• Nuclear Engineering and Technology
• /
• v.45 no.6
• /
• pp.731-744
• /
• 2013

Energy security is a topic of high importance to many countries throughout the world. Countries with access to vast energy supplies enjoy all of the economic and political benefits that come with controlling a highly sought after commodity. Given the desire to diversify away from fossil fuels due to rising environmental and economic concerns, there are limited technology options available for baseload electricity generation. Further complicating this issue is the desire for energy sources to be sustainable and globally scalable in addition to being economic and environmentally benign. Nuclear energy in its current form meets many but not all of these attributes. In order to address these limitations, TerraPower, LLC has developed the Traveling Wave Reactor (TWR) which is a near-term deployable and truly sustainable energy solution that is globally scalable for the indefinite future. The fast neutron spectrum allows up to a ~30-fold gain in fuel utilization efficiency when compared to conventional light water reactors utilizing enriched fuel. When compared to other fast reactors, TWRs represent the lowest cost alternative to enjoy the energy security benefits of an advanced nuclear fuel cycle without the associated proliferation concerns of chemical reprocessing. On a country level, this represents a significant savings in the energy generation infrastructure for several reasons 1) no reprocessing plants need to be built, 2) a reduced number of enrichment plants need to be built, 3) reduced waste production results in a lower repository capacity requirement and reduced waste transportation costs and 4) less uranium ore needs to be mined or purchased since natural or depleted uranium can be used directly as fuel. With advanced technological development and added cost, TWRs are also capable of reusing both their own used fuel and used fuel from LWRs, thereby eliminating the need for enrichment in the longer term and reducing the overall societal waste burden. This paper describes the origins and current status of the TWR development program at TerraPower, LLC. Some of the areas covered include the key TWR design challenges and brief descriptions of TWR-Prototype (TWR-P) reactor. Selected information on the TWR-P core designs are also provided in the areas of neutronic, thermal hydraulic and fuel performance. The TWR-P plant design is also described in such areas as; system design descriptions, mechanical design, and safety performance.

• Journal of Food Hygiene and Safety
• /
• v.25 no.1
• /
• pp.10-15
• /
• 2010

This study was practiced to survey food-borne bacterial aspects of Escherichia coli and Bacilhus cereus etc. from 210 processed seasoned marine products in Garak fishery wholesale market in Seoul, 2009. Distributions of these bacterial isolates were 28 coliforms, 32 Bacillus spp., 71 Staphylococcus spp., 11 Listeria spp, and 10 Enterococcus spp. in 157 dried squids, 23 dried file fishes, and 20 dried pollacks etc. respectively. Results in 16 kinds of antibiotics susceptibility test by disc diffusion method, special multiple drugs resistance patterns were NOR + LVX + CIP + SAM + VA + S + TE + CF, SAM + C + VA, VA + S + TE, and VA + S in 9 E. coli strains, also, AMC + SAM + CF, SAM + CF, and VA + CF in 21 Bacillus cereus strains respectively. On the basis of the results above, many seasoned dried fishes had multiple drugs resistances, conclusively, we suggest limited guideline and special management on use of antibiotics in floating net cages of fishery farms.

• Korean journal of applied entomology
• /
• v.44 no.3 s.140
• /
• pp.213-217
• /
• 2005

Adult development and fecundity of the green peach aphid, Myzus persicae $S\H{u}lzer$, were studied at $15{\sim}32.5^{\circ}C$ with $60{\sim}70%$ RH under 16L:8D and the results were put together to build a life table. The longevity shortened as temperatures rose at and below $25^{\circ}C$ whereas it remained relatively constant at $27.5^{\circ}C$. Total fecundity was not significantly different at all temperatures except at $30^{\circ}C$. Daily fecundity gradually increased from $15\;to\;22.5^{\circ}C$. It was 5.1 at $25^{\circ}C$ and as temperatures either went down or up, it decreased to 2.8 at both $15^{\circ}C\;and\;30^{\circ}C$. Fecundity model built from total fecundity at various temperatures suggests that $18.3^{\circ}C$ was the optimum temperature for the maximum progeny of 51. Net reproduction rate RO was highest of 36.5 at $27.5^{\circ}C$. The intrinsic rate of increase per day $r_m$ and the finite rate of increase per day $\lambda$ were highest of 0.4 and 1.6, respectively and the doubling time Dt was shortest of 1.6. Constructed life table suggests that the optimum temperature for adult development for the green peach aphid was $27.5^{\circ}C$ at which the mean generation time was 8.1.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.2
• /
• pp.130-142
• /
• 2014

