MECO Magnet Vendor Briefing at MT18

1
MECO Magnet Vendor Briefing at MT-18
October 23, 2003 Bradford A. Smith, MIT-PSFC MECO
Magnet Subsystem Manager
2
Outline of Topics

• Conceptual design overview
• A few words about procurement
• Draft SOW overview
• Magnet Work Breakdown Structure (WBS)

3
Conceptual Design Status

• MIT-PSFC completed in Feb02 a conceptual design
  for the magnet system with a successful final
  review by a national review committee.
• Conceptual design effort also included a detailed
  cost and schedule estimate for final design and
  fabrication
• CDR Chapters

1. Introduction and summary 2. Interfaces 3.
Field specs and field matching 4. Conductor
design 5. Insulation design 6. Joint design 7.
Current lead and bus bar design 8. Quench
detection system 9. Quench protection system
10. Power supplies, dump resistors and
switches 11. Structural design criteria 12. PS
system stress analysis 13. TS system stress
analysis 14. DS system stress analysis 15.
Cryogenics system design 16. Magnet assembly 17.
Magnet installation
Available http//meco.ps.uci.edu/MIT_MECO_CDR.pd
f
4
System Overview
29,000 kg 28,000 kg
53,000 kg
53,000 kg
5
Magnet Interfaces

• Current magnet interface information is available
  by WBS at
• http//meco.ps.uci.edu/ref_design/ref_design.html

6
Field Requirements

• Magnetic field varies more or less monotonically
  from 5 T at the high field end of the PS to 1 T
  at the low field end of the DS.
• Field matching is required over a curvilinear
  cylindrical volume around the magnet axes as
  defined by a detailed specification.

Field specification characteristics
7
Field Solution Method

• Postulate a set of n coils, coil builds and
  ampere-turns that might meet the field
  requirements.
• Calculate fields at n points and influence
  coefficients for each coil at each point.
• Calculate the field contributed by the iron.
• Compare the field at n points against the field
  required by the specification.
• Invert the influence coefficient matrix to obtain
  a corrected set of ampere-turns for each coil.
• Check the field against the spec along three
  paths.
• Iterate as required.
• Final iteration and field calculation done with
  actual conductors, NI and builds

Field specification paths
8
Field Solution

• A system of 94 solenoids, some with generally
  similar axial extent, but generally different
  radial builds meet the field requirement.
• Coils are powered in 6 sets
• PS 3500 A
• TS13u 1500 A
• TS2 4000 A
• TS3d5 1500 A
• TS4 4000 A
• DS 4000 A

• Conductor placement tolerance study indicated
  maximum current limits for TS and DS coils.

• TS Straight sections 1500 A
• TS Bends 4000 A
• DS 4000 A

9
Conductors 1

• MECO has permission to draw from existing
  inventories of SSC inner and outer cable

• Conceptual design focused on and succeeded in
  achieving a design with acceptable margins using
  SSC cables

10
Conductors 2

• Design guidelines
• Fraction of critical ? 0.65 (will be revised to
  ? 0.4), and
• Temperature Margin ? 1.5 K
• SSC cables will be soldered into half-hard copper
  channels to meet protection guidelines (Max V 2
  kV, Max T 150 K).
• PS is subject to nuclear heat load

Coil boundary (1st PS coil)
He
He
Contours of constant temperature margin in high
field PS coil
11
Conductors 3
PS 3500 A

• Current limited by nuclear heating and
  temperature margin
• 41 km of SSC Inner Cable (includes 25 overage)
• fc 0.31
• Bmax 5.9 T

TS 1500 4000 A

• Current limited by conductor placement tolerances
• 30 km of SSC Outer Cable (includes 25 overage)
• fc 0.12, 0.28 respectively
• Bmax 3.5, 2.8 T, respectively

DS 4000 A

• Current limited by conductor placement tolerances
• 30 km of SSC Outer Cable (includes 25 overage)
• fc 0.26
• Bmax 2.03 T

12
Electrical Joints

• Joints are lap solder joints

• Joints must meet the same margin requirements as
  the conductor

• Fraction of critical current ? 0.65 (? 0.4
  when updated)
• Temperature Margin ? 1.5 K

• Conceptual design showed these margins can be
  achieved with the proper choice of solders and
  overlap lengths
• Channel solder 60Sn-40Pb
• Hands solder 44In-42Sn-14Cd (Indalloy 8)
• Overlap length 2 cable twist pitches (19 cm)

13
Insulation

• Turn ground insulation is epoxy impregnated
• Turn insulation
• 1-mil, half-lapped Kapton 3 mil, half-lapped
  fiberglass (S-glass in PS)
• Voltage stress is about 10 V/mil on dump, max.
  for combined thickness
• Ground insulation
• Turn insulation plus 40 mil (1 mm) of fiberglass
  (S-glass in PS)
• Voltage stress is about 40 V/mil on dump
• PS Insulation must be designed to withstand
  nominal 30 Mrad
• Radiation level is not significant for insulation
  compressive or shear strength.
• Gas evolution deserves to be minimized.
• Industrial study by Cryogenic Materials, Inc.
  recommended an epoxy system with the following
  components and cure
• DGEBF resin, 90 ppw, Vatico (Ciba Geigy) GY282
• PPGDGE toughener, 10 ppw, Dow Chemical DER 732
• DETD hardener, 26 ppw, Vantico (Ciba Geigy)
  HY5200
• Gel at 90 C for 15 hours
• Cure at 130 C for 15 hours

14
Quench Detection and Protection

• Because all coil inductances are generally not
  alike, a digital quench detection system is
  proposed.
• Each coil and coil-coil joint is voltage tapped.
• In addition, all coil currents are monitored and
  dI/dt values are calculated.
• System calibration is performed at installation
  during charge and discharge.
• External dump minimizes helium loss and recovery
  times
• MIT quench code (SOLQUENCH) has been run on the
  highest field coils in each of the PS, TS and DS
  temperature distributions are output to ANSYS for
  structural analysis.

