05000331/FIN-2009005-03
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Finding | |
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| Title | Failure to Comply with Technical Specification and Diving Survey Requirements During Work In The Torus Resulted In Unnecessary Radiation Exposure |
| Description | A self-revealed finding of very low safety significance and an associated NCV of Technical Specification 5.4.1(a) was identified for the failure to comply with the requirements of the Diving Operation within Radiological Areas procedure during torus underwater diving operations on February 17, 2009. Specifically, two divers entered the water in the torus bay no.7 to perform wall coating repairs. Dives were performed approximately 10 feet from the water surface. The diving was monitored by two tenders and two health physics (HP) technicians. The HP technicians provided continuous coverage and monitored activities through a Teleview system that continuously monitored the divers electronic dosimetry (ED). At approximately 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> into the dive, the senior HP technician glanced at the Teleview monitor and discovered that an accumulated dose alarm condition had occurred several minutes earlier for a three-minute duration on one of the divers. This resulted in one diver receiving an accumulated dose of 133 millirem (mrem). Both divers were ordered out of the water and were subsequently surveyed and were found free of contamination. The licensee failed to recognize the radiological impact of various operational activities on dive conditions, which introduced discrete radioactive particles (DRPs) into the torus water. Drain down of the reactor cavity and the torus spray header along with the storage of contaminated filters in the torus all contributed to the presence of DRPs. Although underwater radiation surveys were performed shiftly by the radiation protection (RP) staff, these surveys were limited to the immediate dive area. Surveys were not sufficiently comprehensive or timely, as required by the licensees procedure, to ensure that changes in radiological conditions were identified to maintain diver dose as-low-asreasonably- achievable (ALARA). Sufficiently comprehensive surveys of the torus were last performed four-days prior to the February 17th incident. As a result, one of the torus divers encountered radiation levels greater than expected and received additional unanticipated dose. The licensees corrective actions included counseling of the involved diving crew and conducting a stand-down with the dive crew to reinforce radiological requirements along with communication expectations such as notifying RP supervisors of any reported plant operations that may affect radiological conditions prior to the start of diving activities. The licensee had completed an extent of condition evaluation and formulated additional actions to prevent recurrence. The finding was more than minor because it was associated with the program and process attribute of the Occupational Radiation Safety Cornerstone and affected adversely the cornerstone objective of ensuring adequate protection of worker health and safety from exposure to radiation, in that, access into underwater high radiation areas whose radiological conditions were unknown placed the divers at risk for unnecessary radiation exposure. The finding was determined to be of very low safety-significance because it was not an ALARA planning issue, there was no overexposure or substantial potential for an overexposure, and the licensees ability to assess worker dose was not compromised. The finding involved a cross-cutting aspect in the area of human performance related to decision making, in that, the licensee did not use conservative assumptions in its decision making to ensure that the torus diving activity was radiologically safe. Specifically, the licensee did not perform underwater dose surveys that were sufficiently thorough to provide an accurate characterization of the radiological conditions. (H.1.b |
| Site: | Duane Arnold  |
|---|---|
| Report | IR 05000331/2009005 Section 2OS1 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | NCV: Green |
| cornerstone | Or Safety |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71121.01 |
| Inspectors (proximate) | K Riemer R Orlikowski R Baker T Go R Russell C Scott R Murray M Audrain D Mcneil |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Duane Arnold - IR 05000331/2009005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Duane Arnold) @ 2009Q4
Self-Identified List (Duane Arnold)
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