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Laguna Verde is a two-unit boiling water reactor (BWR) plant in Mexico. Following prior chemical decontaminations to reduce plant dose rates, the plant experienced rapid recontamination of reactor recirculation piping. This is a common observation at BWRs, and is related to legacy source term within the system (primarily in the fuel crud), which gets redistributed and deposited on plant piping.

In response to this operating experience, Comisión Federal de Electricidad (CFE), the state-owned electric utility that operates Laguna Verde plant implemented a dose excellence plan to reduce dose rates at the site. This plan included repeating chemical decontaminations, this time in conjunction with high efficiency ultrasonic fuel cleaning (HE-UFC^TM) to reduce the source term and LT-ZiP^TM to passivate the piping. Both HE-UFC^TM and LT-ZiP^TM help to protect against recontamination following chemical decontamination, and the decision to include these activities was based on favorable operating experience at US BWRs.

These collective activities reduced plant dose rates by a factor of 10 or more, and HE-UFC^TM was effective in removing more than 10,000 Ci of legacy crud activity from both units. LT-ZiP^TM effectively deposited zinc and platinum on recirculation piping after chemical decontamination and prior to plant restart. Dose rates have remained low during subsequent operation, indicating that the combination of LT-ZiP^TM and HE-UFC^TM have been effective in preserving the benefit of chemical decontamination and avoiding rapid recontamination as has been observed in the past at Laguna Verde.