PURPOSES : Carbon dioxide (CO2) is a cheaper and easier to installer fire suppressant than other extinguishing gases and is easy to install, but extinguishes fires by is suffocation. As a result, suffocation accidents continue to occur in facilities equipped with CO2 fire-extinguishing facilities, Emission standards have yet to be established. This study aims to address the issue. METHODS : To effectively remove CO2 emitted from installed systems, we reviewed and analyzed previous related research and existing international standards. RESULTS : In protected areas where CO2 fire-extinguishing systems are installed, emission facilities should discharge the emitted CO2 before it enters the protected spaces. CO2 sensors can determine whether safe entry is possible or whether respirators are required. CONCLUSIONS : This study presented a specific installation method for emission facilities capable of actively discharging CO2. Applying this method is expected to contribute to improving safety in facilities equipped with CO2 fire-extinguishing facilities.

In nuclear facilities, a graded approach is applied to achieve safety effectively and efficiently. It means that the structures, systems, and components (SSCs) that are important to safety should be assured to be high quality. Accordingly, SSCs that consist of nuclear facilities should be classified with respect to their safety importance as several classes, so that the requirements of quality assurance relevant to the designing, manufacturing, testing, maintenance, etc. can be applied. Guidance for the safety classification of SSCs consisting of nuclear power plants and radioactive waste management facilities was developed by U.S.NRC and IAEA. Especially, in guidance for nuclear power plants, safety significance can be evaluated as following details. The single SSC that mitigates or/and prevents the radiological consequence or hazard was assumed to be failure or malfunction as the initiating event/accident occurred and the following radiological consequence was evaluated. Considering both the consequence and frequency of the occurrence of the initiating event/accident, the safety significance of each SSC can be evaluated. Based on the evaluated safety significance, a safety class can be assigned. The guidance for the safety classification of the spent nuclear fuel dry storage systems (DSS) was also developed in the United States (NUREG/CR-6407) and the U.S.NRC acknowledges the application of it to the safety classification of DSS in the United States. Also, worldwide including the KOREA, that guidance has been applied to several DSSs. However, the guidance does not include the methodology for classifying the safety or the evaluated safety significance of each SSC, and the classification criteria are not based on quantitative safety significance but are expressed somewhat qualitatively. Vendors of DSS may have difficulties to apply this guidance appropriately due to the different design characteristics of DSSs. Therefore, the purpose of this study is to evaluate the safety significance of representative SSCs in DSS. A framework was established to evaluate the safety significance of SSCs performing safety functions related to radiation shielding and confinement of radioactive materials. Furthermore, the framework was applied to the test case.

The deep geologic repository (DGR) concept is widely accepted as the most feasible option for the final disposal of spent nuclear fuels. In this concept, a series of engineered and natural barrier systems are combined to safely store spent nuclear fuel and to isolate it from the biosphere for a practically indefinite period of time. Due to the extremely long lifetime of the DGR, the performance of the DGR replies especially on the natural geologic barriers. Assessing the safety of the DGR is thus required to evaluate the impacts of a wide range of geological, hydrogeological, and physicochemical processes including rare geological events as well as present water cycles and deep groundwater flow systems. Due to the time scale and the complexity of the physicochemical processes and geologic media involved, the numerical models used for safety evaluation need to be comprehensive, robust, and efficient. This study describes the development of an accessible, transparent, and extensible integrated hydrologic models (IHM) which can be approved with confidence by the regulators as well as scientific community and thus suitable for current and future safety assessment of the DGR systems. The IHM under development can currently simulate overland flow, groundwater flow, near surface evapotranspiration in a modular manner. The IHM can also be considered as a framework as it can easily accommodate additional processes and requirements for the future as it is necessary. The IHM is capable of handling the atmospheric, land surface, and subsurface processes for simultaneously analyzing the regional groundwater driving force and deep subsurface flow, and repository scale safety features, providing an ultimate basis for seamless safety assessment in the DGR program. The applicability of the IHM to the DGR safety assessment is demonstrated using illustrative examples.

