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At least 19 records

Transportation of Low-Level Radioactive Waste from KAERI to the Final Repository - 18179

The Korea Atomic Energy Research Institute (KAERI) collects the radioactive wastes generated during the operation of nuclear facilities and R and D processes. Radioactive wastes are treated and repackaged according to the national radioactive waste management policy, and then transferred to the final disposal site at the Korea Radioactive Waste Agency (KORAD). After 2015, the wastes delivered to the final disposal site have consisted of spent filters and combustible wastes such as clothes and gloves generated during R and D or facility operation processes at KAERI. The wastes generated by each facility are collected at the radioactive waste treatment facility, then treated and repackaged in 200 L drums according to their generation characteristics, i.e. each drum contains waste of the same type from the same facility, and with the same date of generation. Then, a radionuclide inventory is obtained for the repackaged drum by using a direct measurement method such as the drum assay system, radiochemical analysis through random sampling or an indirect measurement method such as applying a scaling factor. When performing sampling of the radioactive waste drums, the waste samples with a high contamination are selected in a conservative approach as representative. The radioactive waste drums are inspected and checked for acceptability by the Quality Management Division of KAERI, and a preliminary inspection is carried out on-site by KORAD. At this time, the acceptability of the radioactive waste drums is assessed through visual inspection, the appropriateness of their nuclide analysis value is confirmed, and a survey or smear test of sample drums is performed. Drums that meet the acceptance criteria are transferred to KORAD after a radiation environmental impact assessment of the transportation. Since 2015, 1,084 low-level operational radioactive wastes have been transferred from KAERI to the final disposal site, and further preparation work is now being made for the transportation of additional drums. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Xenon Abatement Simulations to Support the KAERI Medical Isotope Facility

To maintain and improve the verification regime that is outlined by the Preparatory Commission of the Comprehensive Nuclear Test-Ban Treaty there is a need to understand and reduce the radioxenon releases from medical isotope production facilities. In support of this objective Pacific Northwest National Laboratory (PNNL) was tasked with, modeling and evaluate the abatement process and delay bed designs for the medical isotope production facility under construction by the Korea Atomic Energy Research Institute (KAERI). This report includes this analysis and provides PNNL proposed modifications to the KAERI adsorption bed design.

07 ISOTOPE AND RADIATION SOURCES↗

Development of tritium technologies at KAERI

Korea has been operating a CANDU nuclear power plant since 1983. Tritium generated in the heavy water of the plant is removed by the Wolsong TRF (Tritium Removal Facility) and measurement campaigns of tritium near the power plant have shown the efficiency of the TRF system. The HANARO reactor uses heavy water as both reflector and moderator. In HANARO the tritiated water removal system consists of compressors, condensers, and adsorption beds. A tritium behavior analysis code (TRIBAC) for a Very High Temperature Gas-Cooled Reactor (VHTR) is under development at KAERI. The TRIBAC computer software has been equipped with models for tritium production, purification, and leakage, as well as chemisorption and tritium behavior, in the hydrogen production system. Korea takes part into the ITER program and is responsible for the supply of an SDS (Tritium Storage and Delivery System). Within this program Korea has launched an experimental program to study the physico-chemical properties of metal and their hydrides in which hydrogen isotope gases can be stored and removed safely.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

KAERI Underground research tunnel (KURT) - phase II activities for HLW disposal technology development in Korea - 15253

Phase I construction of the KAERI Underground Research Tunnel (KURT), a small-scaled underground research facility, was completed in November 2006. Since then various in-situ tests and experiments at KURT for phase I have been carried out to develop safe and reliable disposal techniques for high-level radioactive waste in a deep geological formation. The KURT extension project was approved by the Korean government in 2012 and the design of the tunnel layout and construction methods were decided by early 2013. Site investigation and installation of a monitoring system for the extension were completed by Oct. 2013. The construction activity was started from December 2013 and will be completed by the end of 2014. Phase II experiments in KURT will be carried out for the next 10 years. KURT continues to play a significant role in validating the safety and feasibility of a deep geological disposal system in the research program in Korea. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Research on the IAEA State-Level Safeguards Approach in KAERI

