[en] Comparisons of the calculation of the differential pressure through four MOV's between Flowmaster code and SFM model has been presented. The Flowmaster and SFM model basically use 1-D steady-state equation, but for the transient analysis, the Flowmaster uses Joukowsky equation considering the effect of fluid velocity variation and wave speed, while, the SFM model uses quasi-steady equation including fluid inertia effect due to pipe inertia. The maximum differential pressures in opening stroke are almost the same between Flowmaster and SFM model, because the two code have the same steady-state equation. For closing stroke, however, the maximum differential pressure is somewhat different, the Flowmaster code shows higher large estimation than SFM code

[en] According to the requirement, the items for the evaluation system were distinguished with the understanding of the code and it's value, the relation of the technology and it's problems, the relation with the systematical structure of the DECOMMIS-I and its' advantages and disadvantages. The detailed data model (the connection with entities) was structured as of the Information and data on the evaluation items. The ERD(Entity Relationship Diagram) on the characterization was set up. The conceptual modeling (the prototyping) which be on the base of these all result was established

[en] A fuel test loop has been developed in HANARO for nuclear fuel irradiation tests. The facility provides experimental conditions similar to the normal operational pressures, temperatures and water chemistry of commercial pressurized-water reactors. The project for the fuel test loop development began in December 2001. And then the design for the out-pile system, which is a processing system, ended in April 2004 and the design for the in-pile system ended in October 2004. The construction of the facility were done from July 2006 to March 2007. The cold function tests were performed since April 2007 and the hot function tests were completed by May 2009. The safety analysis report was prepared by the end of 2004. The change of HANARO operation license was requested to the ministry of science and technology on January 6, 2005 in order to install and operate the fuel test loop in HANARO. Thereafter on July 21, 2007 the ministry of science and technology approved the change of HANARO operation license with 10 pending items. The 10 pending items including safety analyses on the first test fuels should be resolved before the fuel test loop operation. Therefore the design and safety analyses of the test fuels were carried out and reviewed by Korea Institute of Nuclear Safety. Finally the 10 pending items were resolved completely by September 1, 2009

[en] Korea Research Reactor 1 (KRR-1), the first research reactor in Korea, has been operated since 1962, and the second one, Korea Research Reactor 2 (KRR-2) since 1972. The operation of both of them was phased out in 1995 due to their lifetime and operation of the new and more powerful research reactor, HANARO (High-flux Advanced Neutron Application Reactor; 30MW). Both are TRIGA Pool type reactors in which the cores are small self-contained units sitting in tanks filled with cooling water. The KRR-1 is a TRIGA Mark II, which could operate at a level of up to 250 kW. The second one, the KRR-2 is a TRIGA Mark III, which could operate at a level of up 2,000 kW. The decontamination and decommissioning (D and D) project of these two research reactors, the first D and D project in Korea, was started in January 1997 and will be completed to stage 3 by 2008. The aim of this decommissioning program is to decommission the KRR-1 and 2 reactors and to decontaminate the residual building structure s and the site to release them as unrestricted areas. KAERI (Korea Atomic Energy Research Institute) submitted the decommissioning plan and the environmental impact assessment reports to the Ministry of Science and Technology (MOST) for the license in December 1998, and was approved in November 2000

[en] The object of the research is to develop a new imaging inspection technology for the quality testing of plate-type nuclear fuel whose demanding is currently increasing in nuclear research reactors. A new noncontact imaging inspection technique is developed for the detection of internal defects in plate-type nuclear fuel. To develop the imaging inspection technique, a hardware system based on active optical interference is configured. An operating software for the developed nondestructive inspection system is developed after designing an advanced signal processing algorithm to improve the detection capability of the system. The developed system is optimized through experiments and optimal heating condition is studied. The performance of a lock-in thermography is also evaluated to see the possibility of the plate-type nuclear fuel application

