This morning Don Jackson commented to Grant Minor that he believed the tank lid was still not raised high enough to safely operate the Remote Handling bridge and trolleys, despite it having been raised 0.5" yesterday to the point of engaging the limit switches (see e-log from yesterday).  Don said he believed this to be the case as a result of a visual inspection with binoculars from the outside of the tank, as well as from the views achievable with the remote cameras.

Don also believed he had caused further damage to the equipment inside the tank by orbiting with the bridge.

After a teleconference with Klaus Reiniger after lunch (Yuri Bylinski, Dan Louie, Don Jackson, Grant Minor present), the following was confirmed:

• There is a complete set of limit switches at station 1, and duplicate set at station 10 for redundancy.
• Both stations 1 and 10 have an operator upper limit switch, as well as an over-travel limit set slightly higher than the upper limit.
• The lid has traditionally been raised to the point of the upper limit switch tripping, then the lift procedure stops there.
• The wooden stick was traditionally set to just touch the roof beams with the lid at the upper limit.  This means if the stick is contacting the roof beams within 1/32nd inch or so and the upper limit trips, the lid has been raised fully.
• Klaus could only remember one incident of the lid being raised so high before tripping the upper limit that the wooden stick actually bowed under pressure from the roof beams.  In other words, this was not a normal occurrence.
• Klaus also reminded us that the limit switches have some mechanical hysteresis and need to be actuated through their full range of motion to reset them.

Don Jackson indicated that another 1/4" of clearance would be adequate to safely operate the RH equipment in his opinion.

At around 5pm Grant Minor and Ron Kuramoto reset the upper limit switches at both stations 1 and 10 by adjusting the block that both upper limit and over-travel are mounted to, see attached photos.

• A line was scribed in the primer paint to mark the original position of the limit switch mounting block.
• The bolt was loosened, and the block was raised fully to reset the switches, and then set 1/4" higher than the scribed line, measured with a Starrett scale accurate within about 1/64"
• The bolt was re-tightened.

Dan Louie and a shift operator reset the wooden stick 1/4" lower than the roof beams, this was double checked by Grant.

Dan Louie started up the system and confirmed the limit switches were properly reset.  He then raised the lid until the limit switches tripped again, confirmed by checking the illumination of the upper limit lamp (see attached photo).

After the raising of the lid, the wooden stick was confirmed to be contacting the roof beams by Grant Minor.

Dan Louie also confirmed that the master synchro counter had advanced almost exactly 250 counts (proportional to about 250 thousands of an inch).

Mechanical counter readings at each station (where accessible) were taken before and after this 1/4" rise by Dan Wright and Grant Minor:

Grant Minor had dosimeter 208 today, which was signed out at 0.61 mSv and signed in at 0.69 mSv.  Thus elevating system assessments and adjustments resulted in approximately 0.08 mSv dose.