RAMI Research Thrusts and Issues from a Remote Maintenance Perspective Tom Burgess Remote Systems Group Leader ([email protected], 865-574-7153)[email protected]

RARAMMI Research Thrusts and Issues from a I Research Thrusts and Issues from a Remote Remote MMaintenance Perspectiveaintenance Perspective

Tom BurgessTom BurgessRemote Systems Group LeaderRemote Systems Group Leader([email protected], 865-574-7153)

ReNew WorkshopReNew WorkshopHarnessing Fusion Power ThemeHarnessing Fusion Power Theme

March 2 - 4, 2009March 2 - 4, 2009

UCLAUCLA

Nuclear Science and Technology DivisionNuclear Science and Technology Division

2 Managed by UT-Battellefor the Department of Energy T Burgess, Renew Workshop, UCLA, March 2 – 4, 2009

FESAC 2007 report RAMI knowledge gap– G-15 Maintainability Gap

ITER–era device design maintainability – ITER and ST CTF examples

RAMI remote maintenance specific research thrusts and issues in Fusion Nuclear Science (FNS)

FNS Facility (FNSF) role in closing the maintainability gap as a fully enabled fusion nuclear environment

OutlineOutline


FESAC 2007 Report RAMI Knowledge Gap

Identifies “Reliability, Availability, Maintainability” (and Inspectability, or RAMI) as one of the 15 knowledge gaps between ITER and Demo that must be closed in order to provide the technology base to design and construct Demo

More specifically, RAMI is cited as critical to Demo success in order to “demonstrate the productive capacity of fusion power and validate economic assumptions about plant operations by rivaling other electrical energy production technologies”

In addition, RAMI research is necessary to build “the knowledge base for efficient maintainability of in-vessel components to guarantee the availability goals of Demo are achievable”


FESAC Report on Opportunities, etc. identified 15 gaps for fusion energy – 9 in engineering and nuclear science and technology

A - Creating predictable high-performance steady - state plasmas: ITER + stellarators + superconducting tokamaks + modeling; plasma control technologies (magnets, plasma heating and current drive, fueling etc.) – likely via international collaborations.B - Taming the plasma-material interface: plasma wall interactions (sputtering, melting etc), plasma facing materials and components (high heat flux, rf antennas etc.) under very high neutron fluenceC - Harnessing fusion power: tritium breeding & handling, high grade heat extraction, low activation materials, safety, remote handling

3 Themes: A B C

4


The Fusion Remote Maintenance Challenge

The fusion nuclear environment is viewed by many as the most challenging of the remote handling applications

Characterized by:– Extreme shutdown radiation levels (≥ 106 rad/hr gamma)

State-of-the-art rad hardness RH tech = 108 rad TAD– Space-constrained in-vessel access ports that are in direct

conflict with simple, expedient handling and maintainability “Ship-in-a-bottle” maintenance approach

– Large, heavy in-vessel components with complex mounting and service connections

– Precision component positioning and complex handling kinematics by robotic mechanisms that are well beyond today’s state-of-the-art technology

– Handling and transport of large activated components through plant facilities, followed by refurbishment in hot cell laboratories

Operations that are challenging and unprecedented in themselves


Dexterous Manipulation of Heavy Payloads Involves Significant Scientific and Technical Challenges

101 102 103 10410-1

100

101

102

Payload (kg.)

Pre

cisi

on

(m

m)

x

x

x

x

x

xx

xearthmoving equipment

electric robots

Conventional Machines

DMHP Machines

x

x

x

x

The precision with which certain components in burning plasma experiments (ITER and beyond) are to be manipulated is beyond the realm of the state of the art

R&D in the areas of advanced control algorithms based on non-linear mathematical modeling and advanced telerobotic control architectures are needed

Development and implementation of human-in-the-loop control of remote manipulation systems are also needed


Where We Are Only one fusion experiment has applied remote

maintenance technology to an appreciable extent - JET

No fusion experiment ever built and operated is representative of a nuclear fusion power source

ITER is expected to operate only a small percentage (annual plasma duty factor ~ 1 to 2 %)

ITER remote maintenance is performed in a very time inefficient manner with remote maintenance outage durations that range from several months to multiple years

Availability goal of Demo (≥ 50%) is extremely challenging and unprecedented given the very limited operation and power production of fusion experiments to date, and the inherent complexity of all envisioned fusion reactors


Current Baseline Requirements for In-vessel/ex-vessel RH InterventionsCurrent Baseline Requirements for In-vessel/ex-vessel RH Interventions

• The ITER remote handling equipment design and procurement is based on a maintenance requirement plan.

