What is it with the Yellow "Radioactive Waste" Barrels?

Recently, @malacodeed (aerospace engineer based in Denmark) asked me to post a thread covering the risks posed by radioactive wastes in the context of chemical wastes and such:

Ms. Deed @MalacoDeed

Hey, @Mining_Atoms, people are always talking about the dangers of nuclear waste etc. Could you make a thread about other industries and their dangerous chemicals and partial steps that would be disastrous if they were to escape, and how that release is controlled and mitigated?

Here’s my attempt. I apologize for the length but the topic deserves quite a lot of context. I’ve spent my nearly 30-year legal career working through risk and regulatory issues in both EPA and NRC programs. Usually these fields are highly compartmentalized. This thread breaks down the compartments.

Human and environmental risk assessment hinges on the concept of Exposure Pathway, starting from a release and ending with somebody being exposed to a contaminant. This is common sense.

An exposure pathway requires several links that must be present for harm to occur. There must be an uncontrolled release that ends up physically connecting to human beings or other receptors.

But if one of the elements of the pathway is broken, then there is no harm. It turns out that natural radon was collecting in my basement so we installed a sub-slab pump that discharges radon above the roof of my house. The radon is still under my house but we interrupted the exposure pathway. Hence, a primary focus of environmental management is breaking or preventing exposure pathways, both for the present time and the future.

At this point I would draw distinctions between accidental or legacy releases that have already occurred (say in an old mining district), and pre-planned waste management such as landfilling, incineration, re-injection. In all cases, exposure pathways are at the heart of the matter.

Prospector Square, Park City, Utah

In the 1970s, real estate developers in the Park City, Utah (2002 Winter Olympics) area built a large residential and commercial development literally on top of an enormous impoundment of mill tailings from mining operations in the Park City Mining District. Mill tailings had elevated levels of metals such as lead, arsenic, and zinc, with associated toxic and carcinogenic risks. Actual image - mill tailings in a residential area.

The U.S. Superfund law was enacted in 1980. EPA targeted Prospector Square for listing on the National Priorities List for a major response action and pandemonium ensued. Property values plummeted. After years of study and debate, EPA agreed to refrain from further actions, in part, based on Park City’s adoption of a municipal ordinance that imposed rather modest landscaping controls (6” clean cover) to break the exposure pathway. After a while, everything normalized; loans were approved; property values went back up. Everybody recognized that, as a practical matter, it did not require much to break the exposure pathway for residential occupants. The fact that the area is under snow all winter helped. The broken exposure pathway was the key to the solution.

Midvale Slag Becomes Bingham Junction

In the center of Salt Lake Valley, there was a large mill (Sharon Steel) and smelter (Midvale Slag). The Midvale Slag site was some 446 acres and EPA listed it on the National Priorities List. It was considered to be one of the most polluted sites in the USA. It looked like the surface of the moon. Among other issues, the old smelter produced lots of arsenic. Shallow groundwater has lethal arsenic levels.

Yet today, Bingham Junction is some of the most valuable real estate in the Salt Lake Valley—thousands of people live there safely. It turns out that solving the problems was quite simple. The contaminated surface was re-graded a bit; slag was spread out and compacted; and a final cover soil was installed. Groundwater wells were prohibited. The exposure pathways were broken with reasonable controls. People are safe today and will be safe in the future.

Unlike Prospector Square, stakeholders had plenty of time to plan in ahead how to redevelop the site. No homes were to be built directly in dangerous wastes. Deep utilities were carefully managed through the city. Midvale City adopted a comprehensive municipal ordinance implementing the institutional controls. It was a classic win-win scenario. Contamination is covered; people are safe. Again, breaking the exposure pathway was the key.

Waste Disposal - Break the Exposure Pathway; Monitor; Enforce.

Elementary solid waste management is nothing more than an engineering exercise designed to break the very first exposure pathway (an uncontrolled release into the environment). To do this, engineered landfill cells (liners, leachate collection, and leak detection-monitoring) are used to protect against releases via the groundwater pathway. Final covers protect against surface water infiltration and other pathways (such as air). Other controls include siting, environmental controls, planning and zoning, and so forth to protect against future land uses that may be incompatible. The entire paradigm is about managing exposure pathways.