The Korean government is considering implementation of the marine ecosystem restoration technology program (MERTP) to analyze the current status of the marine ecosystems and causes for the ecosystem deterioration as well as to eventually establish a master strategic plan for restoring ecosystem functions and preventing ecosystem functional loss. In order to determine likelihood of successful implementation, it is essential to perform an analysis of the economic feasibility of the program. The present study assessed economic feasibility of the MERTP. To this end, the dichotomous choice contingent valuation (CV) method is used. In particular, dichotomous choice (DC) format is employed as a method of eliciting willingness-to-pay (WTP) response to incentive-compatible mechanisms. The study also employed the spike model to deal with zero WTP responses from the DC CV survey. This survey of 1,000 randomly selected households in accordance with the guidelines provided by the National Oceanic and Atmospheric Administration (USA) was carried out nationwide in 2013. And, the respondents were asked in person-to-person interviews about their WTP for implementing the MERTP. The results showed that the annual mean WTP was estimated to be 5,414 won per household. Consequently, the annual benefit from the MERTP would be about 98.6 billion won for the next five years. Economic feasibility assessment utilizing the MERTP investment cost and expansion cost of the value provided that net present value, benefit/cost ratio, and internal rate of return are 337.8 billion won, 5.20, and 65.9 %, respectively, which are bigger than 0, 1.0, and 5.5 %, and that the MERTP passes the cost-benefit analysis.

• Journal of Food Hygiene and Safety
• /
• v.17 no.3
• /
• pp.129-136
• /
• 2002

This study was conducted to Provide basic information Promoting egg qualify improvement and hygienic control by grasping of present market egg distribution system and hygienic quality. The eggs of 57 brands collected from the department food stores in Incheon Metropolitan City were examined. Eggs were kept in room temperature in all the market and 70.2% of the brands were marked the expiration date indicating that eggs would be available over 28 days after being laid. Fifty-four % of the market eggs was classified as a special or functional egg. Expiration date and date of laying were common labelling items in all brands. These items were labelled in trade mark sheet or eggs tray. Only 66.6% of the brands had the mark about net quantity of contents. The inspection about the exterior and contents of eggs has results as follows: eggshell contamination of feces and feather-9.5%, abnormal and broken eggshell -3.9%, blood and meat spots in contents -14.7% and watery whites -1.8%. Average of Haugh Unit(HU) was 56.1 and below HU 31 were 18 of 285 eggs(6.3%), in addition, more than one egg detected in 12 brands(21.1%) among 57 brands have inferior quality. Salmonella enteritidis from eggshell and antibodies directed from S. enteritidis in the yolks of eggs available in the market were not detected. Ranges of Total bacterial count (CFU/ml) on eggshell of eggs were < 10~8.2$\times$10$_3$, and isolation ratio of Escherichia coli were 4.7%. Tetracyclines were detected in 1.8% of the eggs(1 of57 brands) by CHARMII. As mentioned above, quality control and improving distribution system were required to facilitate egg consumption and improve public health by complementing labelling items and quality standards.

• Nuclear Engineering and Technology
• /
• v.53 no.8
• /
• pp.2534-2546
• /
• 2021

Nuclear emergency preparedness and response is an essential part to ensure the safety of nuclear power plant (NPP). Key support technologies of nuclear emergency decision-making usually consist of accident diagnosis, source term estimation, accident consequence assessment, and protective action recommendation. Source term estimation is almost the most difficult part among them. For example, bad communication, incomplete information, as well as complicated accident scenario make it hard to determine the reactor status and estimate the source term timely in the Fukushima accident. Subsequently, it leads to the hard decision on how to take appropriate emergency response actions. Hence, this paper aims to develop a method for rapid source term estimation to support nuclear emergency decision making in pressurized water reactor NPP. The method aims to make our knowledge on NPP provide better support nuclear emergency. Firstly, this paper studies how to build a Bayesian network model for the NPP based on professional knowledge and engineering knowledge. This paper presents a method transforming the PRA model (event trees and fault trees) into a corresponding Bayesian network model. To solve the problem that some physical phenomena which are modeled as pivotal events in level 2 PRA, cannot find sensors associated directly with their occurrence, a weighted assignment approach based on expert assessment is proposed in this paper. Secondly, the monitoring data of NPP are provided to the Bayesian network model, the real-time status of pivotal events and initiating events can be determined based on the junction tree algorithm. Thirdly, since PRA knowledge can link the accident sequences to the possible release categories, the proposed method is capable to find the most likely release category for the candidate accidents scenarios, namely the source term. The probabilities of possible accident sequences and the source term are calculated. Finally, the prototype software is checked against several sets of accident scenario data which are generated by the simulator of AP1000-NPP, including large loss of coolant accident, loss of main feedwater, main steam line break, and steam generator tube rupture. The results show that the proposed method for rapid source term estimation under nuclear emergency decision making is promising.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.7
• /
• pp.909-917
• /
• 2017

