HOUSTON, March 19 The U.S. Nuclear Regulatory
Commission (NRC) on Tuesday voted to delay 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
upgrades, according to an NRC memo posted on its website.
The commission's memo also enhances a March 2012 order
requiring "hardened" venting systems at 31 boiling-water
reactors with Mark I and Mark II containments.
But the action falls short of calling for operators to
install filters able to retain radioactive material during
severe accidents. The NRC memo also lays out a rule-making
process to further study the issue.
In January, the NRC staff recommended that filters be
The venting changes are in response to lessons learned from
the 2011 Fukushima nuclear disaster in Japan.