We should all be familiar with municipal solid waste (MSW). In the USA, EPA regulations govern its management and disposal. MSW landfill cells are single lined. Groundwater is monitored. Waste is compacted and covered daily. Landfills are highly engineered and exposure pathways pre-emptively broken.

More Risk = More Engineering Controls

In waste disposal, the higher the risks, the more engineering controls that are required and vice versa. Inert waste (e.g. construction and demolition debris) poses low risk to groundwater. Usually, no liner is required. On the other extreme, hazardous wastes present unique risks to groundwater. A single liner is not enough. EPA regulations require a double liner system with leak detection between the first and second liner. Hazardous waste generation, storage, and transportation are more stringently regulated than solid waste.

One notable exception to the idea that higher risks should be addressed through engineering controls is California, where regulators love solar panels so much that there is no way for waste solar panels to present any risks—recyclers are apparently grinding them up for sale as sand and other consumer products. Welcome to Prospector Square California:

Waste Solar Panels: Toxic Goo or Paydirt? Part 1

Post-Closure Monitoring & Care

The requirement of long-term post-closure monitoring and compliance is a critical requirement aimed at ensuring that landfills continue to perform as designed (to contain wastes) over time. For EPA’s programs, this period is 30 years and it is built into the permit. Applicants must post enough funding from the beginning to cover all the costs of post-closure monitoring and care. Usually, funding assumes some level of post-closure corrective action.

For example, this webpage goes into some detail about EPA’s requirements for post-closure for hazardous waste landfills.

Radioactive Waste Disposal

Radioactive waste management is not much different than the way the EPA manages solid and hazardous waste disposal. In the USA, the relevant federal agency is the Nuclear Regulatory Commission (NRC). The NRC’s program distinguishes between low-level waste (LLW) and high-level waste (HLW).

Let’s start with LLW. The NRC uses the A-B-C classification paradigm for LLW but other agencies use different approaches. I find this presentation about classification to be particularly useful.

The International Atomic Energy Assocoation uses what I see as a more pragmatic program than the NRC version, but they are substantially the same. It is a continuum of required engineering controls based on the risks the wastes pose.

In the NRC LLW paradigm, LLW is measured in concentration (curies per cubic meter). The engineering controls are more rigorous for Class B and C waste than for A. But generally speaking, A waste is decayed away by 100 years; B by 250; and C by 500 years. If you ever need some light reading from the NRC, here’s a link. Dr. Ruzic’s lecture on LLW is especially informative.

It is worth pointing out that the NRC’s post-closure monitoring care and maintenance requirements are more than 300% more conservative than EPA’s. The NRC requires 100 years of post-closure monitoring and institutional controls, bonded, as a condition of licensing. But the NRC’s 100-year post-closure requirement, some states go well beyond. Both Texas and Utah impose perpetual care funding requirements for low-level waste disposal.

How Much Risk is Acceptable?

There is no completely safe dose of any genotoxic carcinogen. Yet, rational people all around the world recognize that it is not feasible to totally eliminate all exposures to known or suspected carcinogens. Ever wonder how EPA determines if your tap water is safe to drink? Or how OSHA determines whether it’s safe enough to work in a chemical plant or mine? If you think it’s because drinking tap water or brseathing silica dust will never make you sick, you’d be mistaken. Governments make policy decisions for you about how much risk is acceptable.

Just focusing on the EPA construct for cancer risks, the EPA has determined that if an exposure gives you a risk of excess cancer greater than 1 in 10k, the risk is unacceptable, but risks above this level may still be acceptable.

All EPA programs—from drinking water maximum contaminant levels, to air pollution exposures, to cleanup of contaminated sites like Prospector Square and Midvale Slag—all programs are based on the EPA's excess cancer risk standard.

Occupational risks are the same. While the excess risk from low exposures to carcinogens may be small, it is generally presumed to be greater than zero. In the workplace, some target or acceptable risk level is needed for purposes of establishing occupational exposure limits for carcinogens. Target risk levels in the general population are usually set quite low, in the range of 1 in 10,000 to 1 in 1 million lifetime excess risk of cancer.

