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Sano, Kyohei; Tameta, Yuito; Akuzawa, Tadashi; Kato, Soma; Takano, Yugo*; Akiyama, Kazuki
JAEA-Technology 2024-018, 68 Pages, 2025/02
JAEA-Technology-2024-018.pdf:4.73MB
High Active Solid Waste Storage Facility (HASWS) at the Tokai Reprocessing Plant (TRP) is a facility for storing highly radioactive solid waste generated from the reprocessing operation. Wet cells in HASWS store hull cans that contain fuel cladding tubes (hull) and fuel end pieces remained after the spent nuclear fuel shearing and dissolving, as well as used filters and contaminated equipment. Dry cells in HASWS store analytical waste containers that contain waste jugs and the other waste generated from analytical operation of samples in TRP. Since HASWS does not have waste recovery equipment from the cells, it is considered that recovery equipment to be installed. In the wet cells, methods of recovery wet-stored waste are being considered that utilize a ROV, which has been used in decommissioning in the UK, and a lifter, which is used in the marine industry to float and transport items sinking to the bottom of the sea. To confirm the feasibility of the recovery method that combines the functions of the ROV and the lifter, tests for removing waste were conducted in steps that came closer to the real environment: a "unit test" to confirm the functions required of each of the ROV and the lifter, a "combination test" to combine the ROV and the lifter to move waste underwater, and a "comprehensive test" to retrieve waste in an environment simulating the hull storage facility. Through this test, the ROV and the lifter were able to perform a series of tasks required to recovery waste - cutting the wires attached to the waste, attaching a lifter to the waste, moving the waste to under the opening, and attaching the recovery device to the moved waste - in series, confirming the feasibility of the method for recovery wet-stored waste using the ROV and the lifter.
Tameta, Yuito; Sano, Kyohei; Ito, Satoshi; Akiyama, Kazuki
no journal, ,
We are developing a system to take out waste from wet storage for the decommissioning of HASWS in Tokai Reprocessing Plant. The main component of the system is an underwater ROV, which has been used for decommissioning in the U.K. However, since the underwater ROV alone cannot handle the waste, we are considering combining it with an underwater buoyancy, which is used for lifting and transporting submarine items in the offshore field. In mock-up tests, simulated waste has been placed in a mock-up facility that simulates an actual HASWS, and tests have been conducted to lift up simulated waste using various shapes of underwater buoyancy and to move simulated waste by combining an underwater ROV and an underwater lifter. We report the results of these tests, as we obtained results regarding the removal of waste using underwater buoyancy.
Sano, Kyohei; Tameta, Yuito; Ito, Satoshi; Akiyama, Kazuki
no journal, ,
Toward the decommissioning of HASWS in Tokai Reprocessing Plant, we are developing equipment for recovery waste from wet storage. So far, after conducting surveys and operability confirmations of ROVs that have been used for decommissioning in the UK, we have conducted mock-up trials using an ROV tester. In the mock-up trial, simulated waste was placed in various postures and orientations in a mock-up facility simulating the HASWS. We confirmed that the ROV could cut the wires attached to the waste, that the waste could be moved using the underwater ROV and buoyancy, and that the ROV could attach hanging tools to the waste. A result was obtained regarding the removal of waste using an underwater ROV, etc., so I will report it.
Ito, Satoshi; Sano, Kyohei; Tameta, Yuito; Akiyama, Kazuki
no journal, ,
The High Active Solid Waste store HASWS of Tokai Reprocessing Plant. HASWS don't have a equipment to retrieve the High Active Solid Waste. Therefore, I examined the Using remotely machine at decommissioning of domestic and international. In the technical investigation, I investigated the machine and others which could perform work of (1)-(3). (1) Cutting work of the wire attached to Hull Can. (2) Moving work of Hull Can. (3) Attach the hoisting accessory work of Hull Can. I compared the extracting machine and others. As a result, I chosed the Remotely operated Vehicle And underwater buoyancy.
Tameta, Yuito; Sano, Kyohei; Akuzawa, Tadashi; Akiyama, Kazuki
no journal, ,
For the decommissioning of HASWS at TRP, we are considering using a ROV and a lifter to retrieve waste stored in the wet cell. We are considering using a lifter (grab type) to retrieve hull cans that are difficult to move with the ROV and the lifter (hook type), and conducted a mock-up test to confirm the feasibility of moving hull cans by the ROV and the lifter (grab type). Through the test, we confirmed that the hull cans placed in various positions in the mock-up facility could be moved by the ROV and the lifter (grab type). We are also conducting further studies on grabs suitable for gripping hull cans for safer and more reliable retrieval of the hull cans.
Sano, Kyohei; Tameta, Yuito; Akuzawa, Tadashi; Akiyama, Kazuki
no journal, ,
JAEA are considering using a ROV and lifters to recovery waste stored in the HASWS wet cell at the TRP. To confirm the feasibility of the recovery method using a ROV, we conducted tests in an environment simulating the storage state. The test results confirmed that tasks required for the waste recovery method using a ROV can be performed for waste in simulating the real environment. In addition, we confirmed that in a dark environment, it is difficult to grasp the position of the cables from the camera inside the cell, so it is necessary to improve the working environment, such as installing a new light source at the penetration.
Akuzawa, Tadashi; Tameta, Yuito; Sano, Kyohei; Akiyama, Kazuki
no journal, ,
In preparation for the decommissioning of the HASWS, we are considering using an underwater ROV and a submersible lifter (grab type) to remove hull cans, stainless steel filters and stirrers. In this case, to confirm the feasibility of this method, we placed simulated filters and contaminated equipment in various positions in a mock-up facility simulating a wet cell and conducted a test to move them using an underwater ROV and a submersible lifter (grab type). As a result of the test, we confirmed that in all positions, the filters and contaminated equipment could be grasped and floated by the underwater lifter (grab type) and then moved by the underwater ROV.