Pickering’s big– and growing — waste problem

The nuclear power industry likes to claim that it produces “clean” energy.  This statement ignores the very significant amounts of radioactive waste created by extracting energy from uranium. 

 

 

 

Currently, the Pickering Nuclear Station has two “dry storage” facilities for the storage of spent nuclear fuel (and other radioactive wastes).  These facilities currently store more than 340,000 highly radioactive spent fuel assemblies loaded in containers that each hold 384 assemblies.  Radioactive assemblies more recently removed from reactors are stored in open water-filled pools. Roughly 400,000 spent fuel assemblies —more than half of Pickering’s current waste — are currently stored in these pools. Ontario Power Generation (OPG) is planning to add three additional radioactive waste storage buildings to the Pickering site, which would bring the total storage capacity up to 1,152,768 spent fuel assemblies, which is enough storage to continue to operate all six of Pickering’s operational reactors for a decade or more beyond 2024, which is when OPG currently says it plans to stop operating all of the plant’s reactors.

This is a very significant amount of waste.  As of the end of 2017, this waste included roughly 56,000 kg. of plutonium.  If the plant continues to operate until it reaches its maximum licensed waste storage capacity, this amount would grow to about 88,000 kg.  of plutonium — more than can be found in all operational nuclear warheads worldwide today.

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Ontario Clean Air Alliance Research asked nuclear risk expert Dr. Gordon Thompson from the Institute for Resource and Security Studies in Massachusetts to look at the risks of storing this large quantity of radioactive waste at a plant that is surrounded by millions of people. In 2005, Dr. Thompson was asked to prepare a report on reasonably foreseeable security threats to options for long-term management of radioactive waste in the United Kingdom by the UK government’s Committee on Radioactive Waste Management.

Dr. Thompson notes in his report that the Pickering Nuclear Station is “suboptimal as a spent nuclear fuel-storage site from perspectives including defensibility, proximity of populations, and potential to contaminate Lake Ontario.”  He concludes that while steps could be taken to reduce risks, there is simply no way to fully eliminate the risks involved in storing more than a million spent fuel assemblies in the middle of our largest urban area, right on the shore of the source of drinking water for tens of millions of people.

The waste being stored at Pickering is far from benign. Besides plutonium, these wastes contain the radioactive isotope Cs-137.  In 95% of its decays, Cs-137 yields Ba-137m, a radionuclide that can be absorbed by the body. Cs-137 sheds dangerous isotopes readily when nuclear fuel is overheated, such as in a fire or explosion.  Therefore, the quantity of Cs stored at Pickering represents a good measure of the radiological risk posed by the site.  Dr. Thompson compared Cs at Pickering to the quantities at Fukushima and found that when Pickering reaches its full waste storage capacity, it will have roughly a third more Cs than was deposited on land after the Fukushima explosion. So the radiological risk posed by Pickering is significant should Cs ever be released through a container failure or fire.

As noted above, the spent fuel assemblies at Pickering also contain significant amounts of plutonium, which again is produced on an ongoing basis through the nuclear reaction at the heart of the plant’s operation (the plant produces approximately 18,000-22,000 used fuel assemblies each year). This plutonium is “reactor grade” but Dr. Thompson notes that various experts have stated that it is still suitable for use in weapons.  As one expert noted, “The difficulties of developing an effective [nuclear explosive] design of the most straightforward type are not appreciably greater with reactor-grade plutonium than those that have to be met for the use of weapons-grade plutonium.”  Only an amount shaped into roughly the size of an orange — about 4.5 kg. of plutonium — would be needed to create a critical mass for a nuclear explosion.   

More importantly, plutonium could be used to simply spread radioactive elements through either a bomb or other means of dispersing the material over a wide area or by secreting the radioactive material near a target and exposing those in the vicinity over a period of time.  Dr. Thompson points out that a 2007 study sponsored by Defence Research and Development Canada estimated that the economic impact of an open-air explosion of a radiological dispersal device (a.k.a, dirty bomb) at the CN Tower in Toronto would be $250 billion.

Dr. Thompson notes that most North American nuclear plants, including Pickering, are actually relatively “lightly defended” with armed guards, vehicle barriers, alarms, etc.  He points out that it would likely be possible for a well-armed and well-trained small force to breach these defences. The station also has no direct defenses against an attack from air or water with missiles, bombs or fuel-laden aircraft. 