The IAEA has verified the declared nuclear material according to the comprehensive safeguards agreement under NPT between the Republic of Korea and the IAEA, as well as the undeclared nuclear material and nuclear activities under the Additional Protocol. In the safeguards Implementation Report for 2007, the Agency drew a broader conclusion for Korea that all nuclear material has remained in peaceful activities in Korea because there was no indication of the diversion of declared nuclear material, and no indication of undeclared nuclear material and activities in the ROK. The IAEA also informed that the implementation of Integrated Safeguards (IS) in Korea started on 1 July, 2008 in accordance with the state level IS approach after a drawing of the broader conclusion. In addition, for now, a State-Level Safeguards Approach (SLA) is adopted for the ROK, including 11 Material Balance Areas (MBAs) in KAERI. This paper describes a comparison analysis between IS and SLA.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

R and D activities on VHTR materials at KAERI - 18496

KAERI started VHTR materials R and D in 2006 as part of its role in supporting the development of key technology for the nuclear research and development program. Over the past ten years, research has been conducted on various materials including Alloy 617 for an IHX and hot gas duct, 9Cr-1Mo for an RPV, graphite for a reflector and the support structures in the core region, Cf/C and SiCf/SiC composites for a control rod, and Fe-Si, SiC, Hastelloy{sup R}, and other novel metals for an SI process reactor. Mechanical properties including creep and fatigue, environmental effects, and irradiation behaviors have also been heavily evaluated as part of the materials research. Most of the results have been contributed to the GEN-IV VHTR materials collaboration. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Proposed New STELLA-2 Tests

In 2025, KAERI and Argonne initiated a collaboration based on software validation using data from tests performed at KAERI’s STELLA-2 facility. STELLA-2 is a large-scale sodium thermal-hydraulic test facility that was originally developed to support KAERI’s development of the PGSFR design concept. KAERI has performed a large number of tests at STELLA-2, providing valuable data to support sodium fast reactor code validation. KAERI will be conducting new tests in 2026, targeting system conditions that were not achieved during previous test campaigns. KAERI has requested from Argonne proposed tests that could be performed during the upcoming test campaign. This report documents Argonne’s proposed tests in fulfillment of KAERI’s request.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Development of Chlorination Process for Cladding Hull Waste and its Combination with Pyroprocessing

The Korea Atomic Energy Research Institute (KAERI) is spending efforts to minimize the amount of radioactive wastes generated during pyro-processing. One of the major issues is management of cladding hull waste owing to its large amount (25 wt.% of fuel) and high radioactivity. Although the cladding hull waste might be classified as an intermediate-level waste according to the Korean regulation, the large amount makes it reasonable to develop a way to reduce the amount of cladding hull waste. Previously performed radioactivation analysis results revealed that selective recovery of zirconium from the cladding hull waste will produce a weak beta-decaying zirconium. As a means of selective Zr recovery, KAERI is working on a chlorination process which employs a chemical reaction between metallic zirconium and chlorine gas. The chlorination process generates zirconium tetrachloride (ZrCl{sub 4}) which sublimes at 331 deg. C leading to an easy separation from other radioactive nuclides. KAERI has started the chlorination process R and D with small quartz reactors with grams of cladding hulls, and now its work is proceeded to fundamental approaches and scale-up. In this work, the progress achieved by KAERI on the chlorination process is reviewed and a recent approach to combine the chlorination process with pyro-processing, so-called MKZP (Min Ku Zirconium Process) is introduced. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Seismic Fragility Analysis of a Condensate Storage Tank with Age-Related Degradations

