Irradiated Material Examination Facilit
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Irradiated Material Examination Facility, IMEF

Figure 1 Birdeye view of IMEF
  • history and scale of IMEF
    • Irradiated Material Examinations Facility (IMEF) was constructed to perform post-irradiation examinations of the capsules for newly developed nuclear fuels and the reactor core structural materials irradiated at HANARO. Furthermore, the surveillance programs have been performed to evaluate the integrity of structural materials in nuclear power plants. The construction started from 1989, and the normal operation have been performed since 1996.

      IMEF has three stories and one basement with the section area 28.0 m × 51.0 m and about 4,000 m2 in the floor space. The hot cells which are main facilities had 26 work units with the length of 60 m originally. They extended to 71 m in a total length with 31 work units after construction of new hot cells in bottom floor to develop the advanced fuel cycle process techniques. In addition a pool with the depth of 10 m is located in the service area to transfer the transporting casks into hot cells. The maximum wall thickness of hot cells is 1.2 m to shield the radiation from the source with the maximum radioactive level of 37 PBq.

      figure2construction of imef


      Figure 3 Arrangements of hotcells in ground and bottom floors
  • Hot cell Layout and Functions
    • The hot cells can be grouped into 4 lines according to the functions of them as shown in Figure 4; a structural material examination line, a nuclear fuel examination line, a DUPIC fuel line and pyro process line. In a nuclear fuel line non-destructive tests like as a visual inspection, a dimension measurement, a gamma ray scanning, an eddy current, a X-ray radiography are performed. After non-destructive tests a capsule or a fuel bundle is dismantled, and specimensare assorted for a mechanical test, a metallography a density measurement, and etc. In a structural material examination line the mechanical tests as impact tests, bending tests, compression tests, tensile tests, fatigue tests and etc. are performed. Metallography observation, hardness tests and density measurement are performed in lead hot cells.

      In a DUPIC fuel line the special fuel project are performed to develop CANDU fuels from spent PWR fuels, and in a pyro process line a new spent fuel program to protect the nuclear proliferation are carried out. Table 1 shows the specifications and main equipments in the hot cells.



      Figure 4 Staus of functional hotcell lines


  • Table 1 Hot cell specifications and main equipments list in IMEF

    Table 1 Hot cell specifications and main equipments list in IMEF
    Pool/Cell Function Inside
    Dimension (m)
    Windows
    (ea)
    Major Cell Equipment
    Pool Receiving Cask 6.0 × 3.0 × 10.0 (depth) - Bucket Elevator, Pool Water Purification System
    M1 Cell NDT 7.0 × 3.0 × 6.0 3 Eddy Current, Gamma Scanning System
    X-Ray System, Dimension Measurement
    M2 Cell Specimen fabrication 7.0 × 3.0 × 6.0 3 CNC Machine, Capsule Cutting Machine
    Electric Discharge Machine
    M3 Cell Metallographic
    sample prep.
    4.7 × 3.0 × 6.0 2 Low Speed Saw, Mounting Press
    Grinder/Polisher, Periscope
    M4 Cell Sample storage 2.3 × 3.0 × 6.0 1 Specimen Storage Rack
    M5a Cell Mechanical Test 7.1 × 2.0 × 4.0 3 Impact Tester, Small Specimen Tester
    Heat Treatment Furnace, Highscope
    M5b Cell Mechanical Test 4.8 × 2.0 × 4.0 2 Dynamic UTM, Static UTM
    M7 Cell
    (M7a, b)
    Metallographic Observation 1.5 × 2.6 × 4.65 2 Optical Microscopy, Micro Hardness Tester,
    Micro Balancer
    Hot Laboratory Micro Analysis 5.8 × 7.5 ×8.4 - TEM, EPMA
    M6 Cell
    (M6a, b)
    Sequential
    Process Test
    23.4 × 2.0 × 4.0 10 DUPIC facility
    M8 Cell
    (M8a, b)
    Sequential
    Process Test
    10.3 × 2.0 × 4.3 5 ACP facility
  • Main procedure of hot cell tests
    • Capsules for fuels and structural materials irradiated at HANARO, and Casks for the reactor core materials operated in power plants are shipped in the pool. From the pool the fuel materials are transferred into M1 hot cell through a canal as shown in Figure 5. They are performed non-destructive tests in M1 cell, and transported to M2 cell. In M2 cell they are dismantled into each fuel specimen or fuel rods, and fabricated to various kinds of special specimen. After some fuels are processed to be metallography specimen in M3 cell, and transported to M7 cell to perform metallography observation. Finally EPMA analysis and TEM investigation are performed in Hot Lab.

