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13_030922_CLN_01.doc

***TO: DISTRIBUTION***

***FROM: C NEUMEYER***

***SUBJECT: TF JOINT INSTRUMENTATION***

The fiber optic signal measurement system available from FISO
Technologies, Inc., is recommended for use on the NSTX TF joint for
temperature, strain, and displacement measurements which will be used to
confirm the analysis and guide in the operation of the NSTX TF system.

The basis for selecting the FISO system is as follows:

1)  The fiber optic measurement technique is immune to magnetic fields
    and can be used in a high voltage environment.

2)  The FISO temperature probe can be supplied in a custom form
    (sheathless) such that the time lag of the measurement is minimized
    to less than 100mS, which is important for NSTX due to the short
    pulse length (600mS flat top time).

3)  Since the FISO signal conditioning system supports a variety of
    transducers (temperature, strain, displacement) it can satisfy all
    of the NSTX measurement requirements using the same modules. This
    avoids the use of multiple types of signal conditioners, and offers
    the flexibility that different transducer types can be plugged into
    the signal conditioning system depending on the type of testing
    underway.

4)  The FISO system is compatible with the NSTX pulse waveform since it
    samples at a fast rate (1kHz) and accepts an external trigger.

5)  The FISO system output is an analog voltage which can be easily
    interfaced to a digitizer and ported into the NSTX MDS data
    acquisition system.

6)  The signal conditioner module set-up and trigger is accomplished via
    an RS-232 port which can be interfaced an RS-232 driver module and
    the NSTX EPICS system.

7)  ORNL has used the FISO system for the SNS project and has commented
    favorably on their experience with same.

The following measurement points are planned:

*Temperature*

There are four unique locations on NSTX for which temperature
measurements close to the flag joint are desirable, namely the inner and
outer layer flags on top of the machine and the same on the bottom. Each
of these locations is unique in terms of flag cooldown via conduction
and convection. And of course the inner and outer layer flags are loaded
differently in terms of current density and pressure across the joint.
Temperature will be FISO type FOT-C. They will be installed in grooves
on the flag edge closest to the midplane of NSTX, prior to application
of flag insulation and potting in the flag boxes. Although detailed
dimensional information still needs to be obtained from the
manufacturer, it is anticipated that a 1/64" groove, 0.4" long,
beginning 1/8" away from the joint, followed by a 1/16" groove extending
to the end of the flag, will be suitable for these probes. FISO will
recommend a suitable epoxy adhesive. See figures 1 and 2.

![](media/image2.jpeg){width="5.084722222222222in"
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*Figure 1 -- Edge View of Grooves in Flag to Accommodate Fiber Optic
Probes*

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*Figure 2 -- Cross Section View of Grooves In Flag*

*(note that centers of 1/16" and 1/64" grooves are aligned)*

*Strain*

It is desirable to measure radial strain near the flag edge closest to
the midplane of NSTX, and axial (z direction) strain at the shear shoe.
To confirm the analysis, both inner and outer flags need to be measured.
For consistency with the temperature measurements these strain
measurements should be made on the same flags as the temperature
measurements, namely the inner and outer layer flags on top of the
machine and the same on the bottom, total four flags.

The radial strain on the flag needs to be measured on both sides of the
flag to properly capture out-of-plane effects. The FISO type FOS gauge
shall be used. The strain range shall be 0 to 2500 μstrain (allowing up
to 30ksi in copper with modulus of 18e6psi). The same groove style as
the temperature probes can be used, except displaced 0.125" from the
sides of the flag to capture the out-of-plane effects (figures 1 and 2).

The same probe type and groove style can be used in a vertical
arrangement on the shear shoe as shown in figure 3. This will allow up
to 50ksi in stainless steel with modulus of 28e6psi. The fiber optic
cable can be routed out along the water cooling line for mechanical
support.

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*Figure 3 -- Grooves for Probe in Shear Shoe*

*Displacement*

The FISO displacement transducer accommodates a 20mm (0.787") linear
stroke. One transducer will be positioned on the top of the machine to
measure the relative axial displacement of the spline w.r.t. the
umbrella cover, which is calculated to be 0.35" maximum.

Four additional displacement transducers will be use to measure the
angular twist of the hub assembly and a flag end w.r.t. the umbrella, on
the top and on the bottom of the machine. If the transducers are
positioned on the umbrella at r=40" and actuated from extension arms
mounted off the rotating elements, then allowing half of the stroke in
either direction the measurable angular twist will be of order 0.55
degrees.

Measurements are summarized in the following table.

  -------------- -------------- -------------- -------------- --------------
  Measurement    Location       Quantity       Range          

  Temperature    Flag Edge      4 x 1 = 4      0-150C         

  Strain         Flag Edge      4 x 2 = 8      0-2500 μStrain 

  Strain         Shear Shoe     4 x 1 = 4      0-2500 μStrain 

  Displacement   Spline         1              0-20mm         

  Displacement   Hub            2 x 1 = 2      0-20mm         

  Displacement   Flag           2 x 1 = 2      0-20mm         
  -------------- -------------- -------------- -------------- --------------

The following equipment will be required.

  ---------- ------------- ---------------------------------- -------- --------
  Quantity   Part \#       Description                        Unit     Total
                                                              Cost     Cost

  1          BUS-CHA       19" rackmount chassis for BUS      3300     3300
                           system channel modules                      

  8          BUS-MOD       BUS system channel module, 1kHz,   2750     22000
                           +/-10V BNC output                           

  4          FOT-C         Custom fiber optic temperature     500      2000
                           probe 0-150C                                

  12         FOT-S         Fiber optic strain gauge,          220      2640
                           temperature compensated, 0-2500             
                           microStrain                                 

  5          FOD           Fiber optic displacement           485      2425
                           transducer, 20mm linear stroke              

  16         CFO-PO3-025   25 m fiber optic extension cable,  100      1600
                           ST connectors                               

  1          BUS-CAS       Carrying Case for BUS System       270      270

                                                                       34235
  ---------- ------------- ---------------------------------- -------- --------

The above 25m extension lengths are based on input from F. Jones as to
the distance required to connect to the instrumentation racks.

Cc:

J Chrzanowski J Dong T Egebo P Heitzenroeder M Kalish

R Marsala G Oliaro M Ono H Schneider A Von Halle

M Williams I Zatz