Analysts fear that a long shutdown could hurt the economy.
And the groups argue that a long shutdown would not be necessary.
The government was closed for six days, the longest shutdown in history.
Incidents like that have led to long shutdowns at other plants.
Today it becomes the longest shutdown in professional sports history.
Northeast Utilities had fought to bring the plant back on line after a long shutdown for safety issues.
The longest shutdown was the players' 50-day strike in 1981.
Experts disagree on what the effect will be if there is a long shutdown.
Four others have been restarted after long shutdowns since 1985.
A long shutdown, however, would cause problems in the summer, when demand for electricity is much higher.