The Korea Atomic Energy Research Institute (KAERI) is conducting a five-year research project to develop a realistic seismic risk evaluation system which includes the consideration of aging of structures and components in nuclear power plants (NPPs). The KAERI research project includes three specific areas that are essential to seismic probabilistic risk assessment (PRA): (1) probabilistic seismic hazard analysis, (2) seismic fragility analysis including the effects of aging, and (3) a plant seismic risk analysis. Since 2007, Brookhaven National Laboratory (BNL) has entered into a collaboration agreement with KAERI to support its development of seismic capability evaluation technology for degraded structures and components. The collaborative research effort is intended to continue over a five year period. The goal of this collaboration endeavor is to assist KAERI to develop seismic fragility analysis methods that consider the potential effects of age-related degradation of structures, systems, and components (SSCs). The research results of this multi-year collaboration will be utilized as input to seismic PRAs. This report describes the research effort performed by BNL for the Year 4 scope of work. This report was developed as an update to the Year 3 report by incorporating a major supplement to the Year 3 fragility analysis. In the Year 4 research scope, an additional study was carried out to consider an additional degradation scenario, in which the three basic degradation scenarios, i.e., degraded tank shell, degraded anchor bolts, and cracked anchorage concrete, are combined in a non-perfect correlation manner. A representative operational water level is used for this effort. Building on the same CDFM procedure implemented for the Year 3 Tasks, a simulation method was applied using optimum Latin Hypercube samples to characterize the deterioration behavior of the fragility capacity as a function of age-related degradations. The results are summarized in Section 5 and Appendices G through I.

42 ENGINEERING↗

A Procedure for Determination of Degradation Acceptance Criteria for Structures and Passive Components in Nuclear Power Plants

The Korea Atomic Energy Research Institute (KAERI) has been collaborating with Brookhaven National Laboratory since 2007 to develop a realistic seismic risk evaluation system which includes the consideration of aging of structures and components in nuclear power plants (NPPs). This collaboration program aims at providing technical support to a five-year KAERI research project, which includes three specific areas that are essential to seismic probabilistic risk assessment: (1) probabilistic seismic hazard analysis, (2) seismic fragility analysis including the effects of aging, and (3) a plant seismic risk analysis. The understanding and assessment of age-related degradations of structures, systems, and components and their impact on plant safety is the major goal of this KAERI-BNL collaboration. Four annual reports have been published before this report as a result of the collaboration research.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Resonance Region Nuclear Data Analysis to Support Advanced Fuel Cycle Development

The Oak Ridge National Laboratory (ORNL) and the Korean Atomic Energy Research Institute (KAERI) are performing collaborative research as part of a three-year United States (U.S.) / Republic of Korea (ROK) International Nuclear Energy Research Initiative (I-NERI) project to provide improved neutron cross-section data with uncertainty or covariance data important for advanced fuel cycle and nuclear safeguards applications. ORNL and KAERI have initiated efforts to prepare new cross-section evaluations for 240Pu, 237Np, and the stable Cm isotopes. At the current stage of the I-NERI project, ORNL has recently completed a preliminary resonance-region cross-section evaluation with covariance data for 240Pu and initiated resonance evaluation efforts for 237Np and 244Cm. Likewise, KAERI is performing corresponding high-energy cross-section analyses (i.e., above the resonance region) for the noted isotopes. The paper provides results pertaining to the new resonance region evaluation efforts with emphasis on the new 240Pu evaluation.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Seismic Fragility Analysis of a Degraded Condensate Storage Tank

