Fuel Pool Decontamination Project, Unplanned Exposure, West Valley, United States of America

For the specific case in question, the following actions were carried out: – Strengthened hazard evaluation and monitoring to ensure that hazards were adequately re-evaluated when changes in anticipated conditions were encountered (e.g. changes in pool water clarity, and discovery of components with design features that accumulated pool sediments); – Only allowed use of low pressure spray to rinse (not decontaminate) components to minimize modes for transport of contaminated water; – Ensured that all decontamination was performed underwater; – Specified the use of respiratory protection for activities where pool water was disturbed (e.g. sparging, spraying and equipment removal), unless a thorough review was conducted prior to the activity, which indicated that such respiratory protection was not necessary. In general, changes in environmental conditions that may change the associated hazards were not always readily recognized. In this case, historical data from sample results, previous work performed and expected working conditions were relied upon to prepare the work document. Consideration was not given to the changing water chemistry and the likelihood of contamination in suspension from sediments on components being lifted from the pool. As a result, there was no clear requirement included in the work document mandating that equipment requiring decontamination or the removal of sediment be performed only underwater. Performing this activity underwater would have minimized the spread of airborne contamination. In addition to performing characterization of environmental conditions where there is potential for the spread of airborne contamination, identifying specific criteria and directions for performing activities in these areas should prevent such an occurrence