Having reliable knowledge of the radioactivity of the wastes that the DGR will hold is of course crucial for evaluating its safety. OPG and the CNSC give us ballpark figures for the level this radioactivity with the designations Low Level Waste (LLW), Intermediate Level Waste (ILW), and High Level Waste (HLW). Only LLW and ILW are officially being allowed in the proposed DGR. OPG and CNSC have taken the position that single storage facility and procedure can be appropriate, so long as no HLW is included.
The problem is that for ILW especially, there is a tremendous variety in the level and life-span of its radioactivity – and its consequent hazard to people and the environment. The current definition of ILW being used for this project includes waste that just about everyone else in the world includes along with their High Level Waste. This not only makes the project less safe, it means that studies done elsewhere in the world cannot be used to validate the safety of the proposed OPG project, since this proposed DGR includes “ILW” of much higher radioactivity than those studies. This is especially important since OPG’s own estimates of the radioactivity of its wastes are significantly lower than actual measured values of those wastes.
Back when the DGR was first proposed, there were two definitions of these categories in use: one by the International Atomic Energy Agency (IAEA), and one by the province of Manitoba that was designed to keep the federal government from using its research site at Whiteshell to store nuclear waste from around the country.
In 2008, after the current proposal process was underway, with the lesson of Manitoba in mind, the Canadian government had the Canadian Standards Association produce a new standard that made it easier for crown companies like OPG to categorize their dangerous waste as ILW instead of HLW. For the moment, we will just give OPG’s own definition, as this is the operational one for the proposed DGR:
OPG considers that all its radioactive waste that is not used fuel is LLW or ILW. OPG considers waste as LLW if the corresponding waste package has a dose rate of less than 10 mSv/h at 30 cm, and as ILW if the dose rate is greater than or equal to 10 mSv/h at 30 cm, or known to have a significant amount of long-lived radionuclides.
Responses to Information Requests Package #11 p. 11
Note that the definition of ILW is open-ended: there is a minimum value, but no upper bound. Earlier definitions invoked judgment in classifying waste as HL if it had a high enough level of radioactivity. OPG’s definition restricts HLW to spent nuclear fuel.
No doubt this is a convenient definition for bureaucrats, who would no longer need to conduct pesky measurements of radiation levels in order to classify nuclear waste. But it flies in the face of established practice. For example, William H. Lenneman, Head of the Waste Management Section, Division of Nuclear Safety and Environmental Protection, IAEA characterized it thus:
High-level waste is characterized, of course, by high radiation levels …. Examples are solidified high-level waste or… spent fuel and possibly cladding hulls. Other examples of what sometimes is considered a high-level waste are removed highly irradiated reactor components, such as control rods, piping or flow orifices….
IAEA Bulletin, Vol. 21, #4. p. 2
This is in distinction to OPG’s plans to include “pressure tubes, end fittings and calandria tubes” in its ILW inventory, which is especially significant since it significantly underestimates their radiation levels.
Other countries’ solutions
We do note that the IAEA discussion says that such “highly irradiated reactor components” are “sometimes” considered high-level waste; but we also note that even countries that do not consider such components to be HLW still treat them in the same manner as their HLW, in consideration of their highly dangerous nature. For example, the Swiss Nagra agency, in forming the plans for its own DGR, says that
Nagra’s mission is to develop safe geological repositories in Switzerland for all radioactive wastes arising in Switzerland. Two types of repositories are foreseen, one for low and intermediate level waste (L/ILW) and one for spent fuel, vitrified high level waste and long-lived ILW (SF/HLW/ILW).
Nagra Technical Report NTB 09-06, p.I
The more long-lived ILW is to be treated in the same way as the HLW, and this turns out to be standard practice among other countries that are pursuing their own DGRs. In fact, such Long-Lived ILW often gets its own acronym: LLW, or LL-ILW. In any case, while a country might still choose to process its HLW and LLW streams separately, they are still treated as similarly dangerous, and the best practices in decisions about what to do with them is to treat these decisions as part of the same process. For example:
The December 30, 1991 French Waste Act entrusted Andra, the French national agency for radioactive waste management, with the task of assessing the feasibility of deep geological disposal of High Level and Long-lived waste (HLLLW).
S. Voinis, A. Roulet, D. Claudel, A. Lesavre, Agence Nationale pour la gestion des déchets radioactifs (Andra), “Operational Safety and Radioprotection Considerations When Designing the ILW-LL Disposal Zone”, p. 1
Similarly, see this article in the newsletter of the European Nuclear Society, a nuclear energy advocacy group that bills itself as the “largest nuclear group for science and industry.” Although the article’s title is “HLW disposal: Status and Trends”, it quickly goes on to expand its purview to LL-ILW:
LL-ILW and HLW originate almost exclusively from nuclear reactors and their fuel cycle facilities, as well as the defense facilities of those countries which developed nuclear weapons. Though quite limited in volume, they constitute the bulk of the waste radioactivity. For those countries with no weapons activities and which do not reprocess their spent fuel, all their HLW and LL-ILW is inside their spent fuel assemblies which constitute for them the ultimate waste. We shall now focus only on those two categories of waste.
Bertrand Barré for The International Nuclear Energy Academy, “HLW disposal: Status and Trends”
The UK, likewise, tasked its Committee on Radioactive Waste Management (CoRWM) to make “recommendations to Government on the management of the UK’s intermediate-level (ILW) and high-level (HLW) radioactive wastes.” Miller, Tooley and Thomson, “Storage and Disposal of ILW and HLW in the UK”, p. 1
Basically, there is no other country besides Canada that has decided it’s appropriate to take all of their ILW and store it permanently in the same manner and place as their LLW.
Safety, but also economy
There are numerous problems in using the same procedures and facilities to store a body of waste with widely varying levels of radioactivity. We have emphasized the safety problems that attend on underestimating the radioactivity of the waste to be stored. But there are also of course tremendous economic issues with using stringent containment strategies on waste that does not need them. Countries like the UK that have decided to process some of their ILW along with LLW have realized that neither class of waste is homogenous, and that the lower-radioactivity waste stream that requires special attention in this way is “intermediate-level waste (ILW) and for the small amount of low-level waste (LLW) that is unsuitable for near-surface disposal.” In fact, the UK has created a class of waste called Very Low Level Waste (VLLW) and has floated the idea that “in appropriately controlled quantities [this could] be safely disposed of with domestic refuse”. Miller, Tooley and Thomson, “Storage and Disposal of ILW and HLW in the UK”, p. 10
We’re not sure whether disposal “with domestic refuse” is indicated in any case; but there are certainly reliable and effective solutions (such as the status quo) that cost exponentially less than storing all the LLW in custom-designed metal canisters in a huge cavern dug hundreds of meters into the ground.
The OPG’s proposed all-in-one solution, then, represents the worst of both worlds: it stores highly radioactive waste under conditions that have not been found safe for it, and it stores Low Level Waste under expensive conditions that are not required. It substitutes bureaucratic convenience for both safety and economy.