COMPONENTS MAINTENANCE REQUIREMENTS PLAN

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WEEKS

YEARS

CLASS 1 & 2 COMBINED MAINTENANCE OPERATIONS(for multiple component's systems, operations are done in parallel)

A. Tesini, June, 2007 Prefit Workshop, Culham Lab


Example ITER Scheduled Annual Remote MaintenanceExample ITER Scheduled Annual Remote Maintenance

* Assuming 16-hr days, 6 work days per week The remote maintenance operation time (alone) would be ~ 26 weeks

(50% of year) The time to shutdown, cool down, vent and then pump down and

condition back to plasma operation adds ~ 4 weeks for 30 weeks (58% of year)

One unscheduled failure requiring separate VV intervention will add 4 weeks and the additional remote maintenance activities, or ~ 8 or more weeks for a port assembly, for 38 weeks (73% of year) or more

ITER Annual Maintenance Activity Example

Time Required*

Parallel Activities

Full Divertor Replacement 26 weeks

TBM 4 weeks

Row of Blanket Modules

13 weeks

Port Limiter 4 weeks

Limiting Total Maintenance Time 26 weeks


The Vision

The most agreed and foreseen solution to acceptable component MTTR time is large integrated in-vessel component modules that are time efficient for remote exchange between the core and hot cell, with off-line refurbishment performed in the hot cell– Concepts of FNSF, ARIES and Demo developed to

date by multiple organizations include this common feature

– But no representative fusion device is officially planned before Demo and the design efforts are small


LowerDiverter

Test Module

Upper Breeding Blanket

Lower Breeding Blanket

Shielding

Blanket Test Section

UpperDiverter

TFC Center

Leg Plasma

R0=1.2A=1.5к=3.2δ=0.4Ip = 12

TFC Return Leg / Vacuum Vessel

Support Platform

Inboard FW (10cm)

OutboardFW

(3cm)

Access Hatch

(VV/TFC Return)

Diverter/SOL Shaping Coil

Sliding Joint

Inlet Piping

Outlet Piping

Vacuum Seals

Neutral Beam Duct

Poloidal Field Coils

ST Component Test ST Component Test Facility (CTF)Facility (CTF)

Provides fusion nuclear technology test environment in support of Demo development

ITER-era

Wall load: ~ 1 MW/m2

Fluence,~ 3 MW-yr/m2, (6 MW-yr/m2 later phase)

High Plasma Duty Factor Goal (~ 10 to 30%)

User Facility maximizing test ports

Builds on ITER RH approach and technology


Disconnect upper pipingRemove sliding electrical jointRemove top hatch

Remove upper PF coilRemove upper diverterRemove lower diverterRemove lower PF coil

Extract NBI linerExtract test modulesRemove upper blanket assemblyRemove lower blanket assembly

Remove centerstack assembly

Remove shield assembly

Upper PipingElectrical JointTop Hatch

Upper PF coilUpper DiverterLower DiverterLower PF coil

Upper Blanket Assy

Lower Blanket Assy

CenterstackAssembly

ShieldAssembly

NBI Liner

Test Modules

• Similar to fission power plants, large vertical top access with large component modules with simple vertical motion expedites remote handling, minimizes MTTR and maintenance outages

• All welds are external to shield boundary are hands-on accessible• Parallel mid-plane/vertical RH operation

ST CTF has High Maintainability, Low MTTR, Using ST CTF has High Maintainability, Low MTTR, Using Large Integrated In-Vessel ModulesLarge Integrated In-Vessel Modules


CTF Vacuum Vessel, Blanket and Port Assembly Shielding Allows Ex-Vessel Hands-on Access

VV, blanket and port shielding

(steel & water)


Midplane port assembly

handling cask

Vertical port handling cask(18 meters)

In-cell servomanipulator

ST CTF Remote Handling

Activated component hot cell

Vertical cask docking port

Midplane cask docking port

To reduce maintenance time / significantly increase plasma duty factor (~ 10 to 30 % goal), a large in-vessel component module approach with vertical replacement is employed

ST CTF Top Vertical Port Facilitates Large Component ST CTF Top Vertical Port Facilitates Large Component Replacement To Minimize Maintenance TimeReplacement To Minimize Maintenance Time


ST CTF Preliminary RH Class 1 Annual Maintenance ST CTF Preliminary RH Class 1 Annual Maintenance Time Estimate = ~ 1/4 YearTime Estimate = ~ 1/4 Year Typical annual RH Class 1 (scheduled) remote maintenance campaign might replace:

– 2 divertor modules (6 weeks*)

– 6 midplane port assemblies (3 weeks ea.*)

– NBI ion sources (1 week ea.*)

* Two 8 hr shifts per day, 6 work days per week during shutdown

– Each uses a different RH system, parallel operations are possible, and the midplane port changeouts are limiting provided at least 2 are being changed (6 weeks serial time)

– Assuming 3 midplane port RH casks are available for parallel operations, it is estimated to take ~ 8 weeks to complete the above tasks provided spare units are available.

