Adjacent to the operating Grand Gulf station, is an unfinished concrete structure that was to be the containment for Unit 2, a twin to the existing Unit 1. In December 1979, staggered by construction cost, Entergy stopped work on Unit 2. On September 22, 2005, it was announced that Grand Gulf had been selected as the site for a GE ESBWR reactor. For details, see Nuclear Power 2010 Program. This was to be Unit 3. In 2007, the U.S. Nuclear Regulatory Commission issued an Early Site Permit to Grand Gulf. In 2008, Entergy and NuStart submitted a Combined Construction and Operating License application for a potential new nuclear unit at the Grand Gulf. On January 9, 2009, Entergy indefinitely postponed work towards the license and construction of Unit 3. In September 2015 the NRC withdrew the COL for the ESBWR unit, at the request of Entergy.
Surrounding population
The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of, concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about, concerned primarily with ingestion of food and liquid contaminated by radioactivity. The 2010 U.S. population within of Grand Gulf was 6,572, a decrease of 18.6 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 U.S. population within was 321,400, a decrease of 0.4 percent since 2000. Cities within 50 miles include Port Gibson, Vicksburg. Alcorn State University is 25 miles southwest of the plant.
Seismic risk
The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Grand Gulf was 1 in 83,333, according to an NRC study published in August 2010.
After heavy rains in late April, 2011, workers were pumping standing water that had collected in the abandoned, never-completed Unit 2 turbine building into the Mississippi River. Detectors sounded alarms at the presence of tritium in the water, and the pumping was stopped, and the accidental release was reported to the Mississippi Health Department and to the NRC. As of the dates of the news reports, it was unknown both how much tritium had entered the river, and how the tritium had collected in the standing water, given that Unit 2 was not an operational reactor, and had never been completed. It is unknown how much tritium entered the river, because samples were not taken at the time of the leak. The NRC is investigating to find the source of the leak.