Once systems, structures and components (SSCs) of dry storage systems are classified with respect to safety function or safety significance (i.e., safety classification), appropriate engineering rules can be applied to ensure that they are designed, manufactured, maintained, managed (e.g. aging management) etc. In Unites States, the systems, structures and components (SSCs) consisting DSSs are classified into two or several grades (i.e., class A, B and C or not important to safety, and important to safety (ITS) or not important to safety (NITS)) with respect to intended safety function and safety significance. This classification methods were based on Regulatory Guide 7.10 (i.e., guidance for use in developing quality assurance programs for packaging). Also, in Korea, SSCs of DSSs should be classified into ITS and NITS in much the same as method based on Regulatory Guide 7.10. In that guidance, for providing graded approach to manage the SSCs of packaging, they were trying to classifying SSCs in accordance with radiological consequences. But there was limitations that the provided classification criteria was still qualitative, so that it was not enough for managing the SSCs according to graded approach. On the other hand, in some other nuclear facilities (i.e., nuclear power plant, radioactive waste management facility and disposal facility etc.), quantitative criteria relevant to radiological consequence (i.e., radiation doses to workers or to the public) or inventory of radioactivity are existed so that it can be applied for classifying safety classes. In summary, the study on the application safety classification that applied quantitative criteria to perform safety classification of SSCs in DSS is inadequate or insufficient. The purpose of this study is proposing the preliminary framework for estimating safety significance of SSCs in DSS which can be utilized in our further advanced studies. In this study, a framework was established to estimate the safety significance of SSCs related to radiation shielding and confinement using MCNP® 6.2 and Microsoft Excel. Referring to the methodology of IAEA Specific Safety Guide 30, we assumed severity for failures of components that could lead to degradation of the SSC’s performance. The safety class of SSC was decided based on the impact of SSC’s failure on consequences.

정부와 안전보건공단에서는 건설현장의 안전사고를 줄이기 위하여 감독․점검, 기술지도, 재정지원 등의 산업재해예방 활동을 지속적으로 수행하여 왔다. 하지만, 전체 산업의 사고사망만인율과 재해율이 전반적으로 감소 추세에 있는 반면에, 건설업의 사고사망만인율 및 재해율은 2014년 이후 오히려 증가 추세에 있다. 특히, 2016년 재해통계를 기준으로 전체 건설업 재해자의 약 70%가 공사금액 20억 미만의 소규모 건설현장에서 발생하였다. 이러한 소규모 건설현장의 재해를 줄이기 위해서는 현재의 산업안전보건법 상의 소규모 건설현장 산업안전보건관리체제와 고용노동부 및 안전보건공단에서 수행하고 있는 소규모 건설현장재해예방 사업에 대한 실효성을 파악하고 개선할 필요가 있다. 현 산업안전보건관리체제에서는 건축공사 기준으로 120억 이상인 공사인 경우 안전관리자를 의무 선임하도록 되어 있으며 3억에서 120억 미만 공사의 경우 재해예방지도기관의 기술지도를 받도록 되어 있다. 또한, 안전보건공단에서는 민간위탁기관을 지정하여 3억 미만 건설공사의 안전관리를 지원하고 있으며, 클린사업장 조성지원사업을 통해 20억 미만 소규모 건설현장의 추락재해예방을 위해 시스템 비계, 사다리형 작업발판 및 안전방망 등의 설치 비용을 지원하고 있다. 본 연구에서는 공사금액별 재해통계 및 안전관리자 선임관련 제도를 분석하여 안전관리자 선임 대상을 현행 건축공사 120억 이상인 공사에서 단계적으로 50억까지 확대할 것을 제안한다. 설문조사와 전문가 의견을 수렴하여 재해예방지도기관의 기술지도 영역을 조정하고 실효성을 강화하기 위한 방안을 수립하고, 클린사업장 조성지원사업의 사업 확대 요구 및 개선사항을 도출한다.

This paper addresses the problem of how to effectively use virtual reality(VR) for improving the quality of safety training systems. As the working environment and the working system in the industry are more and more complex and large-scaled, the concern with system safety is accordingly growing. Safety training systems are regarded as an effective way for increasing workers’ interest in system safety and enhancing their ability of preventing and handling accidents/incidents. Recently, it has been reported that VR would be effectively used for improving the quality of safety training systems, with its technically specialized features. However, little attention has been given to the problem of how to effectively use VR for safety training systems. In order to make the best use of new technology such as VR, it is important to examine its advantages and disadvantages and the contexts to which its use can be beneficial. This paper firstly reviews the current status of safety training systems and the use of VR for safety training systems in the inside and outside of the country. Next, we summarize the interview with safety managers in four manufacturing companies, which was conducted to understand the requirements of stake-holders of the issue. Based on the review and the interview, we suggested the ways of using VR in safety training systems in an effective manner. They are described from the four perspectives: development and maintenance cost, lack of specialized workers, design of accident scenarios used with VR, and empirical demonstration of the effectiveness of VR in safety training.

