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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
Journal Basic Information
Journal DOI :
The Korean Radioactive Waste Society
Editor in Chief :
Volume & Issues
Volume 13, Issue 4 - Dec 2015
Volume 13, Issue 3 - Sep 2015
Volume 13, Issue 2 - Jun 2015
Volume 13, Issue 1 - Mar 2015
Selecting the target year
Characterization of Domestic Well Intrusion Events for the Safety Assessment of the Geological Disposal System
Kim, Jung-Woo ; Cho, Dong-Keun ; Ko, Nak-Youl ; Jeong, Jongtae ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 1~10
DOI : 10.7733/jnfcwt.2015.13.1.1
In the safety assessment of the geological disposal system of the radioactive wastes, the abnormal scenarios, in which the system is impacted by the abnormal events, need to be considered in addition to the reference scenario. In this study, characterization and prediction of well intrusion as one of the abnormal events which will impact the disposal system were conducted probabilistically and statistically for the safety assessment. The domestic well development data were analyzed, and the prediction methodologies of the well intrusion were suggested with a computation example. From the results, the annual well development rate per unit area in Korea was about 0.8 well/yr/km
in the conservative point of view. Considering the area of the overall disposal system which is about 1.5 km
, the annual well development rate within the disposal system could be 1.2 well/yr. That is, it could be expected that more than one well would be installed within the disposal system every year after the institutional management period. From the statistical analysis, the probabilistic distribution of the well depth followed the log-normal distribution with 3.0363 m of mean value and 1.1467 m of standard deviation. This study will be followed by the study about the impacts of the well intrusion on the geological disposal system, and the both studies will contribute to the increased reliability of safety assessment.
Electrorefining Behavior of Zirconium Scrap with Multiple Cathode in Fluoride-Based Molten Salt
Park, Dong Jae ; Kim, Seung Hyun ; Park, Kyoung Tae ; Mun, Jong Han ; Lee, Hyuk Hee ; Lee, Jong Hyeon ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 11~19
DOI : 10.7733/jnfcwt.2015.13.1.11
The production of nuclear fuel cladding tube is expected to increase with the nuclear power plant expansion. Zirconium(Zr) scrap that is generated during manufacturing is also expected to increase. Zr electrorefining experiment was carried out in the fluoride salt of LiF-KF-ZrF
using multiple electrode for scale up and improving throughput Zr electrorefiner develop-ment. The Zr reduction peak observed at-0.8 V(vs.Ni). Polarization behavior showed that the amount of applied current increases because of decreasing cell resistance as the number of cathode increases. Experimental results showed the highest recovery rate about 98% at lowest current density of 25.64 mA/cm
using 6 electrodes. XRD and TG analysis result show that pure Zr was recovered 99.92% and ICP analysis shows that lower impurity content than conventional impurity content of the Anode(97.8%). Electrorefining consumes energy about 7.15 kWh/kg less than 39.7% compared to the Kroll process using 6 electrode width of 20 mm and height of 65 mm. Because of increasing cell efficiency and recovery rate, using multiple cathode is determined as an efficient technique for scale up electrorefining Zr scrap.
Verification of MCNP/ORIGEN-2 Model and Preliminary Radiation Source Term Evaluation of Wolsung Unit 1
Noh, Kyoungho ; Hah, Chang Joo ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 21~34
DOI : 10.7733/jnfcwt.2015.13.1.21
Source term analysis should be carried out to prepare the decommissioning of the nuclear power plant. In the planning phase of decommissioning, the classification of decommissioning wastes and the cost evaluation are performed based on the results of source term analysis. In this study, the verification of MCNP/ORIGEN-2 model is carried out for preliminary source term calculation for Wolsung Unit 1. The inventories of actinide nuclides and fission products in fuel bundles with different burn-up were obtained by the depletion calculation of MCNPX code modelling the single channel. Two factors affecting the accuracy of source terms were investigated. First, the neutron spectrum effect on neutron induced activation calculation was reflected in one-group microscopic cross-sections of relevant radio-isotopes using the results of MCNP simulation, and the activation source terms calculated by ORIGEN-2 using the neutron spectrum corrected library were compared with the results of the original ORIGEN-2 library (CANDUNAU.LIB) in ORIGEN-2 code package. Second, operation history effect on activation calculation was also investigated. The source terms on both pressure tubes and calandria tubes replaced in 2010 and calandria tank were evaluated using MCNP/ORIGEN-2 with the neutron spectrum corrected library if the decommissioning wastes can be classified as a low level waste.
Decontamination of Uranium-Contaminated Gravel
Park, Uk Ryang ; Kim, Gye Nam ; Kim, Seung Soo ; Moon, Jei Kwon ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 35~43
DOI : 10.7733/jnfcwt.2015.13.1.35
A large amount of radioactively-contaminated gravel can be produced on the demolition/restoration of facilities related the back end of fuel cycle. However, because of the lacking in basic knowledge for decontamination of radioactive-contami-nated gravel, this study has performed the basic tests using for soil-washing. To find effective decontamination condition, several experiments were carried out for the selection of optimal decontamination agents. Washing by 0.1 M nitric acid was proved to be more effective than that by distilled water or surfactant for decontamination of uranium-contaminated gravel. In addition, crushing/grinding of uranium-contaminated gravel prior to washing was contributed to increase in of removal efficiency of uranium and reduction of decontamination time. The smaller the sizes of crushed gravel was, the more the removal efficiency increased. Also, small the sized particles improved chances for meeting the clearance requirement of the treated gravel.