Add shutdown and machine pump down / conditioning time of 1 month, and the total outage from plasma burn to plasma burn is ~3 month or 0.25 of the year

One unplanned port assembly failure (TBM, RF heating or diagnostics) that shuts the machine down, and that can't be delayed until the scheduled maintenance time, will consume ~ 6 weeks of maintenance time and 1 month of shutdown / startup time, or ~ 0.25 of the remaining year.

Every shutdown requiring opening and venting of the vessel will require in excess of a month to recover, hence in-vessel maintenance should be planned and grouped together

If components are operated to failure, 1 divertor + 1 midplane port failure not occurring at the same time frame could consume ~ 5 to 6 months of the year


FNS Cross-Cutting Remote Maintenance Technology R&D Gap Thrust Areas

Credible, low MTTR in-vessel component design solutions (time efficient and reliable remote mounting and service connections) that are also highly reliable (high MTBF)

Large scale, radiation-hard robotic devices that can provide dexterous manipulation and precise positioning of highly activated in-vessel components; preferably with simple linear and time efficient motions

Multitude of specialty remote tooling and end-effectors, including precision remote metrology systems to measure PFC alignment and erosion in the extreme fusion environment (high radiation, bake-out temps, vacuum)

Supporting hot cell facility remote handling systems and tooling necessary to refurbish and/or waste process the activated in-vessel components

Methods to expedite vessel opening and conditioning back to plasma operation (reduce the 1 month adder to every intervention)


The Path Forward First step in the R&D process is the development of the conceptual

and more advanced designs of the high plasma DF / high Availability device, whether a ST CTF or other tokamak, including:

– the remote maintenance features of the components

– the supporting remote handling systems

– facility and hot cell laboratories

This must be done working in close collaboration with the various component designers in order to develop reliable, fully functional, and efficiently maintainable component solutions

Many remote handling elements of these designs will be new and unique, and must be prototyped, tested and demonstrated in mock-ups ranging from relatively small to large in scale

The final and most important step of the development process is the construction and operation of a FNSF from the break-in through the final advanced stages of science and technology demonstration

A FNSF during the ITER era, and beyond, should address all elements of the remote maintenance knowledge gap to Demo, and provide the required step towards developing the experience and knowledge base for credible Demo design solutions.


Summary and Recommendations

Nuclear fusion remote maintenance solutions are very undeveloped and critical to the success of Demo (current TRL quite low*)

ITER will certainly add to the knowledge base but is very unrepresentative, and major changes are needed to gain efficiency

A TRL level of ~ 6 is needed to close the Maintainability Gap to Demo

In the near term, a strong fusion base program in RAMI with more effort on next step and Demo-representative machines (e.g., FNSF and ARIES) engineering design and R&D is recommended to investigate and advance viable solutions, including the necessary hardware R&D (cold and hot testing) as identified

Ultimately, a FNSF (ST CTF / FDF) device is required to provide the “fully enabled fusion nuclear environment” next step to close the knowledge gap to Demo if it is to achieve an acceptable availability – In addition to closing many other FNS knowledge gaps to Demo

* M.S. Tillack et al, “An evaluation of fusion energy R&D gaps using technology readiness levels”, (TRLS), 18 th TOFE, September, 2008

Back-up slides


How Do We Get There (Demo)?