• Maximum hot spot temperature and maximum voltage
  requirements are met, while stresses and
  temperatures remain below allowables.

15
Structural Design and Criteria
Overview

• MECO magnet system is divided into 4 magnet
  assemblies, each with its own cryostat PS, TSu,
  TSd, and DS.
• Division is based on shipping limitations and
  natural boundaries formed by each magnets
  function.
• Loads between assemblies are reacted through
  their respective cold mass supports to the
  facility foundation.
• Any or all coil groups may be energized
• Warm bores may be at atmosphere or vacuum

Design criteria

• Combination of fusion and ASME criteria are used
  for guidance in coil structural design.
• Fusion criteria allow primary membrane stress to
  be based on the lesser of 2/3 Yield (Sy) or ½
  Ultimate (Su) when coils are supported by cases.
• Otherwise ASME code criteria are used
• Bases primary stress on 1/3 Su
• Bending discontinuity and secondary stresses
• Bolting and column buckling guidance is taken
  from AISC
• Sy and Su are taken at the loaded temperature

16
Coil Structures

• Production Solenoid (epoxy impregnated coils,
  bath cooled)

• Outer Al shells provide hoop load support
• Spherical-end rods take TS attractive loads
• He can designed for 5 atm (quench)

• Transport Solenoid (epoxy impregnated,
  conduction cooled)

• Coils are wound outside H-shaped SS mandrels
• Horizontal V formed by spherical-end-rod pair
  restricts horizontal motion at Be window
• Mid-span rod reacts centering load and is
  designed for tension only
• Vertical V spans proton beam port, provides
  lateral restraint and assists with gravity load

• Detector Solenoid (epoxy impregnated, conduction
  cooled)

• Uses spherical-end rods and H-shaped SS mandrels
  like TS

17
Cryostats and Cryogenics
All cryostats have stainless steel vacuum shells
and LN2-cooled thermal radiation shields.

• Production solenoid
• Natural convection/force-cooled with 6700 liter
  LHe volume to safely remove 192 W of nuclear heat
  load at 4.5 K
• 25 cm diameter quench vent stack keeps quench
  pressure below 5 atmospheres
• Transport and detector solenoids
• Lack of nuclear heat load enables conduction
  cooling
• Inner and outer copper shells intercept radiation
  heat load and take it to He-traced copper heat
  sinks at the top of each coil

18
Cryogenic Heat Loads
Supports

8.0


Valves

2.99



Vacuum separators

0.86


Therma
l radiation from 80 K

3.28


High energy radiation

192


Conductor electrical joints (qty 10)

1.24


Current leads


11.2
PS dewar


1.3
GRAND TOTALS

269.31

61.8
19
Cryogenic Flow Diagram

• Current plan is to purchase a new
  refrigerator/liquefier to a spec developed by the
  magnet Vendor.
• System is designed to be flexible and accommodate
  all modes of operation

20
Conclusions on Conceptual Design

• Feasibility has been demonstrated.
• Review (February 2002) was successful.
• Led to further specific industrial studies that
  have been completed to reduce risk.
• Insulation study
• Refrigerator/liquefier study
• Winding and impregnation approach
• Magnet Tech Spec and SOW for procurement is being
  drafted.
• Safety review studies have been initiated at BNL.
• Results from Conceptual Design, Industrial and
  Safety Studies will be integrated into the Magnet
  Technical Specification and SOW for Final Design,
  Manufacturing, Installation and Commissioning.

21
A Few Words about Procurement

• Draft RFP
• Based on draft technical and interface
  requirements.
• Will be used to initiate response from industry
• Contracting terms
• Need for clarification
• Final RFP
• Based on final technical and interface
  requirements
• Clarified technical and contractual requirements.

22
Draft SOW - Overview

• Items furnished by MECO project
• SSC cable
• General Responsibilities of the Vendor
• Deliverables with the proposal
• Final design
• Fabrication
• Installation
• Acceptance test
• Reporting

23
General Responsibilities of the Vendor

• The Vendor shall, unless otherwise noted, furnish
  all labor, materials, equipment and facilities to
  design, fabricate, assemble, install and test the
  MECO magnet system in accordance with the
  SOW/spec document.
• Magnet system conductor, coils, cold structure,
  cryostats, cold-to-warm and warm supports, PS and
  DS iron returns, bus and leads, control dewars,
  power supplies, quench detection and protection
  systems, cryogenic valves and piping, cryostat
  vacuum equipment, instrumentation and controls
• Installation/acceptance test site Brookhaven
  National Laboratory
• The Vendor shall supply all documentation
  required in the specification.

24
Preliminary Magnet WBS
25
PS Magnet WBS (Lower Level Sample)