• Nuclear Engineering and Technology
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• v.20 no.1
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• pp.1-8
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• 1988

During power plant operation, the flow rate from the CVCS makeup system is estimated using the continuity equation and mass balance equation, when the primary loop boron concentration change is required due to the power transient. For this purpose, primary loop, pressurizer and VCT(volume control tank)(in CVCS) are modeled by three control volumes which contain each mass and boron concentration. Connecting pipes between primary loop, pressurizer and CVCS are also modeled by time delay. Calculation for 14-2-6-2 (power 100-50-100) load follow case (at EOL, for KNU 7) is made using these models.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.109-109
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• 2002

• Journal of Korean Medical Science
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• v.33 no.45
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• pp.280.1-280.9
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• 2018

Background: Surveillance and interventions of central line-associated bloodstream infections (CLABSIs) had mainly been targeted in intensive care units (ICUs). Central lines are increasingly used outside ICUs. Therefore, we performed a hospital-wide survey of CLABSIs to evaluate the current status and develop strategies to reduce CLBASI rates. Methods: All hospitalized patients with central venous catheters (CVCs) were screened for CLABSIs from January 2014 through December 2015 at a 1,328 bed tertiary care teaching hospital in Korea using an electronic data-collecting system. Clinical information including type of CVC was collected. CLABSI rates were calculated using the definitions of the National Health and Safety Network after excluding mucosal barrier injury laboratory-confirmed bloodstream infection (BSI). Results: A total of 154 CLABSIs were identified, of which 72 (46.8%) occurred in general wards and 82 (53.2%) in ICUs (0.81 and 2.71 per 1,000 catheter days), respectively. Nontunneled CVCs were most common (68.6%) among 70 CLABSI events diagnosed within one week of their maintenance. On the other hand, tunneled CVCs and peripherally inserted central catheters (PICCs) were more common (60.5%) among 114 CLABSI events diagnosed more than a week after maintenance. Whereas the majority (72.2%) of CLABSIs in ICUs were associated with non-tunneled CVCs, tunneled CVCs (38.9%) and PICCs (36.8%) were more common in general wards. Conclusion: CLABSIs are less common in general wards than in ICUs, but they are more often associated with long-term indwelling catheters. Therefore, interventions to prevent CLABSIs should be tailored according to the type of ward and type of catheter.

• Clinical and Experimental Pediatrics
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• v.54 no.9
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• pp.363-367
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• 2011

Central venous catheters (CVCs) are regularly used in intensive care units, and catheter-related bloodstream infection (CRBSI) remains a leading cause of healthcare-associated infections, particularly in preterm infants. Increased survival rate of extremely-low-birth-weight infants can be partly attributed to routine practice of CVC placement. The most common types of CVCs used in neonatal intensive care units (NICUs) include umbilical venous catheters, peripherally inserted central catheters, and tunneled catheters. CRBSI is defined as a laboratory-confirmed bloodstream infection (BSI) with either a positive catheter tip culture or a positive blood culture drawn from the CVC. BSIs most frequently result from pathogens such as gram-positive cocci, coagulase-negative staphylococci, and sometimes gram-negative organisms. CRBSIs are usually associated with several risk factors, including prolonged catheter placement, femoral access, low birth weight, and young gestational age. Most NICUs have a strategy for catheter insertion and maintenance designed to decrease CRBSIs. Specific interventions slightly differ between NICUs, particularly with regard to the types of disinfectants used for hand hygiene and appropriate skin care for the infant. In conclusion, infection rates can be reduced by the application of strict protocols for the placement and maintenance of CVCs and the education of NICU physicians and nurses.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.753-759
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• 1995

One of the important features of the advanced nuclear power plants is the system simplification. In this work, a model has been introduced to quantitatively evaluate the system simplification. A few models have been developed for quantitative evaluation of design simplification and the design enhancements of CVCS of the advanced reactors have been evaluated with models based on the entropy concept and the system availability. In addition, operational interface of CVCS with peripheral systems has been considered to develop a new evaluation model in this work. The quantification results for the design of the System 80+ and KSNPP indicate that the simplicity of the CVCS is primarily dependent on the type and number of charging pumps.

• Biomedical Science Letters
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• v.13 no.3
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• pp.175-182
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• 2007

In vitro ciprofloxacin (CFX)-release study and bioassay using microorganisms were performed to estimate the retention of the antimicrobial activity of the CFX-incorporated central venous catheters (CFX-CVCs). The release experiments were carried out under the optional CFX-release conditions to mimic the in vivo environment. The release of CFX experienced an initial burst followed by a slow and steady matrix-diffusion controlled release. The 1.0CP (polyurethane catheter containing 1.0% (w/w) of CFX) under dynamic condition showed a near zero-order CFX release profile, which is beneficial for the long-tenn antimicrobial activity. The modified Kirby-Bauer method was performed employing S. aureus and E. coli to evaluate the retention of antimicrobial activity of the catheters retrieved from the release experiments. The 1.0CP showed the long-term antimicrobial activity (${\geq}\;21$ days) against both S. aureus and E. coli. These results indicate that 1.0CP is useful as a long-tenn indwelling CVC.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.484-490
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• 1996

The Pressurizer Level Control System (PLCS) logic for YGN 5&6 was developed to incorporate the design changes on the Chemical and Volume Control System (CVCS). The YGN 5&6 CVCS uses the centrifugal charging pumps and letdown orifices replacing the positive displacement pumps and letdown control valves in the YGN 3&4 and UCN 3&4. The purpose of this study is to develop new PLCS as well as validate newly developed control logic and its implementation method in the simulation computer code. The analysis results show that the new PLCS has adequate ability to control the pressurizer level in response to the design bases events, and the simulation computer code is useful for YGN 5&6 NSSS design code.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.549-550
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• 2004

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.11a
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• pp.345-352
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• 2001

• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.108-109
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• 2011