The live fire test has been playing a critical role in evaluating the goals-to-meet of the weapon systems which utilize the power of explosives. As such, the successful development of the test systems therein is quite important. The test systems development covers that of ranges and facilities including system-level key components such as mission control, instrumentation or observation, safety control, electric power, launch pad, and so on. In addition, proper operational guidelines are needed with well-trained test and operation personnel. The emerging weapon systems to be deployed in future battle field would thus have to be more precise and dynamic, smarter, thereby requiring more elaboration. Furthermore, the safety consideration is becoming more serious due to the ever-increasing power of explosives. In such a situation, development of live fire test systems seems to be challenging. The objective of the paper is on how to incorporate the safety and other requirements in the development. To achieve the goal, an architectural approach is adopted by utilizing both the system components relationship and safety requirement when advanced instrumentation technology needs to be developed and deteriorated components of the range are replaced. As an evaluation method, it is studied how the level of maturity of the test systems development can be assessed particularly with the safety requirement considered. Based on the concepts of both systems engineering and SoS (System-of-Systems) engineering process, an enhanced model for the system readiness level is proposed by incorporating safety. The maturity model proposed would be helpful in assessing the maturity of safety-critical systems development whereas the costing model would provide a guide on how the reasonable test resource allocation plan can be made, which is based on the live fire test scenario of future complex weapon systems such as SoS.

The weapon systems development has some distinct characteristics in that a big size of government budget (derived from national tax) has been expended frequently and the completion of the development projects seems to take long. Thus, the impact of the potential changes in the required operational capability on the development activities can induce some type of project risks. As such, proper management of project risk has been one of crucial subjects in the weapon systems development. Although a variety of methods can be considered, an approach based on the test and evaluation (T&E) process has been selected in this paper in order to appropriately handle those potential risks. In the study of the underlying T&E process, the safety consideration (for instance, explosiveness) of weapon systems is also included. To achieve the objective of the paper, a step-by-step procedure is first presented in the analysis of the T&E process. Then, to pursue some enhancement on the process, a set of necessary and useful activities are added in terms of risk and safety management. The resultant process is further analyzed and tailored based on a design structure matrix method. The case study of a tank development is also discusse

오늘날 대 산업분야는 과학 기술의 진보에 따라 비약적인 기술발달을 이루었다. 따 라서, 고객이 요구(Needs)하는 다양한 기능을 구현하기 위해 상당수 부분을 소프트웨 어 중심으로 달성하고 있다. 이렇듯, 과거의 하드웨어 중심의 자동차와 달리 소프트웨 어 중심의 기능 구현이 이행되고 있는 실정이다. 이렇다 보니, 시스템이 보다 복잡해 짐에 따라 시스템을 설계하고 제어하는데 있어서 상당한 어려움이 따르고 있다. 따라 서, 유럽에서는 자동차 분야의 전자제어 장비로 인한 기능안전을 달성하기 위해 ISO26262라는 국제표준을 제정하였다. 국제표준의 제정에 따라 국내 자동차 산업은 차량 시스템을 설계하는데 있어서의 노력, 뿐만 아니라, 기능안전이라는 안전부분을 대비해야하는 상황에 직면하게 되었다. 본 연구에서는 자동차 시스템의 상위 수준의 설계인 개념설계 단계에서 FMEA를 통한 안전성 활동 반영을 통한 하나의 단일화된 개발 방법론을 본 연구를 통해 제시하고자 한다. 따라서, 본 연구를 기반으로 향후 추가 연구를 수행한다면, 국내 자동차 산업, 뿐만 아니라, 대형복합 안전 중시 시스템 으로 확대하여 설계단계에서 안전성을 동시 고려한 시스템 설계 신뢰성 확보를 위해 도움이 될 것으로 기대 된다.

The demand from customers on better products and systems seems to be ever increasing. To meet the demand, the systems are becoming more and more complicated in terms of both scale and functionality, thereby requiring enormous effort in the development. One bright spot of this trend is that such effort has been the driving forces of the remarkable advancement in modern systems development. On the other hand, safety issues appear to be critical in many large-scale systems such as transportation and weapon systems including high-speed trains, airplanes, ships, missiles/rockets launchers, and so on. Such systems turn out to be prone to a variety of faults and thus the resultant failure can cause disastrous accidents. For the reason, they can be referred to as safety-critical systems. The systems failure can be attributed to either random or systemic factors (or sometimes both). The objective of this paper is on how to reduce potential systemic failure in safety critical systems. To do so, a proper system design is pursued to minimize the risk of systemic failure. A focus is placed on the fact that complex systems have a lot of complicated interfaces among the system elements. To effectively handle the sources of hazards at the complicated interfaces and resultant failure, a method is developed by utilizing a design structure matrix. As a case study, the developed method is applied in the design of train control systems.

