NuMI Target Hall

1
NuMI Target HallAir System Review Introduction

• Air system for cooling target pile
• Requirements
• Provide thermal stability to keep beam components
  aligned
• Prevent materials from overheating
• Provide reasonable pile thermal cool-down time
  for servicing
• Minimize radioactivated air release
  (re-circulating)
• Keep humidity low to reduce corrosion
• What motivated us to adopt air system?
• Cooling must equal beam heating target hall is
  like brick oven
• Air system maintenance items are external to pile
  (as opposed to e.g. cooling coils) so ALARA is
  easier
• Extended volume, many things to cool air is
  reasonably simple
• Where was air system insufficient, and water
  cooling used?
• Horn conductor cooling
• Target fin cooling
• Hanger/clamp from module to horn (and module to
  target carrier)

2
Where does 400 kW ofproton beam energy go?
18 kW in target/horn water cooling
129 kW / 141 kW (L.E. / M.E. focus) in rest of
target pile -gt air system
150 kW / 132 kW in decay
region

60 kW in hadron absorber
(rest of energy in nuclear binding energy, muons,
neutrinos) Used 158 kW in
specification for air system
3
Target Hall Side View Layout
Air Path
4
NuMI Target Hallbeams eye view
HornModule in transit Stripline
Concrete Cover (oops really only
one layer) Carriage - Module
Support Beams Horn Shielding Module
Horn Steel Shielding Air returns down center
of beam-line Concrete Shielding
Top air seal
Air from chiller runs down outside of pile
5
Target Pile Cutaway
6
Target / Baffle componentand its support module
Drive motors
Module
Baffle
Target
T/B Carrier
Coiled water, vacuum lines
7
Horn, stripline, and support module and
target/baffle
Motor drives for transverse and vertical motion
of carrier relative to module
25 cm wide, 2 m deep Steel endwalls with
positioning, water, electric feedthroughs
Target/Baffle Module
Horn 1 Module
Remote Stripline Clamp
Stripline
Baffle
Carrier
Water tank
Target
Horn 1
Target moves relative to carrier for
insertion into horn for Low Energy beam, and back
for Semi-Medium Energy beam
8
Target Hall Layout
Drop-shaft from surface power supply
RAW water
for horn utility room
Compressor
target pile re-circulating air cooling system
Cooling coils
pre-target beamline
target hall drop hatch to
pre-target
hot work cell
9
Target HallClosed Loop Air Conditioning
Blower Duct Sight riser
Plan View
26,000 cfm air flow 240 kW of cooling for
spec. 158 kW beam heating of pile 18 mph wind in
beam channel
27 ft
Filters Survey hole in duct for sight riser
Chiller coils
Side Views
10
Thermal Stability Concept
11
Air-flow down module wallkeeps module end-wall
cool
Air flow supply T-block shielding Module
end-wall Stripline Air flow return Horn Shower
from one beam proton
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Air Cooling System
Thermal model of horn 1 module end-plate in
target pile (left half of symmetric target
hall) Closed loop air recirculating system Cool
air flow upstream on outside of pile Then
downstream inside target chase Module at
comfortable 66 deg C Module motors less than 40
deg C
13
But thermal stability motivatedwater-cooled horn
clamps
Horn vertical centerline
14
Horn Power Stripline Cooling- air is sufficient
Aluminum stripline reaches 100 deg C with air
at 13 deg C
15
Rest of items in beam spray

• Have also checked (or designed such) that air
  cooling is sufficient for
• Horn alignment cross hair
• Target carrier rails, frame
• Target casing (requires He fill instead of
  vacuum)
• Baffle
• Decay pipe window
• Have not checked
• BLM for horn cross hair system
• but believe this will be OK,
• (only used occasionally at low
  intensity, could be removed for hot runs)

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Purpose of review
This is the final review of the air system before
ordering compressor, chiller coils, filter
bank, blower, controls, instrumentation,
etc. The primary purpose of this review is to
catch any mistakes in the engineering design of
the air system. The secondary purpose is to
communicate the design to other stakeholders who
may have integration issues. Radiation issues
are being separately reviewed, and are not really
in the scope of todays review.