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Title: Causal Analysis of the Inadvertent Contact with an Uncontrolled Electrical Hazardous Energy Source (120 Volts AC)

On September 25, 2013, a Health Physics Technician (HPT) was performing preparations to support a pneumatic transfer from the HFEF Decon Cell to the Room 130 Glovebox in HFEF, per HFEF OI 3165 section 3.5, Field Preparations. This activity involves an HPT setting up and climbing a portable ladder to remove the 14-C meter probe from above ball valve HBV-7. The HPT source checks the meter and probe and then replaces the probe above HBV-7, which is located above Hood ID# 130 HP. At approximately 13:20, while reaching past the HBV-7 valve position indicator switches in an attempt to place the 14-C meter probe in the desired location, the HPT’s left forearm came in contact with one of the three sets of exposed terminals on the valve position indication switches for HBV 7. This resulted in the HPT receiving an electrical shock from a 120 Volt AC source. Upon moving the arm, following the electrical shock, the HPT noticed two exposed electrical connections on a switch. The HPT then notified the HFEF HPT Supervisor, who in turn notified the MFC Radiological Controls Manager and HFEF Operations Manager of the situation. Work was stopped in the area and the hazard wasmore » roped off and posted to prevent access to the hazard. The HPT was escorted by the HPT Supervisor to the MFC Dispensary and then preceded to CFA medical for further evaluation. The individual was evaluated and released without any medical restrictions. Causal Factor (Root Cause) A3B3C01/A5B2C08: - Knowledge based error/Attention was given to wrong issues - Written Communication content LTA, Incomplete/situation not covered The Causal Factor (root cause) was attention being given to the wrong issues during the creation, reviews, verifications, and actual performance of HFEF OI-3165, which covers the need to perform the weekly source check and ensure placement of the probe prior to performing a “rabbit” transfer. This resulted in the hazard not being identified and mitigated in the procedure. Work activities with in HFEF-OI-3165 placed the HPT in proximity of an unmitigated hazard directly resulting in this event. Contributing Factor A3B3C04/A4B5C04: - Knowledge Based Error, LTA Review Based on Assumption That Process Will Not Change - Change Management LTA, Risks/consequences associated with change not adequately reviewed/assessed Prior to the pneumatic system being out of service, the probe and meter were not being source checked together. The source check issue was identified and addressed during the period of time when the system was out of service. The corrective actions for this issue resulted in the requirement that a meter and probe be source checked together as it is intended to be used. This changed the activity and required an HPT to weekly, when in use, remove and install the probe from above HBV-7 to meet the requirement of LRD 15001 Part 5 Article 551.5. Risks and consequences associated with this change were not adequately reviewed or assessed. Failure to identify the hazard associated with this change directly contributed to this event.« less
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Resource Type:
Technical Report
Research Org:
Idaho National Laboratory (INL)
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Country of Publication:
United States
24 POWER TRANSMISSION AND DISTRIBUTION contact; electrical; energy; hazard; identification; shock