Successful development of weapon systems requires a stringent verification and validation (V&V) process due to the nature of the weapons in which continual increase of operational capability makes the system requirements more complicated to meet. Thus, test and evaluation (T&E) of weapon systems is becoming more difficult. In such a situation, live fire tests appear to be effective and useful methods in not only carrying out V&V of the weapon systems under development, but also increasing the maturity of the end users operability of the system. However, during the process for live fire tests, a variety of accidents or mishaps can happen due to explosion, pyro, separation, and so on. As such, appropriate means to mitigate mishap possibilities should be provided and applied during the live fire tests. To study a way of how to accomplish it is the objective of this paper. To do so, top-level sources of hazard are first identified. A framework for T&E is also described. Then, to enhance the test range safety, it is discussed how test scenarios can be generated. The proposed method is based on the use of the anticipatory failure determination (AFD) and multiple event tree analysis (ETA) in analyzing range safety. It is intended to identify unexpected hazard components even in the environment with constraints. It is therefore expected to reduce accident possibilities as an alternative to the traditional root-cause analysis.

New e-navigation strains require new technologies, new infrastructures and new organizational structures on bridge, on shore as well as in the cloud. Suitable engineering and safety/risk assessment methods facilitate these efforts. Understanding maritime transportation as a sociotechnical system allows the application of system-engineering methods. Formal, simulation based and in situ verification and validation of e-navigation technologies are important methods to obtain system safety and reliability. The modelling and simulation toolset HAGGIS provides methods for system specification and formal risk analysis. It provides a modelling framework for processes, fault trees and generic hazard specification and a physical world and maritime traffic simulation system. HAGGIS is accompanied by the physical test bed LABSKAUS which implements a physical test bed. The test bed provides reference ports and waterways in combination with an experimental Vessel Traffic Services (VTS) system and a mobile integrated bridge: This enables in situ experiments for technological evaluation, testing, ground research and demonstration. This paper describes an integrated seamless approach for developing new e-navigation technologies starting with simulation based assessment and ending in physical real world demonstrations.

Modern weapon systems are getting more complex in terms of the functionality and also the conditions on the environment and range in which they are deployed and used. Therefore, many development programs can easily be exposed to a variety of risks, resulting in delayed schedules and cost overrun. As such, effective means are necessary to keep the defence budget at an affordable level while competitive edges on technological aspects are retained. As one way to meet those need, modeling and simulation (M&S) methods have widely been used, particularly in the test and evaluation (T&E) process for weapon systems development. The result of M&S-based systems development should be evaluated by the verification, validation & accreditation (VV&A) process to assure keeping reliability at a desired level. On the other hand, due to the explosiveness, the weapons systems development naturally requires to consider safety issues in both the T&E and operational periods. The purpose of this paper is to improve the VV&A process by reflecting the safety requirements therein. To do so, the VV&A process has been analyzed and graphically modeled first and then safety elements have been incorporated effectively. The use of the improved process in the war ships development has also been discussed. Based on the process proposed and the consequent database constructed, the target system can be expected to benefit from reducing development risks while assuring systems safety.

Modern systems development becomes more and more complicated due to the need on the ever-increasing capability of the systems. In addition to the complexity issue, safety concern is also increasing since the malfunctions of the systems under development may result in the accidents in both the test and evaluation phase and the operation phase. Those accidents can cause disastrous damages if explosiveness gets involved therein such as in weapon systems development. The subject of this paper is on how to incorporate safety requirements in the design of safety-critical systems. As an approach, a useful system structure using the method of design structure matrix (DSM) is studied while reflecting the need on systems safety. Specifically, the effects of system components failure are analyzed and numerically modeled first. Also, the system components are identified and their interfaces are represented using a component DSM. Combining the results of the failure analysis and the component DSM leads to a modified DSM. By rearranging the resultant DSM, a modular structure is derived with safety requirements incorporated. As a case study, application of the approach is also discussed in the development of a military UAV plane.

최근 현대 무기체계는 국방예산 절감과 보다 빠르게 전략화하기 위해 시험평가에 소요 되는 기간을 줄이고자 하고 있다. 이에 따라 기존의 무기체계 시험평가 프로세스 에서 다루는 시스템 설계에 대한 단계별 안전 활동 강화의 필요성 역시 강조되고 있 다. 본 논문에서는 무기체계 획득 프로세스에서 위험 완화의 구성 요소로 확인 (Verification), 검증(Validation) 및 인정(Accreditation) 활동을 고려한 시험평가 프로세 스의 개선사항 도출과 모델링을 통해 무기체계 시스템인 함정 무기체계를 대상으로 적용 및 조정 구축에 대한 내용을 기술하고 있다. 본 연구의 결과를 토대로 시험평가 의 위험요소, 위험평가 데이터의 관리 및 추적 기능을 개선함으로써 향후 M&S기반 획득 시험평가 시 체계 개발 및 운용에서 발생할 수 있는 비용 및 시간을 절감 시킬 수 있을 것으로 기대된다.