The Korea Atomic Energy Research Institute (KAERI) and Brookhaven National Laboratory are conducting a collaborative research project to develop seismic capability evaluation technology for degraded structures and components in nuclear power plants (NPPs). One of the goals of this collaboration endeavor is to develop seismic fragility analysis methods that consider the potential effects of age-related degradation of structures, systems, and components (SSCs). The essential part of this collaboration is aimed at achieving a better understanding of the effects of aging on the performance of SSCs and ultimately on the safety of NPPs. A recent search of the degradation occurrences of structures and passive components (SPCs) showed that the rate of aging related degradation in NPPs was not significantly large but increasing, as the plants get older. The slow but increasing rate of degradation of SPCs can potentially affect the safety of the older plants and become an important factor in decision making in the current trend of extending the operating license period of the plants (e.g., in the U.S. from 40 years to 60 years, and even potentially to 80 years). The condition and performance of major aged NPP structures such as the containment contributes to the life span of a plant. A frequent misconception of such low degradation rate of SPCs is that such degradation may not pose significant risk to plant safety. However, under low probability high consequence initiating events, such as large earthquakes, SPCs that have slowly degraded over many years could potentially affect plant safety and these effects need to be better understood. As part of the KAERI-BNL collaboration, a condensate storage tank (CST) was analyzed to estimate its seismic fragility capacities under various postulated degradation scenarios. CSTs were shown to have a significant impact on the seismic core damage frequency of a nuclear power plant. The seismic fragility capacity of the CST was developed for five cases: (1) a baseline analysis where the design condition (undegraded) is assumed, (2) a scenario with degraded stainless steel tank shell, (3) a scenario with degraded anchor bolts, (4) a scenario with anchorage concrete cracking, and (5) a perfect correlation of the above three degradation scenarios. This paper will present the methodology for the time-dependent fragility calculation and discuss the insights drawn from this study. To achieve a better understanding of the effects of aging on the performance of structures and passive components (SPCs) in nuclear power plants (NPPs), the Korea Atomic Energy Research Institute (KAERI) and Brookhaven National Laboratory (BNL) are collaborating to develop seismic fragility analysis methods that consider age-related degradation of SPCs. The rate of age-related degradation of SPCs was not found to be significantly large, but increasing as the plants get older. The slow but increasing rate of degradation of SPCs can potentially affect the safety of the older plants and become an important factor in decision making in the current trend of extending the operating license period of the plants (e.g., in the U.S. from 40 years to 60 years, and even potentially to 80 years). In this paper, a condensate storage tank (CST) was analyzed to estimate its seismic fragility capacities under various postulated degradation scenarios. This paper will present the methodology for the time-dependent fragility calculation and discuss the insights drawn from this study.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Experience and Lessons Learned from Conditioning of Spent Sealed Sources in Singapore - 13107

In 2010, IAEA requested KAERI (Korea Atomic Energy Research Institute) to support Singapore for conditioning spent sealed sources. Those that had been used for a lightning conductor, check source, or smoke detector, various sealed sources had been collected and stored by the NEA (National Environment Agency) in Singapore. Based on experiences for the conditioning of Ra-226 sources in some Asian countries since 2000, KAERI sent an expert team to Singapore for the safe management of spent sealed sources in 2011. As a result of the conditioning, about 575.21 mCi of Am-241, Ra-226, Co-60, and Sr-90 were safely conditioned in 3 concrete lining drums with the cooperation of the KAERI expert team, the IAEA supervisor, the NEA staff and local laborers in Singapore. Some lessons were learned during the operation: (1) preparations by a local authority are very helpful for an efficient operation, (2) a preliminary inspection by an expert team is helpful for the operation, (3) brief reports before and after daily operation are useful for communication, and (4) a training opportunity is required for the sustainability of the expert team. (authors)

