Bong Goo Kim

DEVELOPMENT STATUS OF IRRADIATION DEVICES AND INSTRUMENTATION FOR MATERIAL AND NUCLEAR FUEL IRRADIATION TESTS IN HANARO

The High flux Advanced Neutron Application ReactOr (HANARO), an open-tank-in-pool type reactor, is one of the multi-purpose research reactors in the world. Since the commencement of HANARO’s operations in 1995, a significant number of experimental facilities have been developed and installed at HANARO, and continued efforts to develop more facilities are in progress. Owing to the stable operation of the reactor and its frequent utilization, more experimental facilities are being continuously added to satisfy various fields of study and diverse applications. The irradiation testing equipment for nuclear fuels and materials at HANARO can be classified into capsules and the Fuel Test Loop (FTL). Capsules for irradiation tests of nuclear fuels in HANARO have been developed for use under the dry conditions of the coolant and materials at HANARO and are now successfully utilized to perform irradiation tests. The FTL can be used to conduct irradiation testing of a nuclear fuel under the operating conditions of commercial nuclear power plants. During irradiation tests conducted using these capsules in HANARO, instruments such as the thermocouple, Linear Variable Differential Transformer (LVDT), small heater, Fluence Monitor (F/M) and Self-Powered Neutron Detector (SPND) are used to measure various characteristics of the nuclear fuel and irradiated material. This paper describes not only the status of HANARO and the status and perspective of irradiation devices and instrumentation for carrying out nuclear fuel and material tests in HANARO but also some results from instrumentation during irradiation tests.

IN-SITU CREEP TESTING CAPABILITY FOR THE ADVANCED TEST REACTOR

An instrumented creep testing capability is being developed for specimens irradiated in pressurized water reactor coolant conditions at the Advanced Test Reactor (ATR). A test rig has been developed such that samples will be subjected to stresses up to 350 MPa at temperatures up to 370°C in pile. Initial Idaho National Laboratory (INL) efforts to develop this creep testing capability for the ATR are summarized. In addition to providing an overview of in-pile creep test capabilities available at other test reactors, this paper reports efforts by the INL to evaluate a prototype test rig in an autoclave at INL’s High Temperature Test Laboratory. Data from autoclave tests with Type 304 stainless steel and copper specimens are reported.

Instrumentation for Materials Irradiation Tests in Hanaro

Abstract HANARO (High flux Advanced Neutron Application ReactOr) is an open-tank-in-pool-type, multipurpose research reactor. Since the commencement of HANARO operations in 1995, a significant number of experimental facilities have been developed and installed, and continued efforts to develop more facilities are in progress. Owing to a stable operation of the reactor and its rapid utilization, more experimental facilities are being continuously added to satisfy various fields of study and diverse applications. The equipment is classified into a capsule and a fuel test loop (FTL) for the irradiation tests of the nuclear fuels and materials in HANARO. Capsules for the irradiation tests of nuclear fuels in HANARO, under the conditions of its coolant and materials in dry conditions, have been developed. The FTL can conduct an irradiation test of a nuclear fuel under the operating conditions of commercial nuclear power plants. Three test fuel rods can be irradiated in HANARO by using the FTL. Some instrumentation such as thermocouples, linear variable differential transformers, small heaters, fluence monitors, and self-powered neutron detectors are used to perform the irradiation tests by using these irradiation devices. In this paper, the status of HANARO and its irradiation devices including the instrumentations and some results from these instrumentations during irradiation tests are described.

Development and Application of Irradiation Technology in HANARO

A material capsule system including a main capsule, a fixing, a control, a cutting, and a transport system was developed for an irradiation test of non-fissile materials in HANARO. This capsule system has been actively utilized for the various material irradiation tests requested by users from research institutes, universities, and the industries. Based on the accumulated irradiation experience and the user’s sophisticated requirements, the instrumented capsule technologies for a more precise control of the irradiation temperature and fluence of a specimen were developed in HANARO. 6,000 specimens from domestic research institutes, nuclear industry companies and universities, were irradiated in HANARO for 54,000 hours by using the developed capsule irradiation system. Recently, development of new instrumented capsule technologies for an IP/OR irradiation test and a high temperature irradiation test has been performed in HANARO for relevant ongoing R&D for the international Gen IV Program. New irradiation technologies are also under development for the production of new functional materials including superconductor and optical/electrical materials.

IRRADIATION DEVICE FOR IRRADIATION TESTING OF COATED PARTICLE FUEL AT HANARO

The Korean Nuclear-Hydrogen Technology Development (NHTD) Plan will be performing irradiation testing of coated particle fuel at HANARO to support the development of VHTR in Korea. This testing will be carried out to demonstrate and qualify TRISO-coated particle fuel for use in VHTR. The testing will be irradiated in an inert gas atmosphere without on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The irradiation device contains two test rods, one has nine fuel compacts and the other five compacts and eight graphite specimens. Each compact contains about 260 TRISO-coated particles. The irradiation device is being loaded and irradiated into the OR5 hole of the in HANARO core from August 2013. The device will be operated for about 150 effective full-power days at a peak temperature of about 1030°C in BOC (Beginning of Cycle) during irradiation testing. After a peak burn-up of about 4 atomic percentage and a peak fast neutron fluence of about 1.7×10 21 n/cm 2 , PIE (Post-Irradiation Examination) of the irradiated coated particle fuel will be performed at IMEF (Irradiated Material Examination Facility). This paper reviews the design of test rod and irradiation device for coated particle fuel, and discusses the technical results for irradiation testing at HANARO.

Characterization of a silicon carbide thin layer prepared by a self-propagating high temperature synthesis reaction

Silicon carbide was deposited by a self-propagating high temperature synthesis reaction between graphite and silicon layers on an oxide substrate. Chemical analyses by Auger electron microscopy and X-ray diffractometry revealed that the final product was beta-SiC without an inter-diffusional layer at the interface between the carbide and graphite layers. Transmission electron microscope observation showed that the silicon carbide layer has fine crystalline structure. Numerical analysis showed that the combustion limit decreases with initial reaction temperature, which means that additional heat is required for the complete reaction. Activation energies between liquid silicon and carbon fiber or carbon black were 2875 and 1782 kJ/mol, respectively. The silicon carbide prepared by the combustion reaction between silicon and carbon was formed by the carbon diffusion at the interface between liquid silicon and silicon carbide. The reaction rate significantly depended on the specific surface area of carbon.

Evaluation of Mechanical Properties of Graphite Layers on a Nuclear Fuel Particle by Kinetic Nano-Indentation Technique

Small specimen with simple geometry has advantage for irradiation tests because the tests have limits for experiments and nuclear wastes after irradiation tests. In this study, a kinetic indentation technique is applied to evaluate mechanical properties of coated layers of a particle fuel of a high temperature gas cooled reactor. Hardness of buffer, IPyC and OPyC are 0.55, 0.874 and 2.726 GPa, respectively. The density, strength and friction coefficient estimated by kinetic indentation method are 1.08, 1.15 and 1.81 g/cm3, and 174, 291 and 606 MPa, and 0.51, 0.45 and 0.4, respectively.