Governments are responsible for setting acceptable risks.

A review of international policies for developing occupational exposure limits for carcinogens reveals a range of acceptable lifetime excess risks of up to 4 in 1000 (Netherlands) to 1 in 100,000 (Sweden).

No Risk for Thee

When it comes to determining how much risk may be acceptable, this is where EPA and the NRC diverge, with the NRC being orders of magnitude more conservative. The problem I see is that the people setting acceptable public risk from exposures to genotoxic carcinogens never had a conversation with the people setting acceptable public risks for radioactive materials. For the latter, the only acceptable risk appears to be 0.

For context, consider these three lectures:

First—

Second—

Third—

The NRC has adopted a uniform maximum public dose limit for any kind of license it provides, be it a nuclear reactor, a uranium mill, or a waste disposal facility. The standard is 100 mrem dose above background at the licensed facility fence.

The public dose limit is not related to the risk of excess lifetime cancers. Workers inside licensed facilities can receive an annual occupational dose of 5,000 mrem, which is considered safe under occupational risk assessment standards.

Waste Control Specialists (WCS) in Texas, for instance, manages A, B, and C wastes. It reports that its radiological workers (inside the restricted area) receive an average of 8% of the safe worker dose (5k mrem), while its non-rad workers receive just 10 mrem.

What about High Level Waste?

As an initial matter, a material is a waste only after its owner decides to dispose of it. When most people hear “nuclear waste,” they usually think of high level waste or, more specifically, spent nuclear fuel or SNF. This is what’s left after low-enriched uranium fuel has gone through a single cycle in a light water reactor. Burnup rates are low - over 90% of the thermal value in the fissile and fissionable material remains in the SNF, but the fuel assemblies no longer meet specs and must be remanufactured-reprocessed-recycled before being used as fuel in a fast-spectrum reactor. Russia is doing this today. We could be doing this too except the Clinton-Gore Administration needed to save taxpayers from this technology so we could have windmills dotting the landscape today making garbage power instead of burning SNF in fast-spectrum reactors.

The Invisible Lobby Hates This Idea

Until the USA can figure out how to catch up with Russia and burn up SNF for energy, somebody needs to manage the material.

I have read scores of Twitter comments regarding radioactive waste. Few acknowledge the existence of any regulatory program at all, much less a program as robust as the one imposed by the NRC and other agencies. They would rather post images of rusty, leaky yellow barrels of toxic goo.

The ones that do acknowledge the existence of a regulatory program seem to minimize it. This is likely out of ignorance. Let’s take a closer look.

Possession of SNF requires a license from the NRC. There are some 75 NRC licensees throughout the USA that are permitted to store SNF. Each license requires many things, including surveillance and radiation monitoring at the boundary. Based on the 100 mrem standard, none of the NRC’s licensed facilities has exceeded this limit, even one time, based on continuous monitoring since 1986.

The NRC offers two categories of licenses for the storage of SNF in approved dry casks: Specific and general. The general license is quite a bit more simple than a specific license. Even so, the NRC estimates that the regulatory process to qualify for a general license will require about 200 staff-months. Specific licenses are more complex.

The next time you see a discussion regarding nuclear waste or dry cask storage, you may want to reference this FAQ page from the NRC. It is almost certain to include relevant, factual information. This is a program that the NRC takes seriously and it shows. Some people say that the NRC engages in industry-warping overkill regulatory practices. It’s too bad that most people seem to think that radioactive waste is like the Wild West. Midnight dump the nasty barrels and head out of town.

Finally, Dr. Ruzic's lecture on HLW is worth watching if you've not seen it before:

Conclusions

1. When it comes to exposures to genotoxic carcinogens, people readily recognize that it is not feasible to totally eliminate all exposures.

2. Excess cancer risk between 1:10,000 and 1:1,000,000 is deemed reasonable worldwide.

3. Ever notice that nuclear power risks are always compared against 0 risk?

4. Ever notice that people ignore the extraordinarily rigorous regulatory requirements, financial assurance, etc.?

5. Who keeps ginning up the yellow barrel images? I’ve hardly seen a radioactive waste article without one, even in the “mainstream” media like the BBC News. Nobody questions the barrels.