A major change (expediency) in fusion remote maintenance design and techniques must be developed to achieve the specified availability goals of Demo, or even to achieve a plasma duty factor (DF) an order of magnitude greater than ITER (>10%)

An order of magnitude increase in plasma DF is representative of a FNSF and its ST based design concept has shown that major changes in remote maintenance techniques must be employed

A FNSF combining all the aspects of a nuclear environment is necessary to investigate and close the RAMI gap to Demo


Fusion Nuclear Science Facility Benefits

If acceptable mean-time-to-repair (MTTR) time for all activated fusion components is not developed and demonstrated in conjunction with high component reliability, or high mean-time-before-failure (MTBF), an acceptable fusion power source availability cannot be achieved

A FNSF would provide a major step towards fusion nuclear energy representative remote maintenance techniques, in addition to providing the knowledge base needed in many other important FESAC Report technology gap areas

From “Scientific Exploration” through “Component Engineering Development and Reliability Growth”, all aspects of RAMI would be investigated and advanced in the fully enabled fusion nuclear environment


REMOTE HANDLING OPERATION THEATER

• Inside the Vacuum Vessel

• Inside the Cryostat

• Inside the Neutral Beam Cell

• Inside the Hot Cell

(under nominal operating conditions)

ITER MAINTENANCE SYSTEM (IMS)

• Remote Handling equipment and tools

• Hot Cell facility

ITER Remote HandlingITER Remote Handling


Design features

• 45 ton (equator plugs)

• 20 ton (upper plugs)

Maintenance features

Handling with special robotic vehicle

& manipulator + TRANSFER CASKS


• 4 access ports

• Handling with special robotic vehicle & manipulator + TRANSFER CASKS

Design features

• ˜ 400 modules (∽ 4.5 ton)• Mechanical connection to vessel via bolts• Independent hydraulic connection to cooling circuit

Design features

• 54 cassettes (∽ 11 ton) with removable PFC’s• Mechanical connection to vessel via toroidal rails• Independent hydraulic connection to cooling circuit


• 3 access ports• Handling by robotic movers & manipulator + TRANSFER CASKS

Main ITER In-VV Components to be Remotely HandledMain ITER In-VV Components to be Remotely Handled

BLANKET MODULES PORT PLUGS DIVERTOR CASSETTES


Blanket Remote Handling SystemBlanket Remote Handling System

Blanket module

Max 4.5 tons, exchanged via anIn-Vessel Vehicle (IVT)running on a 250mm wide) x 500mm (high) passive rail deployed around the equatorial region.

JAPAN


Divertor Remote Handling SystemDivertor Remote Handling System

Divertor cassette

3.5m (l) x 2m (h) x 0.8m (w) weight = 8 -10 tonnes.

Exchange via “cassette movers” to lift and carry the cassette coupled with dextrous manipulators to handle tooling.

Access to the divertor region is via 3 equi-spaced maintenance ports.

EUROPE


ITER Remote Maintenance PhilosophyITER Remote Maintenance Philosophy

ITER remote maintenance is based on the removal of

relatively large modular systems followed by refurbishment in a Hot Cell.

The main in-vessel sub-systems comprise:

Blanket modules

Divertor cassettes

Port plugs (containing diagnostics and heating systems)

12 t 45 t


Transfer Cask SystemTransfer Cask System

Lift betweenTokamak levels

EUROPE / CHINA

J.P.Martins


Hot Cell Remote Handling SystemHot Cell Remote Handling System

ITER FUND


ST CTF Builds on ITER Remote Maintenance Approach

Most time-efficient ITER RH (i.e., port assembly handling) design and experience leveraged and applied

Inefficient “ship-in-a-bottle” handling approach for in-vessel components avoided

Hands-on maintenance employed to the fullest extent possible

Activation levels outside vacuum vessel low enough to permit hands-on maintenance

Upper port handling

Equatorial port handling

In-vessel viewing system

Divertor handling

Blanket handling

ITER Remote Handling Systems


Compact Design Allows Close-fitting Shielding, Allowing Ex-Vessel Hands-on Access and Reduces MTTR

Test Module being extracted into

cask

Remote Handling

Cask

TBM

Neutral Beam

Diagnostic

Test Module

RF System

Plasma

TFC Return Leg/Vacuum

Vessel

Shielding

TFC Center

Leg

Inboard First Wall

Midplane ports• Minimize interference

during remote handling (RH) operation

• Minimize MTTR for test modules

• Allow parallel operation among test modules and with vertical RH

• Allow flexible use & number of mid-plane ports for test blankets, NBI, RF and diagnostics


In-vessel components removed as integral assemblies and transferred to hot cell for repair or processing as waste

In-vessel contamination controlled and contained by sealed transfer casks that dock to VV ports

Remote operations begin with hands-on disassembly and preparation of VV closure plate at midplane port or top vertical port

Midplane ports provide access to test blanket modules, heating, and diagnostic systems housed in standard shielded assemblies that are remotely removed

Midplane Port RH Cask

Test Blanket Module

Hot Cell

Cask Docking Ports

Activated Components Transferred Between Machine and Activated Components Transferred Between Machine and Service Hot Cell by RH CasksService Hot Cell by RH Casks