[en] The performance of the emergency cooling water system of HANARO fuel test loop has been predicted by MARS/FTL computer code. The MARS/FTL is a modified version of MARS 3.0. A user input option to use the multipliers of heat transfer correlations has been added to the MARS/FTL. The multipliers were determined from the uncertainties of the heat transfer correlations to predict the performance of the emergency cooling water system conservatively. The accuracy of the MARS computer code has been assessed in three types of problems: eleven phenomenological problems, nineteenth separate effect experiments, and three integral effect experiments. As a result of the assessment it is indicated that the MARS shows a good prediction for the assessment problems. The MARS/FTL is essentially equivalent to the MARS except the user option on the multipliers of heat transfer correlations. The basic field equations, constitutive relations, and thermal hydraulic models of the MARS/FTL are exactly the same as those of the MARS. It was ensured that the user option on the multipliers did work properly. All of the thermal hydraulic transient phenomena to be supposed in the design basis accidents and anticipated operational occurrences of the fuel test loop are also covered in the assessment problems of the MARS. Therefore the MARS/FTL can be used for the thermal hydraulic transient analyses of the fuel test loop

[en] As result of the inputting the decommissioning information and data, the total 3,123,410 items of the 376,434 lists from the KRR decommissioning activities and the total 1,925,888 items of the 230,559 lists from the Uranium Conversion Plant decommissioning activities were input into the DECOMMIS-I. These data is counted by 2.16 Giga byte, which is composed by 1.12 Giga byte from KRR and 1.04 Giga byte from UCP. When the DECOMMIS-I is operating, the 7 programs were revised and the 12 programs were up graded. The hard ware system of the DECOMMIS-I was upgraded and the O/S system was also up dated. The documentation which were 1,934 of the daily work report, 340 lists of the documentation of the radiation scope, 186 lists of the waste management documentation and 97 lists of the Q/A documentation were classified and be took over to the KAERI QA team. The DECOMIS-I system was revised and upgraded. The 7 programs which have uncorrectable and troubled problems were solved and 12 programs were up graded

[en] ISP (Information Strategy Planning), which is the first step of the whole database development, has been studied to manage effectively information and data related to the decommissioning activities of the Korea Research Reactor 1 and 2 (KRR 1 and 2). A record management system (RMS) of large nuclear facilities of national experience such as in the U. S. A., Japan, Belgium, and Russian were reviewed. In order to establish the scope of the decommissioning DB, user requirement and the importance of the information were analyzed and set up the conceptual design of the decommissioning DB. The results have been reviewed an national experience were recognized to acquire the technology of the decommissioning DB for the whole decommissioning process. It has been extracted the principle information such as working information, facilities information, radioactive waste treatment, and radiological surveying and analysis during the interviewing with an experts. These information and data will be used as the basic data to design the prototyping

[en] The result of the decontamination and decommission activities of the 10 lead cells which for chemical process units of radioisotope production at KRR-2 (TRIGA Mark - III) was evaluated. The D and D activities was performed according to the decommissioning plan, radiation protection program and work plan procedures which was based on the method statements. Each 20 related entities, such as man-powers, working time, radiological data and radwaste volumes were raised for input and output the records and data. It was little got out of the estimated planning scope. These analysed records and data will be more useful for the next D and D activities on the KRR-2 reactor and more helpful for the another nuclear facilities decommissioning project in the D and D planning and engineering field

[en] The three dimensional thermal hydraulic analysis of KSNP steam generator for off-design conditions has been carried out by using ATHOS3 code. Four off-design parameters such as the reactor coolant temperature of 10 , the reactor thermal power of 5%, the steam generator tube plugging of 8%, and the feedwater temperature of 10 are considered. Algebraic slip model is used for the two-phase flow analysis in the secondary side of steam generator. The void fraction increases with the increase of reactor thermal power or tube plugging rate, and the decrease of reactor coolant temperature. The vertical mixture velocity of steam and liquid shows the sae trend to the void fraction and increases in general as the steam pressure decreases. The maximum hydrodynamic load based on normal gap velocity on the tube of 41R-83C around the central cavity increases about 14% as the reactor coolant temperature of 10 decreases. Also the maximum hydrodynamic load increases about 15% on the tube with the increase of 5% in reactor thermal power