"In their letter, the senators note that the proposed rule would make it easier for nuclear power plants to obtain exemptions for safety, security and financial protections," Senator Ed Markey said in a press release.
Senators Bernie Sanders, Kirsten Gillibrand, and Kamala Harris also signed the letter.
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Ten US nuclear power plants have announced plans to begin decommissioning between 2019 and 2050, the release noted.
"The rule contains proposed changes to emergency preparedness, physical security, cyber security, funding assurance, financial protection requirements, and environmental considerations… the proposed rule would limit the opportunity for the general public to… express concerns about the decommissioning process," the release said.
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The proposed rule also fails to adequately address concerns over the long-term storage of spent nuclear fuel, as well as reduces the financial protections, especially in case of an accident, which could leave taxpayers and communities liable for millions of dollars, the release added.