Remote maintenance is an important design and interface requirement, particularly for frequently handled items

Components are given a classification to guide the level of design optimization for ease and speed of replacement

ST CTF Preliminary RH Classification of ComponentsST CTF Preliminary RH Classification of Components

Class 1 (Relatively frequent)

Class 2 (Relatively infrequent)

Class 3 (Not expected but possible)

Class 4 (Hands-on)

Upper and Lower Divertor Modules / Coils Midplane Port Assemblies: Test Blankets, RF Heating, Diagnostics Neutral Beam Ion Source Cleaning In-vessel Inspection (viewing/metrology probe)

Upper and Lower Breeder Blanket Center Stack Neutral Beam Components

Vacuum Vessel Sector / TF Coil Leg Shield Blanket

Poloidal Field Coils Ex-vessel Services


Component RH Class

Expected Frequency

RH Operation Time Estimate* (very preliminary, improvable by practicing)

Divertor Module

1 ~ At least annually ~ Parallel operation

Upper module: ~ 4 weeks

Upper and lower: ~ 6 weeks (assuming center stack not removed)

Mid-plane Port Assemblies ~ 3 weeks per port assembly

Neutral Beam Ion Source ~ 1 week per NBI

In-vessel Inspection (viewing/metrology probe)

1 Frequent deployment

Single shift (8-hr) time target (deployed between plasma shots, at vacuum & temp.)

Upper and Lower Breeder Blanket (to approach tritium self-sufficiency)

2

~ Several times in life of machine ~ In parallel with mid-plane operation

Upper: ~ 6 weeks

Upper and Lower: ~ 9 weeks (need to retract mid-plane modules)

Center Stack ~ 6 weeks Neutral Beam Internal Components ~ 2 to 4 weeks

Vacuum Vessel Sector / TF Coil Return Conductor

3 Replacement not expected

Replacement must be possible and would require extended shutdown period

Shield

ST CTF Preliminary Component RH Time EstimatesST CTF Preliminary Component RH Time Estimates


Example Port Assembly Replacement Tasks and Example Port Assembly Replacement Tasks and Time Estimates Time Estimates (from ITER and FIRE)(from ITER and FIRE)

Conditions and Assumptions

Midplane port assembly is removed as an integrated assembly that is lip-seal welded to port, structurally attached at end of port (bolts and/or wedges) and is removed or installed in a single cask docking.

Port assembly is transferred to hot cell and is replaced with a new or spare unit. If the removed assembly is to be reinstalled, the hot cell processing time must be added.

If a port assembly is removed for other than a short period of time, the open port may be shielded to allow personnel access in the ex-vessel region of the machine. The time to install a shielded enclosure at the port is not included in the following estimate and would add days to the estimate.

Operations are conducted in two 8-hour shifts per day (16 hrs total), 6 days per week.

Time to leak check welded lip-seals and pipes not included. Could add a few days to campaign.

Time to detritiate and vent the vessel after shutdown, and pump down and clean the vessel after maintenance are not included. Could add ~ 1 month to shutdown period.


Example Port Assembly Replacement Tasks and Example Port Assembly Replacement Tasks and Time Estimates (Time Estimates (ITER and FIRE basedITER and FIRE based))

Task and Time Summary (assuming 16-hr days, 6 work days per week)

1) Hands-on prepare port for cask docking and 60 hrs 3.75 days

port assembly removal

2) Remotely remove port assembly and transfer to hot cell (remote) 28 hrs 1.75 days

3) Remotely exchange port assembly at hot cell and return to port 20 hrs 1.25 days

4) Remotely replace port assembly in port 25 hrs 1.5 days

5) Hands-on port assembly recovery tasks 56 hrs 3.5 days

189 hrs 11.8 days

Subtotal = 11.8 days + 2 days for leak tests, misc items = 13.8 days = 2.3 weeks (6 work days/week)

With 27.5% contingency = 17.6 days = ~ 3 weeks (6 work days/week, 16 hrs per day)

Assuming 24/7 continuous work weeks = [189 hrs + (2 x 16 hrs)] 1.275 = 282 hrs = 12 days or ~ 2 weeks


Examples of Manipulation of Relatively Heavy Payloads

ORNL Next Generation Munitions Handler

JAERI In-VesselTransporter/Blanket

Module Demo

Documents

RAMI Research Thrusts and Issues from a Remote Maintenance Perspective Tom Burgess Remote Systems Group Leader ([email protected], 865-574-7153)[email protected]