07 ISOTOPE AND RADIATION SOURCES↗

Shielding Design for Prototype Generation-IV Sodium-Cooled Fast Reactor

A Prototype Generation-IV Sodium-cooled Fast Reactor (PGSFR) with 150 MWe power rating is being developed jointly by the Korea Atomic Energy Research Institute (KAERI) and Argonne National Laboratory (ANL). KAERI is responsible for the overall project with the ANL contributions integrated into the KAERI activities. Shielding concept of PGSFR was developed to ensure that the safety limit on internal structural damage and working personnel received dose is not exceeded. The first part evaluated the Displacement Per Atoms (DPA) and fast neutron fluence on the structures inside the reactor vessel, such as lower grid, Upper Internal Structure (UIS), barrel, Redan, and reactor vessels. The analysis determined the thickness of shields required to satisfy the DPA and fast fluence limit. The second part of the shielding analysis evaluated the radiation dose rate above the reactor head due to the primary sodium activation inside the reactor vessel. The analysis determined the necessary thickness of reactor head and additional shield to ensure that the dose rate received by personnel working on top of the reactor is below the safety limit. The last part of the shielding analysis investigated the dose rate received by personnel working near the secondary loop. The secondary sodium is activated inside the Intermediate heat exchanger (IHX). The activated secondary sodium flows out of the reactor vessel and emits high energy photons along the way. The shielding designs both inside the reactor vessel and around the pipes of the secondary loop were investigated. The shielding concept for the PGSFR was developed to minimize radiation exposure to plant personnel and the irradiation damage of the internal structural components. The damage of the internal structural components are mainly due to the loss of the ductility by the neutron irradiation, and the activated gammas of primary and secondary sodium coolants are the major radiation sources that are required to be shielded. Thicker and denser shielding structures are favorable to reduce the radiation dose and protect personnel who work in the plant; however, which enlarges the in-vessel space to accommodate the shielding structures. Thus, in order to install the shielding structures in a reasonable reactor to satisfy the DPA or dose rate limit size, the PGSFR shielding parameters were determined from the sensitivity study, which includes the compositions of the shielding materials and dimensions. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Korean Localization Program for Performance Verification Test of APR1400's RCP

The Korean government together with the Korean nuclear society completed the development of technologies for the design, manufacturing, and performance verification test of the APR1400's Reactor Coolant Pump (RCP) as one of the national programs for the localization of deficient nuclear technology. The RCP localization program was driven by KAERI, which was responsible for the development of the performance verification and evaluation technology, and by DOOSAN heavy industrial company, which was in charge of the design and manufacturing of the RCP. The test facility for the localized APR1400's RCP was constructed at the KAERI site at the end of 2012. The thermal hydraulic and electric capability of the RCP test facility (RCPTF) covers up to 18.5 MPa, 343 deg. C, 11.7 m{sup 3}/s, and 14.0 MW for the design pressure, temperature, flow rate, and maximum electric power, respectively. In 2013, a commissioning test was performed to verify its designed capability, followed by several modifications in the RCPTF including signal processing and control logic to enhance the verification and evaluation capability of the RCP performance. After finishing the commissioning and modification of the RCPTF, a type test for the new-type of RCP was performed successfully. In 2014 and 2015, eight production tests for the localized RCPs, which will be installed in a commercial nuclear power plant in Korea, were successfully completed. As a final stage of the localization program of the RCP, KAERI will perform a seal LOCA test to verify the leakage characteristics and produce experimental data on the localized seal assembly for a safety analysis during a station black out (SBO) condition. In this summary, several technical issues developed through a series of research processes for a performance verification test of the localized RCP are described.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Comparative study with two reduced test facilities for air-cooled RCCS scaling law

Korea Atomic Energy Research Institute (KAERI) and Argonne National Laboratory (ANL) conducted steady-state tests at constant heat flux conditions to investigate the scale effect on heat removal behavior of the air-cooled Reactor Cavity Cooling System (RCCS). Two differently scaled-down test facilities were used in this study, KAERI’s ¼ scale with 4.0-m cavity height, and ANL’s ½ scale with 6.8-m cavity height. Two scaling laws were proposed to simulate the radiation across the cavity and the buoyancy-driven duct flow in the riser, respectively. The test matrix for KAERI and ANL test facilities focused on the scaling effect of the heated riser length with constant heat flux at the PMR200 RCCS design. The test results showed that mixed convection in the riser duct is an important factor for accurately extrapolating the thermo-fluid behavior in the prototype from the test results in the scale-down facilities. The system analysis code, GAMMA+, with improved heat transfer models predicted fairly well the air-cooled RCCS test data from two facilities. GAMMA+ analysis results showed that the predicted radiation fractions on the heated plate in the scale-down test conditions were larger than those on the reactor vessel in the prototype. The scaling law for air-cooled RCCS was improved by considering the mixed convection in the riser duct and the same radiation fraction on the heated plate. The mixed convection effect was calculated by the height ratio. The same radiation fraction provided a conservative extrapolation from the scale-down test results.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Performance Analysis of the Passive Residual Heat Removal System of an Integral Reactor

