Thirty years of nuclear safety regulation are on the table.
That’s what Nuclear Regulatory Commission members signaled May 12 during their first briefing from the nuclear safety task force looking at US nuclear plants in the wake of Japan’s Fukushima disaster.
The years right after the 1979 accident at Three Mile Island-2 saw a frenzy of regulation to cover the gaping safety holes made evident by TMI. The years since have been occupied with efforts to rationalize – or, according to nuclear opponents, water down – much of that frenzy.
But in light of Fukushima, NRC commissioners have signaled they will reconsider virtually everything from the last 30 years. And that signals uncertainty, and potential expense, for the nuclear industry.
Perhaps the biggest item raised: the backfit rule.
NRC Chairman Gregory Jaczko signaled he is concerned the current rule can “hinder” NRC. Are costs and benefits being properly accounted for, or is the analysis preventing “the right kind of backfits,” he asked.
The backfit rule was the first brake on the TMI frenzy, passed in 1985 and rewritten after a court battle to specify that it didn’t apply to rules required to ensure “adequate protection” of public health. It was among Reagan-era initiatives to limit federal regulations. The rule says a regulation’s costs should not outweigh its benefits without a proven safety need, and so a cost-benefit analysis is undertaken for all proposed rules.
Cost-benefit isn’t a last-minute test – it’s part of the NRC staff’s process for writing rules. Ideas that don’t meet the test up front have little chance of getting to first base. Over the years, the rule has been key in blocking or reshaping a lot of bright regulatory ideas that would cost operators a bundle but couldn’t be proven to provide commensurate safety benefits.
It has fed into an increasing use of probabilistic risk assessment – an engineering analysis approach that tries to determine what parts or processes in a complex plant are most likely to cause problems, so those vulnerabilities can be fixed. In the last decade, NRC has embraced a “risk-informed” regulatory approach, aimed at focusing attention and resources on the areas most crucial to safety.
But all risk and cost-benefit calculations are based on probabilities. How much damage is an accident likely to do, what would that likely cost, and what’s it worth spending to avoid the likelihood of an accident? If an event is very unlikely, there’s little benefit to spending a lot to avoid it. That applies even if an accident would mean extensive damage and expense if it happened. Since it probably won’t happen, the calculation says put the money elsewhere. It’s the same calculation we all make when deciding when deciding how much insurance to buy – what’s risky enough that we’d pay to avoid it? What’s rare enough that we’ll take our chances?
At the May 12 meeting, Jaczko asked how the monetary costs of cleaning up the region around a plant after contamination from a severe accident should be included in the cost-benefit calculations. Clean-up costs can easily be figured to amount to billions, depending on key assumptions like how many people live in affected areas and how much land is contaminated – look at the wide-ranging cost estimates for impacts from last year’s Gulf oil spill. Nuclear accident costs include theoretical health effects to exposed individuals and compensation to residents and businesses if their land is made temporarily unusable, as is happening now at Fukushima.
Till now, such scenarios were low enough probability that they didn’t add much to the “benefit” side of the cost-benefit analysis. But Jaczko’s question suggests NRC could reconsider that calculation. Throw in a higher probability due to what’s actually happening at Fukushima, hike up some assumptions about how many people are affected, increase the potential radiation escaping, and you can get a “benefit” of avoiding an accident that can justify nearly any spending.
And Fukushima is forcing NRC to reconsider some pretty pricy decisions, like hydrogen control and use of spent fuel pools.
After TMI, where a hydrogen explosion did occur but did no damage to containment, NRC ordered control measures at all plants. But some of those measures proved costly to maintain, and in the last 20 years, plant operators have used the low likelihood of such explosions to argue, successfully, that some control equipment isn’t needed.
At Fukushima Daiichi, four reactor buildings were badly damaged by hydrogen detonations, and one or more containments may have been breached.
After the 9/11 attacks, NRC considered ordering older spent fuel out of the fuel pools and into dry casks, which can be stored outside, away from the plant proper, to reduce the amount of fuel at risk. The industry successfully argued that the additional cost of casks wasn’t worth changing NRC policy, which now allows more used fuel to be crammed into the pools.
Moreover, spent fuel pools are deep and it takes days for their shielding water to boil off. NRC hasn’t analyzed for accidents that take days to regain control, so the pools aren’t part of most accident scenarios. Their radioactive load isn’t considered when engineers figure how much material can leak out of a nuclear plant.
At Fukushima, the pools did run low and their spent fuel is believed to have leaked radioactive material to the atmosphere.
Assumptions about that radioactive load will also rise as NRC reconsiders potential releases from more than one reactor on a site. Till now, NRC has assumed no more than one unit would be in trouble at a time. At Fukushima, all six units were disabled at once.
And commissioners are even questioning the historic structure of NRC’s regulation, which is divided between “design basis” events – the challenges any plant has to withstand – and “beyond design basis” events, which might happen but are, in principle, too rare to spend much effort on. The Fukushima earthquake and tsunami both qualified as beyond design basis, and they hit the site an hour apart. That has commissioners asking what meaning that distinction has, whether the current “design basis” is what it should be, and whether beyond-design-basis measures should be left to cooperative industry initiatives, as much of it has been, or written into regulation.
Commissioners are questioning the fundamentals of NRC’s regulatory approach, and whether its last three decades’ evolution has been in the right direction.
Fukushima shows the worst can happen. Nothing is sacred.