA125 and characteristic features found by transvaginal sonography, transvaginal color flow imaging and magnetic resonance imaging. Transvaginal ultrasonography showed a sausage-shaped solid mass alongside the right ovary. Transvaginal color Doppler imaging revealed characteristically low impedance vascular flow within the solid components. A pathohistological study confirmed the diagnosis of fallopian tube carcinoma