A demand for small modular reactors (SMRs) is gradually emerging worldwide, especially in Middle East Asia and Africa. SMART (System-integrated Modular Advanced ReacTor) developed by KAERI (Korea Atomic Energy Research Institute) is the first mover among several SMRs. It is designed to produce 100 MW of electricity, or 90 MW of electricity and 40,000 tons of desalinated water concurrently, which is sufficient for 100,000 residents. SMART is currently holding the initiative as the first licensed integral reactor in the world since 4 July 2012, when the standard design approval (SDA) was officially issued by the Nuclear safety and security commission (NSSC). After that, the SMART safety enhancement project was successfully conducted with intense support of the Government, resulting in an in-depth development of the most advanced safety features including the passive residual heat removal system (PRHRS). Recently, an agreement between KAERI and King Abdullah city for atomic and renewable energy (K.A. CARE) was officially signed for the pre-project engineering (PPE) in pursuit of the construction of SMART and developing human resources capability. Both parties are currently conducting a three-year preliminary study to review the feasibility of building SMART and to prepare for its commercialization. KAERI also takes responsibility to train R and D personnel chosen from Kingdom of Saudi Arabia. Sooner or later, SMART will open the global market of SMR and be the best competitive pioneer. Since the Fukushima accident, the passive cooling system of a nuclear reactor has received a great amount of attention. SMART is designed with passive systems in order to ensure the safety of the reactor. The PRHRS is one of the passive safety systems, which is activated after an accident to remove the residual heat from the core and the sensible heat of the reactor coolant system (RCS) through the steam generators (SGs) until the condition of the RCS reaches a safe shutdown condition. In the present study, the thermal performance of the PRHRS is predicted by using in-house code. Temperature of the RCS and the cooling rate of the RCS are traced with time to see if it is satisfactorily designed to meet the design requirements of the PRHRS. The dependency of the mass flow rate of the natural circulation on the filling ratio (FR) is also discussed. The FR is arbitrarily chosen from 0.22 to 0.50 and further parametric study is needed in the future.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

An approach to developing an integrated pyroprocessing simulator

Pyroprocessing has been studied for a decade as one of the promising fuel recycling options in Korea. We have built a pyroprocessing integrated inactive demonstration facility (PRIDE) to assess the feasibility of integrated pyroprocessing technology and scale-up issues of the processing equipment. Even though such facility cannot be replaced with a real integrated facility using spent nuclear fuel (SF), many insights can be obtained in terms of the world's largest integrated pyroprocessing operation. In order to complement or overcome such limited test-based research, a pyroprocessing Modelling and simulation study began in 2011. The Korea Atomic Energy Research Institute (KAERI) suggested a Modelling architecture for the development of a multi-purpose pyroprocessing simulator consisting of three-tiered models: unit process, operation, and plant-level-model. The unit process model can be addressed using governing equations or empirical equations as a continuous system (CS). In contrast, the operation model describes the operational behaviors as a discrete event system (DES). The plant-level model is an integrated model of the unit process and an operation model with various analysis modules. An interface with different systems, the incorporation of different codes, a process-centered database design, and a dynamic material flow are discussed as necessary components for building a framework of the plant-level model. As a sample model that contains methods decoding the above engineering issues was thoroughly reviewed, the architecture for building the plant-level-model was verified. By analyzing a process and operation-combined model, we showed that the suggested approach is effective for comprehensively understanding an integrated dynamic material flow. This paper addressed the current status of the pyroprocessing Modelling and simulation activity at KAERI, and also predicted its path forward.

42 ENGINEERING↗