But putting aside the threat of an attack, there is also the threat of fire or storage cask degradation. Dr. Thompson notes that CANDU and more common light-water reactor (such as those at Fukushima) both employ zircaloy cladding on fuel bundles, which means there is the potential for an exothermic reaction if the zircaloy is exposed to steam or air, leading to fire.  A runaway, exothermic reaction – a “pool fire” – in the spent fuel pool of Fukushima #1 Unit 4 was narrowly avoided during the Fukushima accident.  If the pool had caught fire, it would have been necessary to evacuate much of Tokyo – and the Fukushima nuclear plant is more than the ten times further from Tokyo than downtown Toronto is from Pickering.

Similarly, fuel containers that will have to remain tightly sealed for thousands of years to avoid any radiation leakage could slowly decay or be damaged.  In the U.S., consideration is now being given to the need to equip radioactive waste storage sites with “dry transfer systems” — systems that can be used to inspect or move materials while in storage from one cask to another should the need arise.  Pickering currently has no such system.

In this context, it is important to note Dr. Thompson’s finding that the significant amount of waste currently stored at Pickering will likely remain there for many decades to come.  Given the Nuclear Waste Management Organization’s (NWMO’s) current timelines for establishing a remote repository for nuclear waste and the time it would take to transfer waste to such a facility, Dr. Thompson finds that waste could continue to be stored at Pickering for 100 years or more.  But he also points to the failure in the United States of plans to construct a centralized long-term storage facility at Yucca Mountain in Nevada to explain the growing view that many reactor sites are likely to become long-term storage sites by default.  

It is worth noting the widespread public opposition to plans for a “Deep Geological Repository” near the Bruce Nuclear Station and to a “Near Surface Disposal Area” for waste from the nuclear research facilities at Chalk River Laboratories near Ottawa in this context.  The NWMO’s timeline assumes it can find a “willing host” community, construct a massive underground storage complex, and successfully move hundreds of thousands of radioactive fuel assemblies over long distances to the new remote facility.  These assumptions are all far from assured.

That opens the question of how we manage a site that will need to be maintained and secured for thousands of years. The U.S. Department of Energy has modelled the possibility of waste being stored onsite at reactors and other existing waste sites for up to 10,000 years, but with actual control of these sites lapsing after as little as 60 years in recognition of the large range of uncertainty that come with managing waste that will need to be stored for 400,000 years.  Dr. Thompson notes that the real time frames for waste being stored at Pickering far exceed what OPG has acknowledged and planned for even under the NWMO’s current plans.

The likelihood that radioactive waste could still be stored at the Pickering site a century – or many centuries — from today means it is all the more important that we properly acknowledge the risks involved.  As Dr. Thompson notes, nuclear regulators often downplay what they characterize as remote risks – such as a terrorist attack — without acknowledging that the consequences of such events would be catastrophic.  He believes much more attention needs to be paid to the qualities of these risk and the devastating scale of potential outcomes when weighing the wisdom of continuing to operate six reactors in the heart of a large urban area.

In fact, Dr. Thompson concludes that the first step we can take to reduce radiological, proliferation, and program risks at Pickering is to shut the plant down when its licence expires in August 2018.  This would pave the way for a number of positive outcomes:

• An end to highly radioactive spent fuel waste, including Cs and plutonium, accumulating;
• The opportunity to consolidate existing waste into a more secure (including from aircraft attack) hardened onsite storage facility. This facility would also incorporate a dry transfer system to ensure long-term container integrity;
• No fuel stored in pools with the potential for dangerous fires once the final fuel assemblies are moved to dry storage;
• A return of waterfront lands to the people of Pickering and a more safe and secure community.

It is hard to imagine any other industry being allowed to accumulate large quantities of highly hazardous waste for more than 50 years with only temporary storage methods in place.  Of course, nuclear waste presents challenges on a scale we have never dealt with before: Managing waste sites for thousands of years while keeping materials with high destructive potential completely secure.  So it is perhaps not surprising that the NWMO projects it will take at least 60 years to come up with a long-term waste solution.  And, equally unsurprisingly, that there is a growing skepticism that a viable remote disposal solution will ever be developed.

The nuclear industry has had a free ride on dealing with its deadly waste products for far too long.  It is time to acknowledge that we have better waste-free solutions for meeting our electricity needs and that it is time to stop producing more of these dangerous waste products, while more securely storing what has already been left behind.

To read Dr. Thompson’s full report on the risks of radioactive waste storage at Pickering, click here.