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Study on Fuel Debris Retrieval Method: “Reactor Pressure Vessel 1/1 Scale Model Test”, etc. [Development by Hitachi GE Nuclear Energy] (April 2017)

Apr.17,2017

As part of its R&D efforts for the decommissioning of the Fukushima Daiichi Nuclear Power Station (NPS), the IRID (development by Hitachi GE Nuclear Energy) is involved in developing fundamental technologies for the retrieval and removal of fuel debris and internal reactor structures, and subsidizing costs for the Decommissioning and Contaminated Water Management Project.

 

As one of these fuel debris retrieval methods, we would like to introduce the “R&D status of the Reactor Pressure Vessel (hereinafter called RPV) 1/1 scale model testing,” a remote operation technology for fuel debris retrieval.

●R&D status of “RPV1/1 scale model testing”
・Verification tests for the prevention of radioactive material dispersion while installing common devices*1、and individual devices*2 at the RPV is being conducted.
・Assuming fuel debris cutting, cutting tests of simulated fuel debris that has been flattened after grinding convex surface portions with a grinder are being conducted.

*1 Common device: A platform for the installation of an individual device
*2 Individual device: A box with built-in processing machines for fuel debris cutting, gripping, and collecting. During fuel debris retrieval, the operation of various devices becomes possible by replacing the said individual devices.

1)Fuel debris retrieval by top-entry method / common device + individual device installation test
<Photos during operation>

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Common device installation test for RPV 1/1 scale model using a large crane
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Attaching a milling blade to an individual device Individual device installation test for a common device

2)Grinding test for convex surface portion of simulated fuel debris using a grinder
<Photos during operation>

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3)Cutting test for simulated fuel debris using a milling blade
<Photos during operation>

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[Attachment]
Overview of R&D status of RPV 1/1 scale model testing
http://irid.or.jp/wp-content/uploads/2017/04/20170417.pdf PDF

[Reference]
Additionally, as part of in-house joint research with Hitachi GE Nuclear Energy and Sugino Machine, R&D related to cutting technology using an Abrasive Water Jet (hereinafter called AWJ) and a laser is being conducted, assuming the cutting of internal reactor structures.
<Photos during operation>

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Test for cutting, gripping, and collecting of 10mm
metal via AWJ and laser
Verifying test through observing monitor
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Cutting test of 100mm metal via AWJ

Inquiries regarding this topic may be directed to IRID viaE-mail