In this study, we investigated the relationship between catches of yellowtail and water temperature at the set net fisheries of Gyeongsangbuk-do (Gyeongbuk) and Gangwon-do (Gangwon) off the east coast of Korea from May-November, 1980-2010. We also analyzed the water temperature and fluctuation of catches during the northward moving period (May-August) and southward moving period (September-November) using NOAA satellite images. Although the total catches fluctuated year by year, catches increased during the southward moving period when the water alongside the coast warmed. Yellowtail catches during the southward period in fall were higher than those during the northward period in spring or summer. The catch when the water temperature decreased was larger in Gyeongbuk than in Gangwon for all periods However, the catch when the water temperature increased was much larger in Gangwon than in Gyeongbuk. This indicates that high summer temperatures (> $25^{\circ}C$) affected the coast of Gangwon, with high water temperature ($20^{\circ}C$) maintained in the region during fall. Therefore, the increased catch in Gangwon was due to longer yellowtail presence caused by increased water temperature.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.2
• /
• pp.220-228
• /
• 2019

To determine the horizontal and temporal distribution of common squid larvae, Todarodes pacificus (hereafter T. pacificus), we conducted surveys using an IKMT net (mesh size: $500{\mu}m$) with a Fisheries Research Vessel (FRV, TAMGU 21) in the southwestern part of the East Sea in summer (August and September) and autumn (November) 2015. A total of 228 larvae, ranging in mantle length (ML) from 1.4 mm to 21.9 mm, were collected at 35 stations over the research period. The monthly average mantle length of T. pacificus larvae did not differ significantly in August, September and November. (p > 0.05). Catch densities at positive stations ranged between 0.1 and $7.9inds./1,000m^3$ over the research period. Incidence rates of T. pacificus larvae were similar over three months, in the study area (62.9 % - 68.6 %). The 4 - 5 mm mantle length range had the highest frequency in size-frequency distributions for T. pacificus larvae. The larval survival temperature ($15-24^{\circ}C$) at positive stations for catch densities was located below a 20 m depth in August whereas it was located at the surface of the water in September and November. The survival temperature for larvae existed from the bottom to the surface of the water where larvae were sampled larvae in shallow sea areas. However, the larval survival temperature occurred in a shallower location than the upper layer of the thermocline in deep sea areas at a depth below 100 m.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.1
• /
• pp.102-110
• /
• 2019

The shipbuilding and offshore plant industry of Korea is important and leads Korea's economic growth, designated as the 1st to 4th export items in Korea in terms of export contribution over the period from 2011 to 2015. This study proposes ways to improve the national competitiveness of Korean shipyards in the global offshore drilling market by reviewing a business model for providing an integrated offshore drilling commissioning service in Korea. This commissioning service model, which was attempted in 2014, was reviewed, and a new proposed business model for overcoming the limitations of the previous model and activating further business was evaluated. As a result of an economic evaluation, it was found that a 150-meter water depth model is economically more effective. As the number of integrated commissions increased from 2 to 5 times per year, NPV, IRR and B/C ratios increased and the fee per use decreased. Therefore, for offshore drilling facilities constructed and delivered in Korea, it will be necessary to encourage integrated offshore commissioning.

• 한국사회정책
• /
• v.24 no.4
• /
• pp.113-150
• /
• 2017

This study analyzes how workers become impoverished and have their jobs less stabilized after they suffer from non-job-related sickness. Given that South Korea lacks sickness benefits, which most of OECD member states legislate and implement except US and Switzerland, this study examines its impact on laborers' job stability and povertization in Korea. The researchers have conducted in-depth interviews with nine former or present laborers who have the experiences and four experts on the issue in July-September, 2017 for the qualitative analysis. It is found that laborers, after becoming aware of their sickness, at first endure their pain without informing their employers not to lose their jobs. The attititude is observed especially among non-standard laborers, because sickness more often leads to job loss for them than for standard laborers. After workers have to leave their jobs due to their sickness in the end, they have no choice but to keep working in less stable jobs to compensate for income losses. They become gradually impoverished with their social capital like family bond declining. We observe laborers who are eligible for industrial accident insurance compensation could not benefit from the system because some employers refrain from the legal reporting duty. Due to this illegal practices, some industrial accident victims unduly lose their jobs due to "non-job-related sickness". Second, some employers report to the authority that their sick laborers have left their jobs 'voluntarily' even when they have quitted it without their volition, in which case the newly unemployed are not eligible for unemployment benefits. Large holes in Korea's safety nets for those suffering from multiple risks of sickness and unemployment.