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Project Profile Details

Emergency Planning

Backup Alert and Notification Systems for Xcel Energy

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Federal requirements (FEMA-REP-10) stipulate that the operators of nuclear power plants in the United States must notify the people within the Emergency Planning Zone (EPZ – circle with an approximate 10-mile radius centered at the plant) in the event of an emergency at the plant in a timely fashion. Most plants use an outdoor siren system to accomplish this objective. In the event of a siren failure, backup alert and notification systems are needed. This project determined the number of backup alerting routes and resources needed to alert the population living within the EPZs of the Monticello and Prairie Island Nuclear Generating Stations in the event of siren failure. The route alerting system is a series of drivable routes by Sub‐Area (smaller division of the EPZ, which typically follows political or geographical boundaries) displayed with maps and turn-by-turn directions.

The Challenge

Both the Monticello and Prairie Island Nuclear Generating Stations have an EPZ exceeding 360 square miles and there are approximately 2,400 miles of roadways within the two EPZs. Each Sub-Area within the EPZ is to have its own set of routes that can be driven by emergency personnel to broadcast an alert to residents, businesses and visitors should a siren fail to function properly.

The design criterion of this project was to develop routes that meet the FEMA requirement of notification within 45 minutes of a siren failure. The routes were to be no more than 30 minutes or 12.5 miles in length. The approximate range of broadcasting equipment was 400 feet. Any private driveway longer than 400 feet also needed to be included in the route design to account for the limited range of the broadcasting equipment. All routes were to be driven at less than 25 miles per hour.

KLD's Approach

Data was provided by Xcel Energy which included a street centerline, EPZ boundary, and driveways. Local municipalities provided parcels and address points to help identify additional houses with driveways longer than 400 feet. The centerline data provided was cross-checked with the most current centerline version from Environmental Systems Research Institute’s (ESRI) for speed, one-way roads and elevation characteristics. Driveways were added to the centerline and their connectivity verified so that they may be used by the routing algorithms.

The basis of the analysis was ESRI’s Network Analyst extension which includes complex logistics algorithms to help determine the number of routes needed for each Sub‐Area. The Vehicle Routing Problem functionality within the Network Analyst was used at the start of the analysis. Each Sub‐Area was processed using the Vehicle Routing Problem which produced the number of routes needed at a minimum to cover the Sub‐Area. Once the routes were created, an analyst reviewed each route and made adjustments where necessary.

Project Results

The project resulted in approximately 340 routes for the two EPZs. A detailed map and written driving directions were generated for each route. Summaries of the routes for each Sub-Area were also provided to Xcel Energy and local municipalities for planning purposes. These summaries included the route length and total travel time for the route to verify that the 45 minute or less criterion was realized.

 Key Words: Nuclear plant, emergency, EPZ, siren


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