      In the case of structural materials, capsules are dismantled and classified into each specimen or specimens are fabricated in M2 cell. They are tranported into M5 cell as the next step. In M5 cell various mechanical tests as impact tests, tensile tests, fracture tests, fatigue tests, bending tests and fractured surface investigation etc are carried out. The tested specimen are observed using an EPMA and/or a TEM in M7 cell. A test flow chart and main equipments in hot cells are shown in Figure 6 and 7 respectively.

      Figure 5 Transferred status of a capsule into a hot cell


      Figure 6 Test flow chart in IMEF


      Figure 7-1 Main equipments in M1 hot cell


      Figure 7-2 Main equipments in M2 hot cell


      Figure 7-3 Main equipments in M3 hotcell


      Figure 7-4 Main equipments in M5a hot cell


      Figure 7-5 Main equipments in M5b hot cell


      Figure 7-6 Main equipments in M7 hot cell


      Figure 7-7 Main equipments in hot lab


  • Achievement of Tests and Technique developments
    • The main activities of IMEF are grouped into the fuel capsule tests and the structural capsule tests irradiated in HANARO, the core structural material tests operated in power reactors, basic research capsule tests from universities, and supporting the hardware tools for DUPIC and ACP projects. Figure 8 shows the achievements grouped by the above mentioned categories during mid-term.

      Figure 8 Status of the mid-term achievements from IMEF operation


    • The representative achievements related to nuclear fuels are HITE-I, II, III for the SMART, KOMO-I, II, III for research reactors, DUPIC-I, II and the normal operated HANARO bundles. Figure 9 shows the example of a metallography investigation for KOMO-III fuels. For developing the new test techniques in the hot cells, an annealing furnace system was installed to test for HITE fuels. It was composed of a furnace heating up 1,300 ℃, a temperature controller, a fission gas circulating and collecting system. In addition, a thermal diffusivity tester is setting up to test on the irradiated fuels and structural materials. Figure 10 shows the pre-operations of this equipment and specimen holders to fix .

      Figure 9 Example of the metallography observations for KOMO-III fuels


      Figure 10  Pre-operation of thermal diffusivity tester and it\\\\\\\\\'s holders


    • The tests for reactor vessel surveillance of all PWR´s operated in KOREA have been performed in IMEF, which are impact tests, tensile tests, chemical composition analysis and melting investigations of thermal monitors etc. Figure 11 shows an example of ductile-brittle transition curve from impact tests.

      Figure 11 Ductile brittle transition curve from impact tests


    • The tests of the operated CANDU pressure tubes were performed to evaluate the operation safety in the Wolsung reactors. For this test the specially designed EDM for a hot cell was developed to fabricate various specimens from tubes. Furthermore the reversed DCPD system was also developed to measure a crack length during a fracture test. The detailed test items are tensile tests, a fracture tests and DHCV tests etc. Figure 12 shows an example of fracture test specimen collection in a tube and it´s test results.

      Figure 12 Shape of specimen collection and test results in fracture tests


    • Mechanical testing techniques for PWR fuel claddings have been developed, and applied to perform tests on the irradiated tubes. The detailed test items are tensile tests, compression tests, bending tests, fracture tests, buckling tests and irradiation growth measurements etc. Figure 13 shows a buckling test and compression tests and its jig for fuel assembly parts. The developed techniques will be applied to test for the long-term and high burned fuel claddings.

      Figure 13 Scene of buckling and compression tests