A Pre-Study on the Estimation of NPP Decommissioning Radioactive Waste and Disposal costs for Applying New Classification Criteria
Song, Jong Soon ; Kim, Young-Guk ; Lee, Sang-Heon ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 45~53
DOI : 10.7733/jnfcwt.2015.13.1.45
Since the commercial operation of Kori Unit #1 nuclear power plant(NPP) started in 1978, 23 units at present are operating in Korea. Radioactive wastes will be steadily generated from these units and accumulated. In addition, the life-extension of NPPs, construction of new NPPs and decontamination and decommissioning research facilities will cause radioactive wastes to increase. Recently, Korea has revised the new classification criteria as was proposed by IAEA. According to the revised classification criteria, low-level, very-low-level and exempt waste are estimated to about 98% of total disposal amount. In this paper, current status of overseas cases and disposal method with new classification criteria are analyzed to propose the most reasonable method for estimating the amount of decommissioning waste when applying the new criteria.
Development of the IRIS Collimator for the Portable Radiation Detector and Its Performance Evaluation Using the MCNP Code
Ji, Young-Yong ; Chung, Kun Ho ; Lee, Wanno ; Choi, Sang-Do ; Kim, Change-Jong ; Kang, Mun Ja ; Park, Sang Tae ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 55~61
DOI : 10.7733/jnfcwt.2015.13.1.55
When a radiation detector is applied to the measurement of the radioactivity of high-level of radioactive materials or the rapid response to the nuclear accident, several collimators with the different inner radii should be prepared according to the level of dose rate. This makes the in-situ measurement impractical, because of the heavy weight of the collimator. In this study, an IRIS collimator was developed so as to have a function of controlling the inner radius, with the same method used in optical camera, to vary the attenuation ratio of radiation. The shutter was made to have the double tungsten layers with different phase angles to prevent the radiation from penetrating owing to the mechanical tolerance. The performance evaluation through the MCNP code was conducted by calculating the attenuation ratio according to the inner radius of the collimator. The attenuation ratio was marked on the outer scale ring of the collimator. It is expected that when a radiation detector with the IRIS collimator is used for the in-situ measurement, it can change the attenuation ratio of the incident photon to the detector without replacing the collimator.
Study on the Well Scenario of the LILW Disposal Facility in Korea
Jeong, Mi-Seon ; Cheong, Jae-Yeol ; Park, Jin Beak ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 63~72
DOI : 10.7733/jnfcwt.2015.13.1.63
The low and intermediate-level radioactive waste generated in Korea is disposed of at Wolsong Disposal Facility. For the safety of a disposal facility, it must be assessed by considering some abnormal scenarios including human intrusion as well as those by natural phenomena. The human intrusion scenario is a scenario that an incognizant man of the disposal facility will be occurred by the drilling. In this paper, the well usage scenario was classified into the human intrusion event as the probability of the well drilling is very low during the man's lifecycle and then was assessed by using conservative assumptions. This scenario was assessed using the dilution factor of contaminants released from a disposal facility and then it was introduced the applied methodology in this study. The assessed scenario using this methodology is satisfied the regulatory limits.
Performance Assessment of Low- and Intermediate-Level Radioactive Waste Disposal Facility in Korea by Using Complementary Indicator: Case Study with Radionuclide Flux
Jung, Kang-Il ; Jeong, Mi-Seon ; Park, Jin Beak ;
Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT), volume 13, issue 1, 2015, Pages 73~86
DOI : 10.7733/jnfcwt.2015.13.1.73
The use of complimentary indicators, other than radiation dose and risk, to assess the safety of radioactive waste disposal has been discussed in a number of publications for providing the reasonable assurance of disposal safety and convincing the public audience. In this study, the radionuclide flux was selected as performance indicator to appraise the performance of engineered barriers and natural barrier in the Wolsong low- and intermediate-level waste disposal facility. Radionuclide flux showing the retention capability by each compartment of the disposal system is independent of assumptions in biosphere model and exposure pathways. The scenario considered as the normal scenario of disposal facility has been divided into intact or degraded silo concrete conditions. In the intact silo concrete, the radionuclide flux has been assessed with respect to the radionuclide retardation performance of each engineered barrier. In the degraded silo concrete, the radionuclide flux has been explored based on the performance degradation of engineered barriers and the relative significance of natural barrier quantitatively. The results can be used to optimally design the near-surface disposal facility being planned as the second project phase. In the future, additional complimentary indicators will be employed for strengthening the safety case for improving the public acceptance of low- and intermediate-level waste disposal facility.