The U.S. Nuclear Regulatory Commission has delayed a decision to order operators of more than two dozen older nuclear plants to install filtered vents as part of the agency’s post-Fukushima safety review, according to an NRC memo posted on its website.
The commission moved forward with an order requiring operators at 31 boiling-water reactors with Mark I and Mark II containments — similar to the Fukushima Daiichi design — to modify or install “hardened vents” to more effectively and safely release excessive containment pressure after a serious accident.
But the commission’s action Tuesday fell short of requiring operators to install so-called “filtered” vents able to retain radioactive material during severe accidents as recommended by NRC staff.
The NRC instead will hold a lengthy rule-making process to further study filter options and to develop a final rule by March 2017, six years after reactors at Fukushima were damaged by an earthquake and tsunami.
In January, the NRC staff recommended that filters be installed with the vents while the nuclear industry presented less costly proposals.
The inability of operators to open vents at the Fukushima plant led to damaging hydrogen explosions.
NRC Chairwoman Allison Macfarlane said her decision reflected a trip to the devastated Fukushima Daiichi plant and the surrounding area.
Rep. Edward J. Markey (D-Mass.) and nuclear industry critic, said the NRC “abdicated its responsibility to ensure public health and safety” by delaying a decision on use of filtered vents for several years.
Markey has long called for the NRC to endorse its own technical staff’s work and to quickly adopt all recommendations made by the agency’s Near Term Task Force on Fukushima, including the use of filtered vents that would work in a severe nuclear accident situations.
“Instead of following its top experts’ safety recommendations, it chose to grant the nuclear power industry’s requests for more studies and more delays, and even after the study is completed there is still no guarantee that the NRC will ever make this common sense requirement mandatory,” Markey said.