From: Arthur W. Brooks
Sent: Tuesday, May 03, 2005 10:37 AM
To: Geoffrey J. Gettelfinger
Cc: Wayne T. Reiersen
Subject: Eddy Currents in Base Support

Geoff,

I took a look at the time constants for the base support structure. The loops formed by the 8" SS box beams (3/8" wall) should have time constants less than 5 ms (comparable to the VV). However, I believe we should still be adapting the ALARA philosophy when it comes to breaking up potential loops. I see that the ProE Models of the Base Support Structure already show insulated breaks in these loops. Unless there is a strong motivation for not doing so (ie prohibitive cost) we should avoid loops wherever possible.

Art