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Experiences during Design, Fabrication, Assembly and Factory Acceptance Test of ITER Cryoplant
Termination Cold Box
P Patel1, H Vaghela1, S Muralidhara1, V Shukla1, A Garg1, J Das1, B Dash1, S Madeenavalli1, H-S Chang2, D Grillot2, B Sarkar2, M Cursan2, K Oppolzer3, F
Sander3, E Adler31ITER-India, Institute for Plasma Research, Block-A Sangath Skyz, 380 005,
Ahmedabad, India2ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez
• Introduction• Overall methodology for execution of CTCB from
design to factory acceptance test• Description of Design, manufacturing and FAT• Outcome of Factory acceptance test• Challenges involved during design, fabrication,
• The CTCB is responsible to distribute the cold power to theapplications and cryoplant as per functional requirements at varioustemperature level i.e. 4 K, 50 K and 80 K
• Functions:o The parallel operation of the three LHe planto In case of failure of any single LHe plant, the CTCB redistributes cold
power of the other two LHe planto For Commissioning of LHe planto Heating of the Gaseous helium during warm up of the ITER
superconducting magnets from 4 K to 300 Ko Purging of the interfacing cryolines before initial cool-down
• The CTCB has been designed, manufactured and assembled with variouscomponents like cryogenic valves, internal piping, thermal shield, heaters,filters, vacuum system and I&C systems etc.
• The experiences gained during the CTCB manufacturing will be usefulwhile designing and manufacturing of the other cold boxes of CD system.
• Developed process and instrumentation diagram as per functional process anddifferent operation mode requirements, which also includes sizing andselection of components
• Outer shell of CTCB designed as per EN 13458 &13445• Internal piping designed as per EN 13480-3
CD H A B CD H A B CD H A B
CAB
EF EF
◩◩ ◩◩ ◩
CD EFH CD EF
M
M
M
M=
M
=
= =
= == = =
M M
H
C
D
MAGNET CRYOLINE CRYOPUMP CRYOLINE
Test
Cry
osta
t
LHe Plant 1 LHe Plant 2 LHe Plant 3 80K Plant 1 80K Plant 2
LHe tank
LHe from LHe tank (line A)GHe return of flash/tank pressurization (line B)SHe (line C)LP GHe (line D)80 K GHe to TS (line E)100 K GHe from TS (line F)50 K GHe to HTS current leads (line H)valve 100 % openvalve control openedvalve closedvalve locked closepressure safety valve3-way valverupture disctemperature sensor elementtemperature sensor element (Cernox/PT100 set)temperature switch (PT100)pressure elementSDU (no RD)SDU (with RD)SDU with recovery valveVenturi flow element (with ∆ P /P element)Coriolis mass flow element(cryogenic) filter unit (with PSV and ∆ P /P element)heater unit offheater unit on / operatingconnection to test cryostat (no flow)connection to test cryostat (with flow)Cryolines interfacing Cryodistribution
• There are total ten load combinations, out of total ten load combination, the worst loadcombination has been identified as “normal operation + seismic load + loss of insulationvacuum + interfacing CLs loads”
• The same load combination has been chosen to perform detailed analysis.
• The functional FAT has been performed with the CTCB and all cabinets as percomparable installation requirements at site.
• The hardware FAT has been conducted to check functionality of electricalcabinets
• The software FAT of the CTCB has been performed using PLC and simulator.• All the instrumentations were successfully executed using PLC.• Finalized HMI screens, checked of all alarm signals, control loops (17 nos.)
and I/O signal (~500 nos.) test as per logic diagram in simulation mode etc.
Meeting the balance betweenthe interface tolerance of ±25mm with CLs and theinterface loads from CLs
Interface tolerances for CTCB has been reduced from ±25mm to ±10 mm in order to reduce interface loads i.e.,bending load. Interface should be frozen before finaldesign, whenever feasible.
Management and validationof interface coordinatesbetween CLs and CTCB atdesign and manufacturingphase
Managed and validated proper interface coordinatesbetween CLs and CTCB with exact available 3D modelthrough design database platform (ENOVIA) which is veryuseful tool for complex interface management.
Progressing in the cold boxdesign of this big scale whileinterfaces are at a differentlevel of maturity
Design with a higher safety margin for CLs interface load(conservative design) with provision to adopt additionalstiffeners on CTCB OVJ. Saddle support design has beenoptimized for distributed load transfer to the ground. CLinterface loads should be envisaged from the conceptualdesign phase and inherent line flexibility should beprovided by proper layout.
• For the ITER CD system, starting from the conceptual design of the CTCB to thefactory acceptance test, it has encountered many challenges and summarisesbelow
Recovery of helium through acommon safety relief header linewas not possible due to limiteddownstream mass flow ratehandling capacity.
Recovery valves have been installed upstreamsafety relief valves (SRVs) in order to recover thehelium prior to the opening of the SRVs in case ofpressurization events. Helium recovery from largevolumes are possible using the automatic recoveryvalves.
Bigger size (>DN150) cryogenicvalves to handle mass flow 4 kg/swere not readily available.
Cryogenic valves of DN200 which fulfil the processrequirements were specified, designed,manufactured and factory tested. Opening andclosing time of bigger valve sizes to be consideredfor integrated control system development andcommissioning.
Warm-up requirement of the SuperConducting magnets having coldmass of ~9,000 tons
Large capacity 600 kW electrical heater designed,manufactured and factory tested for functionality.
Control system development for theparallel operation of LHe plants anddisconnections with interfacesystem.
Global level controls (where extensive signalexchange with CTCB is required) were assignedthrough cryogenic system master controller whileprocess control within CTCB managed by CTCBcontrol system
Flow paths in a segment 1 of thermal shield The elements of a segment
• During the FAT, it wasreported that the heliumleak inside the bubblepanel of the TS is higherthan acceptable limit of1 X 10-7 mbar l/ s.
• Thermal and hydraulic analysis has been performed and investigated that heat load on the 80 KTS is almost unchanged and the average surface temperature is observed to be around 88 K,which is below the given limit of 100 K.
• The total heat load on the 4K surface after bypassing thermal shield elements is about 211 Wwhich is within the maximum allowed heat load of 275 W.
• The final helium leak(after bypassing thethree elements) is2.9 X10-8 mbar l/sand it is within theacceptable limits (1 X10-7 mbar l/s).
Inle
t (b
)
E1 (b)E2 (b)
E3 (b) Out
let
(b)
Inle
t (a
) E1 (a) E2 (a) E3 (a)
Out
let
(a)
By pass element
• The CTCB Thermal Shield (TS) is made of hydro-formed bubble panels of total 48 elementsconnected in parallel/series configuration
• The design, fabrication, assembly and factory test of CTCBhas been successfully completed with fulfilling all thefunctional and technical requirements
• The CTCB and its components have been delivered toITER Organization (IO) in February 2019
• The installation of the CTCB is planned in the last quarterof 2019 at ITER organization site to match thecommissioning of the three LHe plants’.
• The performance of the CTCB in normal operationcondition will be demonstrated during the site acceptancetest at IO.
• The experiences observed and lessons learnt during theexecution of the CTCB project will be implemented in othercold boxes of the ITER Cryodistribution system
AcknowledgmentsAuthors would like to thank the colleagues in ITER-Indiaand ITER Organization and as well as Linde Kryotechnikfor their contribution to the ITER Cryodistribution projectexecution.
DisclaimersThe views and opinions expressed herein do notnecessarily reflect those of ITER organization and ITERpartners.