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Environmental Monitoring Phases information

The purpose of the mandated environmental monitoring programs is to assess the environmental impact from operating nuclear power plants and to determine if there is any public heath concerns due to the operation of the nuclear power plants. In order to determine the environmental and public health concerns the environmental monitoring programs consist of the collection of environmental samples from the air, water and terrestrial exposure pathways.

Pre-operational phase

Pre-operational environmental samples were collected and analyzed for radioactivity. This data provides background information on natural and man-made sources of radiation that are present prior to the construction and operation of the considered nuclear power plants.

The pre-operational data is baseline data for comparison of data collected during the operational phase of the nuclear power plant. Pre-operational data should be collected for at least one year prior to the operation of the monitored nuclear power plant. Pre-operational data was collected for all plants for at least one year except for Zion where pre-operational data was not obtained.

Operational phase

The operational phase of the radiological environmental monitoring program is the ongoing continuation of the pre-operational phase.

The collection of environmental samples is continued from preexisting sampling sites from the per-operational sampling phase. The radiological data is compared to pre-operational data in order to assess the environmental and public health concerns due to the operation of the nuclear power plants and to follow and be aware of any trends in that would indicate increases in radioactivity levels due to the operation of the nuclear power plant.

Kewaunee, Point Beach and Prairie Island are in this phase of environmental monitoring. The La Crosse Boiling Water Reactor ceased operation in August, 1987 and the Zion nuclear power plant ceased operation in February, 1998.

Post-operational phase

The post-operational phase of the radiological environmental monitoring program begins when the nuclear power plant ceases operation.

When the nuclear power plant ceases operation and is shut down for decommissioning, environmental sampling is continued at the preexisting sites used in the pre-operational and the operational phases of the environmental monitoring program. The environmental data continues to be compared to the baseline data from the pre-operational phase and the data from the operational phase. This continues the assessment of any environmental or public health concerns during this final phase of the nuclear power plant.

During the post-operational phase of the environmental monitoring program the number of sampling sites and the frequency of sample collection are often reduced.

The La Crosse Boiling Water Reactor and Zion are presently in this phase of monitoring and the number of sampling sites and the frequency of sample collection have been reduced.

Last revised December 22, 2015