NRC May I? An explanation of the nuclear safety implications of 10 CFR 50.59 and its relevance to St. Lucie Unit 2
This blog post by Dave Lochbaum, director of the Nuclear Safety Project with the Union of Concerned Scientists, originally ran on March 4, 2014 in their All Things Nuclear: Insights on Science and Security blog as part of their ongoing Nuclear Energy Activist Toolkit (NEAT) series. Find the original post here.
Mr. Lochbaum’s blog is especially relevant to recent safety concerns that the Southern Alliance for Clean Energy has identified regarding the modifications that were made to the replacement steam generators in FPL’s St. Lucie Unit 2 reactor near Fort Pierce, Florida. The regulation that is discussed below, 10 CFR 50.59, comes into play (and under scrutiny) with St. Lucie Unit 2 as was the case with the now-closed San Onofre Unit 2 and 3 reactors in California, among other nuclear plants across the country. Learn more about our St. Lucie Unit 2 safety concerns here.
NRC May I? Nuclear Energy Activist Toolkit #25
“Mother May I?” is a children’s game. “NRC May I?” is the grown-up version of this game played by owners in determining whether they can modify their nuclear plants or revise its procedures without first obtaining NRC’s permission.
Okay, it’s not called “NRC May I?” The NRC and the nuclear industry call it 10 CFR 50.59, but it is essentially “NRC May I?”
Owners are allowed to modify their plants and revise associated procedures as long as the changes maintain the safety margins and the methods approved by the NRC in establishing those margins.
Section 50.59 to 10 CFR Part 50 governs when owners must obtain prior NRC approval of proposed changes and when they can implement changes on their own. In order to proceed without formal NRC approval, owners must answer “no” to each of the following eight questions:
1. Will the change cause more than a minimal increase in the chances that an accident happens?
2. Will the change cause more than a minimal increase in the consequences from an accident?
3. Will the change cause more than a minimal increase in the chance that safety equipment or structures will malfunction?
4. Will the change cause more than a minimal increase in the consequences from the malfunction of safety equipment or structures?
5. Will the change create a possibility that a new type of accident occurs?
6. Will the change create a possibility that the malfunction of safety equipment or structures causes previously unevaluated outcomes (i.e., the domino effect)?
7. Will the change diminish the integrity of a barrier between fission products and the environment?
8. Does the change rely on evaluation or analytical methods different from those previously used?
How Are These Questions Used?
An example of answering these questions might be a plan to repaint the walls of the control room using a different color. It very likely will be possible to answer “no” to all eight questions. But if the new color comes in a different type of paint that emits toxic chemicals when exposed to 100°F temperature (a condition the control room might experience during postulated accidents), prior NRC approval might be required because the answer to question 4 or question 6 might be “yes.”
Question 8 applies to changes where all the chances and consequences are evaluated to remain within NRC-approved boundaries (i.e., the answers to questions 1-7 are all “no”) but the assessment method differed from the method used when NRC established the boundaries. In other words, if a complex computer analysis was used to show that a safety pump had to provide 5,000 gallons per minute to protect against core damage, an abacus could not be used—without prior NRC approval—to conclude that the pump need only supply 400 gallons per minute and justify replacement with a smaller pump.
“NRC May I?” applies when all eight questions are answered “no” and also when one or more questions is answered “yes.” In the former case, the eight “no” answers mean that the owner may make the proposed change without prior NRC approval. In the latter case, one or more “yes” answers means that the owner must seek the NRC’s written approval before making the change.
NRC inspectors periodically audit samples of 50.59 evaluations performed by owners for changes that resulted in all eight questions being answered “no.” The inspectors are checking whether “no” was the correct answer. They have found dozens of violations of “NRC May I?” regulation in recent years.
“NRC May I?” has a valuable role in preserving the safety levels approved by the NRC without unduly burdening the NRC and plant owners with needless homework for changes clearly having no affect on the safety levels. It allows owners to make changes without prior NRC approval if their evaluation using methods reviewed and approved by the NRC concludes the changes cannot compromise safety levels. It further allows owners to make changes that might compromise safety levels, if the NRC reviews the changes and finds them acceptable.
The dozens of “NRC May I?” violations in recent years is troubling. First, “NRC May I?” has been around for decades and plant owners should be able to play the game fair and square by now. Second, the NRC inspectors only check a tiny sample (less than one percent) of the “NRC May I?” evaluations conducted annually. Thus, each violation they find in the checked pile may represent 99 other violations among the unchecked pile.
“NRC May I?”allows owners to make changes without prior NRC approval as long as their evaluations conclude that safety will not be compromised. When the evaluations are sound, it is a process shortcut. When the evaluations are not sound, it can be a safety shortcut. If owners cannot do a better job achieving sound evaluations, the NRC should consider eliminating the process shortcut option to eliminate safety shortcut outcomes.
–The UCS Nuclear Energy Activist Toolkit (NEAT) is a series of post intended to help citizens understand nuclear technology and the Nuclear Regulatory Commission’s processes for overseeing nuclear plant safety.
About the author: Mr. Lochbaum received a BS in Nuclear Engineering from the University of Tennessee in 1979 and worked as a nuclear engineer in nuclear power plants for 17 years. In 1992, he and a colleague identified a safety problem in a plant where they were working. When their concerns were ignored by the plant manager, the utility, and the Nuclear Regulatory Commission (NRC), they took the issue to Congress. The problem was eventually corrected at the original plant and at plants across the country. Lochbaum joined UCS in 1996 to work on nuclear power safety. He spent a year in 2009-10 working at the NRC Training Center in Tennessee. Areas of expertise: Nuclear power safety, nuclear technology and plant design, regulatory oversight, plant license renewal and decommissioning
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