The NRC has already ordered numerous upgrades to nuclear power plant safety based on what we’ve learned about the Fukushima nuclear incident in 2011. Now, the NRC’s Commission is doing more. They have just approved a two-track approach for additional improvements to systems at 31 U.S. reactors that would vent pressure during accidents.
The Commission’s decision is outlined in a Staff Requirements Memorandum. It provides details about the decision, but this is the bottom line: the NRC will issue an Order requiring stronger venting systems and will use the agency’s rulemaking process to consider the best approach by which these 31 reactors can keep radioactive material from the environment during a severe accident.
Some background: Some of the U.S. reactors that are similar to the Fukushima Dai-ichi plant have vents that reduce pressure during an accident and keep water flowing to the reactor to cool the fuel. The venting systems at Fukushima played a role in their nuclear crisis, and the NRC, last March, issued an Order to the 31 plants with similar designs to take action. The plants either had to install vents or improve their existing venting system. The goal was to make sure the vents can operate during the early phases of an accident, even if the plant lost all power for an extended time.
In their latest decision, the NRC Commission votes to further strengthen these vents. The NRC staff has 60 days to finalize an Order for these enhancements. Generally speaking, these additional requirements mean the vents could handle the pressures, temperatures and radiation levels from a damaged reactor, and that plant personnel could operate the vents under these conditions.
As part of the same decision, the Commissioners directed the staff to begin a formal rulemaking on filtering methods that would prevent radioactive material from escaping containment in an accident, either through new filter systems or a combination of existing systems. The staff will develop the technical analysis, a proposed rule and then a final rule. Throughout this process, the public and various stakeholders will have opportunities to submit comments and attend meetings to ask questions. And there will be many future posts about the progress!