Background: Last April, President Donald Trump signed Executive Order 14270, “Zero-Based Regulatory Budgeting to Unleash American Energy,” which called for the NRC to issue a sunset rule to effectively nullify certain regulations within no more than five years. In response, the NRC inserted conditional sunset dates into several regulations it considered to be obsolete. Of these, the rule that attracted the most attention was 10 CFR 50.150, an aircraft impact assessment rule that required reactor applicants to perform a design-specific assessment to show that a reactor core would maintain cooling or containment would remain intact in the event of a large commercial aircraft impacting the facility.
The comments: Several comments came in regarding the aircraft impact assessment rule, including six submissions that the NRC deemed significant and adverse enough to warrant additional scrutiny. In January, the NRC withdrew the amendment to add a conditional sunset date to 10 CFR 50.150; the other rules in question proceeded with sunsetting as planned.
Among the concerns deemed significant and adverse was that adequate protection would not be maintained if the rule was eliminated. NRC staff countered that 10 CFR 50.150 was never considered necessary to maintain the safety of nuclear power facilities in the event of an airborne threat.
“When that rule was promulgated [in 2009], it was viewed as a safety enhancement but not a safety necessity,” Jeremy Groom, acting director of the NRC’s Office of Nuclear Reactor Regulation, told Nuclear News. “It wasn't a requirement that had to be imposed for adequate protection.”
Among the other issues raised in the public comments were concerns that the move seemingly shifted responsibility to another rule, combining potential commercial aircraft impacts and resulting fires and explosions with impacts from “natural phenomena.” The NRC, however, disagreed with this comment and argued that rule covered much more than just natural events.
2009 vs. 2026: When the aircraft assessment rule was adopted in 2009, the U.S. nuclear power industry was in a different place. Most of the attention was on large light water reactor designs, and utilities were reluctant to commit to building new reactors.
But as noted by Groom and the final rule, things have changed. The NRC has received numerous construction permits and combined license applications, with additional interest from applicants and preapplicants for construction permit, operating license, and combined license applications. Furthermore, the interest in reactors has shifted toward small modular reactors and advanced non-LWRs—options that may require different safety and security needs.
“With the new landscape being a lot of vendors looking at a lot of new reactors, you have to look at the cumulative effect of that rule, and it just doesn't outweigh the cost anymore,” Groom said. “The enhancement doesn't outweigh the cost.”
Meanwhile, airports and aircraft have beefed up security measures to the extent that “the extreme scenarios that were envisioned as part of aircraft impact assessment rule really aren't the same as what they were 20-plus years ago,” Groom said.
