24P108-P
Study of JT-60SA tokamak assembly
JT-60SAトカマク本体の組立検討
Hirotaka Kubo, Takashi Arai, Koichi Hasegawa, Ryo Hoshi, Hisato Kawashima, Yoshitaka Maesaki,Kei Masaki, Hiroaki Sawai, Kiyoshi Shibanuma, Masato Tabe, Naohiro Tsukao, and Junichi Yagyu
久保博孝、新井貴、長谷川浩一、星亮、川島寿人、前崎喜孝、正木圭、澤井弘明、柴沼清、田部正人、塚尾直弘、柳生純一
Japan Atomic Energy Agency
801-1, Mukoyama, Naka-shi, Ibaraki, 311-0193, Japan
日本原子力研究開発機構 〒311-0193 那珂市向山801-1
The JT-60SA tokamak, which is a large superconducting tokamak, needs to be assembled consistently withhigh precision; assembly of the JT-60SA tokamak has been studied. The absolute coordinate system forthe assembly is defined on the basis of the coordinate system of the JT-60 torus hall. The origin ((x, y,z) = (0, 0, 0)) of the absolute coordinate system is defined to be the center of the VV in the plasma
operation. A consistent global scenario of the assembly is studied. Assembly procedures and tools for
major components such as the TFCs are studies.

1. Introduction
The JT-60SA project is a combined project ofJapan-EU satellite tokamak program under theBroader Approach agreement and Japan domesticprogram. In the JT-60SA project, the JT-60U
tokamak is replaced with a full superconducting
tokamak. Substantial major components of theJT-60SA tokamak, such as the cryostat base,vacuum vessel (VV), equilibrium field coils (EFCs),and so on, have already been in the process ofmanufacture. We have been studying the JT-60SA
tokamak assembly toward commencement of theassembly, which is planned around the end of 2012[1]. This paper presents study of the absolutecoordinate system and metrology for the assembly,global assembly scenario, and assembly procedures
and tools of major components.
2. Absolute Coordinate System and Metrology
From requirements of physical experiment andoperation, the JT-60SA tokamak needs to beassembled with very high precision. For assemblyof such a large complex system with highprecision, it is an important key to define a solid
absolute coordinate system and measure theprecise positions of the components consistently.
The absolute coordinate system of JT-60SA is
defined on the basis of the coordinate system of
the JT-60 torus hall, as shown in Fig.1. The
origin ((x, y, z) = (0, 0, 0)) of the absolutecoordinate system is defined to be the center ofthe VV in the plasma operation, which is 8000
mm above the floor of the JT-60 torus hall. The
VV temperature is 323K in the operation, sinceborated water at a temperature of 323K iscirculated between the double walls of the VV for
neutron shielding. In consideration of the thermal
expansion in the operation, the VV midplane isleveled at z = -2 mm in the assembly.
As the original reference points for metrology,
four points on the floor are used to define the x
and y axes and a point on a wall is used to define
the level, as shown in Fig.1. The z axis is definedby the direction of the gravitation force. From theoriginal reference points, additional reference
points are marked on the building walls, cryostat
base, and so on.
Assembly tolerance of the coils is around ± 2
mm in the consideration of the error fields. Using
laser trackers, we can measure positions with anaccuracy of ~ (0.015 + 0.006 d) (mm) at adistance of d (m). We have been conductingdetailed study of metrology procedures for majorcomponents.

Origin(x, y, z) = (0, 0, 0)

zyz = 8000

xX

z = 4000z=(x = 0, y = 1800)

0X(x = -1800, y = 0)z = -4000

X(x = 1800, y = 0)

FL +1000(z = -7000) X X (x = -0, y = -1700)z = -8000

Fig. 1 Absolute coordinate system of JT-60SA andreference points for metrology. The reference points
are indicated by blue crosses.

3. Global Assembly Scenario
Since the JT-60SA tokamak is a very complex
system, a consistent assembly scenario is required.
In Fig. 2, scenes of the assembly are illustrated inorder. After installation of the cryostat base andtemporary placement of the lower EFCs (EF 4-6),
the VV is installed (Fig. 2 (a)). The VV iscomposed of seven 40-degree, two 30-degree, andone 20-degree sectors; the two 30-degree sectors
are set next to the 20-degree sector. The sectors
except the 20-degree sector are welded up to 340
degrees. Next the vacuum vessel thermal shield(VVTS), which is divided into inboard andoutboard segments of 20-degree sectors, isassembled over the VV, except for the 20-degree
opening sector. Each segment of the VVTS is lifted
down into the 20-degree opening of the VV, turned
around the VV toroidally, and assembled at theprescribed poloidal section. Then the TFCs except
the last TFC are also lifted down into the 20-degree
opening, turned around toroidally, and installed.
The last TFC, VV sector, and VVTS sector areinstalled together (Fig. 2 (b), see Section 4). Then,the temporally placed lower EFCs (EF 4-6) areinstalled under the TFCs, and the upper EFCs (EF1-3) are installed on the TFCs (Fig. 2 (c)). After theport thermal shield, the lower and middle parts ofthe cryostat thermal shield (CTS), and the central
solenoids are installed, the cryostat body is(a)Center stage
VV

Lifting jig(b)Guide rails

Last TFC,VV + VVTS sector

assembled (Fig. 2 (d)). After assembly of othercomponents in the cryostat, the cryostat lid isinstalled.
The assembly scenario will be presented in detailusing a movie at this conference.
4. TFC Assembly
Assembly of TFCs is one of the most criticalissues for tokamak assembly. Except for the lastTFC, the TFCs are lifted down into the 20-degree
opening of the VV and toroidally turned around theVV to the prescribed poloidal section using a rotary
crane and guild rails of the assembly frame, whichsurrounds the tokamak. The assembly frame
supports the TFCs until all of the TFCs arecompletely installed. The assembly of the last TFC
is especially complicated, since the last TFC isinserted into the narrow opening. The insertion ofthe last TFC must be done simultaneously with thelast sectors of the VV and VVTS, as shown in Fig.
2 (b). Pre-assembly of the last TFC, VV sector, andVVTS sector is illustrated in Fig.3. The VVTS
sector is temporarily fixed around the VV sector
supported with a pre-assembly jig (Fig. 3 (a)). The
TFC lifted using a lifting beam is combined with
the VV + VVTS sector by changing the supports ofthe pre-assembly jig (Fig. 3 (a) and (b)). The TFC
and the VV + VVTS sector are individually liftedusing the lifting beam (Fig. 3 (c)), and inserted into
the opening of the VV (Fig. 2 (b)).
Assembly of other major components such as
VV will also be discussed at this conference.

(a)

(b)

Lifting beam(c)

VVVV jig
TFC
EF 4-6(c)VVTS

Cryostat baseLifting jig

(d)

CTS

Pre-assembly jig

EF 3
EF 2Fig. 3 Pre-assembly of the last TFC, VV sector, andVVTS sector. In (b), the red broken lines indicate
the supports removed for the TFC assembly.

EF 1

Cryostat bodyFig.2 Scenes of the JT-60SA tokamak assembly.
Assembly of (a) the VV, (b) the last TFC, VV sector
and VVTS sector, (c) EF 3, and (d) the cryostat body.
In (a) and (b), the guide rails and center stage for theassembly are also shown. In (b) and (c), the lifting
jigs for the assembly are shown.

Reference[1] K. Shibanuma, et al., J. Plasma Fusion Res.
SERIES, 9 (2010) 276.