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This preliminary event report is in compli … This preliminary event report is in compliance with Technical Specification 6.6.2 Special Reports confirming in writing the initial report made by telephone to the USNRC Operations Center.</br>During reactor shutdown after normal steady state operation on May 14, 2013 at 2209 CDT, shim safety 1 jammed at 30% withdrawn (70% inserted). Operators lowered the remaining rods with no other issues and after determining the reactor was shut down at 2250 CDT, operators began investigating the cause of the jam. The shutdown margin in this configuration was determined to be $2.91 (negative reactivity) with shim safety 1 jammed at 30%. The Technical Specification requirement for shutdown margin is $0.25 (negative reactivity) which meant the reactor was well within acceptable limits for shutdown. </br>The reactor was determined to be in a safe shutdown state. During inspection a rope that was attached to an experiment was found to be caught inside the Control Rod Drive Mechanism (CRDM) for shim safety 1 about 10 feet from the surface of the pool. This caused a jam in the drive mechanism not allowing the rod to go below 29% and above 32%. </br>A fuel handling team was assembled at 0945 CDT on 5/15/13 in order to remove the control rod assembly for shim safety 1. The rope connecting the experiment to the CRDM was cut in order to allow proper removal of the CRDM. The CRDM was successfully removed and the piece of rope caught inside the drive was removed. After further inspection of the CRDM no other issues were found and it was reinstalled into its normal position. </br>Operability and scram time tests were performed and completed satisfactory at 1130 CDT. The fuel handling team was disbanded at 1137 CDT and the reactor was determined to be operational. At no point during this event was there any danger to the general public or Nuclear Science Center personnel.ublic or Nuclear Science Center personnel. +
03:09:00, 15 May 2013 +
49,033 +
11:03:00, 15 May 2013 +
03:09:00, 15 May 2013 +
This preliminary event report is in compli … This preliminary event report is in compliance with Technical Specification 6.6.2 Special Reports confirming in writing the initial report made by telephone to the USNRC Operations Center.</br>During reactor shutdown after normal steady state operation on May 14, 2013 at 2209 CDT, shim safety 1 jammed at 30% withdrawn (70% inserted). Operators lowered the remaining rods with no other issues and after determining the reactor was shut down at 2250 CDT, operators began investigating the cause of the jam. The shutdown margin in this configuration was determined to be $2.91 (negative reactivity) with shim safety 1 jammed at 30%. The Technical Specification requirement for shutdown margin is $0.25 (negative reactivity) which meant the reactor was well within acceptable limits for shutdown. </br>The reactor was determined to be in a safe shutdown state. During inspection a rope that was attached to an experiment was found to be caught inside the Control Rod Drive Mechanism (CRDM) for shim safety 1 about 10 feet from the surface of the pool. This caused a jam in the drive mechanism not allowing the rod to go below 29% and above 32%. </br>A fuel handling team was assembled at 0945 CDT on 5/15/13 in order to remove the control rod assembly for shim safety 1. The rope connecting the experiment to the CRDM was cut in order to allow proper removal of the CRDM. The CRDM was successfully removed and the piece of rope caught inside the drive was removed. After further inspection of the CRDM no other issues were found and it was reinstalled into its normal position. </br>Operability and scram time tests were performed and completed satisfactory at 1130 CDT. The fuel handling team was disbanded at 1137 CDT and the reactor was determined to be operational. At no point during this event was there any danger to the general public or Nuclear Science Center personnel.ublic or Nuclear Science Center personnel. +
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00:00:00, 15 May 2013 +
R-83 +
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11:03:00, 15 May 2013 +
0.329 d (7.9 hours, 0.047 weeks, 0.0108 months) +
03:09:00, 15 May 2013 +
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