• Title, Summary, Keyword: EOC

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CORE DESIGN FOR HETEROGENEOUS THORIUM FUEL ASSEMBLIES FOR PWR (II) - THERMAL HYDRAULIC ANALYSIS AND SPENT FUEL CHARACTERISTICS

  • BAE KANG-MOK;HAN KYU-HYUN;KIM MYUNG-HYUN;CHANG SOON-HEUNG
    • Nuclear Engineering and Technology
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    • v.37 no.4
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    • pp.363-374
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    • 2005
  • A heterogeneous thorium-based Kyung Hee Thorium Fuel (KTF) assembly design was assessed for application in the APR-1400 to study the feasibility of using thorium fuel in a conventional pressurized water reactor (PWR). Thermal hydraulic safety was examined for the thorium-based APR-1400 core, focusing on the Departure from Nucleate Boiling Ratio (DNBR) and Large Break Loss of Coolant Accident (LBLOCA) analysis. To satisfy the minimum DNBR (MDNBR) safety limit condition, MDNBR>1.3, a new grid design was adopted, that enabled grids in the seed and blanket assemblies to have different loss coefficients to the coolant flow. The fuel radius of the blanket was enlarged to increase the mass flow rate in the seed channel. Under transient conditions, the MDNBR values for the Beginning of Cycle (BOC), Middle of Cycle (MOC), and End of Cycle (EOC) were 1.367, 1.465, and 1.554, respectively, despite the high power tilt across the seed and blanket. Anticipated transient for the DNBR analysis were simulated at conditions of $112\%$ over-power, $95\%$ flow rate, and $2^{\circ}C$ higher inlet temperature. The maximum peak cladding temperature (PCT) was 1,173K for the severe accident condition of the LBLOCA, while the limit condition was 1,477K. The proliferation resistance potential of the thorium-based core was found to be much higher than that of the conventional $UO_2$ fuel core, $25\%$ larger in Bare Critical Mass (BCM), $60\%$ larger in Spontaneous Neutron Source (SNS), and $155\%$ larger in Thermal Generation (TG) rate; however, the radio-toxicity of the spent fuel was higher than that of $UO_2$ fuel, making it more environmentally unfriendly due to its high burnup rate.

Oral Etoposide for Platinum-Resistant and Recurrent Epithelial Ovarian Cancer: a Study by the Anatolian Society of Medical Oncology

  • Kucukoner, Mehmet;Isikdogan, Abdurrahman;Yaman, Sebnem;Gumusay, Ozge;Unal, Olcun;Ulas, Arife;Elkiran, Emir T.;Kaplan, Muhammed A.;Ozdemir, Nuriye;Inal, Ali;Urakci, Zuhat;Buyukberber, Suleyman
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.8
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    • pp.3973-3976
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    • 2012
  • Background: The aim of this study was to evaluate the efficacy and toxicity of long-term, low-dose oral etoposide as an advanced treatment option in patients with platinum resistant epithelial ovarian cancer. Materials and Methods: For the purposes of this study, 51 patients with histologically-confirmed, recurrent or metastatic platinum-resistant epithelial ovarian cancer (EOC) treated at six different centers between January 2006 and January 2011 were retrospectively evaluated. Patients were treated with oral etoposide (50 mg/day for a cycle of 14 days, repeated every 21 days). Results: Among the 51 platinum-resistant patients, 17.6% demonstrated a partial response and 25.5% a stable response. The median progression-free survival (PFS) was 3.9 months (95% CI, 2.1-5.7), while the median overall survival was 16.4 months (11.8.20.9). No significant relationship was observed between the pre-treatment CA 125 levels, post-treatment CA-125 levels and the treatment response rates (p=0.21). Among the 51 patients who were evaluated in terms of toxicity, grade 1 or 4 hematologic toxicity was observed in 19 (37.3%); and grade 1-4 gastrointestinal toxicity occurred in 15 patients (29.4%). Conclusions: Chronic low-dose oral etoposide treatment is generally effective and well-tolerated in platinum-resistant ovarian cancer patients.

A classification of electrical component failures and their human error types in South Korean NPPs during last 10 years

  • Cho, Won Chul;Ahn, Tae Ho
    • Nuclear Engineering and Technology
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    • v.51 no.3
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    • pp.709-718
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    • 2019
  • The international nuclear industry has undergone a lot of changes since the Fukushima, Chernobyl and TMI nuclear power plant accidents. However, there are still large and small component deficiencies at nuclear power plants in the world. There are many causes of electrical equipment defects. There are also factors that cause component failures due to human errors. This paper analyzed the root causes of failure and types of human error in 300 cases of electrical component failures. We analyzed the operating experience of electrical components by methods of root causes in K-HPES (Korean-version of Human Performance Enhancement System) and by methods of human error types in HuRAM+ (Human error-Related event root cause Analysis Method Plus). As a result of analysis, the most electrical component failures appeared as circuit breakers and emergency generators. The major causes of failure showed deterioration and contact failure of electrical components by human error of operations management. The causes of direct failure were due to aged components. Types of human error affecting the causes of electrical equipment failure are as follows. The human error type group I showed that errors of commission (EOC) were 97%, the human error type group II showed that slip/lapse errors were 74%, and the human error type group III showed that latent errors were 95%. This paper is meaningful in that we have approached the causes of electrical equipment failures from a comprehensive human error perspective and found a countermeasure against the root cause. This study will help human performance enhancement in nuclear power plants. However, this paper has done a lot of research on improving human performance in the maintenance field rather than in the design and construction stages. In the future, continuous research on types of human error and prevention measures in the design and construction sector will be required.

Comparison of Clinical Outcomes of BRCA1/2 Pathologic Mutation, Variants of Unknown Significance, or Wild Type Epithelial Ovarian Cancer Patients

  • Eoh, Kyung Jin;Park, Hyung Seok;Park, Ji Soo;Lee, Seung-Tae;Han, Jeongwoo;Lee, Jung-Yun;Kim, Sang Wun;Kim, Sunghoon;Kim, Young Tae;Nam, Eun Ji
    • Cancer Research and Treatment
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    • v.49 no.2
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    • pp.408-415
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    • 2017
  • Purpose The purpose of this study was to investigate the clinical features of epithelial ovarian cancer (EOC) patients according to BRCA1/2 mutation status (mutation, variant of uncertain significance [VUS], or wild type). Materials and Methods We analyzed 116 patients whose BRCA1/2 genetic test results were available for mutation type and clinical features, including progression-free survival (PFS), overall survival (OS), and response rate. These characteristics were compared according to BRCA1/2 mutation status. Results Thirty-seven (37/116, 31.9%) BRCA1/2 mutations were identified (BRCA1, 30; BRCA2, 7). Mutation of c.3627_3628insA (p.Leu1209_Glu1210?fs) in BRCA1 was observed in five patients (5/37, 13.5%). Twenty-five patients had BRCA1/2 VUSs (25/116, 21.6%). Personal histories of breast cancer were observed in 48.6% of patients with BRCA1/2 mutation (18/37), 16.0% of patients with BRCA1/2 VUS (4/25), and 7.4% of patients with BRCA wild type (4/54) (p < 0.001). Patients with BRCA1/2 mutation showed longer OS than those with BRCA1/2 wild type (p=0.005). No significant differences were detected in PFS, OS, or response rates between patients with BRCA1/2 VUS and BRCA1/2 mutation (p=0.772, p=0.459, and p=0.898, respectively). Conclusion Patients with BRCA1/2 mutation had longer OS than those with BRCA1/2wild type. Patients with BRCA1/2 mutation and BRCA1/2 VUS displayed similar prognoses.