Sotan
- 324
- 239
A short presentation of another PDF document from the October 1st update of the Mid and Long Term Roadmap on Tepco’s sit, referring mainly to the spent fuel pools
http://www.tepco.co.jp/nu/fukushima-np/roadmap/images/d151001_07-j.pdf
(in Japanese)
Progress in removal of large debris from the spent fuel pool of Unit 3
Page 5: diagram of the main steps carried out until now and future schedule. Main issues at the moment: placing of further protective panels over the spent fuel racks and removal of the “cover/lid of the CUW F/D hatch”. Intensive work is under way, with a lot of (most of?) the debris to be removed until the end of November.
- Google informs me that this CUW F/D hatch must be related to the “Reactor Water Clean Up System (CUW)”
(http://www.hitachi-hgne-uk-abwr.co.uk/downloads/UKABWR-GA91-9901-0032-00001-Rev2_P-Ver.pdf)
Page 6: Drawing as of Sep 21 showing the placement of protective panels over the fuel racks and the position of the CUW F/D hatch lid.
Page 7 presents the schedule again.
Pag 8 refers to the incident of Sep 3 during preparation work for the removal of the CUW hatch lid. A pressure hydraulic hose of the steel cutting machine got stuck around the handle of a protective panel, which led to the twisting/loosening of a hose connector and to an oil leak. The oil spread over the surface of the SFP but was controlled using the installed oil barrier/fence.
Pages 9 - 11 show the analysis of the incident, causes and corrective measures for the future. The two types of protective panels have different geometries, the height of the “handle” part is different, they didn’t pay enough attention to the risk of some hydraulic hose touching or becoming entangled to certain parts of the panels already placed in the pool. They will consider these things more carefully, and moreover they will strengthen the inspection of the tools used for cutting/handling the debris.
Page 12: Procedure for removing the CUW F/D hatch lid (1/2)
1 – sweep away small concrete debris from the top of the hatch lid
2 – remove pieces of concrete debris from around the hatch lid
3 – slowly lower the special device built for the purpose of lifting the hatch lid
4 – “encapsulate” the lid in the special device and fix it using 4 hydraulic cylinders, and then lift it up.
The last photo shows the concrete debris mentioned in steps 1 and 2 and the metallic handles envisaged to be used for lifting the lid.
Page 13: Procedure for removing the CUW F/D hatch lid (2/2)
5 – bring the lid to a horizontal position and place it temporarily on a rack protective panel
6 – attach some supplementary anti-drop wires to the lid, then lift it out of water and remove it from the SFP.
Page 14: Mockup trial
- Mockup was built at real size and weight and used to verify the procedure. The hydraulic cylinders can be seen in one of the photos.
Pag 15: Explanations about the CUW hatch
There seem to be 2 of them, South of the SFP (red squares in the first drawing).
The lid to be lifted in this operation is the one marked with the curvy red line.
The lid measures approx. 1 x 1 x 2m and weighs about 2.6 tons.
Page 16: Explanations of the specially designed device to be used for lifting the hatch lid
- It has two lifting "eyes", A for the initial lifting and B for bringing the hanging lid to a horizontal position
Page 17-21: areas of operating floors of Unit 1 and 3 to be sprayed with dust-fixing resine, once a months, over 1.5 liters per square meter. Schedule of this operation and so on.
Page 22: removal of the roof of Unit 1 Reactor Building.
Page 23: work done recently on the operating floor of Unit 3 (decontamination, debris removal etc)
Page 24: number and location of the spent nuclear fuel stored in the Fukushima Daiichi plant.
(end)
http://www.tepco.co.jp/nu/fukushima-np/roadmap/images/d151001_07-j.pdf
(in Japanese)
Progress in removal of large debris from the spent fuel pool of Unit 3
Page 5: diagram of the main steps carried out until now and future schedule. Main issues at the moment: placing of further protective panels over the spent fuel racks and removal of the “cover/lid of the CUW F/D hatch”. Intensive work is under way, with a lot of (most of?) the debris to be removed until the end of November.
- Google informs me that this CUW F/D hatch must be related to the “Reactor Water Clean Up System (CUW)”
(http://www.hitachi-hgne-uk-abwr.co.uk/downloads/UKABWR-GA91-9901-0032-00001-Rev2_P-Ver.pdf)
Page 6: Drawing as of Sep 21 showing the placement of protective panels over the fuel racks and the position of the CUW F/D hatch lid.
Page 7 presents the schedule again.
Pag 8 refers to the incident of Sep 3 during preparation work for the removal of the CUW hatch lid. A pressure hydraulic hose of the steel cutting machine got stuck around the handle of a protective panel, which led to the twisting/loosening of a hose connector and to an oil leak. The oil spread over the surface of the SFP but was controlled using the installed oil barrier/fence.
Pages 9 - 11 show the analysis of the incident, causes and corrective measures for the future. The two types of protective panels have different geometries, the height of the “handle” part is different, they didn’t pay enough attention to the risk of some hydraulic hose touching or becoming entangled to certain parts of the panels already placed in the pool. They will consider these things more carefully, and moreover they will strengthen the inspection of the tools used for cutting/handling the debris.
Page 12: Procedure for removing the CUW F/D hatch lid (1/2)
1 – sweep away small concrete debris from the top of the hatch lid
2 – remove pieces of concrete debris from around the hatch lid
3 – slowly lower the special device built for the purpose of lifting the hatch lid
4 – “encapsulate” the lid in the special device and fix it using 4 hydraulic cylinders, and then lift it up.
The last photo shows the concrete debris mentioned in steps 1 and 2 and the metallic handles envisaged to be used for lifting the lid.
Page 13: Procedure for removing the CUW F/D hatch lid (2/2)
5 – bring the lid to a horizontal position and place it temporarily on a rack protective panel
6 – attach some supplementary anti-drop wires to the lid, then lift it out of water and remove it from the SFP.
Page 14: Mockup trial
- Mockup was built at real size and weight and used to verify the procedure. The hydraulic cylinders can be seen in one of the photos.
Pag 15: Explanations about the CUW hatch
There seem to be 2 of them, South of the SFP (red squares in the first drawing).
The lid to be lifted in this operation is the one marked with the curvy red line.
The lid measures approx. 1 x 1 x 2m and weighs about 2.6 tons.
Page 16: Explanations of the specially designed device to be used for lifting the hatch lid
- It has two lifting "eyes", A for the initial lifting and B for bringing the hanging lid to a horizontal position
Page 17-21: areas of operating floors of Unit 1 and 3 to be sprayed with dust-fixing resine, once a months, over 1.5 liters per square meter. Schedule of this operation and so on.
Page 22: removal of the roof of Unit 1 Reactor Building.
Page 23: work done recently on the operating floor of Unit 3 (decontamination, debris removal etc)
Page 24: number and location of the spent nuclear fuel stored in the Fukushima Daiichi plant.
(end)