The Indian Point Energy Center (IPEC), owned and operated by Entergy Nuclear, uses a once-through cooling water configuration to cool its two operating nuclear reactors; this process draws water from the Hudson river via a series of intakes and returns heated water through a common discharge canal back to the river. In support of its license renewal application, IPEC applied for a Water Quality Certification (WQC) under Section 401 of the federal Clean Water Act (CWA), the approval of which is based upon a finding that there are reasonable assurances that its operation is in compliance with applicable New York water quality standards (WQS).
To evaluate compliance RPS was contracted to perform a combination of field program design, data analysis and numerical modeling. The culmination of these efforts was a validated hydrothermal model application which was used to isolate the thermal effects of the IPEC facility within the receiving waters. A worst-case time period based on environmental conditions was identified from analysis of historical data and model was run again with and without plant loading to isolate the thermal plume under extreme conditions.
Mapping of the Thermal Plume from Once Through Cooling of the Nuclear Reactors at Indian Point Energy Center
Entergy Nuclear through Goodwin Proctor LLP
In accordance with the requirements for the New York Water Quality Standards (WQS), the Indian Point Energy Center (IPEC) facility needed to demonstrate the effects of their thermal plume in terms of the size of specific temperature differentials above ambient temperatures. The IPEC facility is located along the Hudson River estuary, and the characteristics of the receiving waters are constantly changing in response to the ebb and flood of the tides, freshwater inputs, and variable thermal structure of the water column. This complex, dynamic setting poses a challenge to defining ambient temperature, since not only is the receiving water influenced by the thermal plume, a point measurement only holds true at is location.
A sophisticated hydrothermal model application was developed using the RPS WQMAP water quality model system component BFHYDRO, which incorporated variable river geometry and bathymetry, tidal, riverine, and meteorological boundary conditions, intake withdrawals, and discharges from the IPEC facility. The model application was first validated against field observations of water level, water velocities, water temperatures, and water salinity at multiple locations. The model was run without plant loading to define the spatially and temporally varying ambient and the differential between the two runs provided the isolated effects of temperature differential from the IPEC facility effluent.